**Meet the editor**

Dr Muhammad Salik Javaid has been working on research, development, execution, management and policy formulation assignments with Corps of Engineers within Pakistan and abroad for over three decades. He also worked as Chief Consulting Engineer and Director General Planning for the reconstruction and rehabilitation work after the 2005 earthquake in Pakistan. He is a

graduate of Georgia Tech, Atlanta, USA where he undertook his Masters and Doctoral studies in the fields of Dam Overtopping and Ocean Bed Hydrodynamics. Presently he is heading the Department of Civil Engineering at University of Lahore at Sihala Campus, Islamabad. He has also conducted courses on 'irrigation and drainage' and 'river engineering' for civil engineering students at various campuses.

Contents

**Preface IX** 

Chapter 1 **Paleodrainage Systems 3**  Luis Américo Conti

Chapter 4 **Common Approximations** 

Chapter 5 **Drainage of Bank Storage** 

Mashael Al Saud

**Part 1 Sustainable Drainage Systems 1** 

Chapter 2 **Sustainable Drainage Systems: An Integrated** 

Chapter 3 **Sustainable Urban Drainage Systems 53**  Cristiano Poleto and Rutinéia Tassi

Marcelo Gomes Miguez, Aline Pires Veról and Paulo Roberto Ferreira Carneiro

**Part 2 Subsurface Drainage – Aquifer Management 71** 

**to the Water Inflow into Tunnels 73**  Homayoon Katibeh and Ali Aalianvari

**in Shallow Unconfined Aquifers 87** 

**Quality in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 109** 

**Part 3 Surface Drainage – Modern Trends and Research 135** 

Chapter 7 **Use of Remote Sensing and GIS to Analyze Drainage System** 

**in Flood Occurrence, Jeddah - Western Saudi Coast 137** 

Chapter 6 **A Study of Subsurface Drainage and Water** 

Mohammed Amin M. Sharaf

**Approach, Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 17** 

Djehiche Abdelkader, Gafsi Mustapha and Kotchev Konstantin

### Contents

#### **Preface XI**

	- **West Central Arabian Shield, Saudi Arabia 109** 
		- Mohammed Amin M. Sharaf
	- **Part 3 Surface Drainage Modern Trends and Research 135**

### Preface

As soon as precipitated or glaciated water is brought through the irrigation system from the rivers to the farms and agricultural fields, the dynamic equilibrium between total water, its consumptive usage, groundwater recharge and discharge is disturbed. The deep percolation of seepage, from water applied to the lands for irrigation, forms a new increment in recharge which must be drained off efficiently. The concepts of irrigation and drainage have complimented each other since the inception of organized agriculture in human society, but drainage has always prevailed as more important of the two. Temporal and spatial variability, as well as uncertainties of water's availability as a natural resource, make the surface and subsurface drainage a permanent challenge for hydraulic engineers and hydrologists. In recent years considerable amount of research material has been published on hydrology, irrigation, and reservoir planning and management.

The subject of drainage, even though more important, has somehow not received due consideration by water experts.This book on drainage systems is a step towards meeting such shortfalls. As we explore the ideas and opinions of various contributing authors, gathered from a host of professional backgrounds, we are able to understand the drainage phenomenon in all its dimensions.

The objective of providing irrigation and drainage is to assist nature in maintaining moisture in the root-zone soil within the range required for maximum agricultural production. Hence, drainage systems may not be planned and designed merely on universal drainage criteria like frequency analysis of rainfall. Multivariate hydrological factors demand that drainage systems be designed on a complete description of statistical properties of flooding caused by a joint action of multiple factors. Ancient civilizations showed great care when constructing urban drainage systems, combining objectives of collecting rainwater, preventing flooding and conveying waste. A lot can be learnt from case histories and expertise from across the world.

The aim of this book, in the borrowed words of International Commission on Irrigation and Drainage, is 'to stimulate and promote the development and application of arts, sciences and techniques of engineering, agriculture, economics, ecological and social sciences in managing water for irrigation, drainage and flood management using research and development'.

#### X Preface

For ease of comprehension and coherence in understanding, the material presented in this book has been divided into three distinct knowledge areas consisting of ten chapters. First three chapters in Part-I deal with sustainable drainage systems. Chapters IV to VI in Part-II deal with subsurface drainage mainly focusing on aquifer management. The last four chapters forming Part-III deal with surface drainage, highlighting modern trends and research.

This book provides a broad understanding of the problems and the potential for improvement of drainage, and may be used by academics, researchers and field professionals. 'Drainage Systems' could not have been written without the hard work of many eminent drainage professionals, hydrologists, water resources engineers, scholars and scientists the world over.

The consistency and perseverance of Ms. Maja Jukic, Publishing Process Manager at InTech Open Access Publisher, are recognized for her constant reminders of the deadlines. The patience and support of my wife Sultana Salik and my children Humaira, Sumayyah and Hammaad during the period I was working on this book is heartily appreciated. I am also grateful to the National University of Sciences and Technology (NUST) and University of Lahore (UoL) for providing the academic forum to undertake this assignment.

Finally, the entire concept of InTech Open Access Publishing is lauded for its global outreach and universal benefit to the human race.

> **Dr. Muhammad Salik Javaid** National University of Sciences and Technology Pakistan

X Preface

highlighting modern trends and research.

scholars and scientists the world over.

to undertake this assignment.

outreach and universal benefit to the human race.

For ease of comprehension and coherence in understanding, the material presented in this book has been divided into three distinct knowledge areas consisting of ten chapters. First three chapters in Part-I deal with sustainable drainage systems. Chapters IV to VI in Part-II deal with subsurface drainage mainly focusing on aquifer management. The last four chapters forming Part-III deal with surface drainage,

This book provides a broad understanding of the problems and the potential for improvement of drainage, and may be used by academics, researchers and field professionals. 'Drainage Systems' could not have been written without the hard work of many eminent drainage professionals, hydrologists, water resources engineers,

The consistency and perseverance of Ms. Maja Jukic, Publishing Process Manager at InTech Open Access Publisher, are recognized for her constant reminders of the deadlines. The patience and support of my wife Sultana Salik and my children Humaira, Sumayyah and Hammaad during the period I was working on this book is heartily appreciated. I am also grateful to the National University of Sciences and Technology (NUST) and University of Lahore (UoL) for providing the academic forum

Finally, the entire concept of InTech Open Access Publishing is lauded for its global

**Dr. Muhammad Salik Javaid**

Pakistan

National University of Sciences and Technology

**Part 1** 

**Sustainable Drainage Systems** 

**Part 1** 

**Sustainable Drainage Systems** 

**1** 

*Brasil* 

**Paleodrainage Systems** 

*Escola de Artes Ciências e Humanidades – Universidade de São Paulo* 

*You can never step into the same river; for new waters are always flowing on to you.* 

From a geomorphological perspective, river systems can be summarized as a hierarchy of water flux processes occurring in different spatial and temporal scales, organized in a specific geographic setting coupled with a climatic system in a condition of dynamic equilibrium. At the lower and detailed level there is localized turbulent water movement within a channel, which can be described by local flux equations. On a more generic level, other aspects and run off processes must be considered such as the sediment flow dynamic, the regional slope and the wider temporal scale variation (seasonal and multi annual). They can be modeled by open channel hydraulic methods. At a broader level of analysis, one can consider the basin scale associated with the geological conditioning and regional plus global

The concept of paleodrainage, as discussed in this chapter, states that large scale changes in fluvial features should be related to wider environmental processes that can alter the very nature of the basin system, thus*,* despite the breadth of the definitions of concepts such as "paleovalley" and "paleochannel" often attributed to local variations in the drainage system (i.e. seasonal flooding or small scale lateral migration), it is considered that only dynamic processes of effective geographical changes in drainage systems can be included in this

These processes do not necessarily occur as isolated events but rather as a set of environmental changes that include variation of sediment supply, topographic and geological settings, local and regional climate, vegetation coverage, etc. In this regional context, most studies involving paleodrainage are based on two types of analysis: The geomorphological approach based on the response of the landforms to the drainage processes (described in works like Al Sulaimi *et al.* 1997, Simpson, 2004 and Dollar, 2004) and Stratigraphic approaches based on the sedimentary records of the fluvial sequences related to conceptual frameworks such as Quaternary Time Stratigraphy (Wheeler, 1958)


and Fluvial Sequence Stratigraphy (Wilgus *et al.* 1988; Strong and Paola, 2008).

**1. Introduction** 

climatological context in long-term processes.


range of definitions and related to most common causes: - Downstream drowning/exposure (base level variation) Luis Américo Conti

*Heraclitus of Ephesus* 

## **Paleodrainage Systems**

Luis Américo Conti

*Escola de Artes Ciências e Humanidades – Universidade de São Paulo Brasil* 

*You can never step into the same river; for new waters are always flowing on to you. Heraclitus of Ephesus* 

### **1. Introduction**

From a geomorphological perspective, river systems can be summarized as a hierarchy of water flux processes occurring in different spatial and temporal scales, organized in a specific geographic setting coupled with a climatic system in a condition of dynamic equilibrium. At the lower and detailed level there is localized turbulent water movement within a channel, which can be described by local flux equations. On a more generic level, other aspects and run off processes must be considered such as the sediment flow dynamic, the regional slope and the wider temporal scale variation (seasonal and multi annual). They can be modeled by open channel hydraulic methods. At a broader level of analysis, one can consider the basin scale associated with the geological conditioning and regional plus global climatological context in long-term processes.

The concept of paleodrainage, as discussed in this chapter, states that large scale changes in fluvial features should be related to wider environmental processes that can alter the very nature of the basin system, thus*,* despite the breadth of the definitions of concepts such as "paleovalley" and "paleochannel" often attributed to local variations in the drainage system (i.e. seasonal flooding or small scale lateral migration), it is considered that only dynamic processes of effective geographical changes in drainage systems can be included in this range of definitions and related to most common causes:


These processes do not necessarily occur as isolated events but rather as a set of environmental changes that include variation of sediment supply, topographic and geological settings, local and regional climate, vegetation coverage, etc. In this regional context, most studies involving paleodrainage are based on two types of analysis: The geomorphological approach based on the response of the landforms to the drainage processes (described in works like Al Sulaimi *et al.* 1997, Simpson, 2004 and Dollar, 2004) and Stratigraphic approaches based on the sedimentary records of the fluvial sequences related to conceptual frameworks such as Quaternary Time Stratigraphy (Wheeler, 1958) and Fluvial Sequence Stratigraphy (Wilgus *et al.* 1988; Strong and Paola, 2008).

Paleodrainage Systems 5

controlled the paleo-Amazon River, which was connected to the Paleo-Orinoco until the mid Miocene period. The final breakthrough of the Amazon River towards its modern course occurred with the final uplift of the central Andean cordillera, related to the rise of the Purus

Tectonic processes have also controlled drainage evolution and basin infill trends in all active zones in the world. In the Himalayas, the Orogen began forming roughly 50 million years ago when India collided with the Asian continent producing complex relationships between regional metamorphism, anatexis, thrust faulting and normal faulting (Hodges, 2000). The establishment of the drainage systems and the evolutionary history of the fluvial network were controlled by this complex scenario characterized by both local and regional structures with multiple phases of deformation and shaped by active erosional dissection. Studies such as those done by Brookfield (1998), Zeitler *et al*, (2001), Najman *et al*. (2003), Clift and Blusztajn (2005), among others, affirmed that the transpressional tectonics across the Himalayan arc have produced large variations in fluvial morphodynamic processes in rivers such as the Indus, Kunar, Marsyangdi and Ganges. Most of these changes as

Fig. 1. Drainage distribution of Northern and Central areas of South America indicating the Amazon/Andes paleodrainage system (and flow direction) during Oligocene (modified

Furthermore, the climatic and erosional processes related to such uplifts, which have determined the resultant landscape structure, are as important as the direct upward topographic responses to tectonic forces. Finnegan *et al*. (2008) analyzing the balance between uplift of the Namche Barwa massif in Tibet related to the Yarlung Tsangpo–

after Potter, 1997 and Horn *et al.* 2010).

Arch (Gregory-Wodzicky, 2000; Figueredo *et al.*, 2009) (Figure 1).

described in Clift *et al.* (2006) can be related to capture/reversal processes.

Moreover, regardless of methodological differences, the analysis of ancient drainage patterns is almost always related to the tracking of large scale environmental conditions, especially those related to Quaternary glacial cycles and tectonic processes; however, it has also been seen as a means to provide a context for observed historical trends and to predict near future conditions in a changing climate as well as human intervention in land cover scenarios (Bloom & Tronqvst, 2000) and the understanding of the dynamic evolution of natural drainage systems can reveal important insights into the modeling, design and implementation of sustainable methodologies that integrate innovative water resource management and land use planning, which is the main focus of this book.

#### **2. Paleodrainage and environmental changes – why do rivers change?**

#### **2.1 Tectonic control and paleodrainage**

Tectonic conditioning of drainage changes have been widely described in the literature, and it is usually studied on the regional and continental scale. It can be considered the most dramatic effect not only for conditioning the pattern and texture of the drainage itself but also for determining the characteristics and amount of sediment that is transported to downstream depositional basins and where this sediment is delivered. Uplift, subsidence and faulting, all modify the overall shape of drainage systems, altering parameters such as slope, valley floor and channel gradient. The form and magnitude of these changes will depend on the amount of deformation and the capacity of the channels to adjust to the altered slope (Shumm, 1977; 1985), thus, in order to understand how tectonic evolution impacts drainage development, evolution and preservation, it is necessary to examine the coupling of externally (allogenic) and internally generated (autogenic) forces.

Examples of the characterization of how the tectonic events impacts drainage development especially associated with orogenic belts - are described in Burbank and Anderson (2001). A good example of such relationships between tectonic processes and drainage changes on a large scale is the case of rivers in Patagonia at the southern end of South America as described in Wilson 1991 and Tankard *et al.* 1995. The rifting process that separated South America and Africa first occurred at the southern part of the continent during the Middle Jurassic, and the development of broad uplifts, rifting and aulacogens were key factors in establishing the drainage patterns. The ancestral flow of the paleo Colorado and Negro rivers, for example, was associated with the Mesozoic paleosurfaces with sources east and north of the Neuquen basin directed to the Pacific Ocean. The Upper Cretaceous Andes arc uplift caused reversion of the slope direction to the southeast, yielding the rivers to flow to the Atlantic, skirting the north side of the Somuncura uplift (Potter, 1997).

The Andean uplift also has controlled the paleo-geographic settings of all drainage in the central and northern cordillera region modifying the position of rivers such as the Orinoco and Magdelena at northwestern part of South America. As described in Horn *et al.* 1995 and Diaz de Gamero, 1996, during the Middle Eocen, the Orinoco River had been flowing southnorth, draining the Central Cordillera of Colombia and the Guayana Highlands, with its mouth associated with the Lake Maracaibo and Caribbean Sea. After the Late Miocene period, the Andes attained their present configuration following the Eastern Cordillera uplift and the southwestern end of the Merida Andes deformation shifted the course of the river, deflecting it to a west-east direction. The eastern and central Cordillera uplift also

Moreover, regardless of methodological differences, the analysis of ancient drainage patterns is almost always related to the tracking of large scale environmental conditions, especially those related to Quaternary glacial cycles and tectonic processes; however, it has also been seen as a means to provide a context for observed historical trends and to predict near future conditions in a changing climate as well as human intervention in land cover scenarios (Bloom & Tronqvst, 2000) and the understanding of the dynamic evolution of natural drainage systems can reveal important insights into the modeling, design and implementation of sustainable methodologies that integrate innovative water resource

management and land use planning, which is the main focus of this book.

coupling of externally (allogenic) and internally generated (autogenic) forces.

the Atlantic, skirting the north side of the Somuncura uplift (Potter, 1997).

**2.1 Tectonic control and paleodrainage** 

**2. Paleodrainage and environmental changes – why do rivers change?** 

Tectonic conditioning of drainage changes have been widely described in the literature, and it is usually studied on the regional and continental scale. It can be considered the most dramatic effect not only for conditioning the pattern and texture of the drainage itself but also for determining the characteristics and amount of sediment that is transported to downstream depositional basins and where this sediment is delivered. Uplift, subsidence and faulting, all modify the overall shape of drainage systems, altering parameters such as slope, valley floor and channel gradient. The form and magnitude of these changes will depend on the amount of deformation and the capacity of the channels to adjust to the altered slope (Shumm, 1977; 1985), thus, in order to understand how tectonic evolution impacts drainage development, evolution and preservation, it is necessary to examine the

Examples of the characterization of how the tectonic events impacts drainage development especially associated with orogenic belts - are described in Burbank and Anderson (2001). A good example of such relationships between tectonic processes and drainage changes on a large scale is the case of rivers in Patagonia at the southern end of South America as described in Wilson 1991 and Tankard *et al.* 1995. The rifting process that separated South America and Africa first occurred at the southern part of the continent during the Middle Jurassic, and the development of broad uplifts, rifting and aulacogens were key factors in establishing the drainage patterns. The ancestral flow of the paleo Colorado and Negro rivers, for example, was associated with the Mesozoic paleosurfaces with sources east and north of the Neuquen basin directed to the Pacific Ocean. The Upper Cretaceous Andes arc uplift caused reversion of the slope direction to the southeast, yielding the rivers to flow to

The Andean uplift also has controlled the paleo-geographic settings of all drainage in the central and northern cordillera region modifying the position of rivers such as the Orinoco and Magdelena at northwestern part of South America. As described in Horn *et al.* 1995 and Diaz de Gamero, 1996, during the Middle Eocen, the Orinoco River had been flowing southnorth, draining the Central Cordillera of Colombia and the Guayana Highlands, with its mouth associated with the Lake Maracaibo and Caribbean Sea. After the Late Miocene period, the Andes attained their present configuration following the Eastern Cordillera uplift and the southwestern end of the Merida Andes deformation shifted the course of the river, deflecting it to a west-east direction. The eastern and central Cordillera uplift also controlled the paleo-Amazon River, which was connected to the Paleo-Orinoco until the mid Miocene period. The final breakthrough of the Amazon River towards its modern course occurred with the final uplift of the central Andean cordillera, related to the rise of the Purus Arch (Gregory-Wodzicky, 2000; Figueredo *et al.*, 2009) (Figure 1).

Tectonic processes have also controlled drainage evolution and basin infill trends in all active zones in the world. In the Himalayas, the Orogen began forming roughly 50 million years ago when India collided with the Asian continent producing complex relationships between regional metamorphism, anatexis, thrust faulting and normal faulting (Hodges, 2000). The establishment of the drainage systems and the evolutionary history of the fluvial network were controlled by this complex scenario characterized by both local and regional structures with multiple phases of deformation and shaped by active erosional dissection. Studies such as those done by Brookfield (1998), Zeitler *et al*, (2001), Najman *et al*. (2003), Clift and Blusztajn (2005), among others, affirmed that the transpressional tectonics across the Himalayan arc have produced large variations in fluvial morphodynamic processes in rivers such as the Indus, Kunar, Marsyangdi and Ganges. Most of these changes as described in Clift *et al.* (2006) can be related to capture/reversal processes.

Furthermore, the climatic and erosional processes related to such uplifts, which have determined the resultant landscape structure, are as important as the direct upward topographic responses to tectonic forces. Finnegan *et al*. (2008) analyzing the balance between uplift of the Namche Barwa massif in Tibet related to the Yarlung Tsangpo–

Paleodrainage Systems 7

Fig. 2. Drainage distribution of Southern Africa with the paleodrainage prior to the union of the middle and upper Zambezi in the early Pleistocene (modified after Thomas and Shaw,

localized events displacing and rearranging local streams. Oilier (1995), describes the relationship between directions of rivers in southeastern Australia (e.g. Hunter, Lachlan and Murrumbidgee) which reversed courses due to an Eocene/ early Oligocene Volcanism effect. On a more localized scale, Branca and Ferrara, 2001, mapped the ancient valley of the Alcantara and S. Paolo Rivers, below the northern flank of Mt Etna. The paleo-valley was filled by lava flow and volcano-sedimentary debris during several events starting from

The first empirical works relating environmental changes with variations in fluvial patterns always attempted to establish a direct correlation between climate changes and the settlement of morphosedimentary processes in drainage systems. Penk (1927) proposed links between incision and deposition patterns of fluvial canals in the Danube River region with glacial climatic cycles, which eventually became one of the main geo-indicators for the existence of glacial cycles. According to the authors, the sequence of terraces formed in fluvial plains would have resulted from alternating glacial (aggradation process) and interglacial (incision process) periods, forming the sequence of terraces that indicate specific environmental conditions. Davis, 1896, recognized the relationship between river

displacement and climatic changes studying the Moselle River (northern France).

1991 and Goudie, 2005).

170,000 years B.P. until 20,000 years B.P.

**2.2 Climatic and hydrologic changes** 

Brahmaputra River system, concluded that the regional denudation driven by extreme efficient river incision, removes a large quantity of sediments yielding to a local relief producing erosional and thermo-mechanical coupling in an active orogen, thrusting Namche Barwa-Gyala Peri above the surrounding landscape in a process of "tectonic aneurysm" (Koons *et al.* 2002 and Simpson, 2004).

The tectonic dynamics can also affect large-scale drainage patterns through volcanism and distention processes in divergent plates. In the African continent there are at least two examples of rivers indicating complex histories involving shifts in the nature of their catchments and courses, associated with volcanism and rifting process. The Nile may be one of the most remarkable examples of drainage evolution in response to non-orogenic tectonic deformation. The Nile evolution model described by Sahin (1985), Foucault and Stanley (1989); Issawi and McCauley (1992) and Goudie (2004), details five phases since the late Eocene.

The first phase (called the "Gilf system" - Eocene) was marked by the presence of a set of parallel north flowing drainages occupying most of northeastern Africa and the present Nile Basin position fed by streams originating from eastern highlands (Red Sea area). The second Stage (Qena system - Miocene) was marked by intense tectonic activity followed by the reversion of the drainages taking up a southward position as well as establishing an immense river flowing south towards Aswan and the Sudan. The third stage (the Nile system – Late Miocene) was marked by a dramatic drop of the base level of the Mediterranean Sea (associated with the closure of the Straits of Gibraltar and the Messien Event – Gautier *et al.*, 1994) producing intense erosional activity forming gorges and canyons (designated as Eonile). As a result of such shifts, the Eonile took a northerly course. The fourth phase (Pliocene flooding), in the early Pliocene, the sea level rose at least 125 m so that an estuary or ria extended more than 900 km inland, reaching Aswan. After the Pleistocene, the Nile has been submitted to constant changes due to climate and hydrological regimes (detailed in Foucault and Stanley, 1985; Coutelier and Stanley, 1997).

The other example of a paleodrainage system controlled by distensive tectonics is the Zambezi River. The longitudinal profile of the Zambezi River forms two concave-upward sections, with their boundary at Victoria Falls, and there are studies suggesting that these sections were disconnected fluvial systems only joined together after the late Quaternary (Goudie, 2004; Nugent, 1990). The paleo-Zambezi was connected to both the Limpopo and Luangwa River system and took its present configuration, probably after the Pliocene with the uplift of the Makagdikgadi Basin along the "Kalahari Zimbabwe axis". The new position of the Middle Zambezi permitted the capturing of east and northeast tributaries such as the Kafue and Luangwa (Thomas and Shaw, 1991) (Figure 2).

The evolutionary history of the Congo River is also linked to the tectonic processes related to south-central Africa vertical crust movements. Stankiewicz & Dewit (2006) suggested that the Congo drained into the Indian Ocean until the uplift of East African Highlands in the Oligocene or Eocene (30– 40 Ma). The Congo then became a landlocked basin, until it was captured during the Miocene by a river system causing it to drain into the Atlantic.

Examples of drainage modifications in catchments affected by the formation and erosion of volcanoes can be found in several scales, from regional drainage system displacements associated with major volcanic structures (such as *Serra Geral*/Etendeka and Deccan) to

Brahmaputra River system, concluded that the regional denudation driven by extreme efficient river incision, removes a large quantity of sediments yielding to a local relief producing erosional and thermo-mechanical coupling in an active orogen, thrusting Namche Barwa-Gyala Peri above the surrounding landscape in a process of "tectonic

The tectonic dynamics can also affect large-scale drainage patterns through volcanism and distention processes in divergent plates. In the African continent there are at least two examples of rivers indicating complex histories involving shifts in the nature of their catchments and courses, associated with volcanism and rifting process. The Nile may be one of the most remarkable examples of drainage evolution in response to non-orogenic tectonic deformation. The Nile evolution model described by Sahin (1985), Foucault and Stanley (1989); Issawi and McCauley (1992) and Goudie (2004), details five phases since the late

The first phase (called the "Gilf system" - Eocene) was marked by the presence of a set of parallel north flowing drainages occupying most of northeastern Africa and the present Nile Basin position fed by streams originating from eastern highlands (Red Sea area). The second Stage (Qena system - Miocene) was marked by intense tectonic activity followed by the reversion of the drainages taking up a southward position as well as establishing an immense river flowing south towards Aswan and the Sudan. The third stage (the Nile system – Late Miocene) was marked by a dramatic drop of the base level of the Mediterranean Sea (associated with the closure of the Straits of Gibraltar and the Messien Event – Gautier *et al.*, 1994) producing intense erosional activity forming gorges and canyons (designated as Eonile). As a result of such shifts, the Eonile took a northerly course. The fourth phase (Pliocene flooding), in the early Pliocene, the sea level rose at least 125 m so that an estuary or ria extended more than 900 km inland, reaching Aswan. After the Pleistocene, the Nile has been submitted to constant changes due to climate and hydrological regimes (detailed in Foucault and Stanley, 1985; Coutelier and Stanley, 1997). The other example of a paleodrainage system controlled by distensive tectonics is the Zambezi River. The longitudinal profile of the Zambezi River forms two concave-upward sections, with their boundary at Victoria Falls, and there are studies suggesting that these sections were disconnected fluvial systems only joined together after the late Quaternary (Goudie, 2004; Nugent, 1990). The paleo-Zambezi was connected to both the Limpopo and Luangwa River system and took its present configuration, probably after the Pliocene with the uplift of the Makagdikgadi Basin along the "Kalahari Zimbabwe axis". The new position of the Middle Zambezi permitted the capturing of east and northeast tributaries such as the

The evolutionary history of the Congo River is also linked to the tectonic processes related to south-central Africa vertical crust movements. Stankiewicz & Dewit (2006) suggested that the Congo drained into the Indian Ocean until the uplift of East African Highlands in the Oligocene or Eocene (30– 40 Ma). The Congo then became a landlocked basin, until it was

Examples of drainage modifications in catchments affected by the formation and erosion of volcanoes can be found in several scales, from regional drainage system displacements associated with major volcanic structures (such as *Serra Geral*/Etendeka and Deccan) to

captured during the Miocene by a river system causing it to drain into the Atlantic.

aneurysm" (Koons *et al.* 2002 and Simpson, 2004).

Kafue and Luangwa (Thomas and Shaw, 1991) (Figure 2).

Eocene.

Fig. 2. Drainage distribution of Southern Africa with the paleodrainage prior to the union of the middle and upper Zambezi in the early Pleistocene (modified after Thomas and Shaw, 1991 and Goudie, 2005).

localized events displacing and rearranging local streams. Oilier (1995), describes the relationship between directions of rivers in southeastern Australia (e.g. Hunter, Lachlan and Murrumbidgee) which reversed courses due to an Eocene/ early Oligocene Volcanism effect. On a more localized scale, Branca and Ferrara, 2001, mapped the ancient valley of the Alcantara and S. Paolo Rivers, below the northern flank of Mt Etna. The paleo-valley was filled by lava flow and volcano-sedimentary debris during several events starting from 170,000 years B.P. until 20,000 years B.P.

#### **2.2 Climatic and hydrologic changes**

The first empirical works relating environmental changes with variations in fluvial patterns always attempted to establish a direct correlation between climate changes and the settlement of morphosedimentary processes in drainage systems. Penk (1927) proposed links between incision and deposition patterns of fluvial canals in the Danube River region with glacial climatic cycles, which eventually became one of the main geo-indicators for the existence of glacial cycles. According to the authors, the sequence of terraces formed in fluvial plains would have resulted from alternating glacial (aggradation process) and interglacial (incision process) periods, forming the sequence of terraces that indicate specific environmental conditions. Davis, 1896, recognized the relationship between river displacement and climatic changes studying the Moselle River (northern France).

Paleodrainage Systems 9

(Maizels, 1990; Langping *et al*. 2009) since the cause-effect relationships between long term rainfall and morphodynamic of paleodrainages are not always direct. In fact, recent studies have mapped near-surface paleochannels in Namibia (Lancaster *et al,* 2000; Lancaster, 2002) indicating that during the late Quaternary, there was no significant changes in precipitation in the desert itself, but there were considerable variations with more frequent and/or longer duration discharges in ephemeral rivers, suggesting an increase of precipitation only in the

It is not only deep variations in climatologic regimes, leading to desertification and drastic opposite states of wet and dry periods, that can be responsible for considerable changes within a drainage system. In some cases, smaller scale/higher frequency variations in factors such as sediment supply, vegetation coverage or catastrophic floods can provoke considerable displacements and shifts in the fluvial systems, with or without the presence of tectonic amplification. The concepts of "River Metamorphosis" (Schumm, 1967 and 1985), "Avulsion" and "Cutoff" (Allen, 1965) and "stream piracy" (Pederson, 2001) have been proposed to describe such processes of channel migration into the watershed and have been widely studied as they are often associated with changes in climatic conditions (e.g. Hocke

Knox, (2000) in an extensive study on the Mississippi and Colorado River Valley and tributaries, described how magnitude and recurrence of paleofloods are linked to major climatic events during the Holocene and suggests that, even relatively modest, changes in climate can cause important flood episodes, and these changes in morphodynamic processes have often occurred abruptly at various time scales from decadal to millennial and even longer. Similar results were described by Benito *et al.* (2003) for the Iberian Peninsula,

Despite that fluvial system adjustments to new climatic and hydrological regimes are able to produce major responses at upstream levels, the effects of base level control in downstream levels (in response to Glacio-eustatic fluctuations) effectively can produce clear paleodrainage records in continental margins and coastal plains, and the significance of these characteristics can be very elucidating for understanding geomorphic processes associated with sea level changes. The paleodrainage characteristics is one of the main geoindicators of continental margin evolution over the Glacial periods when most of the world´s shelves were exposed to sub aerial incision during relative sea level low-stands, and the cross-shelf valleys were directly connected to the continental slope and deep marine environments. From a sequence stratigraphy point of view (see Van Wagoner *et al*. 1990), an understanding of how, when, and where incised valleys are excavated in response to sea level variations remains a topic of considerable interest since the basal surface of paleovalley fills is commonly taken to define the sequence boundary, the most commonly used bounding surface for the identification of allostratigraphic units (Tronqvist *et al.* 2005).

Models developed by Koss *et al.* (1994), Ashley and Sheridan (1994), Meijer (2001); Gutierrez *et al*. (2003), Weber *et al*. (2004) and Hori *et al*. (2002) Strong and Paola (2006) suggest that, despite continental shelves, paleovalleys can be correlated with the paleo-hydrological regime in which the channel was formed; they also can be associated with submerging processes in the incised valleys during marine transgressions, reflecting the interaction between the autogenic and allogenic forcings. Still, the relative and absolute effect of these

1977; Werritty and Ferguson , 1980; Ashworth and Ferguson, 1986; Bridge, 2003).

St.Laurent *et al*. (2001) Canada, Sih et al. (1985) and China among others.

mechanisms remains unclear (Wellner and Bartek, 2003).

upper part of the basin.

Several models involving the relationship between drainage system patterns and climate change have been proposed throughout the 20th century incorporating concepts such as hydraulic geometry (e.g. Leopold and Maddock, 1956), fluvial facies and sequence stratigraphy (e.g. Wescot, 1993) along with dating techniques (e.g. Sanderson *et al*., 2003; Zhang *et al*., 2003, Wallbrink *et al.,* 2002). In recent decades, multidisciplinary studies have proposed a more holistic approach to integrate climate change and paleodrainage pattern response affected by multiple drivers of varying spatial and temporal dominance and complexity (Knox, 1993, Ely *et al.* 1993; Gibbard and Lewin, 2002; Andres *et al.* 2002; Goodbred, 2003, Vandenberghe, 2003).

The control of glacial cycles in a fluvial system occurs at two different levels: Upstream Controls associated with Continental Interiors and Downstream Control in continental margins. At the upstream level, the relationship between variation of climatic regime and fluvial morphodynamics is usually associated with hydrological changes, on a broader scale, as a regional manifestation of a global pattern of atmospheric circulation or internal dynamics, with feedback mechanisms, while in downstream systems, the base level variations (i.e. sea-level) are the underlying drivers of erosion and incision processes.

The variations of drainage patterns in upstream systems relate to climate changes, and their association with hydrologic processes has been the focus of investigations since the publication of the earliest works on fluvial geomorphology. Patterns of marginal terrace construction in glacial periods (in contrast to incision processes in interglacial periods driven by changes in hydrological and sedimentary processes) also can produce more dramatic landforms. The climatic conditions not only affect the hydrologic regime (i.e. the flow increase or decrease in stream discharge) but also act on factors such as the vegetation coverage, weathering processes (which determines the sediment supply to the system) and the role of the sediment transport agents.

The clearest examples of geographical changes in drainage landform patterns controlled by climatic agents are the drying and desertification processes, associated with an increasingly arid climate condition. Most of the world's deserts present clear signals of paleo drainage systems related to humid periods in the past. The Sahara paleo drainage, as an example, has been investigated by McCauley *et al.*, 1986; Pachur and Kroepelin, 1987, Burke *et al*. 1989; Robinson *et al*. 2006; Ghoneim and El-Baz, 2007 among others. Beneath the mobile Eolian sand sheet, sand covers several paleo basins and channels varying from a few to hundreds of meters in width. Most of these systems have been established during the Messinian salinity crisis period (late Miocene, 5–6Ma - previously discussed) when the incision activity reached its maximum, followed by recurring activity during wet periods in the Quaternary. Paiollou *et al.* 2009, using radar images and digital terrain modeling, mapped the Kufrah and Sirt basins (Southern Libya) and concluded that the ancient Kufrah/Wadi Sahabi Rivers would have been active during wet periods (until the Holocene) showing diverse depth levels of incised channels, moreover, during the Eemian interglacial maximum, 125 k.y. ago. The Kufrah River system would have been more than 1200 km-long, comparable in size to the Egyptian Nile.

Studies showing direct links between climatic data and geomorphological analysis of paleodrainage systems in semi arid as well as desert environments are relatively rare1

<sup>1</sup> Exceptions can be found in works related to karst systems (e.g. Frumkin *et al* 1998; Defni *et al* 2010).

Several models involving the relationship between drainage system patterns and climate change have been proposed throughout the 20th century incorporating concepts such as hydraulic geometry (e.g. Leopold and Maddock, 1956), fluvial facies and sequence stratigraphy (e.g. Wescot, 1993) along with dating techniques (e.g. Sanderson *et al*., 2003; Zhang *et al*., 2003, Wallbrink *et al.,* 2002). In recent decades, multidisciplinary studies have proposed a more holistic approach to integrate climate change and paleodrainage pattern response affected by multiple drivers of varying spatial and temporal dominance and complexity (Knox, 1993, Ely *et al.* 1993; Gibbard and Lewin, 2002; Andres *et al.* 2002;

The control of glacial cycles in a fluvial system occurs at two different levels: Upstream Controls associated with Continental Interiors and Downstream Control in continental margins. At the upstream level, the relationship between variation of climatic regime and fluvial morphodynamics is usually associated with hydrological changes, on a broader scale, as a regional manifestation of a global pattern of atmospheric circulation or internal dynamics, with feedback mechanisms, while in downstream systems, the base level

The variations of drainage patterns in upstream systems relate to climate changes, and their association with hydrologic processes has been the focus of investigations since the publication of the earliest works on fluvial geomorphology. Patterns of marginal terrace construction in glacial periods (in contrast to incision processes in interglacial periods driven by changes in hydrological and sedimentary processes) also can produce more dramatic landforms. The climatic conditions not only affect the hydrologic regime (i.e. the flow increase or decrease in stream discharge) but also act on factors such as the vegetation coverage, weathering processes (which determines the sediment supply to the system) and

The clearest examples of geographical changes in drainage landform patterns controlled by climatic agents are the drying and desertification processes, associated with an increasingly arid climate condition. Most of the world's deserts present clear signals of paleo drainage systems related to humid periods in the past. The Sahara paleo drainage, as an example, has been investigated by McCauley *et al.*, 1986; Pachur and Kroepelin, 1987, Burke *et al*. 1989; Robinson *et al*. 2006; Ghoneim and El-Baz, 2007 among others. Beneath the mobile Eolian sand sheet, sand covers several paleo basins and channels varying from a few to hundreds of meters in width. Most of these systems have been established during the Messinian salinity crisis period (late Miocene, 5–6Ma - previously discussed) when the incision activity reached its maximum, followed by recurring activity during wet periods in the Quaternary. Paiollou *et al.* 2009, using radar images and digital terrain modeling, mapped the Kufrah and Sirt basins (Southern Libya) and concluded that the ancient Kufrah/Wadi Sahabi Rivers would have been active during wet periods (until the Holocene) showing diverse depth levels of incised channels, moreover, during the Eemian interglacial maximum, 125 k.y. ago. The Kufrah River system would have been more than 1200 km-long, comparable in size to

Studies showing direct links between climatic data and geomorphological analysis of paleodrainage systems in semi arid as well as desert environments are relatively rare1

1 Exceptions can be found in works related to karst systems (e.g. Frumkin *et al* 1998; Defni *et al* 2010).

variations (i.e. sea-level) are the underlying drivers of erosion and incision processes.

Goodbred, 2003, Vandenberghe, 2003).

the role of the sediment transport agents.

the Egyptian Nile.

(Maizels, 1990; Langping *et al*. 2009) since the cause-effect relationships between long term rainfall and morphodynamic of paleodrainages are not always direct. In fact, recent studies have mapped near-surface paleochannels in Namibia (Lancaster *et al,* 2000; Lancaster, 2002) indicating that during the late Quaternary, there was no significant changes in precipitation in the desert itself, but there were considerable variations with more frequent and/or longer duration discharges in ephemeral rivers, suggesting an increase of precipitation only in the upper part of the basin.

It is not only deep variations in climatologic regimes, leading to desertification and drastic opposite states of wet and dry periods, that can be responsible for considerable changes within a drainage system. In some cases, smaller scale/higher frequency variations in factors such as sediment supply, vegetation coverage or catastrophic floods can provoke considerable displacements and shifts in the fluvial systems, with or without the presence of tectonic amplification. The concepts of "River Metamorphosis" (Schumm, 1967 and 1985), "Avulsion" and "Cutoff" (Allen, 1965) and "stream piracy" (Pederson, 2001) have been proposed to describe such processes of channel migration into the watershed and have been widely studied as they are often associated with changes in climatic conditions (e.g. Hocke 1977; Werritty and Ferguson , 1980; Ashworth and Ferguson, 1986; Bridge, 2003).

Knox, (2000) in an extensive study on the Mississippi and Colorado River Valley and tributaries, described how magnitude and recurrence of paleofloods are linked to major climatic events during the Holocene and suggests that, even relatively modest, changes in climate can cause important flood episodes, and these changes in morphodynamic processes have often occurred abruptly at various time scales from decadal to millennial and even longer. Similar results were described by Benito *et al.* (2003) for the Iberian Peninsula, St.Laurent *et al*. (2001) Canada, Sih et al. (1985) and China among others.

Despite that fluvial system adjustments to new climatic and hydrological regimes are able to produce major responses at upstream levels, the effects of base level control in downstream levels (in response to Glacio-eustatic fluctuations) effectively can produce clear paleodrainage records in continental margins and coastal plains, and the significance of these characteristics can be very elucidating for understanding geomorphic processes associated with sea level changes. The paleodrainage characteristics is one of the main geoindicators of continental margin evolution over the Glacial periods when most of the world´s shelves were exposed to sub aerial incision during relative sea level low-stands, and the cross-shelf valleys were directly connected to the continental slope and deep marine environments. From a sequence stratigraphy point of view (see Van Wagoner *et al*. 1990), an understanding of how, when, and where incised valleys are excavated in response to sea level variations remains a topic of considerable interest since the basal surface of paleovalley fills is commonly taken to define the sequence boundary, the most commonly used bounding surface for the identification of allostratigraphic units (Tronqvist *et al.* 2005).

Models developed by Koss *et al.* (1994), Ashley and Sheridan (1994), Meijer (2001); Gutierrez *et al*. (2003), Weber *et al*. (2004) and Hori *et al*. (2002) Strong and Paola (2006) suggest that, despite continental shelves, paleovalleys can be correlated with the paleo-hydrological regime in which the channel was formed; they also can be associated with submerging processes in the incised valleys during marine transgressions, reflecting the interaction between the autogenic and allogenic forcings. Still, the relative and absolute effect of these mechanisms remains unclear (Wellner and Bartek, 2003).

Paleodrainage Systems 11

Examples of using of integrated methods based on multi parameter investigation of paleodrainage can be related to drying and desertification processes in which the original landform still lies only a few meters above the sand sheet, still remaining recognizable. Ghoneim & Elbaz (2007), based on SRTM elevation data obtained on a near-global scale (3 arcsec resolution) in combination with Radarsat-1 Synthetic Aperture Radar Images and Landsat TM satellite images, made a complete paleoenvironmental analysis of the Tushka basin between Egypt and Sudan (figure 3). Similar methods were used by Sultan *et al* (2004), Marinangeli (2005) Gaber *et al.* (2008) Blumberg *et al*., (2004); Griffin, (2006); Pachur and Altmann, (2006) demonstrating good potential for recognizing topographic patterns of

Fig. 3. (a) typical example of multi data INTEGRATED to characterize paleodrainage networks - Landsat ETM+ color composite (bands 7, 4, 2) covering an area in NW Sudan showing the dominance of surface sand deposits. (b) Radarsat-1 image showing a distinct subsurface drainage network trending eastward; note the absence of the surface sand deposits. (c) The SRTM DEM (90 m) with the delineated drainage network overlain; note the good correspondence between the SRTM-generated channels and the Radarsat-1 subsurface

paleodrainage in semi arid or arid areas.

channels (after Ghoneim & Elbaz, 2007).

A quite thorough review on the fluvial systems response to sea level variations can be found in Bloom and Tronquvist, 2000: According to the authors, fluvial responses to climate and sea-level change can be disaggregated into stratigraphic, morphological and sedimentological components: The stratigraphic responses are produced by aggradation due to increasing accumulation space, degradation as accumulation space decreases and lateral migration when there is no change in accumulation space and the fluvial systems in fluvial systems in subsiding basins. These are characterized by long-term net aggradation, punctuated by relatively short periods (103 - 104 years) of incision and/or lateral migration (in opposition to typical upstream valleys). Morphological responses reflect changes in channel system geometry and sedimentological responses are associated with changes along with the spatial distribution of depositional environments and proprieties of lithofacies.

#### **3. Method of analysis – tracking ancient rivers**

Paleodrainage systems, as previously mentioned, can be a powerful tool for modeling paleoenvironmental scenarios and understanding the geological and climatic dynamics in time scales that ranges from seasons to millions of years, even though the identification and characterization of such features is usually indirect and quite often requiring a detailed process of analysis and integration of data from multiple sources. Perhaps the most comprehensive review of general principles on this topic is provided by Andersen (1962) who previously recognized the main geological aspects of mapping paleodrainage distribution maps. According to the author,

*" […] paleodrainage maps can be constructed in several ways: 1) by making a structural contour map of the erosion surface at the base of the valley fill; 2) by making a number of stratigraphic crosssections which intersect the valley trends - valley axes are approximated by connecting consecutive valley low-points which have been plotted on a map; 3) by making a paleogeologic map of the surface at the base of the valley-fill - valley axes are drawn in the middle of the areas where the oldest rocks are represented; 4) by isopaching the interval between the valley floor and some datum- valley axes are where the valley floor is farthest from or closest to the datum\* depending on whether the datum is above or below the valley floor; and 3) by making an isopach# map of the valley-fill - valley axes are where the fill is the thickest. Knowledge of paleodrainage patterns in a given area allows the geologist to conclude the direction of paleoslope, local paleotopography, the approximate direction of the source area from the study area, the character of the surface into which the valleys were cut, and whether or not there was any structural activity in the study area during the time of valley carving."* 

The development of new methods in geomorphology to record and quantify past and recent geomorphic processes allied with the implementation of techniques of geoprocessing and Geographic Information Systems have permitted increased accuracy in reconstructions of past environments. This new "geomorphological" approach has also provided valuable insights into the formation and evolution of fluvial systems. Mapping topographical attributes, for example, can still be the simplest and most intuitive method to recognize some aspects of the ancient fluvial geomorphology and usually can reveal several characteristics of the fluvial system. In practice, however, the original local landform is rarely preserved after morphodynamic processes that caused the changes in the fluvial patterns, so the use of elevation data (obtained from different sources) should be accompanied by further geophysical investigations, in order to track aspects of the original landform configuration.

A quite thorough review on the fluvial systems response to sea level variations can be found in Bloom and Tronquvist, 2000: According to the authors, fluvial responses to climate and sea-level change can be disaggregated into stratigraphic, morphological and sedimentological components: The stratigraphic responses are produced by aggradation due to increasing accumulation space, degradation as accumulation space decreases and lateral migration when there is no change in accumulation space and the fluvial systems in fluvial systems in subsiding basins. These are characterized by long-term net aggradation, punctuated by relatively short periods (103 - 104 years) of incision and/or lateral migration (in opposition to typical upstream valleys). Morphological responses reflect changes in channel system geometry and sedimentological responses are associated with changes along with the spatial distribution of depositional environments and proprieties of

Paleodrainage systems, as previously mentioned, can be a powerful tool for modeling paleoenvironmental scenarios and understanding the geological and climatic dynamics in time scales that ranges from seasons to millions of years, even though the identification and characterization of such features is usually indirect and quite often requiring a detailed process of analysis and integration of data from multiple sources. Perhaps the most comprehensive review of general principles on this topic is provided by Andersen (1962) who previously recognized the main geological aspects of mapping paleodrainage

*" […] paleodrainage maps can be constructed in several ways: 1) by making a structural contour map of the erosion surface at the base of the valley fill; 2) by making a number of stratigraphic crosssections which intersect the valley trends - valley axes are approximated by connecting consecutive valley low-points which have been plotted on a map; 3) by making a paleogeologic map of the surface at the base of the valley-fill - valley axes are drawn in the middle of the areas where the oldest rocks are represented; 4) by isopaching the interval between the valley floor and some datum- valley axes are where the valley floor is farthest from or closest to the datum\* depending on whether the datum is above or below the valley floor; and 3) by making an isopach# map of the valley-fill - valley axes are where the fill is the thickest. Knowledge of paleodrainage patterns in a given area allows the geologist to conclude the direction of paleoslope, local paleotopography, the approximate direction of the source area from the study area, the character of the surface into which the valleys were cut, and whether or* 

*not there was any structural activity in the study area during the time of valley carving."* 

The development of new methods in geomorphology to record and quantify past and recent geomorphic processes allied with the implementation of techniques of geoprocessing and Geographic Information Systems have permitted increased accuracy in reconstructions of past environments. This new "geomorphological" approach has also provided valuable insights into the formation and evolution of fluvial systems. Mapping topographical attributes, for example, can still be the simplest and most intuitive method to recognize some aspects of the ancient fluvial geomorphology and usually can reveal several characteristics of the fluvial system. In practice, however, the original local landform is rarely preserved after morphodynamic processes that caused the changes in the fluvial patterns, so the use of elevation data (obtained from different sources) should be accompanied by further geophysical investigations, in order to track aspects of the original

lithofacies.

**3. Method of analysis – tracking ancient rivers** 

distribution maps. According to the author,

landform configuration.

Examples of using of integrated methods based on multi parameter investigation of paleodrainage can be related to drying and desertification processes in which the original landform still lies only a few meters above the sand sheet, still remaining recognizable. Ghoneim & Elbaz (2007), based on SRTM elevation data obtained on a near-global scale (3 arcsec resolution) in combination with Radarsat-1 Synthetic Aperture Radar Images and Landsat TM satellite images, made a complete paleoenvironmental analysis of the Tushka basin between Egypt and Sudan (figure 3). Similar methods were used by Sultan *et al* (2004), Marinangeli (2005) Gaber *et al.* (2008) Blumberg *et al*., (2004); Griffin, (2006); Pachur and Altmann, (2006) demonstrating good potential for recognizing topographic patterns of paleodrainage in semi arid or arid areas.

Fig. 3. (a) typical example of multi data INTEGRATED to characterize paleodrainage networks - Landsat ETM+ color composite (bands 7, 4, 2) covering an area in NW Sudan showing the dominance of surface sand deposits. (b) Radarsat-1 image showing a distinct subsurface drainage network trending eastward; note the absence of the surface sand deposits. (c) The SRTM DEM (90 m) with the delineated drainage network overlain; note the good correspondence between the SRTM-generated channels and the Radarsat-1 subsurface channels (after Ghoneim & Elbaz, 2007).

Paleodrainage Systems 13

In downstream systems, the subsurface mapping for locating and analyzing cut and fill structures associated with buried incised channels across continental shelves is probably one of the most widespread applications involving paleodrainage studies. Several studies have considered these factors as indicators of the paleogeography of the subaerial surface as well as the fluvial and hydrological regime during regressive events (see Reynaud *et al.,* 1999;

Despite the focus on direct analysis of channel incision surfaces and their relation to quaternary stratigraphy based on high resolution seismic data (e.g. Thorne, 1994; Lericolais *et al*., 2001; Hori *et al*., 2002; Nordfjord *et al*. 2005, Ashley and Sheridan, 1994; Zaitlin *et al*., 1994), along with the fact that they are covered by marine sediments deposited during and after rises in sea levels (Correa, 1996; Harris and O'Brien, 1996; Collina-Girard, 1999; Abreu and Cagliari, 2005; Finkl *et al*., 2005) and the small number of studies characterizing the topographic expression of the paleo-drainage registers (Strong and Paola, 2008;), it is still

possible to identify and classify the main paleo-valley axis in the surface topography.

paleovalley features in the coastal plain and on the continental shelf.

Incised valleys are also often associated with large-scale sediment bypass zones that feed downdip into large sandy deltas, so the stratigraphic characterizing of these features can provide reliable information on the general characteristics of a paleofluvial regime (Dalrymple *et al.,* 1994). Different sedimentation models based on the fluvial and marine deposition during relative rises and falls of sea level can be constructed based on direct (biostratigraphic, isotopic, and geochemistry data) and indirect (seismic data) analysis of such submarine fans. Examples in the Amazon (Mikkelsen *et al.* 1997 and Figueredo *et al.*

Conti and Furtado 2009, having studied the paleodrainage registers of the southeastern Brazilian continental shelf, observed that the paleo-valley features present diverse topographical expressions and are related differently to the drainage system that generated them. Some of those identified by the Digital Terrain Model (DEM) were quite conspicuous and easily detected, while others could only be distinguished by using enhanced filters on the topography DEM; however, there is no direct relation between the size and dimension of the paleo-valleys and the shape, form, outflow or basin characteristics of the modern rivers. A particularly interesting example of how the use of multi data in a Geographic Information System framework proved to be valuable in understanding the paleo drainage records is the case of the downstream of Ribeira de Iguape River – RIR (southeastern São Paulo state – Brazil). The analysis of remote sensing images (Landsat TM), in particular near infrared bands of the coastal plain of the river, reveal areas with high wetness index values indicating an abandoned channel feature with a divergent orientation in relation to the modern RIR position (figure 4a). A bathymetry digital terrain model (DTM) of the adjacent Continental Shelf mapped two channel-like structures in submarine topography; one clearly related to the present estuary of the RIR and another, more than 15 km southward, apparently connected to the paleochannel have been identified on satellite images (figure 4b). High-resolution seismic profiling data on the supposed point of convergence of these two features (satellite images and DTM) revealed the presence of a prominent cut and fill structure indicative of channel incision (figure 4c). The body of evidence points to two distinct positions of the RIR during two low-stand periods: one associated with the actual position of the river at the north and another one, probably older, diverging more than 30 km from the present estuary, headed seaward in a mostly direct path, forming the

Lericolais *et al*., 2003; Tesson *et al*., 2005; Meijer, 2002).

Furthermore, some of the most interesting studies in paleodrainage recognition have been developed by applying topographical analysis in conjunction with spectral information in tropical/equatorial forests. Haywakawa *et al*. (2010) has analyzed the ancient drainage complex of the Madeira River, one of the main Amazon tributaries and was able to delineate a complex system of abandoned channels due to avulsion processes during the Late Pleistocene- Holocene, despite the area being covered by dense forests (figure 4). Rossetti (2010), after analyzing topographic and spectral data has also produced satisfactory results in understanding the resulting drainage rearrangement in the Amazonian lowlands.

Fig. 4. DEM-SRTM with the regional view of the study area and the location of the paleodrainage network (dashed lines) detected in the Madeira-Manicoré Rivers. B) Topograhic profile (i–i) derived from DEM-SRTM. Observe that paleodrainage occurs in an area topographically higher than the modern Madeira valley (after Haywakawa *et al.* 2010).

Furthermore, some of the most interesting studies in paleodrainage recognition have been developed by applying topographical analysis in conjunction with spectral information in tropical/equatorial forests. Haywakawa *et al*. (2010) has analyzed the ancient drainage complex of the Madeira River, one of the main Amazon tributaries and was able to delineate a complex system of abandoned channels due to avulsion processes during the Late Pleistocene- Holocene, despite the area being covered by dense forests (figure 4). Rossetti (2010), after analyzing topographic and spectral data has also produced satisfactory results

in understanding the resulting drainage rearrangement in the Amazonian lowlands.

Fig. 4. DEM-SRTM with the regional view of the study area and the location of the paleodrainage network (dashed lines) detected in the Madeira-Manicoré Rivers. B)

Topograhic profile (i–i) derived from DEM-SRTM. Observe that paleodrainage occurs in an area topographically higher than the modern Madeira valley (after Haywakawa *et al.* 2010).

In downstream systems, the subsurface mapping for locating and analyzing cut and fill structures associated with buried incised channels across continental shelves is probably one of the most widespread applications involving paleodrainage studies. Several studies have considered these factors as indicators of the paleogeography of the subaerial surface as well as the fluvial and hydrological regime during regressive events (see Reynaud *et al.,* 1999; Lericolais *et al*., 2003; Tesson *et al*., 2005; Meijer, 2002).

Despite the focus on direct analysis of channel incision surfaces and their relation to quaternary stratigraphy based on high resolution seismic data (e.g. Thorne, 1994; Lericolais *et al*., 2001; Hori *et al*., 2002; Nordfjord *et al*. 2005, Ashley and Sheridan, 1994; Zaitlin *et al*., 1994), along with the fact that they are covered by marine sediments deposited during and after rises in sea levels (Correa, 1996; Harris and O'Brien, 1996; Collina-Girard, 1999; Abreu and Cagliari, 2005; Finkl *et al*., 2005) and the small number of studies characterizing the topographic expression of the paleo-drainage registers (Strong and Paola, 2008;), it is still possible to identify and classify the main paleo-valley axis in the surface topography.

Conti and Furtado 2009, having studied the paleodrainage registers of the southeastern Brazilian continental shelf, observed that the paleo-valley features present diverse topographical expressions and are related differently to the drainage system that generated them. Some of those identified by the Digital Terrain Model (DEM) were quite conspicuous and easily detected, while others could only be distinguished by using enhanced filters on the topography DEM; however, there is no direct relation between the size and dimension of the paleo-valleys and the shape, form, outflow or basin characteristics of the modern rivers.

A particularly interesting example of how the use of multi data in a Geographic Information System framework proved to be valuable in understanding the paleo drainage records is the case of the downstream of Ribeira de Iguape River – RIR (southeastern São Paulo state – Brazil). The analysis of remote sensing images (Landsat TM), in particular near infrared bands of the coastal plain of the river, reveal areas with high wetness index values indicating an abandoned channel feature with a divergent orientation in relation to the modern RIR position (figure 4a). A bathymetry digital terrain model (DTM) of the adjacent Continental Shelf mapped two channel-like structures in submarine topography; one clearly related to the present estuary of the RIR and another, more than 15 km southward, apparently connected to the paleochannel have been identified on satellite images (figure 4b). High-resolution seismic profiling data on the supposed point of convergence of these two features (satellite images and DTM) revealed the presence of a prominent cut and fill structure indicative of channel incision (figure 4c). The body of evidence points to two distinct positions of the RIR during two low-stand periods: one associated with the actual position of the river at the north and another one, probably older, diverging more than 30 km from the present estuary, headed seaward in a mostly direct path, forming the paleovalley features in the coastal plain and on the continental shelf.

Incised valleys are also often associated with large-scale sediment bypass zones that feed downdip into large sandy deltas, so the stratigraphic characterizing of these features can provide reliable information on the general characteristics of a paleofluvial regime (Dalrymple *et al.,* 1994). Different sedimentation models based on the fluvial and marine deposition during relative rises and falls of sea level can be constructed based on direct (biostratigraphic, isotopic, and geochemistry data) and indirect (seismic data) analysis of such submarine fans. Examples in the Amazon (Mikkelsen *et al.* 1997 and Figueredo *et al.*

Paleodrainage Systems 15

history of the ancient drainage systems. Freshwater fish, in particular, have indicated strong relationships between historical river connections and phylogeographic patterns since changes in fluvial patterns might have been the source of isolation and divergence for aquatic species, forming barriers to gene flow. In this context, a large number of studies have been suggesting even the influence of the paleodrainage on species evolution and vicariance processes as well as the other way around, resorting to biodiversity in order to reconstruct fluvial paleoenvironments (see Waters, 2001, Cook *et al.*, 2006; Ribeiro, 2006;

There are several open questions involving the evolution of drainage in response to longterm environmental changes. Some of these questions have been debated since the mid 20th century after the publication of major quantitative studies on dynamic fluvial geomorphology (e.g. Horton, 1945; Strahler, 1952; Shreve, 1969; Schumm, 1972; 1977 and 1987). Perhaps one of the most intriguing questions related to the evolution of fluvial systems is the relationship with base level low-stands. The models for incised valleys assume that relative sea-level fall produces an upstream propagating wave of rejuvenation, but how far reaching and how impacting are these processes, is still a matter for discussion. Other key aspects of paleohydrological and paleoenvironmental sciences remains unclear and uncertain, for example, the role of feedback effects on the climatic forcing (such as peak precipitation) to indirect (such as permafrost melting) and partial forcing (such as vegetation suppression) on the evolution of fluvial systems (Vandenberghe, 2003) and the temporal scales, time lapses and coupling of different stages of the geomorphic processes (Harvey, A.M., 2002)*.* In fact, most of the models for reconstructing the morphology and hydrology dynamics in response to climate change (either in continental upstream or continental shelves downstreams) are quite incomplete in delivering quantitative descriptions and predictions, therefore, the development of integrated frameworks is fundamental to

Considering further development of global warming, intense urbanization, deforestation and need for hydroelectric energy, there is no option for the near future, but to develop integrated and multidisciplinary research focused on the study of geomorphological and geological mechanisms of evolution of landscapes, in particular for fluvial systems, and it is very clear that the same uncertainties and achievements can be broadly applied to artificial drainage systems, independent of the temporal and spatial scale. Today, at least one billion people live along or near rivers and channels worldwide (Palmer *et al.* 2008) and only a complete synergy between observation and understanding of empirical evidence of paleodrainages on the local and general scale and theoretical models based on rigorous physical assumptions will provide a robust scientific body of knowledge capable of improving the accuracy and reliability of broader and better-integrated models and theories

The author would also like to acknowledge the financial support of FAPESP (Fundação de

increasing their usability for forecasting, simulating, and planning proposals.

Amparo a Pesquisa do Estado de São Paulo) – Grant: 2011/20563-4

Burridge *et al.* 2007; Flinstone *et al.* 2007).

understanding such relationships.

**5. Acknowledgments** 

**4. Final remarks** 

Fig. 5. Indicators of the paleo Ribeira de Iguape River – Southeastern Brazil. (a) Position of a wet lowlands indicated by vegetation indices from Landsat Images. (b) Digital Terrain Model from the continental shelf bathymetry indicating the presence of two paleovalleys (c) cut and fill structure in a high resolution seismic profile.

2009), Indus (Qayyum *et al.* 1997), Danube (Panin *et al.* 1998), and Pearl River (Pang *et al.* 2006) among others, have proven that the sediment load variability respond not only to climate changes that affect the river discharges but also to processes within the basin such as tectonic and autogenic processes.

Recent improvements in genetic analysis involving biogeography paleoenvironmental reconstructions have been making important contributions to the understanding of the

Fig. 5. Indicators of the paleo Ribeira de Iguape River – Southeastern Brazil. (a) Position of a wet lowlands indicated by vegetation indices from Landsat Images. (b) Digital Terrain Model from the continental shelf bathymetry indicating the presence of two paleovalleys (c)

2009), Indus (Qayyum *et al.* 1997), Danube (Panin *et al.* 1998), and Pearl River (Pang *et al.* 2006) among others, have proven that the sediment load variability respond not only to climate changes that affect the river discharges but also to processes within the basin such as

Recent improvements in genetic analysis involving biogeography paleoenvironmental reconstructions have been making important contributions to the understanding of the

cut and fill structure in a high resolution seismic profile.

tectonic and autogenic processes.

history of the ancient drainage systems. Freshwater fish, in particular, have indicated strong relationships between historical river connections and phylogeographic patterns since changes in fluvial patterns might have been the source of isolation and divergence for aquatic species, forming barriers to gene flow. In this context, a large number of studies have been suggesting even the influence of the paleodrainage on species evolution and vicariance processes as well as the other way around, resorting to biodiversity in order to reconstruct fluvial paleoenvironments (see Waters, 2001, Cook *et al.*, 2006; Ribeiro, 2006; Burridge *et al.* 2007; Flinstone *et al.* 2007).

### **4. Final remarks**

There are several open questions involving the evolution of drainage in response to longterm environmental changes. Some of these questions have been debated since the mid 20th century after the publication of major quantitative studies on dynamic fluvial geomorphology (e.g. Horton, 1945; Strahler, 1952; Shreve, 1969; Schumm, 1972; 1977 and 1987). Perhaps one of the most intriguing questions related to the evolution of fluvial systems is the relationship with base level low-stands. The models for incised valleys assume that relative sea-level fall produces an upstream propagating wave of rejuvenation, but how far reaching and how impacting are these processes, is still a matter for discussion. Other key aspects of paleohydrological and paleoenvironmental sciences remains unclear and uncertain, for example, the role of feedback effects on the climatic forcing (such as peak precipitation) to indirect (such as permafrost melting) and partial forcing (such as vegetation suppression) on the evolution of fluvial systems (Vandenberghe, 2003) and the temporal scales, time lapses and coupling of different stages of the geomorphic processes (Harvey, A.M., 2002)*.* In fact, most of the models for reconstructing the morphology and hydrology dynamics in response to climate change (either in continental upstream or continental shelves downstreams) are quite incomplete in delivering quantitative descriptions and predictions, therefore, the development of integrated frameworks is fundamental to understanding such relationships.

Considering further development of global warming, intense urbanization, deforestation and need for hydroelectric energy, there is no option for the near future, but to develop integrated and multidisciplinary research focused on the study of geomorphological and geological mechanisms of evolution of landscapes, in particular for fluvial systems, and it is very clear that the same uncertainties and achievements can be broadly applied to artificial drainage systems, independent of the temporal and spatial scale. Today, at least one billion people live along or near rivers and channels worldwide (Palmer *et al.* 2008) and only a complete synergy between observation and understanding of empirical evidence of paleodrainages on the local and general scale and theoretical models based on rigorous physical assumptions will provide a robust scientific body of knowledge capable of improving the accuracy and reliability of broader and better-integrated models and theories increasing their usability for forecasting, simulating, and planning proposals.

### **5. Acknowledgments**

The author would also like to acknowledge the financial support of FAPESP (Fundação de Amparo a Pesquisa do Estado de São Paulo) – Grant: 2011/20563-4

Paleodrainage Systems 17

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**2** 

*Brazil* 

**Sustainable Drainage Systems: An Integrated** 

**Approach, Combining Hydraulic Engineering** 

Floods are natural and seasonal phenomena, which play an important environmental role, but when they take place at the built environments, many losses of different kinds occur. By its side, urban growth is one of the main causes of urban floods aggravation. Changes in land use occupation, with vegetation removal and increasing of impervious rates lead to greater run-off volumes flowing faster. Intense urbanisation is a relatively recent process; however, floods and drainage concerns are related to city development since ancient times. Drainage systems are part of a city infrastructure and they are an important key in urban life. If the drainage system fails, cities become subjected to floods, to possible environmental degradation, to sanitation and health problems and to city services disruption. On the other hand, urban rivers, in different moments of cities development history, have been considered as important sources of water supply, as possible defences for urban areas, as a

Thus, there is a paradox in the relation between the water and the cities: water is a fundamental element to city life, but urbanisation is not always accompanied by the adequate planning and the necessary infrastructure is generally not provided, leading both to urban spaces and water resources degradation. An interesting historical register illustrates the problem of urban land occupation. In the 16th Century, the architect Giovani Fontana studied the Tiber River flood in the Christmas of 1598, in Rome (Biswas, 1970). Fontana's conclusions stated that the severe consequences of that flood were related to the occupation of the riparian areas near the confluences of Tiber River with different tributaries and channels, as well as to the lack of information of the people that settled their houses at those places. This situation is pretty similar to what still occurs today: lack of urbanisation planning and control, poor environmental education and the absence of a major framework to unite technical and socio-economic aspects. The main proposition of Fontana to control floods in Rome referred to the enlargement of Tiber River, in order to improve the general flow conditions – a classic view focusing on fast conveying floods to a safe downstream

way of transporting goods, and as a means of waste conveying.

**1. Introduction** 

discharge.

**Design, Urban Land Control and River** 

**Revitalisation Aspects** 

and Paulo Roberto Ferreira Carneiro

*Federal University of Rio de Janeiro* 

Marcelo Gomes Miguez, Aline Pires Veról


### **Sustainable Drainage Systems: An Integrated Approach, Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects**

Marcelo Gomes Miguez, Aline Pires Veról and Paulo Roberto Ferreira Carneiro *Federal University of Rio de Janeiro Brazil* 

#### **1. Introduction**

20 Drainage Systems

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1218.

*Reviews*, 22 . 1123–1129

Floods are natural and seasonal phenomena, which play an important environmental role, but when they take place at the built environments, many losses of different kinds occur. By its side, urban growth is one of the main causes of urban floods aggravation. Changes in land use occupation, with vegetation removal and increasing of impervious rates lead to greater run-off volumes flowing faster. Intense urbanisation is a relatively recent process; however, floods and drainage concerns are related to city development since ancient times. Drainage systems are part of a city infrastructure and they are an important key in urban life. If the drainage system fails, cities become subjected to floods, to possible environmental degradation, to sanitation and health problems and to city services disruption. On the other hand, urban rivers, in different moments of cities development history, have been considered as important sources of water supply, as possible defences for urban areas, as a way of transporting goods, and as a means of waste conveying.

Thus, there is a paradox in the relation between the water and the cities: water is a fundamental element to city life, but urbanisation is not always accompanied by the adequate planning and the necessary infrastructure is generally not provided, leading both to urban spaces and water resources degradation. An interesting historical register illustrates the problem of urban land occupation. In the 16th Century, the architect Giovani Fontana studied the Tiber River flood in the Christmas of 1598, in Rome (Biswas, 1970). Fontana's conclusions stated that the severe consequences of that flood were related to the occupation of the riparian areas near the confluences of Tiber River with different tributaries and channels, as well as to the lack of information of the people that settled their houses at those places. This situation is pretty similar to what still occurs today: lack of urbanisation planning and control, poor environmental education and the absence of a major framework to unite technical and socio-economic aspects. The main proposition of Fontana to control floods in Rome referred to the enlargement of Tiber River, in order to improve the general flow conditions – a classic view focusing on fast conveying floods to a safe downstream discharge.

Sustainable Drainage Systems: An Integrated Approach,

adding value to the city itself.

roughness;

new option at the end of the 1970s (Andoh & Iwugo, 2002).

approach may be briefly described by the following points:

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 23

Focus on the consequences of the urbanisation process, that is, the increase of flow generation, which concentrates on storm drains, should be changed. Source control, acting on the causes of flooding and focusing on storage and infiltration measures, emerged as a

An integrated approach, considering the watershed as the planning unit, may be considered the initial basis for a sustainable system design. The design of an urban drainage system integrated with city development, aiming to reduce impacts on the hydrological cycle, acting on infiltration processes and allowing detention on artificial urban reservoirs, joining concerns, restrictions and synergies from Hydraulic Engineering and Urbanism appears as a fundamental option to treat urban floods. Besides the quantity aspects, the water quality became also a main issue and waste waters and solid waste disposal became matters to be treated together. The first flush and the washing of the catchment also introduced a new perception related to the diffuse pollution. At last, and in a complementarily way, rain water harvesting appears as an opportunity to increase water resources availability in urban environments. Several different conceptions have been proposed in the last decades, with some minor differences among them. All of them, however, tend to consider those questions in an integrated way, trying to rescue natural characteristics of the hydrological cycle, while

Coffman et al. (1998) proposed a design concept of Low Impact Development (LID). LID design adopts a set of procedures that try to understand and reproduce hydrological behaviour prior to urbanisation. In this context, the use of functional landscapes appear as useful elements in the urban mesh, in order to allow the recovering of infiltration and detention characteristics of the natural watershed. It is a change in the traditional design concepts, moving towards a site design that mimics natural watershed hydrological functions, involving volume, discharge, recharge and frequency. The main principles of this

 minimise runoff, acting on impervious rates reduction and maintaining green areas; preserve concentration times of pre-development, by increasing flow paths and surface

In a similar way, another early trend in the drainage system design evolution involved the use of stormwater Best Management Practices (BMP). The term Best Management Practices is frequently used in the USA and Canada and its origin is related with pollution control in the field of industrial wastewaters. Later, it was also referred as a possibility of nonpoint source pollution control and then associated with stormwater management. This way, stormwater BMPs are supposed to work in a distributed way over the watershed, integrating water quantity and water quality control aiming to mitigate effects generated by land use changes, with optimised costs. BMPs are designed to reduce stormwater volume, peak flows, and nonpoint source pollution through infiltration, filtration, biological or chemical processes, retention, and detention. They also may be classified into structural, when referring to installed devices and engineering solutions, or non-structural, when related to procedures changes, like limitations on landscaping practices (US EPA, 2004).

use of retention reservoir for peak discharge control and improve water quality;

use of additional detention reservoirs to prevent flooding, if necessary.

LID and BMP are very often used together and may complement each other.

As cities started to grow, especially after the Industrial Era, urbanisation problems became greater and urban floods increased in magnitude and frequency. The traditional approach for the drainage systems, which were important as a sanitation measure in the first times of the cities development, conveying stormwaters and wastewaters, turned unsustainable. Flow generation increased and end-of-pipe solutions tended to just transfer problems to downstream. In this context, in the last decades, several approaches were developed, in order to better equate flow patterns in space and time. However, not only the hydraulics aspects are important. Technical measures do not stand alone. The water in the city needs to be considered in an integrated way and sustainable solutions for drainage systems have to account for urban revitalisation and river rehabilitation, better quality of communities' life, participatory processes and institutional arrangements to allow the acceptance, support and continuity of these proposed solutions.

#### **2. Historical aspects and background of urban floods and drainage solutions**

Several ancient civilisations showed great care when constructing urban drainage systems, combining the objectives of collecting rainwater, preventing nuisance flooding, and conveying wastes. During the Roman Empire Age, significant advances were introduced in urban drainage systems. Concerns on urban flooding mitigation and low lands drainage were very important to the city of Rome, which arose among the hills of Lazio region, on the margins of Tiber River. To meet urban drainage needs, a complex network of open channels and underground pipes were constructed. This system was also used to convey people's waste from their living areas (Burian and Edwards, 2002).

During the Middle Ages, urban centres suffered a great decay and people tended to live in communities sparsely established in rural areas, near rivers, with minor concerns about urban drainage. Sanitation practices have deteriorated after the decline of the Roman Empire and surface drains and streets were used indiscriminately as the only means of disposal and conveyance of all wastewaters (Chocat *et al.*, 2001). Later, when cities started to grow significantly again, in the Industrial Era, urban drainage found itself regretted to a second plane. The industrial city grew with very few guidelines. The Liberalism influenced urban growth and there was a certain lack of control on the public perspective for city development (Benevolo, 2001). Sanitation, then, became a great problem and inadequate waste disposal led to several sort of diseases and deterioration of public health. The role of urban drainage became very important in helping to solve this problem and, more than often, it was important to fast collect, conduct and dispose securely stormwater and wastewater. Focus was driven to improve conveyance and this was the main goal of urban drainage, until some decades ago. However, considering the fast urban growth of the last two centuries, and the fact that the world population profile is changing from rural to urban, it became hard to simply look at urban drainage and propose channel corrections, rectifications and other similar sort of interventions. Canalisation could not answer for all urban flood problems and, in fact, this isolated action, in a local approach, was responsible for transferring problems more than solving them. The increasing flood problems that the cities were forced to face showed the unsustainability of the traditional urban drainage conception and new solutions started to be researched.

A sustainable approach for drainage systems became an important challenge to be dealt with. Drainage engineers became aware that the existing infrastructure was overloaded.

As cities started to grow, especially after the Industrial Era, urbanisation problems became greater and urban floods increased in magnitude and frequency. The traditional approach for the drainage systems, which were important as a sanitation measure in the first times of the cities development, conveying stormwaters and wastewaters, turned unsustainable. Flow generation increased and end-of-pipe solutions tended to just transfer problems to downstream. In this context, in the last decades, several approaches were developed, in order to better equate flow patterns in space and time. However, not only the hydraulics aspects are important. Technical measures do not stand alone. The water in the city needs to be considered in an integrated way and sustainable solutions for drainage systems have to account for urban revitalisation and river rehabilitation, better quality of communities' life, participatory processes and institutional arrangements to allow the acceptance, support and

**2. Historical aspects and background of urban floods and drainage solutions**  Several ancient civilisations showed great care when constructing urban drainage systems, combining the objectives of collecting rainwater, preventing nuisance flooding, and conveying wastes. During the Roman Empire Age, significant advances were introduced in urban drainage systems. Concerns on urban flooding mitigation and low lands drainage were very important to the city of Rome, which arose among the hills of Lazio region, on the margins of Tiber River. To meet urban drainage needs, a complex network of open channels and underground pipes were constructed. This system was also used to convey people's

During the Middle Ages, urban centres suffered a great decay and people tended to live in communities sparsely established in rural areas, near rivers, with minor concerns about urban drainage. Sanitation practices have deteriorated after the decline of the Roman Empire and surface drains and streets were used indiscriminately as the only means of disposal and conveyance of all wastewaters (Chocat *et al.*, 2001). Later, when cities started to grow significantly again, in the Industrial Era, urban drainage found itself regretted to a second plane. The industrial city grew with very few guidelines. The Liberalism influenced urban growth and there was a certain lack of control on the public perspective for city development (Benevolo, 2001). Sanitation, then, became a great problem and inadequate waste disposal led to several sort of diseases and deterioration of public health. The role of urban drainage became very important in helping to solve this problem and, more than often, it was important to fast collect, conduct and dispose securely stormwater and wastewater. Focus was driven to improve conveyance and this was the main goal of urban drainage, until some decades ago. However, considering the fast urban growth of the last two centuries, and the fact that the world population profile is changing from rural to urban, it became hard to simply look at urban drainage and propose channel corrections, rectifications and other similar sort of interventions. Canalisation could not answer for all urban flood problems and, in fact, this isolated action, in a local approach, was responsible for transferring problems more than solving them. The increasing flood problems that the cities were forced to face showed the unsustainability of the traditional urban drainage

A sustainable approach for drainage systems became an important challenge to be dealt with. Drainage engineers became aware that the existing infrastructure was overloaded.

continuity of these proposed solutions.

waste from their living areas (Burian and Edwards, 2002).

conception and new solutions started to be researched.

Focus on the consequences of the urbanisation process, that is, the increase of flow generation, which concentrates on storm drains, should be changed. Source control, acting on the causes of flooding and focusing on storage and infiltration measures, emerged as a new option at the end of the 1970s (Andoh & Iwugo, 2002).

An integrated approach, considering the watershed as the planning unit, may be considered the initial basis for a sustainable system design. The design of an urban drainage system integrated with city development, aiming to reduce impacts on the hydrological cycle, acting on infiltration processes and allowing detention on artificial urban reservoirs, joining concerns, restrictions and synergies from Hydraulic Engineering and Urbanism appears as a fundamental option to treat urban floods. Besides the quantity aspects, the water quality became also a main issue and waste waters and solid waste disposal became matters to be treated together. The first flush and the washing of the catchment also introduced a new perception related to the diffuse pollution. At last, and in a complementarily way, rain water harvesting appears as an opportunity to increase water resources availability in urban environments. Several different conceptions have been proposed in the last decades, with some minor differences among them. All of them, however, tend to consider those questions in an integrated way, trying to rescue natural characteristics of the hydrological cycle, while adding value to the city itself.

Coffman et al. (1998) proposed a design concept of Low Impact Development (LID). LID design adopts a set of procedures that try to understand and reproduce hydrological behaviour prior to urbanisation. In this context, the use of functional landscapes appear as useful elements in the urban mesh, in order to allow the recovering of infiltration and detention characteristics of the natural watershed. It is a change in the traditional design concepts, moving towards a site design that mimics natural watershed hydrological functions, involving volume, discharge, recharge and frequency. The main principles of this approach may be briefly described by the following points:


In a similar way, another early trend in the drainage system design evolution involved the use of stormwater Best Management Practices (BMP). The term Best Management Practices is frequently used in the USA and Canada and its origin is related with pollution control in the field of industrial wastewaters. Later, it was also referred as a possibility of nonpoint source pollution control and then associated with stormwater management. This way, stormwater BMPs are supposed to work in a distributed way over the watershed, integrating water quantity and water quality control aiming to mitigate effects generated by land use changes, with optimised costs. BMPs are designed to reduce stormwater volume, peak flows, and nonpoint source pollution through infiltration, filtration, biological or chemical processes, retention, and detention. They also may be classified into structural, when referring to installed devices and engineering solutions, or non-structural, when related to procedures changes, like limitations on landscaping practices (US EPA, 2004).

LID and BMP are very often used together and may complement each other.

Sustainable Drainage Systems: An Integrated Approach,

the regional scale;

landscaping;

initiatives.

that direction.

growth as a result.

**3. Interface between rain waters and the city** 

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 25

the integration of the urban water management from the individual allotment scale to

the integration of sustainable urban water management with building architecture and

the integration of structural and non-structural sustainable urban water management

Integration of urban water uses in different spatial scales, with the involvement of different knowledge areas, encompassing hydraulic engineering, urbanism, architecture, social sciences and economy, trying to preserve natural environment and adding value to the built environment, in a participative framework where communities play an important role, seems to be the main point to characterise the WSUD concept. The institutional

Furthermore, actions on urban rivers revitalisation or, in a more optimistic sense, actions to allow urban rivers rehabilitation, also arise as a new possibility. The river revitalisation usually includes solutions for the built environment, reconnecting it to the city, but not necessarily recovering natural patterns. The concept of river rehabilitation, however, tries to integrate the river hydrology and morphology, the hydraulic risks associated to the flood control, the quality of waters and the ecological state of the river. These are very complex tasks to be dealt in urban environments, due to several constraints accumulated over time. River canalisation, flood plains disconnection, lack of free spaces, combined sewers (or even uncontrolled wastewaters disposal, as it happens frequently in developing countries), social pressures and other questions appear as difficulties in the way of a river rehabilitation. By the way, one possible decision in urban development may be to state a vision for the river and how to integrate it with the built environment and try to do the best possible to walk in

Gusmaroli et al. (2011) propose the adoption of an ecosystem approach, in order to supplement or replace the concept of Waterfront Design. The Waterfront Design mainly aims to recover the relationship between river and city around the line where they meet. Stepping ahead brings the opportunity to propose the river rehabilitation concept from the point of view of an environmental improvement, looking at the city as an organism in constant transformation and, therefore, capable of modelling and adapting itself (even only in part) to the demands of recovering more natural features of the watercourses. In this sense, it is a challenge to find ways to recover more natural rivers and rethink the city's

The urbanisation process changes significantly the natural water balance equilibrium. Vegetation removal and its substitution by impervious surfaces reduces the infiltration possibilities, increasing superficial flow volumes. Besides, natural retention is reduced and the runoff is able to travel faster over regularised urban surfaces. In general terms, even when the urbanisation process is conducted within planning standards, the superficial volumes are greater. If the urbanisation does not account for more sustainable patterns, the

peak flow is much greater than the natural one and the peak time occurs early.

arrangements are key elements here, in order to manage this process

Batista *et al.* (2005), in Brazil, consolidated the concepts of Compensatory Techniques in urban drainage design, which meant the introduction of several different measures, focusing on infiltration and storage capacity, with the aim of compensating urban impacts on the hydrological cycle.

Another possibility of improving urban drainage solutions concerns the Sustainable Urban Drainage System (SUDS) concept. In this case, the ideals of sustainable development are included in the drainage system design process, that is, impacts on the watershed due to drainage solutions may not be transferred in space or time. Moreover, besides contributing to sustainable development, drainage systems can be developed to improve urban design, managing environmental risks and enhancing built environment. SUDS objectives account both for reducing quantity and quality problems and maximising amenities and biodiversity opportunities, which form the three way concept: quantity – quality – amenity & biodiversity. All of them have to be managed collectively and the desired solution appears in the interface of these three objectives (CIRIA, 2007). The philosophy of SUDS, similar to LID, is also to replicate, as well as possible, the natural conditions of pre-development site.

The key elements for a more sustainable drainage system consider to:


The continuous evolution of all these concepts and the seek for new urban drainage system solution led also to the Water Sensitive Urban Design (WSUD) concept, initially developed in Australia.

Wong (2006) states that the definition of WSUD appears to be confusing among practioners because of its wide range of applications. WSUD tries to integrate social and physical sciences in a holistic management proposition for urban waters.

Langenbach et al. (2008) define WSUD as the "interdisciplinary cooperation of water management, urban design and landscape architecture which considers all parts of the urban water cycle, combines water management function and urban design approaches and facilitates synergies for the ecological, economical, social and cultural sustainability."

According to Wong (2006): "WSUD brings 'sensitivity to water' into urban design. The words 'water sensitive' define a new paradigm in integrated urban water cycle management that combines the various disciplines of engineering and environmental sciences associated with the provision of water services, including the protection of aquatic environments in urban areas. Community values and aspirations of urban places necessarily govern urban design decisions and therefore water management practices".

WSUD is centred on integration at a number of levels (*ibid*):

the integrated management of potable water, wastewater and stormwater;

Batista *et al.* (2005), in Brazil, consolidated the concepts of Compensatory Techniques in urban drainage design, which meant the introduction of several different measures, focusing on infiltration and storage capacity, with the aim of compensating urban impacts

Another possibility of improving urban drainage solutions concerns the Sustainable Urban Drainage System (SUDS) concept. In this case, the ideals of sustainable development are included in the drainage system design process, that is, impacts on the watershed due to drainage solutions may not be transferred in space or time. Moreover, besides contributing to sustainable development, drainage systems can be developed to improve urban design, managing environmental risks and enhancing built environment. SUDS objectives account both for reducing quantity and quality problems and maximising amenities and biodiversity opportunities, which form the three way concept: quantity – quality – amenity & biodiversity. All of them have to be managed collectively and the desired solution appears in the interface of these three objectives (CIRIA, 2007). The philosophy of SUDS, similar to LID, is also to replicate, as well as possible, the

on the hydrological cycle.

natural conditions of pre-development site.

protect or enhance water quality;

enhancement;

in Australia.

The key elements for a more sustainable drainage system consider to:

encourage natural groundwater recharge (where appropriate);

enhance amenity and aesthetic value of developed areas;

meet the environmental and the local community needs.

sciences in a holistic management proposition for urban waters.

design decisions and therefore water management practices". WSUD is centred on integration at a number of levels (*ibid*):

manage runoff volumes and rates, reducing the impact of urbanisation on flooding;

provide a habitat for wildlife in urban areas, creating opportunities for biodiversity

The continuous evolution of all these concepts and the seek for new urban drainage system solution led also to the Water Sensitive Urban Design (WSUD) concept, initially developed

Wong (2006) states that the definition of WSUD appears to be confusing among practioners because of its wide range of applications. WSUD tries to integrate social and physical

Langenbach et al. (2008) define WSUD as the "interdisciplinary cooperation of water management, urban design and landscape architecture which considers all parts of the urban water cycle, combines water management function and urban design approaches and

According to Wong (2006): "WSUD brings 'sensitivity to water' into urban design. The words 'water sensitive' define a new paradigm in integrated urban water cycle management that combines the various disciplines of engineering and environmental sciences associated with the provision of water services, including the protection of aquatic environments in urban areas. Community values and aspirations of urban places necessarily govern urban

facilitates synergies for the ecological, economical, social and cultural sustainability."

the integrated management of potable water, wastewater and stormwater;


Integration of urban water uses in different spatial scales, with the involvement of different knowledge areas, encompassing hydraulic engineering, urbanism, architecture, social sciences and economy, trying to preserve natural environment and adding value to the built environment, in a participative framework where communities play an important role, seems to be the main point to characterise the WSUD concept. The institutional arrangements are key elements here, in order to manage this process

Furthermore, actions on urban rivers revitalisation or, in a more optimistic sense, actions to allow urban rivers rehabilitation, also arise as a new possibility. The river revitalisation usually includes solutions for the built environment, reconnecting it to the city, but not necessarily recovering natural patterns. The concept of river rehabilitation, however, tries to integrate the river hydrology and morphology, the hydraulic risks associated to the flood control, the quality of waters and the ecological state of the river. These are very complex tasks to be dealt in urban environments, due to several constraints accumulated over time. River canalisation, flood plains disconnection, lack of free spaces, combined sewers (or even uncontrolled wastewaters disposal, as it happens frequently in developing countries), social pressures and other questions appear as difficulties in the way of a river rehabilitation. By the way, one possible decision in urban development may be to state a vision for the river and how to integrate it with the built environment and try to do the best possible to walk in that direction.

Gusmaroli et al. (2011) propose the adoption of an ecosystem approach, in order to supplement or replace the concept of Waterfront Design. The Waterfront Design mainly aims to recover the relationship between river and city around the line where they meet. Stepping ahead brings the opportunity to propose the river rehabilitation concept from the point of view of an environmental improvement, looking at the city as an organism in constant transformation and, therefore, capable of modelling and adapting itself (even only in part) to the demands of recovering more natural features of the watercourses. In this sense, it is a challenge to find ways to recover more natural rivers and rethink the city's growth as a result.

#### **3. Interface between rain waters and the city**

The urbanisation process changes significantly the natural water balance equilibrium. Vegetation removal and its substitution by impervious surfaces reduces the infiltration possibilities, increasing superficial flow volumes. Besides, natural retention is reduced and the runoff is able to travel faster over regularised urban surfaces. In general terms, even when the urbanisation process is conducted within planning standards, the superficial volumes are greater. If the urbanisation does not account for more sustainable patterns, the peak flow is much greater than the natural one and the peak time occurs early.

Sustainable Drainage Systems: An Integrated Approach,

**4. Urban drainage design** 

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 27

downstream areas. Thus, when these new developments areas start to approximate of the riverine areas and suffer from flooding, new canalisations are settled, and the older downstream areas, where the city centre lies, become flooded again. At the end of this process, the natural storage areas are now occupied, all the catchment is canalised, there are no more flood plains, the channels do not have more discharge capacity, flood is transferred to downstream and large portions of the urban surface are inundated. Besides, the city strangles the drainage system and there are very few possibilities of new canalisation works.

Urban drainage design is a relative simple task, when considering the implementation of a project in a new urban area. Channels and pipes are integrated in order to convey the calculated discharge for the design rainfall. Infiltration measures and/or reservoirs may be predicted aiming to keep the generated discharge under a certain limit, and other sort of controls may be imposed, providing a low impact development. In this case, design is made by sub-catchments that are combined and summed in a certain pre-defined order, composing the urban land contribution to the drainage net, in a sequential calculation process. When a drainage system already exists and fails, however, it may become very difficult to propose adequate corrective interventions for the system rehabilitation without considering its systemic behaviour. The combination of superficial generated flows with drainage net flows may be diverse. Waters spilling out of the storm drain system may flow through streets, in an unpredicted way. The streets convey these flows to downstream reaches of the catchment, re-entering the drainage net without control. Sometimes, this superficial flow may even reach a neighbouring catchment, accessing other pipes not yet drowned. Other times, water may be temporarily stored inside lower open areas, like parks or squares, as well as inside buildings, in an undesired way. Urban flood control is a matter of reorganizing flow patterns in space and time (Canholi, 2005). Combination of effects is a difficult question to be assessed in the scale of a catchment and, sometimes, the proposed solutions may not be effective. In this context, mathematical modelling may be an important

Traditional practices of urban drainage design are based on canalisation works, in order to adapt the system to the generated and concentrated flows. This approach equates the undesirable consequences of the flooding process, which are the greater and faster

The urban drainage system comprises two main subsystems: micro-drainage and macrodrainage. The micro-drainage system is essentially defined by the layout of the streets in urban areas, acting in collecting rainfall from urban surfaces. The macro-drainage is intended to receive and provide the final discharge of the surface runoff brought by the micro-drainage net. Macro-drainage corresponds to the main drainage network, consisting of rivers and complementary works, such as artificial canals, storm drains, dikes and other

In general terms, the urban drainage system design comprises the following steps: subdivision of the area into sub-catchments; design of the network integrating urban

tool to support the design of integrated urban flood control projects.

**4.1 Urban drainage traditional design** 

constructed structures.

discharges produced by the built environment.

Uncontrolled urban development, especially in developing countries, where later industrialisation led to a very fast process of city growing, frequently faces the occupation of the natural flood plains and even of the river banks, as it can be illustrated by figure 1. This fact worsens even more the problem of urban floods, because the space needed for flood overbank flows is now occupied by houses, streets and amenities. In this situation, floods tend to spread for larger areas, trying to find room, while affecting urban life in several aspects (sanitation, health, traffic, housing,…) and producing great losses. Once the flood space become limited by urbanisation, the flowing waters try to find other paths, inundating areas not subjected to floods before.

Fig. 1. Riverbanks occupation in the metropolitan area of Rio de Janeiro City, Brazil (Photo Miguez, 2010).

Usually, after the first impacts of urban development, changing urban land use and producing the first floods, the drainage canalisation appears as one of the most frequent consequences, both in the allotment level, with the micro-drainage systems, and in the catchment level, with the major works of macro-drainage canalisation. Canalisation works are frequently related to roads and regular grids of the cities. Canalisation, however, as discussed in the previous topic, tends to solve floods locally, with a partial vision of the problem.

In general terms, the occupation process of a watershed normally starts downstream, at the lower and flat areas. The imperviousness effects and the urbanisation towards riverine areas lead to the first canalisation works as a solution for flood control and urban design in these areas, aggravating floods on the basin outfall. With the continuity of the urbanisation process, the upstream areas start to be also occupied, repeating the formulas of the downstream areas. Thus, when these new developments areas start to approximate of the riverine areas and suffer from flooding, new canalisations are settled, and the older downstream areas, where the city centre lies, become flooded again. At the end of this process, the natural storage areas are now occupied, all the catchment is canalised, there are no more flood plains, the channels do not have more discharge capacity, flood is transferred to downstream and large portions of the urban surface are inundated. Besides, the city strangles the drainage system and there are very few possibilities of new canalisation works.

### **4. Urban drainage design**

26 Drainage Systems

Uncontrolled urban development, especially in developing countries, where later industrialisation led to a very fast process of city growing, frequently faces the occupation of the natural flood plains and even of the river banks, as it can be illustrated by figure 1. This fact worsens even more the problem of urban floods, because the space needed for flood overbank flows is now occupied by houses, streets and amenities. In this situation, floods tend to spread for larger areas, trying to find room, while affecting urban life in several aspects (sanitation, health, traffic, housing,…) and producing great losses. Once the flood space become limited by urbanisation, the flowing waters try to find other paths, inundating

Fig. 1. Riverbanks occupation in the metropolitan area of Rio de Janeiro City, Brazil (Photo

Usually, after the first impacts of urban development, changing urban land use and producing the first floods, the drainage canalisation appears as one of the most frequent consequences, both in the allotment level, with the micro-drainage systems, and in the catchment level, with the major works of macro-drainage canalisation. Canalisation works are frequently related to roads and regular grids of the cities. Canalisation, however, as discussed in the previous topic, tends to solve floods locally, with a partial vision of the

In general terms, the occupation process of a watershed normally starts downstream, at the lower and flat areas. The imperviousness effects and the urbanisation towards riverine areas lead to the first canalisation works as a solution for flood control and urban design in these areas, aggravating floods on the basin outfall. With the continuity of the urbanisation process, the upstream areas start to be also occupied, repeating the formulas of the

areas not subjected to floods before.

Miguez, 2010).

problem.

Urban drainage design is a relative simple task, when considering the implementation of a project in a new urban area. Channels and pipes are integrated in order to convey the calculated discharge for the design rainfall. Infiltration measures and/or reservoirs may be predicted aiming to keep the generated discharge under a certain limit, and other sort of controls may be imposed, providing a low impact development. In this case, design is made by sub-catchments that are combined and summed in a certain pre-defined order, composing the urban land contribution to the drainage net, in a sequential calculation process. When a drainage system already exists and fails, however, it may become very difficult to propose adequate corrective interventions for the system rehabilitation without considering its systemic behaviour. The combination of superficial generated flows with drainage net flows may be diverse. Waters spilling out of the storm drain system may flow through streets, in an unpredicted way. The streets convey these flows to downstream reaches of the catchment, re-entering the drainage net without control. Sometimes, this superficial flow may even reach a neighbouring catchment, accessing other pipes not yet drowned. Other times, water may be temporarily stored inside lower open areas, like parks or squares, as well as inside buildings, in an undesired way. Urban flood control is a matter of reorganizing flow patterns in space and time (Canholi, 2005). Combination of effects is a difficult question to be assessed in the scale of a catchment and, sometimes, the proposed solutions may not be effective. In this context, mathematical modelling may be an important tool to support the design of integrated urban flood control projects.

#### **4.1 Urban drainage traditional design**

Traditional practices of urban drainage design are based on canalisation works, in order to adapt the system to the generated and concentrated flows. This approach equates the undesirable consequences of the flooding process, which are the greater and faster discharges produced by the built environment.

The urban drainage system comprises two main subsystems: micro-drainage and macrodrainage. The micro-drainage system is essentially defined by the layout of the streets in urban areas, acting in collecting rainfall from urban surfaces. The macro-drainage is intended to receive and provide the final discharge of the surface runoff brought by the micro-drainage net. Macro-drainage corresponds to the main drainage network, consisting of rivers and complementary works, such as artificial canals, storm drains, dikes and other constructed structures.

In general terms, the urban drainage system design comprises the following steps: subdivision of the area into sub-catchments; design of the network integrating urban

Sustainable Drainage Systems: An Integrated Approach,

well as optimising the available resources for public investments.

and adaptations in the course of urban development (Canholi, 2005).

thought in order to minimise impacts over the natural hydrological cycle.

**4.2 Urban drainage design trends** 

*measures*.

with floods.

minor costs.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 29

The traditional approach for drainage system design is being supplemented or replaced by newer concepts that seek for systemic solutions, with distributed actions over the catchment, trying to recover flow patterns similar to those that happened prior to urbanisation. Storage and infiltration measures are considered together in integrated layout solutions. Moreover, these new trends add concerns of water quality control, as well as enhance rainwater as a resource to be exploited in an integrated approach for sustainable management of urban stormwaters. Besides, the possibility of combining flood control measures with urban landscape interventions, capable to add value to urban spaces, with multiple functions, is becoming an interesting option from the point of view of revitalising degraded areas, as

The vision of integrating urban drainage projects with urban development plans and land use and occupation management, provides a better temporal and spatial range of action for flood control projects, as it seeks to intervene not on the consequence of heavy rains, but on the inundation causes. The changing to a point of view of more sustainable solutions on urban drainage requires a commitment with the future consequences concerning the decisions taken today; so solutions must be flexible enough to allow possible modifications

In urban drainage, sustainability implies that urban floods may not be transferred in space or time. Urban drainage systems have to be planned in an integrated way with urban growth and drainage solutions should be integrated with urban landscape (Miguez et al., 2007). In this context, urbanisation process and urban land use control have both to be

This discussion leads to an important point: the understanding on how urbanisation interferes with flow patterns is necessary to develop strategies for stormwater management and urban floods control, by one side, and to establish urban development standards on the other side. Urban drainage planning must consider a broad set of aspects and has to be integrated with land use policy, city planning, building code and all the related legislation. It is possible to say that urban flood control demands the adoption of a varied set of different measures and concepts. Among these measures it is possible to distinguish two greater groups of possible interventions: the *structural measures* and the *non-structural* 

*Structural measures* introduce physical modifications on the drainage net and over urban catchment landscapes, like canalisation, dams, reservoirs, urban flood parks, dykes, among others, intending to change the relations between rainfall and runoff and to reorganise flow patterns. *Non-structural measures* work with environmental education, flood mapping, urbanisation and drainage planning for lower development impacts, warning systems, flood proofing constructions, and other actions intending to allow a more harmonic coexistence

*Structural measures* are fundamental when flood problems are installed, in order to bring the situation back to a controlled one. *Non-structural measures* are always important, but are of greater relevance when planning future scenarios, in order to obtain better results, with

patterns and natural flows; definition of the design rainfall, considering a certain time of recurrence and a critical time of duration, associated with the concentration time of each sub-catchment considered; step by step calculation of design discharges for each drainage network reach through the Rational Method or another convenient hydrological method; hydraulic design of each drainage network reach. Figure 2 illustrates this approach.

Fig. 2. Schematic urban drainage system classic design.

This approach greatly simplifies the real situation and focus only in conveying discharges. Although it may be useful in certain design situations, spatial and temporal effects combination are main factors to be considered when urban floods occur. It is important to have the assistance of a mathematical model as an assessment tool and solutions should be addressed to the catchment as a whole.

#### **4.2 Urban drainage design trends**

28 Drainage Systems

patterns and natural flows; definition of the design rainfall, considering a certain time of recurrence and a critical time of duration, associated with the concentration time of each sub-catchment considered; step by step calculation of design discharges for each drainage network reach through the Rational Method or another convenient hydrological method;

Local topography Subdivision of the quarters into

+

A Q = Discharge <sup>1</sup>

This approach greatly simplifies the real situation and focus only in conveying discharges. Although it may be useful in certain design situations, spatial and temporal effects combination are main factors to be considered when urban floods occur. It is important to have the assistance of a mathematical model as an assessment tool and solutions should be

Mh<sup>1</sup> Mh<sup>2</sup> Mh<sup>3</sup>

A2 A3

Q<sup>1</sup> Q1+Q<sup>2</sup>

Fig. 2. Schematic urban drainage system classic design.

addressed to the catchment as a whole.

contributing areas

Mh = Manholes

= Gully = Gutter

A = Contributing drainage áreas

hydraulic design of each drainage network reach. Figure 2 illustrates this approach.

The traditional approach for drainage system design is being supplemented or replaced by newer concepts that seek for systemic solutions, with distributed actions over the catchment, trying to recover flow patterns similar to those that happened prior to urbanisation. Storage and infiltration measures are considered together in integrated layout solutions. Moreover, these new trends add concerns of water quality control, as well as enhance rainwater as a resource to be exploited in an integrated approach for sustainable management of urban stormwaters. Besides, the possibility of combining flood control measures with urban landscape interventions, capable to add value to urban spaces, with multiple functions, is becoming an interesting option from the point of view of revitalising degraded areas, as well as optimising the available resources for public investments.

The vision of integrating urban drainage projects with urban development plans and land use and occupation management, provides a better temporal and spatial range of action for flood control projects, as it seeks to intervene not on the consequence of heavy rains, but on the inundation causes. The changing to a point of view of more sustainable solutions on urban drainage requires a commitment with the future consequences concerning the decisions taken today; so solutions must be flexible enough to allow possible modifications and adaptations in the course of urban development (Canholi, 2005).

In urban drainage, sustainability implies that urban floods may not be transferred in space or time. Urban drainage systems have to be planned in an integrated way with urban growth and drainage solutions should be integrated with urban landscape (Miguez et al., 2007). In this context, urbanisation process and urban land use control have both to be thought in order to minimise impacts over the natural hydrological cycle.

This discussion leads to an important point: the understanding on how urbanisation interferes with flow patterns is necessary to develop strategies for stormwater management and urban floods control, by one side, and to establish urban development standards on the other side. Urban drainage planning must consider a broad set of aspects and has to be integrated with land use policy, city planning, building code and all the related legislation. It is possible to say that urban flood control demands the adoption of a varied set of different measures and concepts. Among these measures it is possible to distinguish two greater groups of possible interventions: the *structural measures* and the *non-structural measures*.

*Structural measures* introduce physical modifications on the drainage net and over urban catchment landscapes, like canalisation, dams, reservoirs, urban flood parks, dykes, among others, intending to change the relations between rainfall and runoff and to reorganise flow patterns. *Non-structural measures* work with environmental education, flood mapping, urbanisation and drainage planning for lower development impacts, warning systems, flood proofing constructions, and other actions intending to allow a more harmonic coexistence with floods.

*Structural measures* are fundamental when flood problems are installed, in order to bring the situation back to a controlled one. *Non-structural measures* are always important, but are of greater relevance when planning future scenarios, in order to obtain better results, with minor costs.

Sustainable Drainage Systems: An Integrated Approach,

devices, where they can act in squares or even inside the lots.

Fig. 4. A detention pond in Santiago, Chile (Photo Miguez, 2009).

Lagord, aiming for the treatment of rainwater.

Another possibility for stormwater storage measures may be the use of reservoirs that have the goal of improving water quality. These structures are the *retention ponds* and the *constructed wetlands*. It should be noted that the main objective of these measures is the treatment of rainwater, remaining smaller its quantitative effects. This is due, in part, by the need to provide a permanent pool and also a greater time of permanence of the water inside the reservoirs, to enable the treatment processes with the required efficiency. Figure 5 presents a picture of a *retention pond,* constructed in the city of Lagord, France. This pond is part of a drainage plan of the whole region of La Rochelle, which includes the city of

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 31

Canalisation is, undoubtedly, the more traditional measure adopted in flood control interventions. Its main objective is to improve the hydraulic discharge capacity of the macro drainage network, through the removal of obstructions to the flow on the main channels, the river channel rectification and the revetment of the riverbanks. Another traditional measure widely used to contain river overflow is the implementation of dykes associated with polders, especially in low areas of the catchment, which allow the protection of the urbanised plains. The protected areas, which remain unable to drain the precipitated water over its own local catchment during the river flood events, are generally linked to the main water body by one-way gates (FLAP gates) or by pumping stations. Thus, it is necessary to preserve unoccupied areas inside the polder to receive and temporarily store these waters. Another set of measures, as an alternative to the simple improving conveyance, proposes to act with the possibilities of storage and infiltration. Important examples of this set of measures are the *detention ponds*. These measures used to be generally designed at the upstream reaches of the most urbanised regions, where the occupation still is sparser and where there are available areas for the implementation of the ponds. In situations where the urbanisation occupies every available space, the detention ponds have been adapted to other scales, allowing the use of public spaces such as parks, parking lots and squares, in order to temporarily store the rainwater from less frequent events and also add value to the urban environment and region, as can be seen in Figure 4, showing a detention pond implemented in Santiago (Chile), which is associated with a landscaping design. The use of this kind of structure has a very wide spectrum, and it may be used through the implementation of large ponds, or by the distribution over the watershed of several of these

Under this new perspective, the urban drainage projects, in theory and whenever possible, should neutralize the effects of the urbanisation, restoring the hydrological conditions of the pre-urbanisation, bringing benefits to the quality of life of the population and aiming the environmental preservation.

#### **4.2.1 Structural measures**

Structural measures can be classified according to their performance in the catchment. According to Tucci (1995), they can be divided in *distributed measures*, *measures in the micro drainage* and *measures in the macro drainage*, as detailed below and exemplified in Figure 3.


Fig. 3. Examples of flood control measures according to their working principle: 1. Distributed Measures; 2. Measures in the micro drainage; 3. Measures in the macro drainage (Rezende, 2010).

Under this new perspective, the urban drainage projects, in theory and whenever possible, should neutralize the effects of the urbanisation, restoring the hydrological conditions of the pre-urbanisation, bringing benefits to the quality of life of the population and aiming the

Structural measures can be classified according to their performance in the catchment. According to Tucci (1995), they can be divided in *distributed measures*, *measures in the micro drainage* and *measures in the macro drainage*, as detailed below and exemplified in Figure 3.

*Distributed Measures*: these measures act on the lot, squares and sidewalks. They are also

*Measures in the micro drainage*: these measures act on the resulting hydrograph from one

*Measures in the macro drainage*: these measures act on the rivers and channels.

**4 – Sem controle** 

Traditional drainage –

**Lotes Casas Microdrenagem** 

Fig. 3. Examples of flood control measures according to their working principle: 1. Distributed Measures; 2. Measures in the micro drainage; 3. Measures in the macro

Lot Building Micro drainage

RIVER Detention pond Square detention

**3.1 - Canalização** 

Canalisation

Rio ou canal

**3.2 – Reservatório de Detenção** 

Reservoir

**2.1 – Bacia de detenção 2.2 – Reservatório em praça** 

environmental preservation.

**4.2.1 Structural measures** 

or more lots.

**1 – Reservatórios de lote** 

**LEGENDA**

drainage (Rezende, 2010).

known as source control measures.

On-site detention without control

Canalisation is, undoubtedly, the more traditional measure adopted in flood control interventions. Its main objective is to improve the hydraulic discharge capacity of the macro drainage network, through the removal of obstructions to the flow on the main channels, the river channel rectification and the revetment of the riverbanks. Another traditional measure widely used to contain river overflow is the implementation of dykes associated with polders, especially in low areas of the catchment, which allow the protection of the urbanised plains. The protected areas, which remain unable to drain the precipitated water over its own local catchment during the river flood events, are generally linked to the main water body by one-way gates (FLAP gates) or by pumping stations. Thus, it is necessary to preserve unoccupied areas inside the polder to receive and temporarily store these waters.

Another set of measures, as an alternative to the simple improving conveyance, proposes to act with the possibilities of storage and infiltration. Important examples of this set of measures are the *detention ponds*. These measures used to be generally designed at the upstream reaches of the most urbanised regions, where the occupation still is sparser and where there are available areas for the implementation of the ponds. In situations where the urbanisation occupies every available space, the detention ponds have been adapted to other scales, allowing the use of public spaces such as parks, parking lots and squares, in order to temporarily store the rainwater from less frequent events and also add value to the urban environment and region, as can be seen in Figure 4, showing a detention pond implemented in Santiago (Chile), which is associated with a landscaping design. The use of this kind of structure has a very wide spectrum, and it may be used through the implementation of large ponds, or by the distribution over the watershed of several of these devices, where they can act in squares or even inside the lots.

Fig. 4. A detention pond in Santiago, Chile (Photo Miguez, 2009).

Another possibility for stormwater storage measures may be the use of reservoirs that have the goal of improving water quality. These structures are the *retention ponds* and the *constructed wetlands*. It should be noted that the main objective of these measures is the treatment of rainwater, remaining smaller its quantitative effects. This is due, in part, by the need to provide a permanent pool and also a greater time of permanence of the water inside the reservoirs, to enable the treatment processes with the required efficiency. Figure 5 presents a picture of a *retention pond,* constructed in the city of Lagord, France. This pond is part of a drainage plan of the whole region of La Rochelle, which includes the city of Lagord, aiming for the treatment of rainwater.

Sustainable Drainage Systems: An Integrated Approach,

**5. Sustainable urban drainage systems concepts** 

installation of alerts in the area.

Master Plan.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 33

structure, relocation of structures out of the flooding area, use of water resistant material in new structures, regulation of the occupation of the flooding areas, control of new community settlements, regulation of parcelling and building codes, purchase of flood hazard areas, flood insurance, implementation of forecasting and flood warning systems with evacuation plan, adoption of tax incentives for a prudent use of the flood area, and

The urban drainage system needs to be viewed in an integrated way in the context of the sustainable urban development. It is crucial to understand the crossed relationships between urban growing and flood problems. The aspects involved vary from environmental conservation, land use control, low impact development, and healthy city life. To achieve these goals, related to a sustainable urban drainage, however, it is necessary to construct a framework integrating legal, institutional, social, technical and economical aspects. In this context, it is important to clearly identify the applied regulation in terms of urban zoning and land use control, the water resources policies and the water resources management practices, the integrated environmental sanitation opportunities and constraints, the building standards and limitations, the role of the institutional agents and community participation. Areas to be protected from urban growth need to be delimited, as well as, sometimes, it will be important to recover areas already occupied. This is not simple, due to social pressures against possible dwelling relocation procedures. In developing countries, for example, it is common to have "informal" cities, conforming slum areas growing on risky situation, along riverine areas or hill slopes. Landscape changing should be minimised and original river characteristics could be recovered. In this context, preventing urban land to be heavily impervious is one of the major goals. Minimising impacts on the urban water cycle is of fundamental importance. The development project must comply with natural hydrological aspects or provide compensatory measures for urbanisation changes. The watershed, as a complex and integrated system has to be considered as a whole, not only in physical terms. This must be the unit of planning and design. The documents that integrate urban development and the strategies for a sustainable drainage system, and, therefore, a sustainable city, are the Urban Development Master Plan and The Urban Stormwaters

The non-existence or non-fulfilment of plans for urban development leads to drainage and flood control projects that are restricted to emergency, reactive, and sporadic actions,

This scenario, usually based on the simple and quick removal of water from highly impervious areas by means of canalisations, has become unsustainable and requires a new vision into the problem of urban flooding. Holz & Tassi (2007) suggested that the current drainage system should dismiss the solution of simple removal, as fast as possible, of the non-infiltrated stormwaters that come from the increasing in soil imperviousness, replacing it with measures aiming to mitigate the impacts of this process by facilitating the infiltration and water retention in order to regenerate the hydrological conditions of pre-urbanisation. They emphasize, however, the importance of combining the use of traditional and unconventional drainage structures in order to optimise the system. The fall of the old paradigm should not be simply substituted by a new one. The traditional techniques have to

defined just after the occurrence of disasters (Pompêo, 2000).

Fig. 5. A retention pond in Lagord, France (Photo Rezende, 2009).

Measures that aim to favour infiltration processes of the rainwater in the ground, allowing the partial recovery of the natural hydrology of the watershed, are also interesting options in the context of flood control. They may assume different configurations, according to its operation.

An important measure in this context, also because its environmental implications, may be the *reforestation* of degraded areas, such as hill slopes and riverbanks that have been illegally occupied. Miguez & Magalhães (2010) indicate that reforestation prevents soil erosion, preserves the superficial soil layer and promotes the infiltration and, thus, the volume of runoff is reduced, allowing the correct functioning of drainage structures, since smaller amounts of water and sediments reach the system.

#### **4.2.2 Non-structural measures**

Structural interventions for flood control do not provide a complete risk protection for the design areas. These areas may be still subjected to flood events with a magnitude greater than that of the protection designed level. So, measures that aim to prevent the population from these risks and help them to deal with flooding are necessary. Unlike the structural measures, which act physically changing flow relations, the non-structural measures goal is to reduce the exposure of lives and properties to flooding. A wide range of possible actions, from urban planning and flooding zoning until individual flood-proof constructions, compose this set of measures.

Johnson (1978) identified the following non-structural measures: installation of temporary or permanent sealing in the opening parts of the buildings, elevation of pre-existing structures, construction of new elevated structures, construction of small walls or dykes surrounding the structure, relocation or protection of goods that could be damaged within the existing structure, relocation of structures out of the flooding area, use of water resistant material in new structures, regulation of the occupation of the flooding areas, control of new community settlements, regulation of parcelling and building codes, purchase of flood hazard areas, flood insurance, implementation of forecasting and flood warning systems with evacuation plan, adoption of tax incentives for a prudent use of the flood area, and installation of alerts in the area.

#### **5. Sustainable urban drainage systems concepts**

32 Drainage Systems

Measures that aim to favour infiltration processes of the rainwater in the ground, allowing the partial recovery of the natural hydrology of the watershed, are also interesting options in the context of flood control. They may assume different configurations, according to its

An important measure in this context, also because its environmental implications, may be the *reforestation* of degraded areas, such as hill slopes and riverbanks that have been illegally occupied. Miguez & Magalhães (2010) indicate that reforestation prevents soil erosion, preserves the superficial soil layer and promotes the infiltration and, thus, the volume of runoff is reduced, allowing the correct functioning of drainage structures, since smaller

Structural interventions for flood control do not provide a complete risk protection for the design areas. These areas may be still subjected to flood events with a magnitude greater than that of the protection designed level. So, measures that aim to prevent the population from these risks and help them to deal with flooding are necessary. Unlike the structural measures, which act physically changing flow relations, the non-structural measures goal is to reduce the exposure of lives and properties to flooding. A wide range of possible actions, from urban planning and flooding zoning until individual flood-proof constructions,

Johnson (1978) identified the following non-structural measures: installation of temporary or permanent sealing in the opening parts of the buildings, elevation of pre-existing structures, construction of new elevated structures, construction of small walls or dykes surrounding the structure, relocation or protection of goods that could be damaged within the existing

Fig. 5. A retention pond in Lagord, France (Photo Rezende, 2009).

amounts of water and sediments reach the system.

**4.2.2 Non-structural measures** 

compose this set of measures.

operation.

The urban drainage system needs to be viewed in an integrated way in the context of the sustainable urban development. It is crucial to understand the crossed relationships between urban growing and flood problems. The aspects involved vary from environmental conservation, land use control, low impact development, and healthy city life. To achieve these goals, related to a sustainable urban drainage, however, it is necessary to construct a framework integrating legal, institutional, social, technical and economical aspects. In this context, it is important to clearly identify the applied regulation in terms of urban zoning and land use control, the water resources policies and the water resources management practices, the integrated environmental sanitation opportunities and constraints, the building standards and limitations, the role of the institutional agents and community participation. Areas to be protected from urban growth need to be delimited, as well as, sometimes, it will be important to recover areas already occupied. This is not simple, due to social pressures against possible dwelling relocation procedures. In developing countries, for example, it is common to have "informal" cities, conforming slum areas growing on risky situation, along riverine areas or hill slopes. Landscape changing should be minimised and original river characteristics could be recovered. In this context, preventing urban land to be heavily impervious is one of the major goals. Minimising impacts on the urban water cycle is of fundamental importance. The development project must comply with natural hydrological aspects or provide compensatory measures for urbanisation changes. The watershed, as a complex and integrated system has to be considered as a whole, not only in physical terms. This must be the unit of planning and design. The documents that integrate urban development and the strategies for a sustainable drainage system, and, therefore, a sustainable city, are the Urban Development Master Plan and The Urban Stormwaters Master Plan.

The non-existence or non-fulfilment of plans for urban development leads to drainage and flood control projects that are restricted to emergency, reactive, and sporadic actions, defined just after the occurrence of disasters (Pompêo, 2000).

This scenario, usually based on the simple and quick removal of water from highly impervious areas by means of canalisations, has become unsustainable and requires a new vision into the problem of urban flooding. Holz & Tassi (2007) suggested that the current drainage system should dismiss the solution of simple removal, as fast as possible, of the non-infiltrated stormwaters that come from the increasing in soil imperviousness, replacing it with measures aiming to mitigate the impacts of this process by facilitating the infiltration and water retention in order to regenerate the hydrological conditions of pre-urbanisation. They emphasize, however, the importance of combining the use of traditional and unconventional drainage structures in order to optimise the system. The fall of the old paradigm should not be simply substituted by a new one. The traditional techniques have to

Sustainable Drainage Systems: An Integrated Approach,

its potential uses.

should be ensured.

(Ministério das Cidades, 2004):

of the urban occupation.

local River Basin Committee, if any.

(Ministério das Cidades, 2004):

urbanisation.

services.

Reduce the damage caused by floods.

economic, social and environmental principles.

Regulate the occupation of areas at risk of flooding.

Format an investment program of short, medium and long term.

river network sustainable management.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 35

the solution of rainstorm problems can no longer be regarded as a simple technical service supported only by the Drainage Department, because these waters now represent an important positive resource to the population, inserted in the urban environment. It's important to emphasize the value of water in the city as a demanded resource, not wasting

The failure to consider the drainage in the urban development plans may result in more expensive solutions for flood control, often noneconomical. The successful implementation of a Sustainable Drainage System depends on the cooperation among the different technical departments responsible for urban planning and the active participation of the population. In this context, the existence of compatibility among the Urban Development Sanitation, Solid Waste and Urban Drainage Master Plans, aiming the integrated planning of the city

The design of the Urban Stormwater Management currently presents, according to Righetto et al. (2009), the aggregation of a structural and non-structural set of actions and solutions,

The Stormwater Management Plan of the City must necessarily meet the principles of Sustainable Management of Urban Stormwater, and should seek the following objectives

Improve the health of the population and of the urban environment, within the

Plan the urban management mechanisms for the stormwaters and the municipality

Plan the distribution of stormwaters in time and space, based on the trend of evolution

Partially restore the natural hydrological cycle, reducing or mitigating the impacts of

The drainage projects proposed by the plan should provide the most cost-effective relation, covering social and economic aspects, as well as being integrated into the guidelines of the

The plan must also contemplate a socio-environmental work, through the development of a project that addresses social mobilization, communication, training of educators / agents in the area of environmental sanitation and other environmental education activities, aiming a social-economic and environmental sustainability, including the community participation in the phases of design, implementation, evaluation and use of the proposed works and

The premises to be considered in the creation of the Stormwater Management Plan are

Interdisciplinary approach in diagnosing and solving the problems of flooding.

involving large and small works and planning and management of the urban space.

be adapted to a new use, adding the accumulated knowledge to the sustainable solution. Pompêo (2000) emphasizes the need to think the activities related to mitigation of floods in a preventively way, highlighting the value of planning applied to flood control projects. In this context it is introduced the ecosystem approach, which represents the evolution of the reactive thought of the conventional Drainage Master Plan for a proactive and advanced thought in the form of management of the natural and built environment, considering them as interdependent and integrated components. An ecosystem approach can result in lower costs, since it seeks to reduce the need for costly and complex actions of remediation, emphasizing the orientation and planning decisions on land use changes. This option tends also to reduce costs of maintenance over time, because more natural arrangements tend to work by themselves.

This new vision has been based on the concept of Sustainable Development. It's possible to affirm that these systems are designed to both manage the environmental risks of urban stormwater and contribute, whenever possible, to an improved environment and quality of urban life.

Sustainable drainage projects aim to reduce runoff through rainwater control structures in small units. This way, the runoff control performed on source reduces the need for large structures of mitigation and control on the river channels.

Environmental issues presented today to the cities highlight the failure of technical solutions for urban drainage projects, demanding a new approach which should focus on the problem of urban flooding by incorporating the social dynamics and the multisectoral planning in the search of solutions (Pompêo, 1999).

The urban infrastructure systems are interdependent and the fact of not considering the effects of one system over another, or of a system over the urban environment, can reduce the efficiency of these systems or even turn not viable their operation, as is the case of the relations between Drainage and Flood Control systems and Water and Sanitation, Solid Waste, Land Use and Housing systems. Two trivial examples in peripheral countries are the failure of the drainage system operation by the inefficiency or lack of management of municipal solid waste; or the deterioration of health by the inefficient sanitation conditions which, combined with flood events, provide the proliferation of water related diseases.

Problems associated with urban drainage systems are not exclusively technical, but primarily of institutional nature, such as the lack of cooperation between the different departments responsible for urban management and the communication between the city and its citizens (Stahre, 2005). The lack of cooperation between departments may arise from conflicting interests and priorities.

According to Stahre (2005), the Drainage Department of Malmo, Sweden, sees the approach of the sustainable drainage system as an ideal way to achieve its goals and objectives with a low cost, if compared to the traditional drainage system, whereas the Department of Parks and Recreation sees the sustainable drainage solutions as a good ally for the development and improvement of quality of life in the urban environment by increasing the value of urban parks. As a consequence of this sharing of interests, the costs of structures, deployment and maintenance can be divided between the two departments, and also with others that will share the benefits of implementing this system. Stahre (2005) concluded that the solution of rainstorm problems can no longer be regarded as a simple technical service supported only by the Drainage Department, because these waters now represent an important positive resource to the population, inserted in the urban environment. It's important to emphasize the value of water in the city as a demanded resource, not wasting its potential uses.

The failure to consider the drainage in the urban development plans may result in more expensive solutions for flood control, often noneconomical. The successful implementation of a Sustainable Drainage System depends on the cooperation among the different technical departments responsible for urban planning and the active participation of the population.

In this context, the existence of compatibility among the Urban Development Sanitation, Solid Waste and Urban Drainage Master Plans, aiming the integrated planning of the city should be ensured.

The design of the Urban Stormwater Management currently presents, according to Righetto et al. (2009), the aggregation of a structural and non-structural set of actions and solutions, involving large and small works and planning and management of the urban space.

The Stormwater Management Plan of the City must necessarily meet the principles of Sustainable Management of Urban Stormwater, and should seek the following objectives (Ministério das Cidades, 2004):

Reduce the damage caused by floods.

34 Drainage Systems

be adapted to a new use, adding the accumulated knowledge to the sustainable solution. Pompêo (2000) emphasizes the need to think the activities related to mitigation of floods in a preventively way, highlighting the value of planning applied to flood control projects. In this context it is introduced the ecosystem approach, which represents the evolution of the reactive thought of the conventional Drainage Master Plan for a proactive and advanced thought in the form of management of the natural and built environment, considering them as interdependent and integrated components. An ecosystem approach can result in lower costs, since it seeks to reduce the need for costly and complex actions of remediation, emphasizing the orientation and planning decisions on land use changes. This option tends also to reduce costs of maintenance over time, because more natural arrangements tend to

This new vision has been based on the concept of Sustainable Development. It's possible to affirm that these systems are designed to both manage the environmental risks of urban stormwater and contribute, whenever possible, to an improved environment and quality of

Sustainable drainage projects aim to reduce runoff through rainwater control structures in small units. This way, the runoff control performed on source reduces the need for large

Environmental issues presented today to the cities highlight the failure of technical solutions for urban drainage projects, demanding a new approach which should focus on the problem of urban flooding by incorporating the social dynamics and the multisectoral

The urban infrastructure systems are interdependent and the fact of not considering the effects of one system over another, or of a system over the urban environment, can reduce the efficiency of these systems or even turn not viable their operation, as is the case of the relations between Drainage and Flood Control systems and Water and Sanitation, Solid Waste, Land Use and Housing systems. Two trivial examples in peripheral countries are the failure of the drainage system operation by the inefficiency or lack of management of municipal solid waste; or the deterioration of health by the inefficient sanitation conditions which, combined with flood events, provide the proliferation of water related diseases.

Problems associated with urban drainage systems are not exclusively technical, but primarily of institutional nature, such as the lack of cooperation between the different departments responsible for urban management and the communication between the city and its citizens (Stahre, 2005). The lack of cooperation between departments may arise from

According to Stahre (2005), the Drainage Department of Malmo, Sweden, sees the approach of the sustainable drainage system as an ideal way to achieve its goals and objectives with a low cost, if compared to the traditional drainage system, whereas the Department of Parks and Recreation sees the sustainable drainage solutions as a good ally for the development and improvement of quality of life in the urban environment by increasing the value of urban parks. As a consequence of this sharing of interests, the costs of structures, deployment and maintenance can be divided between the two departments, and also with others that will share the benefits of implementing this system. Stahre (2005) concluded that

structures of mitigation and control on the river channels.

planning in the search of solutions (Pompêo, 1999).

conflicting interests and priorities.

work by themselves.

urban life.


The drainage projects proposed by the plan should provide the most cost-effective relation, covering social and economic aspects, as well as being integrated into the guidelines of the local River Basin Committee, if any.

The plan must also contemplate a socio-environmental work, through the development of a project that addresses social mobilization, communication, training of educators / agents in the area of environmental sanitation and other environmental education activities, aiming a social-economic and environmental sustainability, including the community participation in the phases of design, implementation, evaluation and use of the proposed works and services.

The premises to be considered in the creation of the Stormwater Management Plan are (Ministério das Cidades, 2004):

Interdisciplinary approach in diagnosing and solving the problems of flooding.

Sustainable Drainage Systems: An Integrated Approach,

rescue superficial retentions, with the use of reservoirs.

evolution may and should be developed.

**experiences management** 

River Revitalisation as one of the tools aligned with this major objective.

is included as an introduction to this section, in the following lines.

environment must be found.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 37

way for urban areas and a consensus solution between the natural landscape and the built

In highly urbanised regions, generally the available areas for interventions are scarce, there are numerous socio-economic problems, which make the revitalisation process very complex, because it involves the need of large riparian areas, in order to find space for the river recover its natural course and flooding areas. However, even if these riparian areas were restored to the original natural condition, the heavy modifications that the catchment suffered over the time would probably lead to floods still happening. Thus, the space that would be required to recover the river course functions today is greater than the natural one. Actions in the basin have to be considered, to decrease the imperviousness and to

Urban water courses restoration is a challenge for managers, researchers, experts and citizens. In urban environments, the main focus must be on the restoration of the lateral connectivity with the river banks and its tributaries, the restoration of the river natural flow regime, as well as the increase of the degree of freedom of the river. The combination of flood risk management concepts with River Revitalisation measures can be a solution of efficient applicability in urban rivers, in comparison with traditional and localised drainage solutions (Jormola, 2008). Thus, what is expected is the creation of a self-sustainable natural river system, in order to maintain the flood control function after the flow patterns restoration. In this context, a sustainable approach for drainage system should consider

However, it's important to note that, even when the adopted measures configure only a partial revitalisation, they are important. In addition to reducing the peak flood, they help in the dissemination of this kind of techniques and provide a new perception about the existence of the river for the involved community. They also allow the river valuing and reintegration as part of urban landscape. Finally, it should be pointed out that any process of revitalisation takes time to be fully developed and find it complete. It is necessary to await the responses of the environment, regarding the "new" conditions to which it was submitted. During this time, complementary actions, resulting from the monitoring of this

**7. Institutional aspects supporting the integration of a sustainable urban drainage system and the water resources management – the Brazilian** 

The legal framework comprising the different institutional and management levels is probably the first arrangement to be settled in the path of the sustainability. One of the questions that first arise refers to the urbanisation responsibilities. City development is an attribution of the Municipality, while water resources management is something that needs to consider the basin scale and, generally, comprises a regional planning. In Brazil, legislation shows a significant concern in providing tools for guiding the different institutional levels in the path to build a sustainable city. However, Brazilian cities, in general, do not present an adequate quality level for the built environment and the city life. In order to have a general view of the Brazilian legal framework for urban development and, in particular, for the achievement of sustainable urban drainage systems, a brief review


It is important to schedule the actions of the Stormwater Management Plan in time, recognizing short, medium and long term actions, to ensure enduring solutions for drainage. Short-term measures intend to correct or mitigate the immediate problems of macro-drainage network, promoting the removal of singularities, desilting and maintenance of the original characteristics of the system. Measures to prepare the required database for the consubstantiation of the plan are also important. The construction of a mathematical model should also be among the initial activities, to provide a systematic evaluation tool. Also among the short-term activities, it is necessary to make a diagnosis for the watershed.

After that initial stage, in the short/medium term, measures should be designed to control runoff at the source and for the recovery of the natural hydrological cycle characteristics. These measures should be scheduled, to be implemented over time. Flood maps should be provided for the evaluation of the proposed scenarios and, also, allow the definition of interactions with land use zoning.

From the developed experiences, it may be possible to produce a practical drainage manual, in the medium/long term, bringing together recommendations for all the developments and future projects. The long-term actions should sustain an adequate operation for the drainage system, through maintenance and monitoring. Environmental education campaigns and community engagement are also needed to help in supporting the proposed solutions.

#### **6. River revitalisation**

It is known that self-sustaining river systems provide important ecological and social goods and services to human life (Postel and Richter, 2003 *apud* Palmer *et al*., 2005). River revitalisation is an issue that comes as a necessity to face the progressive deterioration of river ecosystems worldwide. The results can be analysed not only from the aesthetic viewpoint and to improve the environment, but also in terms of hydrologic and ecologic functioning of restored river reaches, increasing the quantity and quality of river resources and their potential use to riverine population (González del Tánago & García de Jalón, 2007). In urban areas, River Revitalisation is more complex, because of the large modifications suffered by the riverine areas, with the construction of buildings and roads, which make it difficult to have the space needed to recover the natural processes of the river bed and its banks (*ibid*). The river revitalisation process needs to be discussed in a particular

Stormwater Plan is a component of the Urban Master Plan. As drainage is part of the

 The stormwater system should be integrated into the environmental sanitation system, with proposals for the control of solid waste and the reduction of stormwater pollution. The Plan shall regulate the territory occupation by controlling the expansion areas and

 Flood control is a permanent process and should not be limited to regulation, legislation and construction of protection works. A plan to monitor and maintain the proposed

It is important to schedule the actions of the Stormwater Management Plan in time, recognizing short, medium and long term actions, to ensure enduring solutions for drainage. Short-term measures intend to correct or mitigate the immediate problems of macro-drainage network, promoting the removal of singularities, desilting and maintenance of the original characteristics of the system. Measures to prepare the required database for the consubstantiation of the plan are also important. The construction of a mathematical model should also be among the initial activities, to provide a systematic evaluation tool. Also among the short-term activities, it is necessary

After that initial stage, in the short/medium term, measures should be designed to control runoff at the source and for the recovery of the natural hydrological cycle characteristics. These measures should be scheduled, to be implemented over time. Flood maps should be provided for the evaluation of the proposed scenarios and, also, allow the definition of

From the developed experiences, it may be possible to produce a practical drainage manual, in the medium/long term, bringing together recommendations for all the developments and future projects. The long-term actions should sustain an adequate operation for the drainage system, through maintenance and monitoring. Environmental education campaigns and community engagement are also needed to help in supporting the proposed solutions.

It is known that self-sustaining river systems provide important ecological and social goods and services to human life (Postel and Richter, 2003 *apud* Palmer *et al*., 2005). River revitalisation is an issue that comes as a necessity to face the progressive deterioration of river ecosystems worldwide. The results can be analysed not only from the aesthetic viewpoint and to improve the environment, but also in terms of hydrologic and ecologic functioning of restored river reaches, increasing the quantity and quality of river resources and their potential use to riverine population (González del Tánago & García de Jalón, 2007). In urban areas, River Revitalisation is more complex, because of the large modifications suffered by the riverine areas, with the construction of buildings and roads, which make it difficult to have the space needed to recover the natural processes of the river bed and its banks (*ibid*). The river revitalisation process needs to be discussed in a particular

urban infrastructure, it should, therefore, be planned in an integrated way.

 Runoff cannot be intensified by the occupation of the basin. The Plan has as its planning unit each watershed of the city.

This regulation should be done for each watershed as a whole.

limiting the densification of the occupied areas.

measures is needed along time.

to make a diagnosis for the watershed.

interactions with land use zoning.

**6. River revitalisation** 

way for urban areas and a consensus solution between the natural landscape and the built environment must be found.

In highly urbanised regions, generally the available areas for interventions are scarce, there are numerous socio-economic problems, which make the revitalisation process very complex, because it involves the need of large riparian areas, in order to find space for the river recover its natural course and flooding areas. However, even if these riparian areas were restored to the original natural condition, the heavy modifications that the catchment suffered over the time would probably lead to floods still happening. Thus, the space that would be required to recover the river course functions today is greater than the natural one. Actions in the basin have to be considered, to decrease the imperviousness and to rescue superficial retentions, with the use of reservoirs.

Urban water courses restoration is a challenge for managers, researchers, experts and citizens. In urban environments, the main focus must be on the restoration of the lateral connectivity with the river banks and its tributaries, the restoration of the river natural flow regime, as well as the increase of the degree of freedom of the river. The combination of flood risk management concepts with River Revitalisation measures can be a solution of efficient applicability in urban rivers, in comparison with traditional and localised drainage solutions (Jormola, 2008). Thus, what is expected is the creation of a self-sustainable natural river system, in order to maintain the flood control function after the flow patterns restoration. In this context, a sustainable approach for drainage system should consider River Revitalisation as one of the tools aligned with this major objective.

However, it's important to note that, even when the adopted measures configure only a partial revitalisation, they are important. In addition to reducing the peak flood, they help in the dissemination of this kind of techniques and provide a new perception about the existence of the river for the involved community. They also allow the river valuing and reintegration as part of urban landscape. Finally, it should be pointed out that any process of revitalisation takes time to be fully developed and find it complete. It is necessary to await the responses of the environment, regarding the "new" conditions to which it was submitted. During this time, complementary actions, resulting from the monitoring of this evolution may and should be developed.

#### **7. Institutional aspects supporting the integration of a sustainable urban drainage system and the water resources management – the Brazilian experiences management**

The legal framework comprising the different institutional and management levels is probably the first arrangement to be settled in the path of the sustainability. One of the questions that first arise refers to the urbanisation responsibilities. City development is an attribution of the Municipality, while water resources management is something that needs to consider the basin scale and, generally, comprises a regional planning. In Brazil, legislation shows a significant concern in providing tools for guiding the different institutional levels in the path to build a sustainable city. However, Brazilian cities, in general, do not present an adequate quality level for the built environment and the city life. In order to have a general view of the Brazilian legal framework for urban development and, in particular, for the achievement of sustainable urban drainage systems, a brief review is included as an introduction to this section, in the following lines.

Sustainable Drainage Systems: An Integrated Approach,

**7.1 The local planning and the management level**

other public or private actors occur.

levels.

growth.

present challenges.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 39

The jurisdiction of the municipality in federative countries focuses on roles that are generally related to the provision of local public services and to planning, supervision and development functions, which are related, among others, to land use planning, environmental protection and also to a certain level of economic activities regulation (Dourojeanni and Jouravlev, 1999). Considering the Brazilian case, recently the municipalities with larger investment capacity began to incorporate roles related to the provisions of social services that used to be traditionally restricted to the state and federal

It is observed from the 1990's a tendency to extend the role of local public levels regarding the environment management. A lot of factors, however, limit the performance of the municipality in the water management. In Brazil, for instance, there are legal constraints determined by the Federal Constitution, where the cities cannot directly manage the water resources contained within their territories, except for certain formal agreements that transfer some assignments through cooperation arrangements with the State or the Union. Water resources management is a matter of river basin management and cannot be restrained to an administrative territory jurisdiction. Thus the role of the cities is restricted to lower levels of relevance and administrative autonomy (Jouravlev, 2003). Municipality participation in basin organisms for water resources management (called Basin Committees, in Brazil) has been the main stage where the interactions between Municipalities and the

Despite of the fact that the administrative level of the municipality is the closest to social reality, its range of political and administrative roles does not allow a systemic vision of the territory in which it is inserted. In turn, the absence of a clear definition of the extent of local governments functions, in general, linked to the traditional tasks of territorial administration, the supervision and provision of local services, and the fact that most of the municipalities have a reduced financial autonomy, depending on transfers from other government levels, makes it difficult to them to have a more effective participation in the water management. Referring to the financial constraints, Lowbeer & Cornejo (2002) warn that the multilateral financing agencies, except for the Global Environment Facility -GEF, have not yet come to explicit in their agenda the need for integrated management projects of natural resources linked to the territory management and land use, particularly in urban areas. Few are the experiences implemented which have coordination between water conservation/preservation and regulation of the land use against the (dis)functions of urban

Another aspect is that the essentially local nature of the city governments' interests makes them act more like water resources users rather than managers of these resources (Jouravlev, 2003). These aspects are exacerbated in metropolitan areas where local governments have often antagonistic interests and priorities, creating dissent environments with little room for cooperation. The metropolitan question is surely one of the greatest

Even if there are restrictions to the municipalities' participation as direct managers of water resources, there is no doubt about the importance of local governments on planning and ordering the territory, due to its consequences on the water resources conservation. It is the

The Federal Urban Land Parcelling Act (Brazil, 1979) establishes the minimum standards for urban developing. This Act considers that a plot is a parcel of urban land provided with the basic infrastructure, meeting the urban restrictions. This basic infrastructure refers to urban drainage, sewerage, water supply, electricity and public roads. The Act also states that it is not allowed to have allotments in flooding areas, in environmental protected areas or in polluted degraded areas. Another Federal Act, known as "City Statute" (Brazil, 2001), establishes detailed rules for public land use order and social interest that regulate the use of urban property in favour of the collectivity, the security and well-being of citizens and environmental balance. The urban policy aims to organise the fulfilment of the social functions of the city and of urban property by the application of a set of general guidelines, from which the following topics are detached for the purposes of the present discussion:


Several important urban management tools are made available in the context of the City Statute. The Urban Master Plan is considered to be the basic instrument for the urban developing policy.

In the field of water resources management the "Water Act" (Brazil, 1997) defines that the hydrographical basin is the unit of planning and design for water resources purposes. Another important reference is the "Basic Sanitation Act" (Brazil, 2007). This Act establishes the first national guidelines for the federal policy of basic sanitation. An important key element of this Act is the integrated conception of the sanitation services and their relation with the efficient management of water resources. For all purposes this Act considers sanitation as a set of services, infrastructure and operational facilities for drinking water supply; sewerage collection, treatment and disposal; urban solid waste management; urban drainage and storm water management.

As it was said in the beginning of this section, although legislation has merits, there are difficulties in urban development and control. This discussion and the possible ways to go further in urban sustainability, concerning urban waters, are the main points of the next topics.

#### **7.1 The local planning and the management level**

38 Drainage Systems

The Federal Urban Land Parcelling Act (Brazil, 1979) establishes the minimum standards for urban developing. This Act considers that a plot is a parcel of urban land provided with the basic infrastructure, meeting the urban restrictions. This basic infrastructure refers to urban drainage, sewerage, water supply, electricity and public roads. The Act also states that it is not allowed to have allotments in flooding areas, in environmental protected areas or in polluted degraded areas. Another Federal Act, known as "City Statute" (Brazil, 2001), establishes detailed rules for public land use order and social interest that regulate the use of urban property in favour of the collectivity, the security and well-being of citizens and environmental balance. The urban policy aims to organise the fulfilment of the social functions of the city and of urban property by the application of a set of general guidelines, from which the following topics are detached for the

 guarantee the right to sustainable cities, meaning the right to urban land, housing, environmental sanitation, urban infrastructure, transport and public services, work and

 democratic management through people's participation and associations representing various segments of the community in the formulation, implementation and monitoring

planning the development of cities to prevent and correct the distortions of urban

supply of urban infrastructure and community equipments, transport and public

ordering and control of land use to avoid pollution, environmental degradation and

protection, preservation and restoration of the natural and built environment, and

Several important urban management tools are made available in the context of the City Statute. The Urban Master Plan is considered to be the basic instrument for the urban

In the field of water resources management the "Water Act" (Brazil, 1997) defines that the hydrographical basin is the unit of planning and design for water resources purposes. Another important reference is the "Basic Sanitation Act" (Brazil, 2007). This Act establishes the first national guidelines for the federal policy of basic sanitation. An important key element of this Act is the integrated conception of the sanitation services and their relation with the efficient management of water resources. For all purposes this Act considers sanitation as a set of services, infrastructure and operational facilities for drinking water supply; sewerage collection, treatment and disposal; urban solid waste management; urban

As it was said in the beginning of this section, although legislation has merits, there are difficulties in urban development and control. This discussion and the possible ways to go further in urban sustainability, concerning urban waters, are the main points of the next

purposes of the present discussion:

developing policy.

topics.

drainage and storm water management.

leisure for present and future generations;

of plans, programs and projects for urban development;

services to serve the interests and needs of the population;

excessive or inadequate use in relation to urban infrastructure;

growth and its negative effects on the environment;

cultural, historical, artistic and landscape heritages.

The jurisdiction of the municipality in federative countries focuses on roles that are generally related to the provision of local public services and to planning, supervision and development functions, which are related, among others, to land use planning, environmental protection and also to a certain level of economic activities regulation (Dourojeanni and Jouravlev, 1999). Considering the Brazilian case, recently the municipalities with larger investment capacity began to incorporate roles related to the provisions of social services that used to be traditionally restricted to the state and federal levels.

It is observed from the 1990's a tendency to extend the role of local public levels regarding the environment management. A lot of factors, however, limit the performance of the municipality in the water management. In Brazil, for instance, there are legal constraints determined by the Federal Constitution, where the cities cannot directly manage the water resources contained within their territories, except for certain formal agreements that transfer some assignments through cooperation arrangements with the State or the Union. Water resources management is a matter of river basin management and cannot be restrained to an administrative territory jurisdiction. Thus the role of the cities is restricted to lower levels of relevance and administrative autonomy (Jouravlev, 2003). Municipality participation in basin organisms for water resources management (called Basin Committees, in Brazil) has been the main stage where the interactions between Municipalities and the other public or private actors occur.

Despite of the fact that the administrative level of the municipality is the closest to social reality, its range of political and administrative roles does not allow a systemic vision of the territory in which it is inserted. In turn, the absence of a clear definition of the extent of local governments functions, in general, linked to the traditional tasks of territorial administration, the supervision and provision of local services, and the fact that most of the municipalities have a reduced financial autonomy, depending on transfers from other government levels, makes it difficult to them to have a more effective participation in the water management. Referring to the financial constraints, Lowbeer & Cornejo (2002) warn that the multilateral financing agencies, except for the Global Environment Facility -GEF, have not yet come to explicit in their agenda the need for integrated management projects of natural resources linked to the territory management and land use, particularly in urban areas. Few are the experiences implemented which have coordination between water conservation/preservation and regulation of the land use against the (dis)functions of urban growth.

Another aspect is that the essentially local nature of the city governments' interests makes them act more like water resources users rather than managers of these resources (Jouravlev, 2003). These aspects are exacerbated in metropolitan areas where local governments have often antagonistic interests and priorities, creating dissent environments with little room for cooperation. The metropolitan question is surely one of the greatest present challenges.

Even if there are restrictions to the municipalities' participation as direct managers of water resources, there is no doubt about the importance of local governments on planning and ordering the territory, due to its consequences on the water resources conservation. It is the

Sustainable Drainage Systems: An Integrated Approach,

Sanitation Committee of Baixada Fluminense (*Ibid*).

(Carneiro, 2003).

water.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 41

de Janeiro arable and, secondarily, to eradicate yellow fever and to control the local floods

This Committee was the seed of the National Department of Sanitation Works – DNOS (in Portuguese), in 1940, created with the responsibility for implementing the national policy of general sanitation, both in rural and urban spaces, including flooding mitigation, erosion and water pollution control, and the recovery of areas for agricultural or industries uses, as well as the settlement of water supply and sewage systems. Despite the range of assignments given to DNOS, its performance was limited, in its initial phase, to the drainage work for drying wetlands, consolidating and expanding the program prepared by the

Dourojeanni and Jouravlev (2001), referring to the experiences of integrated management in Latin America, point out that many of the institutions set up from the 1940's were increasingly incorporating multiple uses of water, even though they used to have as initial particular goals - like flood control, hydroelectric plants, irrigation projects and water supply. Few were those which began their activities by integrating these multiple uses of

An important experience in water management in the country, considering the perspective of integrated water resources management, was the creation of the Special Committee for Integrated Watershed Studies (CEEIBH, in Portuguese), in 1978. Supported by CEEIBH, several watersheds committees were constituted. However, despite the important role of these committees on the preparation of studies and investment plans for the recovery and management of the related watersheds, the efforts and experiences have not been able to establish an integrated management of the water resources, nor the implementation of proposed actions could reverse the basins degradation. They also failed to avoid sectoral and fragmented management practices. In part, the low effectiveness of these initiatives was

Until early 1985, the National Department of Water and Electrical Energy (DNAEE, in Portuguese) was responsible for the management of water resources in the country. Since 1988, however, with the new Federal Constitution, a set of modifications in the water sector was introduced: the definition of Federal/State dominion of the water bodies, the definition of the water as a public good endowed with economic value and the need for the integration of water resources management with land use management policies. In 1995 it was created the Water Resources Secretariat, linked to the Ministry of Environment, with the objective to act in the planning and control of the actions related to water resources in the Federal Government, among others. This institutional change represented the incorporation of the

With the approval of Act 9,433, in 1997, the country received one of the most complete regulatory frameworks focused on water resources managing in the international scenario. The National Water Resources Management System aims to coordinate the administration of water resources in the country seeking to integrate it with other sectors of the economy; administratively arbitrate conflicts related to water uses; implement the National Water Resources Policy; plan, regulate and control the use, preservation and restoration of water resources; and charge for water use, among others. This Act establishes that the watershed is the territorial unit for the National Water Resources Policy implementation and for the

due to the fact that these committees had a merely advisory feature.

concept of multiple uses of water in the environmental context (CEPAL, 1999).

National Water Resources Management System actions.

county attribution the elaboration, approval and supervision of instruments related to land use zoning and planning for development purposes, such as the Urban Master Plan, the delineation of industrial, urban, rural and environmental preservation areas inside the municipality, land parcelling criteria, the development of housing programs, among other activities that have impact on water resources and sanitation conditions, especially in predominantly urban watersheds.

According to Peixoto (2006), the history of the production process of the urban space and its impact on natural resources and human dwellings quality demonstrates the difficulties for articulation between urban and environmental issues. At the same time, however, it may be observed a trend of convergence of these issues towards sustainability, expressed on the federal Acts previous described in the beginning of this topic. Nevertheless, what is observed in the country is the disconnection between the practical instruments of water management and of land use planning, reflecting, perhaps, the lack of legitimacy in the planning process of Brazilian cities as well as certain gaps in local legislation. Several cities are marked by a high level of informality and even illegality in land use – social problems arise as a critical element and urban mesh degrades with spreading slums, also favouring several environmental impacts. According to Tucci (2004), the greatest difficulty for the implementation of integrated planning stems from the limited institutional capacity of the municipalities to address complex and intersectoral issues. However, it is relevant to point out that there are differences among cities, depending on its size, geographic position, distance from the metropolitan areas, historical urban structuring and evolution, qualification of the technical public staff. Peripheral districts in metropolitan areas, presents, sometimes, an outdated legislation, aggravated by the absence of reliable information and lack of quality technical support.

#### **7.2 Integrated water resources management: interfaces with sectoral policies and territory planning**

The institutional organisation of water resources in Brazil began in the 1930s with the establishment of the Water Code, in 1934. The Water Code represented a milestone in the institutionalisation of the water planning in the country, allowing the expansion of the electricity sector. The granting of hydroelectric developments and electricity distribution services went to the Union with the establishment of this Act. In the same year it was also created the National Department of Mineral Production (DNPN, in Portuguese), within the Ministry of Agriculture, which incorporated the Service of Geology and Mineralogy and the Water Service. During the year of 1938, it was created the National Council of Water and Power, attached to the Presidency that, together with the DNPN, became in charge to decide on water and electrical energy in the country.

Even before the 30's, several governmental committees had been set up in order to coordinate and implement water works. However, the onset of a coordinated action in the water sector has only occurred in 1933, with the creation of the Sanitation Committee of Baixada Fluminense, in the framework of National Department of Ports and Navigation. Baixada Fluminense is an important region, in the metropolitan area of Rio de Janeiro City, characterised by extensive lowlands. This Committee was responsible for the formulation of a comprehensive drainage program for Baixada Fluminense, which was an unprecedented action in the country, with the main aim to make this vast lowland plains of the State of Rio

county attribution the elaboration, approval and supervision of instruments related to land use zoning and planning for development purposes, such as the Urban Master Plan, the delineation of industrial, urban, rural and environmental preservation areas inside the municipality, land parcelling criteria, the development of housing programs, among other activities that have impact on water resources and sanitation conditions, especially in

According to Peixoto (2006), the history of the production process of the urban space and its impact on natural resources and human dwellings quality demonstrates the difficulties for articulation between urban and environmental issues. At the same time, however, it may be observed a trend of convergence of these issues towards sustainability, expressed on the federal Acts previous described in the beginning of this topic. Nevertheless, what is observed in the country is the disconnection between the practical instruments of water management and of land use planning, reflecting, perhaps, the lack of legitimacy in the planning process of Brazilian cities as well as certain gaps in local legislation. Several cities are marked by a high level of informality and even illegality in land use – social problems arise as a critical element and urban mesh degrades with spreading slums, also favouring several environmental impacts. According to Tucci (2004), the greatest difficulty for the implementation of integrated planning stems from the limited institutional capacity of the municipalities to address complex and intersectoral issues. However, it is relevant to point out that there are differences among cities, depending on its size, geographic position, distance from the metropolitan areas, historical urban structuring and evolution, qualification of the technical public staff. Peripheral districts in metropolitan areas, presents, sometimes, an outdated legislation, aggravated by the absence of reliable information and

**7.2 Integrated water resources management: interfaces with sectoral policies and** 

The institutional organisation of water resources in Brazil began in the 1930s with the establishment of the Water Code, in 1934. The Water Code represented a milestone in the institutionalisation of the water planning in the country, allowing the expansion of the electricity sector. The granting of hydroelectric developments and electricity distribution services went to the Union with the establishment of this Act. In the same year it was also created the National Department of Mineral Production (DNPN, in Portuguese), within the Ministry of Agriculture, which incorporated the Service of Geology and Mineralogy and the Water Service. During the year of 1938, it was created the National Council of Water and Power, attached to the Presidency that, together with the DNPN, became in charge to decide

Even before the 30's, several governmental committees had been set up in order to coordinate and implement water works. However, the onset of a coordinated action in the water sector has only occurred in 1933, with the creation of the Sanitation Committee of Baixada Fluminense, in the framework of National Department of Ports and Navigation. Baixada Fluminense is an important region, in the metropolitan area of Rio de Janeiro City, characterised by extensive lowlands. This Committee was responsible for the formulation of a comprehensive drainage program for Baixada Fluminense, which was an unprecedented action in the country, with the main aim to make this vast lowland plains of the State of Rio

predominantly urban watersheds.

lack of quality technical support.

on water and electrical energy in the country.

**territory planning** 

de Janeiro arable and, secondarily, to eradicate yellow fever and to control the local floods (Carneiro, 2003).

This Committee was the seed of the National Department of Sanitation Works – DNOS (in Portuguese), in 1940, created with the responsibility for implementing the national policy of general sanitation, both in rural and urban spaces, including flooding mitigation, erosion and water pollution control, and the recovery of areas for agricultural or industries uses, as well as the settlement of water supply and sewage systems. Despite the range of assignments given to DNOS, its performance was limited, in its initial phase, to the drainage work for drying wetlands, consolidating and expanding the program prepared by the Sanitation Committee of Baixada Fluminense (*Ibid*).

Dourojeanni and Jouravlev (2001), referring to the experiences of integrated management in Latin America, point out that many of the institutions set up from the 1940's were increasingly incorporating multiple uses of water, even though they used to have as initial particular goals - like flood control, hydroelectric plants, irrigation projects and water supply. Few were those which began their activities by integrating these multiple uses of water.

An important experience in water management in the country, considering the perspective of integrated water resources management, was the creation of the Special Committee for Integrated Watershed Studies (CEEIBH, in Portuguese), in 1978. Supported by CEEIBH, several watersheds committees were constituted. However, despite the important role of these committees on the preparation of studies and investment plans for the recovery and management of the related watersheds, the efforts and experiences have not been able to establish an integrated management of the water resources, nor the implementation of proposed actions could reverse the basins degradation. They also failed to avoid sectoral and fragmented management practices. In part, the low effectiveness of these initiatives was due to the fact that these committees had a merely advisory feature.

Until early 1985, the National Department of Water and Electrical Energy (DNAEE, in Portuguese) was responsible for the management of water resources in the country. Since 1988, however, with the new Federal Constitution, a set of modifications in the water sector was introduced: the definition of Federal/State dominion of the water bodies, the definition of the water as a public good endowed with economic value and the need for the integration of water resources management with land use management policies. In 1995 it was created the Water Resources Secretariat, linked to the Ministry of Environment, with the objective to act in the planning and control of the actions related to water resources in the Federal Government, among others. This institutional change represented the incorporation of the concept of multiple uses of water in the environmental context (CEPAL, 1999).

With the approval of Act 9,433, in 1997, the country received one of the most complete regulatory frameworks focused on water resources managing in the international scenario. The National Water Resources Management System aims to coordinate the administration of water resources in the country seeking to integrate it with other sectors of the economy; administratively arbitrate conflicts related to water uses; implement the National Water Resources Policy; plan, regulate and control the use, preservation and restoration of water resources; and charge for water use, among others. This Act establishes that the watershed is the territorial unit for the National Water Resources Policy implementation and for the National Water Resources Management System actions.

Sustainable Drainage Systems: An Integrated Approach,

flooding and urban drainage;

cities planning in Brazil.

and water users.

**7.3.1 Watershed committees** 

space reference for Brazilian institutions

different water aspects in urban areas.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 43

inadequate design for urban systems control: an important part of the technicians who

 fragmented vision of the urban planning: urban planning and development do not always incorporate integrated aspects related to water supply, sewage, solid waste,

lack of management capacity: the cities are not designed for proper management of the

The situation is even more critical in the metropolitan areas that have a high level of conurbation. It is no coincidence that new institutional arrangements for the cities management have aroused the interest of technicians and researchers who identify the need for the resumption of planning on a regional basis, without neglecting, of course, issues that could and should be treated locally. Therefore, the challenges related to urban waters management combined with the intense process of territory occupation, develop into specific problems of the built environment that require a tailored approach. The following sub-items discuss the new institutional arrangements and the perspectives they bring to fill the institutional gap left by the absence of metropolitan instances for intensely urbanised

The central figure in the water resources management system is the watershed committee. The committees are public political organisms of decision making, with legislative, deliberative and advisory powers, concerning the use, protection and restoration of water resources, involving a wide representation of organised sectors of civil society, governments

The committees work as a decentralised locus for discussion on the water uses issues of a watershed, acting as a mediating instance among different interests. These committees are seen as "water parliaments", playing the role of the decision maker within the basin context. The committees composition, as provided by Act 9,433, comprises the Union, the States and the Cities located, even if partially, in the respective basin; the water users within basin area;

Nevertheless, it is a fact that the committees established in the country have found great difficulties in fulfilling their decisions and in executing their investment plans. Two main aspects can be identified as constraints to the action of the committees. The first one is that the revenues from charging water uses, which is the only funding source of the committees, are not enough to make the necessary investments for the watersheds recovery. Thus, the committees remain dependent on the traditional sources of investment, which have their own mechanisms for eligibility and prioritisation. The second aspect is that the committees have not gained the necessary political and institutional legitimacy for the public policies coordination related to the watershed, nor could it guide the investments to target actions of its interest. This last aspect stems from the fact that the basin does not constitute a political

and the civil water resources entities with activities in the basin.

of magnitude of 10 times the costs of on-source control measures;

work in urban issues is outdated about the environmental concerns;

they represent high costs and impacts. Generally, the channels transfer flood downstream, affecting another part of the community. These works can reach an order

The principles adopted by the Water Act, as the Act 9.433 became known, are adherent to the statements of the major international conferences that have dealt with the water issues and which substantially contributed to the concept of development on a sustainable basis. However, as several authors emphasize (Dourojeanni & Jouravelev, 2001; Cepal, 1999), the integrated management of water resources requires a change on planning paradigms, in both public and private levels. Integrating these variables implies on operate in various fields of public policies, especially in those related to regional and urban development and the institutional arrangements that shape those policies. According to Silva & Porto (2003), the institutional planning and management of water resources system faces four types of integration challenges:


#### **7.3 New institutional arrangements: watersheds and metropolitan areas**

The current approach for the water resources management in urban areas presupposes an inseparable and integrated planning for urban development projects. Tucci (2004) proposed an approach where aspects related to watershed protection, sewerage collection and treatment, solid waste collection and disposal, urban drainage, river floods and land use are treated in an integrated way, considering the Urban Master Plan as the central point.

Gouvea (2005) stated that the dynamics of the urban growth, often disordered and even chaotic, was gradually showing the ineffectiveness of many programs and projects implemented in isolated modules and developed from the mistaken idea that the urban reality could be divided and treated in a compartmentalised way. The author notes that actually the city must be seen not only as a specific and complex system, but also as part of a larger system, regional or even national, made up of several subsystems, such as habitation, public transportation, sanitation, natural environment, etc., which are closely related and require an integrated and multidisciplinary approach.

Tucci (2004) lists some factors that hinder the application of the integrated management concepts in cities, as follows:

 absence of adequate knowledge on the subject: the population and professionals from different fields and levels who do not have adequate information on the problems and their real causes. The decisions usually result in high costs. For example, the use of canalisation works as drainage solutions is a widespread practice in Brazil, even when they represent high costs and impacts. Generally, the channels transfer flood downstream, affecting another part of the community. These works can reach an order of magnitude of 10 times the costs of on-source control measures;


The situation is even more critical in the metropolitan areas that have a high level of conurbation. It is no coincidence that new institutional arrangements for the cities management have aroused the interest of technicians and researchers who identify the need for the resumption of planning on a regional basis, without neglecting, of course, issues that could and should be treated locally. Therefore, the challenges related to urban waters management combined with the intense process of territory occupation, develop into specific problems of the built environment that require a tailored approach. The following sub-items discuss the new institutional arrangements and the perspectives they bring to fill the institutional gap left by the absence of metropolitan instances for intensely urbanised cities planning in Brazil.

#### **7.3.1 Watershed committees**

42 Drainage Systems

The principles adopted by the Water Act, as the Act 9.433 became known, are adherent to the statements of the major international conferences that have dealt with the water issues and which substantially contributed to the concept of development on a sustainable basis. However, as several authors emphasize (Dourojeanni & Jouravelev, 2001; Cepal, 1999), the integrated management of water resources requires a change on planning paradigms, in both public and private levels. Integrating these variables implies on operate in various fields of public policies, especially in those related to regional and urban development and the institutional arrangements that shape those policies. According to Silva & Porto (2003), the institutional planning and management of water resources system faces four types of

 Integration among activities directly related to the water use in the basin: water supply, wastewater depuration, flood control, irrigation, industrial use, energy production, in order to optimise the multiple use under the perspective of a joint management of

 Regulatory articulation with sectoral systems that do not use directly the water resources, such as housing and urban transportation, in order to prevent excess of

 Territorial integration with the instances of urban planning and management, in order to apply preventive measures in relation to the urbanisation process, avoiding the increasing demand of quantity and/or quality of existing water resources, including

 Articulation with neighbouring basins, celebrating stable agreements on the current and future conditions of imported and exported flows of the waters used in the basin.

The current approach for the water resources management in urban areas presupposes an inseparable and integrated planning for urban development projects. Tucci (2004) proposed an approach where aspects related to watershed protection, sewerage collection and treatment, solid waste collection and disposal, urban drainage, river floods and land use are

Gouvea (2005) stated that the dynamics of the urban growth, often disordered and even chaotic, was gradually showing the ineffectiveness of many programs and projects implemented in isolated modules and developed from the mistaken idea that the urban reality could be divided and treated in a compartmentalised way. The author notes that actually the city must be seen not only as a specific and complex system, but also as part of a larger system, regional or even national, made up of several subsystems, such as habitation, public transportation, sanitation, natural environment, etc., which are closely related and

Tucci (2004) lists some factors that hinder the application of the integrated management

 absence of adequate knowledge on the subject: the population and professionals from different fields and levels who do not have adequate information on the problems and their real causes. The decisions usually result in high costs. For example, the use of canalisation works as drainage solutions is a widespread practice in Brazil, even when

treated in an integrated way, considering the Urban Master Plan as the central point.

imperviousness or urban pollution impacting water sources;

**7.3 New institutional arrangements: watersheds and metropolitan areas** 

require an integrated and multidisciplinary approach.

integration challenges:

water quality and quantity;

flood occurrences;

concepts in cities, as follows:

The central figure in the water resources management system is the watershed committee. The committees are public political organisms of decision making, with legislative, deliberative and advisory powers, concerning the use, protection and restoration of water resources, involving a wide representation of organised sectors of civil society, governments and water users.

The committees work as a decentralised locus for discussion on the water uses issues of a watershed, acting as a mediating instance among different interests. These committees are seen as "water parliaments", playing the role of the decision maker within the basin context. The committees composition, as provided by Act 9,433, comprises the Union, the States and the Cities located, even if partially, in the respective basin; the water users within basin area; and the civil water resources entities with activities in the basin.

Nevertheless, it is a fact that the committees established in the country have found great difficulties in fulfilling their decisions and in executing their investment plans. Two main aspects can be identified as constraints to the action of the committees. The first one is that the revenues from charging water uses, which is the only funding source of the committees, are not enough to make the necessary investments for the watersheds recovery. Thus, the committees remain dependent on the traditional sources of investment, which have their own mechanisms for eligibility and prioritisation. The second aspect is that the committees have not gained the necessary political and institutional legitimacy for the public policies coordination related to the watershed, nor could it guide the investments to target actions of its interest. This last aspect stems from the fact that the basin does not constitute a political space reference for Brazilian institutions

Sustainable Drainage Systems: An Integrated Approach,

**7.3.3 Sanitation sector regulation** 

sanitation sector.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 45

discuss how to promote the regional development, manage solid and wastewaters disposal, and build new hospitals or schools. They have their origin in the municipalities associations, which were already established in the Constitution of 1937. One of the purposes of the public consortia is to enable and make viable the public administration of the metropolitan

The consortium also allows small municipalities to act in partnership and, with a gain in scale, improve their technical, operational and financial capabilities. It is also possible to make alliances in areas of common interest, such as watersheds or regional development poles, improving public services. Indeed, the new Act brought to the public scene a promising tool for the management of common problems in urban areas, offering to the

After a long period without a regulatory mark for the sanitation services, it was approved, on 5 January 2007, the Basic Sanitation Act, nº 11,445. With this Act, the country established a modern regulatory mark for the sanitation sector, integrated with the National Policy of Water Resources Management, and establishes the national guidelines for the basic

This Act considers as basic sanitation the public supply of potable water services; the collection, transportation, treatment and adequate sewage final disposal; the collection, transportation, transfer, treatment and final disposal of household waste and garbage originated in the public streets and open areas; the drainage and urban storm water management, considering the conduction, detention or retention of the flood flows and the

The Act states in its fundamental principles, among other things, the need of making the sanitation services available for all urban areas, preserving citizens health and public and private structures. The sanitation services need to be articulated with urban and regional policies of development and integrated with water resources management. These principles clearly demonstrate the integrative perspective of the Act, fleeing from the traditional view of the sanitation sector in the country, especially when compared with the actions of the

The Basic Sanitation Act also provides several innovations, among others, the possibility of

Another unprecedented advance is the possibility of including in the contracts some progressive and gradual goals for services expansion, increasing in quality, efficiency and

Members of the Federation are also allowed to establish funds, separately or together in public consortia, which may be composed, among other resources, by a portion of the revenue from the services, in order to cover the costs of the universalisation of the public sanitation. These funds, in addition to traditional funding sources, can solve the chronic lack of financing for the sector, especially in relation to urban drainage, where resource

the holders of public sanitation services delegate these services to Public Consortia.

areas, where urban problems solutions require joint policies and actions.

public entities a viable alternative for cooperation at the supra-municipal level.

treatment and final disposal of the rainwater drained from the urban areas.

former National Department of Sanitation Works (DNOS).

rational use of water, and energy rationalisation.

allocation is more uncertain.

Without disregarding the committees importance in the public policies decentralisation and in the society participation, the above pointed aspects restrict the possibilities of the committees working as integrators of public regional policies.

#### **7.3.2 Public consortia**

The possibility of forming consortia in Brazil dates from the late nineteenth century; however, there were, over time, numerous configurations and autonomy design of these instances of inter-municipal cooperation. Table 1 summarises the forms of consortia planned in Brazil for over a century.


Source: Adapted from Rieiro, 2007.

Table 1. Consortia Models provided in Brazil in the period 1891-2007.

As it can be seen, between 1964 and 1988 administrative consortia arose as simple collaboration agreements, without legal personality, reflecting the period of centralism of the military government. From the 1990s, based on the Constitution of 1988, a great number of public consortia appeared in Brazil, especially in the health field. Consortia were also formed around specific themes, being the most common the regional development and the environment, water resources and sanitation.

Most of the consortia established in the country involve small and medium communities. Only 5% of the consortia include cities with more than 500,000 inhabitants (Spink, 2000, apud Gouvea, 2005). Gouvea (2005) states that the main obstacle to the formation of intermunicipal cooperation is still the autarchic aspect of the Brazilian municipalities, in a 'compartmentalised' federalism context, which rigidly separates the counties. Thus, the Brazilian federative framework does not ease the cooperation between municipalities.

The discussion about the new Public Consortia Act began in August 2003, aiming to regulate the Article 241 of the Constitution and give more legal and administrative security to the partnerships among the consortium parts. In 2005, the Congress approved the new Act. The public consortia, according to this Act, are partnerships formed by two or more entities of the federation to achieve common interest goals, in any area. The consortia can

discuss how to promote the regional development, manage solid and wastewaters disposal, and build new hospitals or schools. They have their origin in the municipalities associations, which were already established in the Constitution of 1937. One of the purposes of the public consortia is to enable and make viable the public administration of the metropolitan areas, where urban problems solutions require joint policies and actions.

The consortium also allows small municipalities to act in partnership and, with a gain in scale, improve their technical, operational and financial capabilities. It is also possible to make alliances in areas of common interest, such as watersheds or regional development poles, improving public services. Indeed, the new Act brought to the public scene a promising tool for the management of common problems in urban areas, offering to the public entities a viable alternative for cooperation at the supra-municipal level.

#### **7.3.3 Sanitation sector regulation**

44 Drainage Systems

Without disregarding the committees importance in the public policies decentralisation and in the society participation, the above pointed aspects restrict the possibilities of the

The possibility of forming consortia in Brazil dates from the late nineteenth century; however, there were, over time, numerous configurations and autonomy design of these instances of inter-municipal cooperation. Table 1 summarises the forms of consortia planned

1891 - 1937 The consortia were contracts celebrated among municipalities whose effectiveness depended upon state approval.

<sup>1937</sup>The Constitution recognises that municipalities association in consortia

1964 - 1988 Administrative consortia arise as collaboration agreements without legal

2007 The Decree 6,017, of 17-01-2007, regulates the Public Consortia Act

As it can be seen, between 1964 and 1988 administrative consortia arose as simple collaboration agreements, without legal personality, reflecting the period of centralism of the military government. From the 1990s, based on the Constitution of 1988, a great number of public consortia appeared in Brazil, especially in the health field. Consortia were also formed around specific themes, being the most common the regional development and the

Most of the consortia established in the country involve small and medium communities. Only 5% of the consortia include cities with more than 500,000 inhabitants (Spink, 2000, apud Gouvea, 2005). Gouvea (2005) states that the main obstacle to the formation of intermunicipal cooperation is still the autarchic aspect of the Brazilian municipalities, in a 'compartmentalised' federalism context, which rigidly separates the counties. Thus, the Brazilian federative framework does not ease the cooperation between municipalities.

The discussion about the new Public Consortia Act began in August 2003, aiming to regulate the Article 241 of the Constitution and give more legal and administrative security to the partnerships among the consortium parts. In 2005, the Congress approved the new Act. The public consortia, according to this Act, are partnerships formed by two or more entities of the federation to achieve common interest goals, in any area. The consortia can

Creation of several public consortia. The Constitutional Amendment n0 19 changed the art. 24 of the Constitution of 1988, introducing the concepts of public consortia and the associated management of public services.

committees working as integrators of public regional policies.

**Period Organisation Model** 

1961 It is created the first Brazilian inter-federative autarchy.

Table 1. Consortia Models provided in Brazil in the period 1891-2007.

are legal public entities.

personality.

environment, water resources and sanitation.

2005 Public Consortia Act

Source: Adapted from Rieiro, 2007.

**7.3.2 Public consortia** 

in Brazil for over a century.

From 1998

After a long period without a regulatory mark for the sanitation services, it was approved, on 5 January 2007, the Basic Sanitation Act, nº 11,445. With this Act, the country established a modern regulatory mark for the sanitation sector, integrated with the National Policy of Water Resources Management, and establishes the national guidelines for the basic sanitation sector.

This Act considers as basic sanitation the public supply of potable water services; the collection, transportation, treatment and adequate sewage final disposal; the collection, transportation, transfer, treatment and final disposal of household waste and garbage originated in the public streets and open areas; the drainage and urban storm water management, considering the conduction, detention or retention of the flood flows and the treatment and final disposal of the rainwater drained from the urban areas.

The Act states in its fundamental principles, among other things, the need of making the sanitation services available for all urban areas, preserving citizens health and public and private structures. The sanitation services need to be articulated with urban and regional policies of development and integrated with water resources management. These principles clearly demonstrate the integrative perspective of the Act, fleeing from the traditional view of the sanitation sector in the country, especially when compared with the actions of the former National Department of Sanitation Works (DNOS).

The Basic Sanitation Act also provides several innovations, among others, the possibility of the holders of public sanitation services delegate these services to Public Consortia.

Another unprecedented advance is the possibility of including in the contracts some progressive and gradual goals for services expansion, increasing in quality, efficiency and rational use of water, and energy rationalisation.

Members of the Federation are also allowed to establish funds, separately or together in public consortia, which may be composed, among other resources, by a portion of the revenue from the services, in order to cover the costs of the universalisation of the public sanitation. These funds, in addition to traditional funding sources, can solve the chronic lack of financing for the sector, especially in relation to urban drainage, where resource allocation is more uncertain.

Sustainable Drainage Systems: An Integrated Approach,

integrated manner.

Area of Rio de Janeiro.

instruments for the urban development on a sustainable basis.

**Sarapuí river basin at Rio de Janeiro state, Brazil** 

of land tenure and urban regularisation, and lack of sanitation.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 47

management of land use, using a wider range of legal, economic and tax-oriented

Finally, the improvement of the technical management of cities and metropolitan areas challenge remains. Again, it is stressed the need for creation of cooperative structures, not only among the various municipalities of the same metropolitan area, but also between these municipalities and the state, for the definition and implementation of policies in an

**8. Case study: the seek for sustainable solutions for urban floods in Iguaçu-**

A case study regarding the Iguaçu-Sarapuí River Basin, located in the western portion of the Guanabara Bay Basin, which lies in the Metropolitan Region of Rio de Janeiro is discussed. Figure 6 shows a map of this area, with the Cities that are in this basin. This is one of the most critical areas in the state regarding urban flooding. This region is densely occupied and presents great urban and industrial development areas, as well as wide rural zones in an urbanising process, and reminiscent areas of natural vegetation on the upstream reaches of the basin. This case study intends to illustrate and complement the conceptual discussion held in this chapter and to show how complex the interaction of urban drainage problems and the city growth can be in a context of an unplanned and non integrated reality. In this region, urban expansion dynamics is, in general, marked by irregular occupation, in terms

UTM

Fig. 6. Iguaçu-Sarapuí River Basin at Baixada Fluminense Lowlands in the Metropolitan

The Act consolidates the possibility of formation of the Public Consortium for providing regionalised public sanitation services, as stated in the Public Consortium Act.

The Decree nº 6,017 of 17 January 2007, that regulated the Public Consortia Act, details the way public bodies may constitute consortia. The first aspect to be noted is that the public consortium will be constituted as a legal entity formed solely by members of the Federation, organised as a public association, with legal personality under public law and autarchic nature, or as a legal entity of private law with non-profit aims.

The goal of the consortium will be determined by the associated public entities, assuming, among others, the following possibilities:


The prevision for the exercise of the multi-sectoral functions opens the way for the establishment of a technical agency with legal competence for integrating the public policies involving environment, water resources, sanitation and land use planning within a regional scope.

#### **7.4 Integrated perspectives: water resources, sanitation and urban development**

Probably, the most urgent and complex task of the agenda of public managers really committed to build a sustainable future for the cities refers to promote the integration of public policies concerning water resources, sanitation and urban land use ordering.

The metropolitan question is an issue of increasing importance, and the built environment worsens with the growing of the cities and the conurbation process. At the moment, in Brazil, there are available tools for building institutional arrangements that resume the management in metropolitan basis, replacing the model that prevailed in the last twenty years, which focused in local and fragmented policies. Thus, there are reasons to believe that the new institutional arrangements figuring in the country offer alternatives for the shared management between states and municipalities, especially in the larger urban agglomerations. The public consortia may have more political and legal legitimacy to plan the interventions that could cause better impacts in the territory, in an integrated manner, interacting with all the levels of government and society. It is strongly needed the long-term planning resumption, based on effective cooperation mechanisms.

Specifically regarding the action of the municipalities, there is a vast field of possibilities to be sought, especially after the approval of the City Statute. The new Master Plans, previewed in this statute, can and should incorporate mechanisms for a more effective

The Act consolidates the possibility of formation of the Public Consortium for providing

The Decree nº 6,017 of 17 January 2007, that regulated the Public Consortia Act, details the way public bodies may constitute consortia. The first aspect to be noted is that the public consortium will be constituted as a legal entity formed solely by members of the Federation, organised as a public association, with legal personality under public law and autarchic

The goal of the consortium will be determined by the associated public entities, assuming,

services provision, including technical assistance, structures construction and goods

sharing or common use of the equipments or instruments, including those for

performance of functions in the water resources management system that have been to

The prevision for the exercise of the multi-sectoral functions opens the way for the establishment of a technical agency with legal competence for integrating the public policies involving environment, water resources, sanitation and land use planning within a regional

Probably, the most urgent and complex task of the agenda of public managers really committed to build a sustainable future for the cities refers to promote the integration of

The metropolitan question is an issue of increasing importance, and the built environment worsens with the growing of the cities and the conurbation process. At the moment, in Brazil, there are available tools for building institutional arrangements that resume the management in metropolitan basis, replacing the model that prevailed in the last twenty years, which focused in local and fragmented policies. Thus, there are reasons to believe that the new institutional arrangements figuring in the country offer alternatives for the shared management between states and municipalities, especially in the larger urban agglomerations. The public consortia may have more political and legal legitimacy to plan the interventions that could cause better impacts in the territory, in an integrated manner, interacting with all the levels of government and society. It is strongly needed the long-term

Specifically regarding the action of the municipalities, there is a vast field of possibilities to be sought, especially after the approval of the City Statute. The new Master Plans, previewed in this statute, can and should incorporate mechanisms for a more effective

local and regional policies and actions for urban and socio-economic development.

**7.4 Integrated perspectives: water resources, sanitation and urban development** 

public policies concerning water resources, sanitation and urban land use ordering.

planning resumption, based on effective cooperation mechanisms.

supply to the direct or indirect administration of the consortium members;

water resources rational use promotion and the environment protection;

regionalised public sanitation services, as stated in the Public Consortium Act.

nature, or as a legal entity of private law with non-profit aims.

among others, the following possibilities:

technical studies production;

scope.

them delegated or authorised;

associated management of public services;

management, maintenance, data processing;

management of land use, using a wider range of legal, economic and tax-oriented instruments for the urban development on a sustainable basis.

Finally, the improvement of the technical management of cities and metropolitan areas challenge remains. Again, it is stressed the need for creation of cooperative structures, not only among the various municipalities of the same metropolitan area, but also between these municipalities and the state, for the definition and implementation of policies in an integrated manner.

#### **8. Case study: the seek for sustainable solutions for urban floods in Iguaçu-Sarapuí river basin at Rio de Janeiro state, Brazil**

A case study regarding the Iguaçu-Sarapuí River Basin, located in the western portion of the Guanabara Bay Basin, which lies in the Metropolitan Region of Rio de Janeiro is discussed. Figure 6 shows a map of this area, with the Cities that are in this basin. This is one of the most critical areas in the state regarding urban flooding. This region is densely occupied and presents great urban and industrial development areas, as well as wide rural zones in an urbanising process, and reminiscent areas of natural vegetation on the upstream reaches of the basin. This case study intends to illustrate and complement the conceptual discussion held in this chapter and to show how complex the interaction of urban drainage problems and the city growth can be in a context of an unplanned and non integrated reality. In this region, urban expansion dynamics is, in general, marked by irregular occupation, in terms of land tenure and urban regularisation, and lack of sanitation.

Fig. 6. Iguaçu-Sarapuí River Basin at Baixada Fluminense Lowlands in the Metropolitan Area of Rio de Janeiro.

Sustainable Drainage Systems: An Integrated Approach,

Some of the proposed actions were:

the consolidated urban areas;

implementation of urban parks;

Three kinds of parks were designed:

more detailed examples of the proposed parks.

**Area of Restricted Urban Occupation**

**Fluvial Urban Park AMAPÁ**

> **BELFORD ROXO CITY**

**Flooding Urban Park AMAPÁ**

Preservation Areas;

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 49

maintenance of spaces free of urbanisation, preventing the aggravation of flooding at

land use regulation and control, by means of the establishment of Environmental

creation of public consortiums for integrated planning of policies for multi-counties

1. Fluvial Urban Park – longitudinal parks along rivers, with the purpose of protecting water course banks, also avoiding their irregular occupation by low income population. 2. Flooding Urban Park – longitudinal parks implemented in low elevation areas to allow

3. Environmental Urban Park - parks with greater dimensions, flat or not, with the purpose of environmental preservation and land use valuing, aiming to minimise

Figure 8 shows the general propositions for Iguaçu River Basin, while Figure 9 shows two

**Environmental Urban Park SÃO BENTO**

**DUQUE DE CAXIAS CITY**

Google

**Flooding Urban Park SÃO BENTO**

**CIDADE DOS MENINOS**

**Flooding Urban Park**

interests (recognising the importance of the metropolitan planning); revision and adaptation of the municipalities urban planning instruments.

frequent inundations, which will help to damp flood peaks.

runoff generation and maintaining a buffer of pervious surfaces.

**OUTEIRO**

Fig. 8. Flood control measures proposed for Iguaçu River Basin.

**Flooding Urban Park**

The region under consideration has a great portion of Baixada Fluminense Lowlands. Interventions for flood mitigation were supported by Federal Government on 1930's (canals construction, dams, floodgates and pumping stations). At that time, the hydraulic structures were projected for agricultural uses. A migratory process for this area began on the 1950 's and accelerated from the 1970's on. In the beginning of the 1990 decade, Baixada Fluminense Lowlands sheltered more than 2 million inhabitants in 6 counties. More than 350 thousand of these inhabitants suffered the effects of significant floods. The chaotic process of urbanisation resulted in the occupation of the main rivers bed, what has made almost impossible the maintenance of the watercourses; the acceleration of the process of rivers and canals sedimentation due to deforestation of the slopes and inadequate solid waste disposal; and the increase of the runoff, due to uncontrolled vegetal removal and consequent substitution by impervious surfaces.

The basin of Iguaçu-Sarapuí River, in the past years, became a stage for articulated actions focusing on flood control and environmental recovery, in the context of the revision of its Water Resources Master Plan, in a study made by the Federal University of Rio de Janeiro for the State Institute of the Environment (INEA, in Portuguese). This study was supported by a mathematical model, called MODCEL, capable to represent the system in integrated terms (Mascarenhas & Miguez, 2002). Figure 7 shows the mapped flood conditions for present situation, represented over the modelled area of Iguaçu River Basin.

Fig. 7. Flood map of Iguaçu River Basin, for a design rainfall of 20 years of return period, calculated with a mathematical model aid.

Some of the proposed actions were:

48 Drainage Systems

The region under consideration has a great portion of Baixada Fluminense Lowlands. Interventions for flood mitigation were supported by Federal Government on 1930's (canals construction, dams, floodgates and pumping stations). At that time, the hydraulic structures were projected for agricultural uses. A migratory process for this area began on the 1950 's and accelerated from the 1970's on. In the beginning of the 1990 decade, Baixada Fluminense Lowlands sheltered more than 2 million inhabitants in 6 counties. More than 350 thousand of these inhabitants suffered the effects of significant floods. The chaotic process of urbanisation resulted in the occupation of the main rivers bed, what has made almost impossible the maintenance of the watercourses; the acceleration of the process of rivers and canals sedimentation due to deforestation of the slopes and inadequate solid waste disposal; and the increase of the runoff, due to uncontrolled vegetal removal and consequent

The basin of Iguaçu-Sarapuí River, in the past years, became a stage for articulated actions focusing on flood control and environmental recovery, in the context of the revision of its Water Resources Master Plan, in a study made by the Federal University of Rio de Janeiro for the State Institute of the Environment (INEA, in Portuguese). This study was supported by a mathematical model, called MODCEL, capable to represent the system in integrated terms (Mascarenhas & Miguez, 2002). Figure 7 shows the mapped flood conditions for

Fig. 7. Flood map of Iguaçu River Basin, for a design rainfall of 20 years of return period,

Water Depths (m) Rivers Basin Limits

Localisation map

Guanabara Bay

present situation, represented over the modelled area of Iguaçu River Basin.

substitution by impervious surfaces.

calculated with a mathematical model aid.


Three kinds of parks were designed:


Figure 8 shows the general propositions for Iguaçu River Basin, while Figure 9 shows two more detailed examples of the proposed parks.

Fig. 8. Flood control measures proposed for Iguaçu River Basin.

Sustainable Drainage Systems: An Integrated Approach,

concerns.

**10. Acknowledgments** 

**11. References** 

Program FP7 IRSES PEOPLE 2009.

Portland, Oregon, USA, 2002.

*Drainage*, Portland, September 2002.

*Goytacazes*, Annablume, São Paulo, Brazil.

*Technology*, Vol. 43, No. 5, (2001), pp. (61–68).

8586238430, São Paulo, Brazil.

Chile.

Combining Hydraulic Engineering Design, Urban Land Control and River Revitalisation Aspects 51

opportunities to be explored as integrated solutions, in the fields of hydraulic engineering, architecture and urbanism, city planning and management, social disciplines and economy

The authors acknowledge CNPq for the scholarships and for financing their researches. Also, they would like to highlight that this research is part of the project SERELAREFA (*Semillas REd LAtina Recuperación Ecosistemas Fluviales y Acuáticos*) in the context of the

Andoh, R. Y. G. & Iwugo, K. O. (2002). Sustainable Urban Drainage Systems: - A UK

Arzet K. (2010). O Rio Isar; Munique, Alemanha, In: *Revitalização de Rios no Mundo: América,* 

Batista, M.; Nascimento, N. & Barraud, S. (2005). *Técnicas Compensatórias em Drenagem*

Biswas, A.K. (1970). *History of Hydrology*, North Holland Publishing Company, Amsterdam. Brazil. (1979). *Federal Act 6,766, of December 19, 1979.* Federal Official Gazette of Brazil, Brasília, DF, 20 December. 1979. Section 1, Brasília, Brazil. (in Portuguese) Brazil. (1997) *Federal Act 9,433, of January 8, 1997.* Federal Official Gazette of Brazil, Brasília, DF, n. 6, 09 January. 1997. Section 1, Brasília, Brazil. (in Portuguese) Brazil. (2001) *Federal Act 10,257, of July 10, 2001.* Federal Official Gazette of Brazil, Brasília,

Brazil. (2007) *Federal Act 11,445, of January 5, 2007.* Federal Official Gazette of Brazil, Brasília, DF, n. 8, 11 January. 2007. Section 1, Brasília, Brazil. (in Portuguese) Burian, S.J. & Edwards, F.G. (2002). Historical perspectives of urban drainage, Global

Canholi, A.P. (2005). *Drenagem urbana e controle de enchentes*, Oficina de Textos, ISBN

Carneiro, P. R. F. (2003). *Dos Pântanos à Escassez: uso da água e conflito na Baixada dos* 

CEPAL – Comisión Económica para América Latina y el Caribe. (1999). *Tendencias actuales de* 

Chocat, B., Krebs, P., Marsalek, J., Rauch, W. & Schilling W. (2001). Urban Drainage

Solutions for Urban Drainage, *Proceedings of the 9th International Conference on Urban* 

*la gestión del agua en América Latina y el Caribe (avances en la implementación de las recomendaciones contenidas en el capítulo 18 del Programa 21*. LC/L.1180, Santiago de

Redefined: from Stormwater Removal to Integrated Management. *Water Science and* 

DF, n. 133, 11 July. 2001. Section 1, Brasília, Brazil. (in Portuguese)

978.85.98659.08.4, Belo Horizonte, Brazil. (in Portuguese)

*Urbana*, ABRH, ISBN 858868615-5, Porto Alegre, Brazil. Benevolo, L. (2001). *História da Cidade,* Editora Perspectiva, São Paulo, Brazil.

Perspective. *Proceedings of the 9th International Conference on Urban Drainage*,

*Europa e Ásia*. Machado A.T.G.M., Lisboa A.H., Alves C.B.M., Lopes D.A., Goulart E.M.A., Lite F.A., Polignano M.V., pp 153-168, Instituto Guaicuy, ISBN

Complementary actions held by the State include the articulation with every Municipality in the basin, in order to implement the proposed measures, create local conditions for urban land uses control and develop environmental education campaigns, with the financing of the Federal Government, through a specific Program of Developing Acceleration.

Fig. 9. Fluvial Urban Park and Flooding Urban Park examples.

According to INEA information, these interventions will benefit directly and indirectly, around 3 million inhabitants of Baixada Fluminense and, encompassing: the recovery of 80 km of degraded riverbanks, promoting the resettlement of 2,200 families from risk areas to new housing developments at neighbouring areas; the implementation of parks and recreational areas to protect the recovered riverbanks from new occupations and for storing temporarily floods; the definition of new areas for environmental preservation purposes; the construction or recovery of approximately 70 km of streets along the areas of intervention, as well as the recovery of narrow crossings, bridges, aqueducts, gates and polders. It is also estimated the planting of more than 200,000 trees along the riverbanks. In order to sensibilise and mobilise the local communities for social and environmental problems and the importance of participation and social control, INEA has been developing the process of monitoring and evaluating this project through local committees and through the regional forum of participation and social control.

#### **9. Conclusion**

City growth is a world trend and sustainability is a central point to be considered in the next times to come. In a general way, however, great cities present lots of problems to deal with: land use control needs, sub-habitation, unemployment, poverty, inefficient transportation, insufficient public services, lack of infrastructure, among others. The question of water resources management and sanitation aspects are of fundamental importance in this scenery. The urban flood problem is certainly one of the most important challenges that cities will have to face. The urbanisation process is one of the man-made actions that most affect floods. On the other side, in the context of a city, the flood process is one of the facts that most degrades it. Considering urban drainage in the context of the integrated city development, however, the sustainability perspective opens a diversified set of opportunities to be explored as integrated solutions, in the fields of hydraulic engineering, architecture and urbanism, city planning and management, social disciplines and economy concerns.

#### **10. Acknowledgments**

The authors acknowledge CNPq for the scholarships and for financing their researches. Also, they would like to highlight that this research is part of the project SERELAREFA (*Semillas REd LAtina Recuperación Ecosistemas Fluviales y Acuáticos*) in the context of the Program FP7 IRSES PEOPLE 2009.

#### **11. References**

50 Drainage Systems

Complementary actions held by the State include the articulation with every Municipality in the basin, in order to implement the proposed measures, create local conditions for urban land uses control and develop environmental education campaigns, with the financing of

According to INEA information, these interventions will benefit directly and indirectly, around 3 million inhabitants of Baixada Fluminense and, encompassing: the recovery of 80 km of degraded riverbanks, promoting the resettlement of 2,200 families from risk areas to new housing developments at neighbouring areas; the implementation of parks and recreational areas to protect the recovered riverbanks from new occupations and for storing temporarily floods; the definition of new areas for environmental preservation purposes; the construction or recovery of approximately 70 km of streets along the areas of intervention, as well as the recovery of narrow crossings, bridges, aqueducts, gates and polders. It is also estimated the planting of more than 200,000 trees along the riverbanks. In order to sensibilise and mobilise the local communities for social and environmental problems and the importance of participation and social control, INEA has been developing the process of monitoring and evaluating this project through local committees and through the regional

City growth is a world trend and sustainability is a central point to be considered in the next times to come. In a general way, however, great cities present lots of problems to deal with: land use control needs, sub-habitation, unemployment, poverty, inefficient transportation, insufficient public services, lack of infrastructure, among others. The question of water resources management and sanitation aspects are of fundamental importance in this scenery. The urban flood problem is certainly one of the most important challenges that cities will have to face. The urbanisation process is one of the man-made actions that most affect floods. On the other side, in the context of a city, the flood process is one of the facts that most degrades it. Considering urban drainage in the context of the integrated city development, however, the sustainability perspective opens a diversified set of

**Fluvial Urban Park Amapa** 

the Federal Government, through a specific Program of Developing Acceleration.

**Flooding Urban Park Amapa**

forum of participation and social control.

**9. Conclusion** 

Fig. 9. Fluvial Urban Park and Flooding Urban Park examples.


Sustainable Drainage Systems: An Integrated Approach,

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*sustentável de águas pluviais aplicado à Baixada Fluminense*. MSc. Thesis, Federal

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**3** 

*Brazil* 

**Sustainable Urban Drainage Systems** 

Water is a natural resource renewed through the physical processes of the hydrologic or water cycle. Through the action of solar energy, water is evaporated from the surfaces of oceans, lakes, and rivers and from land surfaces, returning to the atmosphere in the form of water vapor. Water is also returned through plants, which use it to satisfy their physiological needs and send it back in the form of transpiration. The whole process of transfer of water vapor from the Earth's surface to the atmosphere is called evapotranspiration. Once present in the atmosphere, it may precipitate in the form of rain, snow, dew, or frost. When it reaches a surface, it may run off the surface or infiltrate soil layers. Due to topographical conditions, surface runoff converges to valley regions, giving rise to rivers and lakes, which drain to ever larger bodies of water until reaching the ocean. The infiltrated water may flow to deeper soil layers, emerging in the form of springs, or percolate to even deeper layers, reaching underground aquifers. When an aquifer is in direct contact with the surface, it is said to be non-confined, and the water is stored in what is called the water table, which is acted on by atmospheric pressure. When there is a geological formation which separates the water storage zone from the soil surface, the aquifer is said to be confined and it is subject to a pressure greater than atmospheric pressure. The water stored in either of these aquifers may emerge in the form of base flow, due to the topographic gradient, feeding rivers, lakes, and other bodies of water. Indeed, this base flow

The process described above does not cease, it is continually activated by solar energy, and for that reason it is called the hydrologic cycle. Nevertheless, for this cycle to continue in its natural course, there may not be alteration in the water volumes that remain in one or another phase of the process, that is, in the atmosphere, on the surface, and in the soil.

Actually, there are a large number of human and non-human activities that can destabilize the hydrologic cycle. Among human activities that have the greatest impact on the natural

Urbanization leads to impermeabilization of the soil by means of paving, and soil compaction from the passage of vehicles and from buildings, among other things, which impedes rainwater infiltration (Silveira, 2002). This water that was formerly able to infiltrate soil now flows off surfaces, creating a greater volume of runoff, which ends up converging to regions of a lower topographic level, thus generating areas of flooding. The increase of

is responsible for regularization of river flow during dry periods.

hydrologic cycle is the urbanization process.

**1. Introduction** 

Cristiano Poleto1 and Rutinéia Tassi2

*2Federal University of Santa Maria (UFSM),* 

*1Federal University of Technology - Paraná (UTFPR),* 


## **Sustainable Urban Drainage Systems**

Cristiano Poleto1 and Rutinéia Tassi2

*1Federal University of Technology - Paraná (UTFPR), 2Federal University of Santa Maria (UFSM), Brazil* 

#### **1. Introduction**

54 Drainage Systems

Tucci, C. E. M. (2004). Gerenciamento integrado das inundações urbanas no Brasil.

United States Environmental Protection Agency – US EPA. (2004). *The Use of Best* 

Wong, T.H.F. (2006). Water Sensitive Urban Design – the Journey Thus Far. *Australian* 

Selvakumar, A.; Field, R.; Sullivan , D. EPA/600/R-04/184S.

*Journal of Water Resources*, Vol. 10, No. 3, (2006), pp. 213-222.

(59-73).

*Rega/Global Water Partnership South América*, Vol. 1, No. 1, (January-June, 2004), pp.

*Management Practices (BMPs) in Urban Watersheds,* by Muthukrishnan, S.; Madge, B.;

Water is a natural resource renewed through the physical processes of the hydrologic or water cycle. Through the action of solar energy, water is evaporated from the surfaces of oceans, lakes, and rivers and from land surfaces, returning to the atmosphere in the form of water vapor. Water is also returned through plants, which use it to satisfy their physiological needs and send it back in the form of transpiration. The whole process of transfer of water vapor from the Earth's surface to the atmosphere is called evapotranspiration. Once present in the atmosphere, it may precipitate in the form of rain, snow, dew, or frost. When it reaches a surface, it may run off the surface or infiltrate soil layers. Due to topographical conditions, surface runoff converges to valley regions, giving rise to rivers and lakes, which drain to ever larger bodies of water until reaching the ocean. The infiltrated water may flow to deeper soil layers, emerging in the form of springs, or percolate to even deeper layers, reaching underground aquifers. When an aquifer is in direct contact with the surface, it is said to be non-confined, and the water is stored in what is called the water table, which is acted on by atmospheric pressure. When there is a geological formation which separates the water storage zone from the soil surface, the aquifer is said to be confined and it is subject to a pressure greater than atmospheric pressure. The water stored in either of these aquifers may emerge in the form of base flow, due to the topographic gradient, feeding rivers, lakes, and other bodies of water. Indeed, this base flow is responsible for regularization of river flow during dry periods.

The process described above does not cease, it is continually activated by solar energy, and for that reason it is called the hydrologic cycle. Nevertheless, for this cycle to continue in its natural course, there may not be alteration in the water volumes that remain in one or another phase of the process, that is, in the atmosphere, on the surface, and in the soil.

Actually, there are a large number of human and non-human activities that can destabilize the hydrologic cycle. Among human activities that have the greatest impact on the natural hydrologic cycle is the urbanization process.

Urbanization leads to impermeabilization of the soil by means of paving, and soil compaction from the passage of vehicles and from buildings, among other things, which impedes rainwater infiltration (Silveira, 2002). This water that was formerly able to infiltrate soil now flows off surfaces, creating a greater volume of runoff, which ends up converging to regions of a lower topographic level, thus generating areas of flooding. The increase of

Sustainable Urban Drainage Systems 57

These four goals of SUDS contribute to flood control in urban watersheds, principally when they are still in the urbanization phase and the application of SUDS in new undertakings is

This system is designed to manage the environmental risks resulting from urban runoff and to contribute wherever possible to environmental enhancement. SUDS objectives are, therefore, to minimize the impacts from the development on the quantity and quality of the

Uncertainty about long‐term maintenance and other operational factors have retarded the widespread adoption of SUDS but environmental regulators and many local authorities and developers are keen to implement this approach in addition to traditional urban drainage

To understand the concepts, proposals, and need for implementation of Sustainable Systems, it is necessary to contextualize, in a historical manner, how the urban drainage

Through time, and up to the Modern Age, drainage works, as a rule, were not considered as necessary infrastructures providing conditions for the development and ordering of urban centers (Matos, 2003). Nevertheless, rainwater drainage systems have been found in much

In the period prior to the Christian Era, systems implemented by the Persians and Greeks are worthy of note. Drainage networks constructed by the Romans (8th Century B.C. ~ 3rd Century A.D.) may be observed yet today, with small sections still in operation. The same holds true for ruins of cities built by Pre-Columbian peoples in various countries of Latin

Before giving an account of the important transformation which occurred in the 19th Century related to sanitary waste systems and rainwater drainage, it is worthwhile to go back some years in history when, according to Silveira (2002), a period of elimination of flooded areas began, the burying of septic tanks and then their replacement by underground channeling systems. This process for removal of waste and rainwater began in Italy as a result of observing a correlation between mortality rates of people and animals and the sanitation system; after that, it was adopted in innumerable European cities as a public

Thus emerged the concept of sanitary and hygiene related drainage systems, with the principle of expelling waters from cities, whether rainwater or waste water, giving the false impression of a "problem solved". To understand why this solution did not completely solve the problem, one need only look at the resulting physical aspects and observe the immense erosion caused at the end of these drainage systems, as well as all the

morphological changes imposed on receiving bodies of water.

runoff, and maximize amenity and biodiversity opportunities (Woods et al., 2007).

Conservation of natural characteristics of bodies of water;

Balance of hydrological variables in watersheds.

possible.

systems (Andoh & Iwugo, 2002).

more ancient cities or city ruins.

systems being used in our cities were developed.

**2. History of SUDS** 

America (TIM, 2008).

health measure.

surface runoff may also lead to overflow of streams, gullies, ditches, and rivers, creating problems of riverside flooding.

Flooding results in risks to people's health and quality of life, in addition to social and economic losses. This is a recurrent event, practically every year, in large Brazilian urban centers. Specialists affirm that the trend is for the number of critical events to increase because, currently, at least some point of flooding may be detected in almost all mediumsized cities in Brazil.

In the face of this situation, up to the 1990s, the solution to flooding problems had been dealt with according to a health services approach (Silveira, 2002). Up to this period, flooding problems were solved through construction of a rainwater drainage system which had the purpose of increasing water flow efficiency, sending rainwater to another downstream body of water.

However, this solution did not effectively solve flooding problems because whenever a city grew and soil impermeability increased, new points of flooding were observed and the use of ever larger means of channeling of water became necessary. In other words, the natural hydrologic cycle was totally altered, and the process of increasing the water flow efficiency of this channeling was continued, at ever increasing costs.

In addition to this aspect, rainwater in urban areas may be contaminated while still in the atmosphere if the atmosphere is polluted or may become polluted upon coming into contact with urban surfaces, due to the washing of oil, greases, and fecal material, among other pollutants. As a consequence, soil becomes contaminated and bodies of water degraded, compromising availability of surface water.

In the face of this unsustainable situation, in the midst of the 1990s, various countries, following the example of the United States, France, and Australia, proposed a set of new strategies for qualitative and quantitative treatment of rainwater in the urban milieu. The main idea contained in the proposals presented for rainwater management in the urban milieu is maintenance of natural water flow mechanisms, or the use of structures that seek to "imitate" some process of the natural hydrologic cycle that was altered.

Thus, the main techniques used contemplate the use of structures that seek to reproduce water infiltration capacity in the soil lost due to impermeabilization. As a result, a smaller volume of surface runoff is created, and there is a reduction in flooding problems. Furthermore, this promotes recharging of underground aquifers and improvements in water quality.

Although the natural hydrologic cycle is not totally restored through the aid of these techniques, there is significant improvement of the urban environment. Currently, the set of best practices for water management in the urban environment is considered to be the Sustainable Urban Drainage System (SUDS).

SUDS are designed to allow water to either infiltrate into the ground or be retained in devices in order to mimic the natural disposal of surface water (Charlesworth et al. 2003; Charlesworth 2010). Among the goals of SUDS, are:


surface runoff may also lead to overflow of streams, gullies, ditches, and rivers, creating

Flooding results in risks to people's health and quality of life, in addition to social and economic losses. This is a recurrent event, practically every year, in large Brazilian urban centers. Specialists affirm that the trend is for the number of critical events to increase because, currently, at least some point of flooding may be detected in almost all medium-

In the face of this situation, up to the 1990s, the solution to flooding problems had been dealt with according to a health services approach (Silveira, 2002). Up to this period, flooding problems were solved through construction of a rainwater drainage system which had the purpose of increasing water flow efficiency, sending rainwater to another downstream body

However, this solution did not effectively solve flooding problems because whenever a city grew and soil impermeability increased, new points of flooding were observed and the use of ever larger means of channeling of water became necessary. In other words, the natural hydrologic cycle was totally altered, and the process of increasing the water flow efficiency

In addition to this aspect, rainwater in urban areas may be contaminated while still in the atmosphere if the atmosphere is polluted or may become polluted upon coming into contact with urban surfaces, due to the washing of oil, greases, and fecal material, among other pollutants. As a consequence, soil becomes contaminated and bodies of water degraded,

In the face of this unsustainable situation, in the midst of the 1990s, various countries, following the example of the United States, France, and Australia, proposed a set of new strategies for qualitative and quantitative treatment of rainwater in the urban milieu. The main idea contained in the proposals presented for rainwater management in the urban milieu is maintenance of natural water flow mechanisms, or the use of structures that seek

Thus, the main techniques used contemplate the use of structures that seek to reproduce water infiltration capacity in the soil lost due to impermeabilization. As a result, a smaller volume of surface runoff is created, and there is a reduction in flooding problems. Furthermore, this promotes recharging of underground aquifers and improvements in

Although the natural hydrologic cycle is not totally restored through the aid of these techniques, there is significant improvement of the urban environment. Currently, the set of best practices for water management in the urban environment is considered to be the

SUDS are designed to allow water to either infiltrate into the ground or be retained in devices in order to mimic the natural disposal of surface water (Charlesworth et al. 2003;

to "imitate" some process of the natural hydrologic cycle that was altered.

of this channeling was continued, at ever increasing costs.

compromising availability of surface water.

Sustainable Urban Drainage System (SUDS).

Quantitative control of surface runoff;

Charlesworth 2010). Among the goals of SUDS, are:

Improvement in the quality of water from surface runoff;

problems of riverside flooding.

sized cities in Brazil.

of water.

water quality.


These four goals of SUDS contribute to flood control in urban watersheds, principally when they are still in the urbanization phase and the application of SUDS in new undertakings is possible.

This system is designed to manage the environmental risks resulting from urban runoff and to contribute wherever possible to environmental enhancement. SUDS objectives are, therefore, to minimize the impacts from the development on the quantity and quality of the runoff, and maximize amenity and biodiversity opportunities (Woods et al., 2007).

Uncertainty about long‐term maintenance and other operational factors have retarded the widespread adoption of SUDS but environmental regulators and many local authorities and developers are keen to implement this approach in addition to traditional urban drainage systems (Andoh & Iwugo, 2002).

### **2. History of SUDS**

To understand the concepts, proposals, and need for implementation of Sustainable Systems, it is necessary to contextualize, in a historical manner, how the urban drainage systems being used in our cities were developed.

Through time, and up to the Modern Age, drainage works, as a rule, were not considered as necessary infrastructures providing conditions for the development and ordering of urban centers (Matos, 2003). Nevertheless, rainwater drainage systems have been found in much more ancient cities or city ruins.

In the period prior to the Christian Era, systems implemented by the Persians and Greeks are worthy of note. Drainage networks constructed by the Romans (8th Century B.C. ~ 3rd Century A.D.) may be observed yet today, with small sections still in operation. The same holds true for ruins of cities built by Pre-Columbian peoples in various countries of Latin America (TIM, 2008).

Before giving an account of the important transformation which occurred in the 19th Century related to sanitary waste systems and rainwater drainage, it is worthwhile to go back some years in history when, according to Silveira (2002), a period of elimination of flooded areas began, the burying of septic tanks and then their replacement by underground channeling systems. This process for removal of waste and rainwater began in Italy as a result of observing a correlation between mortality rates of people and animals and the sanitation system; after that, it was adopted in innumerable European cities as a public health measure.

Thus emerged the concept of sanitary and hygiene related drainage systems, with the principle of expelling waters from cities, whether rainwater or waste water, giving the false impression of a "problem solved". To understand why this solution did not completely solve the problem, one need only look at the resulting physical aspects and observe the immense erosion caused at the end of these drainage systems, as well as all the morphological changes imposed on receiving bodies of water.

Sustainable Urban Drainage Systems 59

The Hydrologic Cycle represents the passage of water through its three physical states: solid, liquid, and gas. All the factors described above have a large influence on the behavior

However, on a local scale, the quantity of water and the speed at which it circulates through the different phases of the hydrologic cycle are directly influenced by factors such as plant

As we can say that the hydrologic cycle basically consists of a continuous process of transport of water masses from the ocean to the atmosphere, and from it once more to the ocean through precipitation and runoff/flow (surface and underground), it may also be inferred that alterations in the variables involved in this system can modify its

Within the context of sustainable watersheds, the main variables (evaporation, evapotranspiration, precipitation, surface runoff and underground flow) need to be

Descriptively speaking, the hydrologic cycle functions because water from the Earth's surface receives energy from the Sun to undergo heating and rise to the atmosphere in evaporation. Gravity causes condensate water to fall, and there is precipitation. Upon arriving at the surface, water circulates through waterways (surface runoff) that gather into rivers until reaching the oceans, or it infiltrates in soils and rocks through their pores,

But not all water from precipitation will advance in this flow because part of it will be retained in constructions, trees, bushes, and plants; therefore, it never reaches the soil

So, it may be said that waters that arrives at the soil may take various routes; some of them will evaporate and return to the atmosphere and others will infiltrate the ground. But if the intensity of rain goes beyond the infiltration and evaporation portion, small accumulations

When these depressions fill and overflow, water begins to move along the surface, which is designated as surplus rainfall. Upon forming a layer of water that covers the trajectory of movement, we say that surface runoff has begun. If this runoff is stored during its trajectory,

Even so, it must be remembered that the process is complex and the other phases continue occurring simultaneously; therefore, part of the flow may infiltrate the soil or it may evaporate, returning to the atmosphere before reaching a body of water. The water that infiltrates the soil enters first in the soil zone containing plant roots. This upper part of the soil may retain a limited quantity of water, and this quantity is known as field capacity.

Another route for the water that infiltrates the soil is direct evaporation to the atmosphere, which, through transpiration of the plant that took it up, returns it to the atmosphere. This process is called evapotranspiration and occurs at the top of the non-saturated zone, that is,

in the zone where spaces between the soil particles contain both air and water.

maintained or compensated for by direct actions on one or more of these variables.

cover, altitude, topography, temperature, type and use of the soil, and geology.

**3. Hydrologic concepts used in SUDS** 

characteristics locally.

of this cycle, principally when we think on a global scale.

fissures, and cracks, creating underground water flow.

of water called depression storage is formed.

this phase comes to be called detention storage.

(evaporates), and is thus known as loss through interception.

Interestingly enough, rainwater drainage as a public measure did not evolve as a result of modernization of engineering practices in search of comfort, but rather as a recommendation of medical prophylaxis. Evidently, the task of making it concrete in public works and integrating it with the urban landscape belonged to engineers and urban planners, but, unfortunately, this only received greater impulse with the occurrence of cholera epidemics in large cities around the world in the 19th Century. Epidemics which occurred in Europe in the years 1832 and 1849 are of special note.

Between 1850 and the end of the 19th Century, many important cities of the world, principally European capitals, were provided with large single underground networks for waste materials (rainwater drainage and sewage conducted by the same conduits) (Silveira, 2002). According to Jones & MacDonald (2007), in terms of urban drainage, one of the most famous examples of this period was the reconstruction of Paris in the Second Empire of Haussmann and Napoleon III, who used a system designed to rapidly remove waters from the city.

The sanitary hygiene concept, as already mentioned, foresees rapid expulsion of waters from the city for the purpose of preserving the health of the population and eliminating any type of discomfort the water could cause. Nevertheless, what was not foreseen in this effort for channeling is the impact caused downstream, since the sanitary hygiene concept acts only in a local manner in the sense of transferring the problem to other regions. Thus, this concept, associated with rapid growth of the urban population, and by the latter, understanding all the characteristics brought about by urbanization such as impermeabilization of the soil and removal of plant cover, is responsible for constant flooding, landslides, and problems created in relation to recharging of aquifers.

Such a concept was adopted worldwide up to the 1960s of the past century (20th Century). In this period, developed countries began to perceive the conflict generated between the existing rainwater drainage system and the environment. Thus began a new drainage concept, an evolution of the former; concerned not only with public health, but also with the environmental question.

In recent decades, new focus approaching sustainability have been studied, with various names: Low Impact Development (LID), in the USA and Canada; Sustainable Urban Drainage Systems (SUDS), in the United Kingdom; Water Sensitive Urban Design (WSUD), in Australia; and Low Impact Urban Design and Development (LIUDD), in New Zealand. Regardless of the name, the ideas and concepts of the sustainable systems presented are very similar and all make reference to balance among the variables of the hydrologic cycle and their effects on watersheds.

Landscaping, environmental, and economic gains reinforce the advantages presented by this conception of urban drainage treatment, controlling not only the peak flows, but also the volume, the frequency, the duration, and the quality of runoff and drainage (Souza, 2005).

In contrast, developing countries are relatively behind the times, since quantitative control of urban drainage is still limited and quality control of the water drained is still far from accomplished. This reinforces the need for researching means for encouraging the use of techniques, like charging for water use, with the goal of control at the source and maintenance of characteristics of the pre-development hydrologic cycle.

Interestingly enough, rainwater drainage as a public measure did not evolve as a result of modernization of engineering practices in search of comfort, but rather as a recommendation of medical prophylaxis. Evidently, the task of making it concrete in public works and integrating it with the urban landscape belonged to engineers and urban planners, but, unfortunately, this only received greater impulse with the occurrence of cholera epidemics in large cities around the world in the 19th Century. Epidemics which

Between 1850 and the end of the 19th Century, many important cities of the world, principally European capitals, were provided with large single underground networks for waste materials (rainwater drainage and sewage conducted by the same conduits) (Silveira, 2002). According to Jones & MacDonald (2007), in terms of urban drainage, one of the most famous examples of this period was the reconstruction of Paris in the Second Empire of Haussmann and Napoleon III, who used a system designed to rapidly remove waters from

The sanitary hygiene concept, as already mentioned, foresees rapid expulsion of waters from the city for the purpose of preserving the health of the population and eliminating any type of discomfort the water could cause. Nevertheless, what was not foreseen in this effort for channeling is the impact caused downstream, since the sanitary hygiene concept acts only in a local manner in the sense of transferring the problem to other regions. Thus, this concept, associated with rapid growth of the urban population, and by the latter, understanding all the characteristics brought about by urbanization such as impermeabilization of the soil and removal of plant cover, is responsible for constant

Such a concept was adopted worldwide up to the 1960s of the past century (20th Century). In this period, developed countries began to perceive the conflict generated between the existing rainwater drainage system and the environment. Thus began a new drainage concept, an evolution of the former; concerned not only with public health, but also with the

In recent decades, new focus approaching sustainability have been studied, with various names: Low Impact Development (LID), in the USA and Canada; Sustainable Urban Drainage Systems (SUDS), in the United Kingdom; Water Sensitive Urban Design (WSUD), in Australia; and Low Impact Urban Design and Development (LIUDD), in New Zealand. Regardless of the name, the ideas and concepts of the sustainable systems presented are very similar and all make reference to balance among the variables of the hydrologic cycle

Landscaping, environmental, and economic gains reinforce the advantages presented by this conception of urban drainage treatment, controlling not only the peak flows, but also the volume, the frequency, the duration, and the quality of runoff and drainage (Souza, 2005). In contrast, developing countries are relatively behind the times, since quantitative control of urban drainage is still limited and quality control of the water drained is still far from accomplished. This reinforces the need for researching means for encouraging the use of techniques, like charging for water use, with the goal of control at the source and

maintenance of characteristics of the pre-development hydrologic cycle.

flooding, landslides, and problems created in relation to recharging of aquifers.

occurred in Europe in the years 1832 and 1849 are of special note.

the city.

environmental question.

and their effects on watersheds.

### **3. Hydrologic concepts used in SUDS**

The Hydrologic Cycle represents the passage of water through its three physical states: solid, liquid, and gas. All the factors described above have a large influence on the behavior of this cycle, principally when we think on a global scale.

However, on a local scale, the quantity of water and the speed at which it circulates through the different phases of the hydrologic cycle are directly influenced by factors such as plant cover, altitude, topography, temperature, type and use of the soil, and geology.

As we can say that the hydrologic cycle basically consists of a continuous process of transport of water masses from the ocean to the atmosphere, and from it once more to the ocean through precipitation and runoff/flow (surface and underground), it may also be inferred that alterations in the variables involved in this system can modify its characteristics locally.

Within the context of sustainable watersheds, the main variables (evaporation, evapotranspiration, precipitation, surface runoff and underground flow) need to be maintained or compensated for by direct actions on one or more of these variables.

Descriptively speaking, the hydrologic cycle functions because water from the Earth's surface receives energy from the Sun to undergo heating and rise to the atmosphere in evaporation. Gravity causes condensate water to fall, and there is precipitation. Upon arriving at the surface, water circulates through waterways (surface runoff) that gather into rivers until reaching the oceans, or it infiltrates in soils and rocks through their pores, fissures, and cracks, creating underground water flow.

But not all water from precipitation will advance in this flow because part of it will be retained in constructions, trees, bushes, and plants; therefore, it never reaches the soil (evaporates), and is thus known as loss through interception.

So, it may be said that waters that arrives at the soil may take various routes; some of them will evaporate and return to the atmosphere and others will infiltrate the ground. But if the intensity of rain goes beyond the infiltration and evaporation portion, small accumulations of water called depression storage is formed.

When these depressions fill and overflow, water begins to move along the surface, which is designated as surplus rainfall. Upon forming a layer of water that covers the trajectory of movement, we say that surface runoff has begun. If this runoff is stored during its trajectory, this phase comes to be called detention storage.

Even so, it must be remembered that the process is complex and the other phases continue occurring simultaneously; therefore, part of the flow may infiltrate the soil or it may evaporate, returning to the atmosphere before reaching a body of water. The water that infiltrates the soil enters first in the soil zone containing plant roots. This upper part of the soil may retain a limited quantity of water, and this quantity is known as field capacity.

Another route for the water that infiltrates the soil is direct evaporation to the atmosphere, which, through transpiration of the plant that took it up, returns it to the atmosphere. This process is called evapotranspiration and occurs at the top of the non-saturated zone, that is, in the zone where spaces between the soil particles contain both air and water.

Sustainable Urban Drainage Systems 61

Coefficient, which is the ratio between the volume of surface water runoff and the volume of

Various problems are caused by change in the Runoff Coefficient. These problems go beyond erosion of the drainage area; they cause imbalances in the rainwater channel

Alteration of natural drainage basin, either by the impact of forestry, agriculture, or urbanization,

Along with urbanization, new engineering works arise such as buildings, paving of streets, sidewalks, and consequent removal of original plant cover from the environment, which causes a change in the natural permeability of these areas. Due to this impermeabilization, there is a reduction in rainwater infiltration, leading to a strong increase of rainwater runoff. Currently, in Brazil, all large cities have some point of flooding and medium-sized cities have at least some inundated points during high water periods. This problem has worsened

This occurs principally because urbanization tends to remove existing vegetation in watersheds and it is replaced by impermeable areas (sidewalks, paved streets, roofs, parking lots, etc.). These changes end up leading to changes in the local hydrograph, causing concentration times to be reduced and peak flows to be expanded. In the same degree of precipitation, the runoff volume is expanded and thus the lower or flat areas of the

Some engineering solutions bet on transfer of the problem by improving or increasing the rainwater drainage system, but in general, they end up transferring problems further downstream. In addition, upon transferring a greater volume of runoff to the final point of

In addition, the presence of peak flows has resulted in increases of the frequency and seriousness of flooding and in intensification of erosion processes with increase of production, transport, and deposit of sediments. Impacts like these directly affect the quality

Changes in the local hydrologic cycle and its consequences due to the urbanization process, as previously mentioned, directly affect the environmental balance and, thus, the quality of life of the resident population. Problems arise both due to the inflows to the system, which in future will be less certain, and increasing downstream hydraulic and regulatory

In this context, it may be observed that the conventional rainwater drainage system with the principle of rapid flow downstream is not able to eliminate any disturbance that these

Among the sustainable systems that are being developed and implemented, the following

can impose dramatic changes in the movement and storage of water (Booth, 1991).

year after year in Brazilian cities, which seem lost in trying to control these events.

(erosion and silting) and the ever so frequent urban flooding.

the drainage system, serious erosion problems are generated.

rainwater.

**4. The effect of urbanization** 

watershed will tend to flood.

of bodies of water in these watersheds.

constraints on outflows (Ashley et al., 2007).

**5. Types of sustainable systems** 

devices or techniques may be highlighted:

waters may bring about.

Therefore, processes may be distinguished as:


The main factors that interfere in the processes of Evaporation and Evapotranspiration are:


When the water that passed through the previous phases continues to infiltrate, it reaches the saturated zone, enters in underground circulation, and contributes to increase stored water, therefore recharging the aquifers. In the saturated zone or aquifer, the soil pores or fractures in rock formations are completely filled by water, and are therefore saturated. The top of the saturated zones corresponds to the level of the water table and for that reason they are also most susceptible to contamination.

Underground circulation continues and water may come to the surface through springs and feed bodies of water or discharge directly into the ocean.

The problem begins when human activities begin to interfere in the aforementioned processes, and these alterations produced by man on the ecosystem may alter part of the hydrologic cycle.

Thinking globally, human activities that release elevated concentration of gases to the atmosphere increase the greenhouse effect and consequently change the conditions of thermal radiation emissions and cause imbalance in the system.

Locally, engineering works in general cause changes in variables such as infiltration, evaporation, and runoff. Among these works are water engineering works which act on rivers, lakes, and oceans, modifying their natural routes.

In addition, practically all activities that carry out deforestation for utilization of wood, or even for cleaning the area for new construction work, act negatively on behavior of the watershed. Among the main effects of deforestation are increased runoff and reduction of evapotranspiration for the same amount of precipitation (varying in terms of the different types of soil use).

But of all human activities, urbanization is that which produces the greatest local changes in the processes of the Earth's hydrologic cycle. The most rapidly changed factor is the Runoff

 Evaporation: this is the physical process in which a liquid or solid passes to the gaseous state due to solar radiation and to the processes of molecular and turbulent diffusion; Transpiration: this is the release of water vapor by plants by means of stomata and

 Evapotranspiration: this is the sum of the evaporation and transpiration processes, given the difficulty of separating the two phenomena. Evapotranspiration is expressed

The main factors that interfere in the processes of Evaporation and Evapotranspiration are: Air temperature: the greater the temperature, the greater the capacity of the air for

(Relative) atmospheric humidity: the lower the relative air humidity, the greater the

Wind: the displacement of air masses constantly renews the mass of water vapor over

When the water that passed through the previous phases continues to infiltrate, it reaches the saturated zone, enters in underground circulation, and contributes to increase stored water, therefore recharging the aquifers. In the saturated zone or aquifer, the soil pores or fractures in rock formations are completely filled by water, and are therefore saturated. The top of the saturated zones corresponds to the level of the water table and for that reason

Underground circulation continues and water may come to the surface through springs and

The problem begins when human activities begin to interfere in the aforementioned processes, and these alterations produced by man on the ecosystem may alter part of the

Thinking globally, human activities that release elevated concentration of gases to the atmosphere increase the greenhouse effect and consequently change the conditions of

Locally, engineering works in general cause changes in variables such as infiltration, evaporation, and runoff. Among these works are water engineering works which act on

In addition, practically all activities that carry out deforestation for utilization of wood, or even for cleaning the area for new construction work, act negatively on behavior of the watershed. Among the main effects of deforestation are increased runoff and reduction of evapotranspiration for the same amount of precipitation (varying in terms of the different

But of all human activities, urbanization is that which produces the greatest local changes in the processes of the Earth's hydrologic cycle. The most rapidly changed factor is the Runoff

Water temperature: the hotter the water, the greater the evaporation;

Salinity: the presence of salts reduces evaporation (2% to 3%).

Therefore, processes may be distinguished as:

organelles located on leaves;

in terms of water depth, in mm.

evaporative capacity of the air;

they are also most susceptible to contamination.

feed bodies of water or discharge directly into the ocean.

thermal radiation emissions and cause imbalance in the system.

rivers, lakes, and oceans, modifying their natural routes.

containing water vapor;

the evaporating surface;

hydrologic cycle.

types of soil use).

Coefficient, which is the ratio between the volume of surface water runoff and the volume of rainwater.

Various problems are caused by change in the Runoff Coefficient. These problems go beyond erosion of the drainage area; they cause imbalances in the rainwater channel (erosion and silting) and the ever so frequent urban flooding.

### **4. The effect of urbanization**

Alteration of natural drainage basin, either by the impact of forestry, agriculture, or urbanization, can impose dramatic changes in the movement and storage of water (Booth, 1991).

Along with urbanization, new engineering works arise such as buildings, paving of streets, sidewalks, and consequent removal of original plant cover from the environment, which causes a change in the natural permeability of these areas. Due to this impermeabilization, there is a reduction in rainwater infiltration, leading to a strong increase of rainwater runoff.

Currently, in Brazil, all large cities have some point of flooding and medium-sized cities have at least some inundated points during high water periods. This problem has worsened year after year in Brazilian cities, which seem lost in trying to control these events.

This occurs principally because urbanization tends to remove existing vegetation in watersheds and it is replaced by impermeable areas (sidewalks, paved streets, roofs, parking lots, etc.). These changes end up leading to changes in the local hydrograph, causing concentration times to be reduced and peak flows to be expanded. In the same degree of precipitation, the runoff volume is expanded and thus the lower or flat areas of the watershed will tend to flood.

Some engineering solutions bet on transfer of the problem by improving or increasing the rainwater drainage system, but in general, they end up transferring problems further downstream. In addition, upon transferring a greater volume of runoff to the final point of the drainage system, serious erosion problems are generated.

In addition, the presence of peak flows has resulted in increases of the frequency and seriousness of flooding and in intensification of erosion processes with increase of production, transport, and deposit of sediments. Impacts like these directly affect the quality of bodies of water in these watersheds.

Changes in the local hydrologic cycle and its consequences due to the urbanization process, as previously mentioned, directly affect the environmental balance and, thus, the quality of life of the resident population. Problems arise both due to the inflows to the system, which in future will be less certain, and increasing downstream hydraulic and regulatory constraints on outflows (Ashley et al., 2007).

In this context, it may be observed that the conventional rainwater drainage system with the principle of rapid flow downstream is not able to eliminate any disturbance that these waters may bring about.

#### **5. Types of sustainable systems**

Among the sustainable systems that are being developed and implemented, the following devices or techniques may be highlighted:

Sustainable Urban Drainage Systems 63

Porous concrete pavement: just as in porous asphalt pavement, it only has a difference

For Silveira (2002), permeable pavements are pavements that normally act in control of the peak and volume of runoff, in control of diffuse pollution, and, when they infiltrate water in the soil, they promote recharging of underground waters. Porous pavements are appropriate for use on light traffic roadways, parking areas, pedestrian streets, squares, and

Schlüter et al. (2002) studies have demonstrated that porous pavement can get good results,

Abbott & Comino-Mateos (2003) have also shown the peaks of storm events were significantly reduced as they flowed out of the pavement system. For example, the peak outflow corresponding to a rainfall intensity of 12 mm/h was 0.37 mm/h. This is a major

Even so, as mentioned above, this system only leads to temporary water storage and therefore needs to be joined with another system for retention and/or infiltration of the

For Urbonas & Stahre (1993), semi-permeable pavements are constructed of hollowed concrete blocks filled with granular material like sand or undergrowth, like grass, placed over a granular base layer and this layer is covered by geotextile filters to avoid migration of

According to studies of Araújo *et al.* (2000), semipermeable pavements may be industrial concrete blocks, as well as paving blocks, among other items. According to Cruz *et al.* (1999), they have the function of providing for reduction in runoff volumes and in the time for

Moreover, according to Araújo *et al.* (2000), in their studies performed on different types of semipermeable pavements (concrete, concrete blocks, compacted soil, paving blocks, and hollowed blocks), after simulations of similar precipitation levels, the following runoffs were obtained, respectively: 17.45 mm, 15.00 mm, 12.32 mm, 10.99 mm, and 0.5 mm. These studies were able to prove the efficiency of different types of pavements in reduction of

Furthermore, according to Araújo *et al.* (2000), the use of permeable pavements eliminates the need for collection boxes and water conduits because the device practically does not generate runoff. In addition to implementation costs of permeable pavements, there are

in the sand fraction as compared to conventional pavements;

lag times of 45 minutes for medium and 145 minutes for small events;

b. enables urban developments to comply more easily with discharge consents.

Semipermeable pavement (described below).

average percentage outflow of just under 50%;

initial rainfall capacity in the order of 2.27 mm.

a. it reduces the capacity of sewerage systems; and,

water absorbed, since this system does not have that function.

benefit of these systems because:

**5.2 Semi-permeable pavement** 

the granular base.

recharging the watershed.

runoff through increase of infiltration rates.

sports courts.

such as:


These devices adopted in sustainable systems seek to mitigate the effects of urbanization through reduction of runoff and provide for significant increases in infiltration rates. To obtain these results, permeable areas and rainwater retention areas must be created as part of a larger complex, which is water resource management.

Such systems may be used jointly or separately according to the proposed project or the local needs and/or possibilities, providing a good cost/benefit ratio, in addition to social, economic, and environmental gains. Even so, in general, systems only produce a good (significant) result when applied jointly and in various parts of the watershed to compose a greater project.

Currently there are a large number of sustainable drainage systems being tested or even already consolidated in innumerable countries. In following, we will present the principal systems that may be adopted in management of urban watersheds as a way for improving or supplementing conventional drainage systems.

#### **5.1 Permeable pavement**

The need for draining surface waters to outside the location where they are being generated may be reduced or eliminated. This may be accomplished by leading it to flow through porous pavements built with materials like concrete blocks, crushed rock, or porous asphalt. Depending on soil conditions (permeability, infiltration rates, etc.), the water may infiltrate directly into the subsoil or be stored in an underground reservoir as, for example, in a layer of crushed rock or in a reservoir, respectively. If infiltration is not possible or appropriate (as, for example, due to soil contamination), an impermeable membrane may be used as a barrier to keep the pavement free of water under all conditions. Even in these cases, removal of most pollutants occurs both on the surface or sub-base of the material itself, or through the filtering action of the reservoir or in the subsoil.

Thus, it may be said that permeable pavement is an alternative infiltration device where surface runoff is diverted through a permeable surface into a rock reservoir located under the same surface (Urbonas & Stahre, 1993). According to the same authors, permeable pavement may be classified into three types:

 Porous asphalt pavement: has its upper layer constructed in a similar way to conventional pavements with a difference in the fraction of fine sand, which is removed from the mixture of the aggregates used in construction of the pavement;

These devices adopted in sustainable systems seek to mitigate the effects of urbanization through reduction of runoff and provide for significant increases in infiltration rates. To obtain these results, permeable areas and rainwater retention areas must be created as part

Such systems may be used jointly or separately according to the proposed project or the local needs and/or possibilities, providing a good cost/benefit ratio, in addition to social, economic, and environmental gains. Even so, in general, systems only produce a good (significant) result when applied jointly and in various parts of the watershed to compose a

Currently there are a large number of sustainable drainage systems being tested or even already consolidated in innumerable countries. In following, we will present the principal systems that may be adopted in management of urban watersheds as a way for improving

The need for draining surface waters to outside the location where they are being generated may be reduced or eliminated. This may be accomplished by leading it to flow through porous pavements built with materials like concrete blocks, crushed rock, or porous asphalt. Depending on soil conditions (permeability, infiltration rates, etc.), the water may infiltrate directly into the subsoil or be stored in an underground reservoir as, for example, in a layer of crushed rock or in a reservoir, respectively. If infiltration is not possible or appropriate (as, for example, due to soil contamination), an impermeable membrane may be used as a barrier to keep the pavement free of water under all conditions. Even in these cases, removal of most pollutants occurs both on the surface or sub-base of the material itself, or through

Thus, it may be said that permeable pavement is an alternative infiltration device where surface runoff is diverted through a permeable surface into a rock reservoir located under the same surface (Urbonas & Stahre, 1993). According to the same authors, permeable

 Porous asphalt pavement: has its upper layer constructed in a similar way to conventional pavements with a difference in the fraction of fine sand, which is removed

from the mixture of the aggregates used in construction of the pavement;

 Permeable pavement; Semipermeable pavement;

 Infiltration trenches; Infiltration gullies; Infiltration wells; Microreservoirs; Rooftop reservoirs; Green roofing;

Grassed strips.

greater project.

**5.1 Permeable pavement** 

Detention and retention reservoirs;

Underground reservoirs; and,

of a larger complex, which is water resource management.

or supplementing conventional drainage systems.

the filtering action of the reservoir or in the subsoil.

pavement may be classified into three types:


For Silveira (2002), permeable pavements are pavements that normally act in control of the peak and volume of runoff, in control of diffuse pollution, and, when they infiltrate water in the soil, they promote recharging of underground waters. Porous pavements are appropriate for use on light traffic roadways, parking areas, pedestrian streets, squares, and sports courts.

Schlüter et al. (2002) studies have demonstrated that porous pavement can get good results, such as:


Abbott & Comino-Mateos (2003) have also shown the peaks of storm events were significantly reduced as they flowed out of the pavement system. For example, the peak outflow corresponding to a rainfall intensity of 12 mm/h was 0.37 mm/h. This is a major benefit of these systems because:


Even so, as mentioned above, this system only leads to temporary water storage and therefore needs to be joined with another system for retention and/or infiltration of the water absorbed, since this system does not have that function.

#### **5.2 Semi-permeable pavement**

For Urbonas & Stahre (1993), semi-permeable pavements are constructed of hollowed concrete blocks filled with granular material like sand or undergrowth, like grass, placed over a granular base layer and this layer is covered by geotextile filters to avoid migration of the granular base.

According to studies of Araújo *et al.* (2000), semipermeable pavements may be industrial concrete blocks, as well as paving blocks, among other items. According to Cruz *et al.* (1999), they have the function of providing for reduction in runoff volumes and in the time for recharging the watershed.

Moreover, according to Araújo *et al.* (2000), in their studies performed on different types of semipermeable pavements (concrete, concrete blocks, compacted soil, paving blocks, and hollowed blocks), after simulations of similar precipitation levels, the following runoffs were obtained, respectively: 17.45 mm, 15.00 mm, 12.32 mm, 10.99 mm, and 0.5 mm. These studies were able to prove the efficiency of different types of pavements in reduction of runoff through increase of infiltration rates.

Furthermore, according to Araújo *et al.* (2000), the use of permeable pavements eliminates the need for collection boxes and water conduits because the device practically does not generate runoff. In addition to implementation costs of permeable pavements, there are

Sustainable Urban Drainage Systems 65

treatment method that uses simple technology which is easily operated and of low cost. In them, there is principally good cycling of nutrients, removal of organic material, and reduction of pathogenic microorganisms present in residual waters. Among the numerous mechanisms that cause this removal, the principal ones are settling (sieving effect caused by microbial biofilm adhering to the roots and substrate), predation and competition among microorganisms and possible toxic substances produced by plants and released through their roots (Brix, 1994). For Zheng et al. (2006), combined wetlands and infiltration ponds are cost-effective 'end of pipe' drainage solutions that can be applied for local source control as

In summary, it may be said that these systems have important functions, among which the

Their capacity for regularization of water flows, moderating peaks of flooding

Capacity for modifying and controlling water quality (in the event of limits to be

Even with these benefits, this system may be adopted only after adequacy studies in regard to characteristics of the location, as well as studies for avoiding problems with proliferation

Infiltration trenches are reservoirs full of rock to which rainwater is directed for initial storage and from which water gradually infiltrates the soil. Its longevity may be increased through incorporation of a filter, or deposit, which removes excessive entry of solids and

According to Silva (2007) infiltration trenches (percolation and/or draining) are linear structures in which length is preponderantly greater than width and depth. Their geometry depends on the infiltrability of the soil and the area available for infiltration to occur. Depending on local conditions and the volume to infiltrate, the design may give priority to infiltration, storage, or both. Generally trenches are planned for large volumes of water to be

According to Silveira (2008), the main function of infiltration trenches is to reduce runoff and promote recharging of aquifers, but another important function is to promote water

Waste filters (also known as French drains) are widely used by authorities along highways. They are similar to infiltration trenches, but use a perforated pipe, which carries the flow along the gulley. This allows storage, filtration, and infiltration of water that passes from the collection area to the final point. Pollutants are removed by absorption, filtering and microbial decomposition in the surrounding soil. That way, these systems may be successfully designed so as to incorporate infiltration as well as to serve as efficient filtration

infiltrated, are closed, and allow landscaping use in harmony with other structures.

 Their importance in the function of reproduction and feeding of aquatic fauna; A form of protection of local biodiversity as a refuge area for land fauna; A silting control system for rivers due to their capacity in retaining sediments.

of insects that may cause health risks to those living near the area.

part of urban development and regeneration.

(according to their designed capacity);

following stand out:

established);

**5.5 Infiltration trench** 

thus avoids colmatation of the system.

treatment by means of soil infiltration.

systems.

maintenance costs, which consist of cleaning the pores of porous pavements (porous concrete) with water jets and machines for vacuuming of dirt and sediment. These costs were not estimated due to the non-existence of companies specialized in maintenance of this type of device in the country. Nevertheless, to have an idea, average expense on maintenance in the United States is in the order of 1% to 2% of the implementation cost of the device.

#### **5.3 Retention and detention reservoirs**

The great advantage of retention reservoirs is that they may be installed in public areas, such as squares, parks, and courts that have another use after precipitations. Detention reservoirs, for their part, are maintained with a water layer and have controlled water quality. They may be applied in grassy marshes or urban reservoirs. Closed detention reservoirs have a cost seven times greater than open reservoirs. There are the further alternatives of off-line systems in which a part of the discharge floods in a lateral manner and then returns to the main waterway (Parkinson *et al*., 2003).

For Cruz *et al.* (1998), the main problem of detention reservoirs is maintenance, as they create heavy obligations on their owner. The reason for this is that with rains, surface runoff carries all types of solid residues and sediments available in the watershed. Therefore, the need for seeking devices for periodic cleaning of the reservoirs must be taken into account, thus avoiding loss in their efficiency.

Consideration of maintenance costs has the greatest influence in the case of the open device since it has a lower cost of implementation, but needs more periodic maintenance due to public health problems; that way, this type of structure presents annual maintenance costs estimated at US\$ 130.00, which may bring it up to the cost of the other systems in 4 or 5 years (Cruz *et al.*, 1998).

#### **5.4 Wetlands**

Wetlands are land areas whose soil remains saturated with water, whether this is permanent or seasonal moisture. They may be natural or constructed, and these areas may also be partially or totally covered by a certain depth of water. This wetlands system includes swamps, marshes, and lowlands, among others. In addition, the water in wetlands may be salt water, fresh water, or brackish water.

Although they may be designed as wet or dry lagoons, they are more visually pleasing and promote biodiversity where permanent water is included. In addition, when dealing with a flooded system, they may be designed to accommodate considerable variations in water levels during precipitations, reinforcing storage capacity against flooding.

Another important characteristic is that the level of solids removal may be significant when there is adequate detention time. Algae and plants of wetlands provide a particularly good level of filtering and removal of nutrients. Thus, lagoons and wetlands may be fed by drainage gullies or piping systems, small areas of urban sewage, as well as serving as a type of sediment "trap", aiding in sedimentation management problems.

According to Costa *et al.* (2003), for minimizing risks of residual waters, also reducing microbiological contamination, constructed wetlands are currently considered as a

maintenance costs, which consist of cleaning the pores of porous pavements (porous concrete) with water jets and machines for vacuuming of dirt and sediment. These costs were not estimated due to the non-existence of companies specialized in maintenance of this type of device in the country. Nevertheless, to have an idea, average expense on maintenance in the United States is in the order of 1% to 2% of the implementation cost of

The great advantage of retention reservoirs is that they may be installed in public areas, such as squares, parks, and courts that have another use after precipitations. Detention reservoirs, for their part, are maintained with a water layer and have controlled water quality. They may be applied in grassy marshes or urban reservoirs. Closed detention reservoirs have a cost seven times greater than open reservoirs. There are the further alternatives of off-line systems in which a part of the discharge floods in a lateral manner

For Cruz *et al.* (1998), the main problem of detention reservoirs is maintenance, as they create heavy obligations on their owner. The reason for this is that with rains, surface runoff carries all types of solid residues and sediments available in the watershed. Therefore, the need for seeking devices for periodic cleaning of the reservoirs must be taken into account,

Consideration of maintenance costs has the greatest influence in the case of the open device since it has a lower cost of implementation, but needs more periodic maintenance due to public health problems; that way, this type of structure presents annual maintenance costs estimated at US\$ 130.00, which may bring it up to the cost of the other systems in 4 or 5

Wetlands are land areas whose soil remains saturated with water, whether this is permanent or seasonal moisture. They may be natural or constructed, and these areas may also be partially or totally covered by a certain depth of water. This wetlands system includes swamps, marshes, and lowlands, among others. In addition, the water in wetlands may be

Although they may be designed as wet or dry lagoons, they are more visually pleasing and promote biodiversity where permanent water is included. In addition, when dealing with a flooded system, they may be designed to accommodate considerable variations in water

Another important characteristic is that the level of solids removal may be significant when there is adequate detention time. Algae and plants of wetlands provide a particularly good level of filtering and removal of nutrients. Thus, lagoons and wetlands may be fed by drainage gullies or piping systems, small areas of urban sewage, as well as serving as a type

According to Costa *et al.* (2003), for minimizing risks of residual waters, also reducing microbiological contamination, constructed wetlands are currently considered as a

levels during precipitations, reinforcing storage capacity against flooding.

of sediment "trap", aiding in sedimentation management problems.

the device.

**5.3 Retention and detention reservoirs** 

thus avoiding loss in their efficiency.

salt water, fresh water, or brackish water.

years (Cruz *et al.*, 1998).

**5.4 Wetlands** 

and then returns to the main waterway (Parkinson *et al*., 2003).

treatment method that uses simple technology which is easily operated and of low cost. In them, there is principally good cycling of nutrients, removal of organic material, and reduction of pathogenic microorganisms present in residual waters. Among the numerous mechanisms that cause this removal, the principal ones are settling (sieving effect caused by microbial biofilm adhering to the roots and substrate), predation and competition among microorganisms and possible toxic substances produced by plants and released through their roots (Brix, 1994). For Zheng et al. (2006), combined wetlands and infiltration ponds are cost-effective 'end of pipe' drainage solutions that can be applied for local source control as part of urban development and regeneration.

In summary, it may be said that these systems have important functions, among which the following stand out:


Even with these benefits, this system may be adopted only after adequacy studies in regard to characteristics of the location, as well as studies for avoiding problems with proliferation of insects that may cause health risks to those living near the area.

#### **5.5 Infiltration trench**

Infiltration trenches are reservoirs full of rock to which rainwater is directed for initial storage and from which water gradually infiltrates the soil. Its longevity may be increased through incorporation of a filter, or deposit, which removes excessive entry of solids and thus avoids colmatation of the system.

According to Silva (2007) infiltration trenches (percolation and/or draining) are linear structures in which length is preponderantly greater than width and depth. Their geometry depends on the infiltrability of the soil and the area available for infiltration to occur. Depending on local conditions and the volume to infiltrate, the design may give priority to infiltration, storage, or both. Generally trenches are planned for large volumes of water to be infiltrated, are closed, and allow landscaping use in harmony with other structures.

According to Silveira (2008), the main function of infiltration trenches is to reduce runoff and promote recharging of aquifers, but another important function is to promote water treatment by means of soil infiltration.

Waste filters (also known as French drains) are widely used by authorities along highways. They are similar to infiltration trenches, but use a perforated pipe, which carries the flow along the gulley. This allows storage, filtration, and infiltration of water that passes from the collection area to the final point. Pollutants are removed by absorption, filtering and microbial decomposition in the surrounding soil. That way, these systems may be successfully designed so as to incorporate infiltration as well as to serve as efficient filtration systems.

Sustainable Urban Drainage Systems 67

masonry, PVC, or another material, having a discharge structure like an orifice. They are normally buried, but they may be open to view provided that there is a height limitation

According to Cruz *et al.* (1998), the general cost of implementation of an underground microreservoir for control in urban lots is, on average, from US\$ 400.00 to US\$ 500.00, with

For Reis *et al.* (2008), infiltration wells are isolated devices that allow infiltration of runoff into the soil. They may be structured through filling with crushed rock (porous medium), as well as being lined by perforated concrete piping or bricks laid in a staggered manner surrounded by a geotextile sheet making the soil/piping interface. They have the advantages of low cost of execution and attempt at balance of the urban hydrologic cycle by

Nevertheless, for Silveira (2002), the well also has its drawbacks for not having the capacity for supporting large loads of sediments and offering risks in regard to infiltration of

According to Reis (2005), the cost of execution of an infiltration well for an area of 500 m²,

According to Silva (2004), this is a device that seeks to compensate the effect of impermeabilization by means of the impact structure itself, which in this case is the roof. According to Azzout *et al.* (1994), the rooftop reservoir functions as provisional storage of rainwater, releasing it gradually to the rainwater network by means of a specific regulating device. For Silva (2004), both roofing tiles as well as concrete roofing structures that can

Nevertheless, Azzout *et al.* (1994) present considerations in regard to the rooftop reservoir, expressing the need to take care with more highly sloped rooftops by the fact that its installation is restricted to rooftops with a slope limit of 2%, also emphasizing the difficulty of installing the reservoir on already existing rooftops and possibly the high cost of the

With respect to its pollutants, roof runoff is generally considered as non-polluted, or at least not significantly polluted, compared to waste waters and highway runoff, since it consists of rainwater flowing over various, in general less abrasive materials, such as tiles, bitumen, less corrosive metals and concrete. In general, it may be stated that the quality of runoff may be ameliorated or become worse compared to the composition of atmospheric deposition depending on the kind of materials used for roof cover and drainage systems and their interaction with the atmospheric deposition. For building materials displaying open air corrosion data or data of leaching experiments, runoff loads can even be assessed (Zobrist et

due to the drainage network.

**5.8 Infiltration well** 

pollutants.

device.

al., 2000).

**5.9 Rooftop reservoir** 

the need for additional spending on its maintenance.

intermediation of recharging the water table.

determined in December 2004, was US\$ 1,312.50.

store rainwater may also be used for the purpose of collecting water.

Thus, according to Nascimento (1996), the advantages in the use of this type of structure are:


The cost of implementation of an infiltration trench, according to Souza & Goldenfum (1999), basically depends on the cost of earthwork and the cost of materials (crushed rock and geotextile). A trench that drains an area of around 300 m² costs around US\$ 239.00 (experimental module). That gives us an estimated cost of US\$ 0.79/m².

Infiltration systems may also be very effective in industrial zones. But the use of solutions based on infiltration for these locations requires careful reflection, principally because there is the risk of environmental damages caused by soil contamination. In this case, the focus will be on not mobilizing the contaminants.

#### **5.6 Infiltration ditch and gulley**

Ditches and gullies are compensatory techniques consisting of simple depressions dug into the ground for the purpose of collecting rainwater, making temporary storage and favoring infiltration (Silva, 2007).

The depressions are linear and on permeable land, where generally there is a grassy covering. In addition, the infiltration gulley may incorporate small deceleration dams that favor infiltration and protect against erosion. Nevertheless, according to Silveira (2002), this system may cause colmatation and allow the passage of pollutants and it has a propensity to retain stagnant water. Therefore it needs frequent maintenance.

Ditches are characteristically works of large width and low slope in the longitudinal direction dug into the earth. Gullies, for their part, are ditches that are not very deep (Brito, 2006). In both cases, they may also be used as one of the management resources within gardened areas of the urbanized watershed, or may even be incorporated in leisure areas.

These systems provide temporary storage for rainwater, reducing peak flows of waters and also aid in filtering of pollutants (deposited in the impermeable areas). They are often installed as part of a drainage network, where they help to connect it to a lagoon or wetland before final discharge into a natural waterway. Even so, they have often been installed along avenues, streets, and roadways to substitute conventional drainage systems.

#### **5.7 Microreservoir**

For Loganathan *et al*. (1985), microreservoirs are storage devices for precipitated water which act in the sense of retarding concentration time, mitigating the peaks of flow hydrographs.

Agra (2001) defines it as simple structures in the form of boxes similar to those used for supply water. They may be made of diverse types of materials as, for example, concrete, masonry, PVC, or another material, having a discharge structure like an orifice. They are normally buried, but they may be open to view provided that there is a height limitation due to the drainage network.

According to Cruz *et al.* (1998), the general cost of implementation of an underground microreservoir for control in urban lots is, on average, from US\$ 400.00 to US\$ 500.00, with the need for additional spending on its maintenance.

#### **5.8 Infiltration well**

66 Drainage Systems

Thus, according to Nascimento (1996), the advantages in the use of this type of structure are:

The cost of implementation of an infiltration trench, according to Souza & Goldenfum (1999), basically depends on the cost of earthwork and the cost of materials (crushed rock and geotextile). A trench that drains an area of around 300 m² costs around US\$ 239.00

Infiltration systems may also be very effective in industrial zones. But the use of solutions based on infiltration for these locations requires careful reflection, principally because there is the risk of environmental damages caused by soil contamination. In this case, the focus

Ditches and gullies are compensatory techniques consisting of simple depressions dug into the ground for the purpose of collecting rainwater, making temporary storage and favoring

The depressions are linear and on permeable land, where generally there is a grassy covering. In addition, the infiltration gulley may incorporate small deceleration dams that favor infiltration and protect against erosion. Nevertheless, according to Silveira (2002), this system may cause colmatation and allow the passage of pollutants and it has a propensity to

Ditches are characteristically works of large width and low slope in the longitudinal direction dug into the earth. Gullies, for their part, are ditches that are not very deep (Brito, 2006). In both cases, they may also be used as one of the management resources within gardened areas of the urbanized watershed, or may even be incorporated in leisure areas.

These systems provide temporary storage for rainwater, reducing peak flows of waters and also aid in filtering of pollutants (deposited in the impermeable areas). They are often installed as part of a drainage network, where they help to connect it to a lagoon or wetland before final discharge into a natural waterway. Even so, they have often been installed along

For Loganathan *et al*. (1985), microreservoirs are storage devices for precipitated water which act in the sense of retarding concentration time, mitigating the peaks of flow

Agra (2001) defines it as simple structures in the form of boxes similar to those used for supply water. They may be made of diverse types of materials as, for example, concrete,

avenues, streets, and roadways to substitute conventional drainage systems.

Reduction or even elimination of the local microdrainage network;

(experimental module). That gives us an estimated cost of US\$ 0.79/m².

retain stagnant water. Therefore it needs frequent maintenance.

Reduction of risks of flooding;

 Reduction in pollution of surface waters; Recharging of underground waters; Good integration with the urban area.

will be on not mobilizing the contaminants.

**5.6 Infiltration ditch and gulley** 

infiltration (Silva, 2007).

**5.7 Microreservoir** 

hydrographs.

It avoids reconstruction of the downstream network in the case of saturation;

For Reis *et al.* (2008), infiltration wells are isolated devices that allow infiltration of runoff into the soil. They may be structured through filling with crushed rock (porous medium), as well as being lined by perforated concrete piping or bricks laid in a staggered manner surrounded by a geotextile sheet making the soil/piping interface. They have the advantages of low cost of execution and attempt at balance of the urban hydrologic cycle by intermediation of recharging the water table.

Nevertheless, for Silveira (2002), the well also has its drawbacks for not having the capacity for supporting large loads of sediments and offering risks in regard to infiltration of pollutants.

According to Reis (2005), the cost of execution of an infiltration well for an area of 500 m², determined in December 2004, was US\$ 1,312.50.

#### **5.9 Rooftop reservoir**

According to Silva (2004), this is a device that seeks to compensate the effect of impermeabilization by means of the impact structure itself, which in this case is the roof. According to Azzout *et al.* (1994), the rooftop reservoir functions as provisional storage of rainwater, releasing it gradually to the rainwater network by means of a specific regulating device. For Silva (2004), both roofing tiles as well as concrete roofing structures that can store rainwater may also be used for the purpose of collecting water.

Nevertheless, Azzout *et al.* (1994) present considerations in regard to the rooftop reservoir, expressing the need to take care with more highly sloped rooftops by the fact that its installation is restricted to rooftops with a slope limit of 2%, also emphasizing the difficulty of installing the reservoir on already existing rooftops and possibly the high cost of the device.

With respect to its pollutants, roof runoff is generally considered as non-polluted, or at least not significantly polluted, compared to waste waters and highway runoff, since it consists of rainwater flowing over various, in general less abrasive materials, such as tiles, bitumen, less corrosive metals and concrete. In general, it may be stated that the quality of runoff may be ameliorated or become worse compared to the composition of atmospheric deposition depending on the kind of materials used for roof cover and drainage systems and their interaction with the atmospheric deposition. For building materials displaying open air corrosion data or data of leaching experiments, runoff loads can even be assessed (Zobrist et al., 2000).

Sustainable Urban Drainage Systems 69

 The Modular System which is composed of prefabricated modules (already planted) where these modules are placed one beside another over an anti-rooting membrane and

For Fendrich (2003), it is worth emphasizing that all captured rainwater will reduce the waters that may cause flooding. Thus, this application is highly important for controlling

When there is the occurrence of rainfall and there is no system for capturing this water, it will end up in storm drains. Until this water arrives at the storm drain, it traces a route where it comes in contact with innumerable type of residues, contaminating it and making it inappropriate for consumption. Nevertheless, this water may potentially be used in many day-to-day situations. According to Pereira (2008), through Brazilian legislation, all water derived from rains is treated as sewage, creating the need for this water to be treated before

According to Silveira (2002), an underground or buried reservoir is a type of impervious tank built below the ground (with impermeable concrete walls) allowing utilization of the surface for another purpose. In general, an underground reservoir operates as an impermeable open air detaining reservoir. Therefore, it weakens the runoff introduced in it through the controlled effect of water release through the orifice and valve at the bottom. Nevertheless it should have a mechanism to avoid the accumulation of pollutants and sediment, it requires frequent maintenance, and it is restricted to areas with more frequent

According to Silveira (2002), grassed or tree-lined strips are conceived to decelerate and partially infiltrate laminar flow coming from impermeable urban surfaces (parking areas and other surfaces), but may have its application associated with other situations. In macrodrainage, they assume the role of escape zones for flooding. Therefore, the main benefit of grassed strips is that in addition to significantly reducing the speed of surface runoff, they significantly help in reduction of peak flows in urban areas (when applied in

Another focus could be given regarding the use of grassed strips. The concentration of sediment decreased exponentially with distance along the grass strip, reaching sometimes a constant value. Particles less than 5.8 μm had a very low trapping efficiency (sometimes negligible), while a substantial proportion of particles above 57 μm were trapped. Knowing that fine particles are the main source of pollution, this implies that grass is very effective for sediment control, but is less efficient in removal of other pollutants. The particle trapping efficiency clearly depended on grass length and particle size. To a some extent, it also

However, some reservations must be made, as for example the need for more constant

depended on sediment concentrations in inflow (Deletic, 2005).

a membrane for retaining of nutrients (support systems of the modules).

water balance and it may play an important social role in areas subject to drought.

**5.11 Reuse of rainwater** 

its use, even without having been used.

**5.12 Underground reservoir** 

rainfall.

**5.13 Grassed strips** 

large stretches).

maintenance.

#### **5.10 Green roofing**

Other techniques that reduce the flow of rainwater and improve water quality include green roofing and its reuse. Green roofing may reduce local peak flows and the total volume discharged into the conventional drainage system. In addition, they may improve thermal and acoustic insulation and increase the useful life of the roofing.

Reuse of rainwater involves collecting it at the location (residential, commercial or industrial) and its use as a substitute for treated water (with high treatment and distribution costs), for example in watering the garden, washing sidewalks, or even for flushing of toilets. Reuse of rainwater will be dealt with in the following item.

According to Heneine (2008), green roofing is currently most widespread in German speaking countries of Central Europe and is spreading to the north and northwest of Europe and North America. Such devices consist of a green covering composed of plants and soil, emphasizing that the plant cover has average growth and is planted on an impermeable base. However, additional layers, as for example, a barrier of roots, and a drainage and irrigation system may and should be included.

Heneine (2008) affirms that green roofing provides for reduction of the effects of torrents of rain, carry benefits for fauna, and mitigate heat in buildings. In relation to planting style, there are two distinct focuses, one being "intensive" (which needs more soil, more depth, and accommodates larger plants that may be as large as trees and bushes) and the other "extensive" (which needs little soil and contains vines and grasses).

This technology arose as a new proposal for retaining precipitated water through the natural holding power existing in the vegetation and also generating delay in runoff from the system. That way, compared with unprotected roofing that has no type of water containment, the volume generated from a roof with the green roofing technology is less and with a greater concentration time in relation to urban drainage systems.

Studies undertaken by Oliveira (2009) show that in addition to its precipitation retaining characteristics and its delaying of runoff, green roofing presents thermal comfort characteristics. It is very efficient in reducing the temperature of the internal and external environment of buildings, even modifying the surrounding microclimate and mesoclimate because this roofing reduces heat emission.

Confirming the thesis that green roofing relieves heat in buildings, this system can lead to a reduction of around 25% in cooling needs, and with a substrate layer of 12 cm, it can reduce outside noise by around 40 decibels, and a substrate layer of 20 cm can reduce it from 46 to 50 decibels.

In general, green roofing makes use of three systems:


 The Modular System which is composed of prefabricated modules (already planted) where these modules are placed one beside another over an anti-rooting membrane and a membrane for retaining of nutrients (support systems of the modules).

#### **5.11 Reuse of rainwater**

68 Drainage Systems

Other techniques that reduce the flow of rainwater and improve water quality include green roofing and its reuse. Green roofing may reduce local peak flows and the total volume discharged into the conventional drainage system. In addition, they may improve thermal

Reuse of rainwater involves collecting it at the location (residential, commercial or industrial) and its use as a substitute for treated water (with high treatment and distribution costs), for example in watering the garden, washing sidewalks, or even for flushing of

According to Heneine (2008), green roofing is currently most widespread in German speaking countries of Central Europe and is spreading to the north and northwest of Europe and North America. Such devices consist of a green covering composed of plants and soil, emphasizing that the plant cover has average growth and is planted on an impermeable base. However, additional layers, as for example, a barrier of roots, and a drainage and

Heneine (2008) affirms that green roofing provides for reduction of the effects of torrents of rain, carry benefits for fauna, and mitigate heat in buildings. In relation to planting style, there are two distinct focuses, one being "intensive" (which needs more soil, more depth, and accommodates larger plants that may be as large as trees and bushes) and the other

This technology arose as a new proposal for retaining precipitated water through the natural holding power existing in the vegetation and also generating delay in runoff from the system. That way, compared with unprotected roofing that has no type of water containment, the volume generated from a roof with the green roofing technology is less

Studies undertaken by Oliveira (2009) show that in addition to its precipitation retaining characteristics and its delaying of runoff, green roofing presents thermal comfort characteristics. It is very efficient in reducing the temperature of the internal and external environment of buildings, even modifying the surrounding microclimate and mesoclimate

Confirming the thesis that green roofing relieves heat in buildings, this system can lead to a reduction of around 25% in cooling needs, and with a substrate layer of 12 cm, it can reduce outside noise by around 40 decibels, and a substrate layer of 20 cm can reduce it from 46 to

 The Alveolar System which permits the use of a greater variety of plants, including native species (ecological system); in this case a roof of grasses may be used because the

 The Planar System characterized by the use of a layer of water over a raised base made of support modules, increases the benefits of retaining precipitated water, and also the

and acoustic insulation and increase the useful life of the roofing.

toilets. Reuse of rainwater will be dealt with in the following item.

"extensive" (which needs little soil and contains vines and grasses).

and with a greater concentration time in relation to urban drainage systems.

irrigation system may and should be included.

because this roofing reduces heat emission.

In general, green roofing makes use of three systems:

alveoli retain a greater quantity of water;

thermal comfort of the area below it;

50 decibels.

**5.10 Green roofing** 

For Fendrich (2003), it is worth emphasizing that all captured rainwater will reduce the waters that may cause flooding. Thus, this application is highly important for controlling water balance and it may play an important social role in areas subject to drought.

When there is the occurrence of rainfall and there is no system for capturing this water, it will end up in storm drains. Until this water arrives at the storm drain, it traces a route where it comes in contact with innumerable type of residues, contaminating it and making it inappropriate for consumption. Nevertheless, this water may potentially be used in many day-to-day situations. According to Pereira (2008), through Brazilian legislation, all water derived from rains is treated as sewage, creating the need for this water to be treated before its use, even without having been used.

#### **5.12 Underground reservoir**

According to Silveira (2002), an underground or buried reservoir is a type of impervious tank built below the ground (with impermeable concrete walls) allowing utilization of the surface for another purpose. In general, an underground reservoir operates as an impermeable open air detaining reservoir. Therefore, it weakens the runoff introduced in it through the controlled effect of water release through the orifice and valve at the bottom. Nevertheless it should have a mechanism to avoid the accumulation of pollutants and sediment, it requires frequent maintenance, and it is restricted to areas with more frequent rainfall.

#### **5.13 Grassed strips**

According to Silveira (2002), grassed or tree-lined strips are conceived to decelerate and partially infiltrate laminar flow coming from impermeable urban surfaces (parking areas and other surfaces), but may have its application associated with other situations. In macrodrainage, they assume the role of escape zones for flooding. Therefore, the main benefit of grassed strips is that in addition to significantly reducing the speed of surface runoff, they significantly help in reduction of peak flows in urban areas (when applied in large stretches).

Another focus could be given regarding the use of grassed strips. The concentration of sediment decreased exponentially with distance along the grass strip, reaching sometimes a constant value. Particles less than 5.8 μm had a very low trapping efficiency (sometimes negligible), while a substantial proportion of particles above 57 μm were trapped. Knowing that fine particles are the main source of pollution, this implies that grass is very effective for sediment control, but is less efficient in removal of other pollutants. The particle trapping efficiency clearly depended on grass length and particle size. To a some extent, it also depended on sediment concentrations in inflow (Deletic, 2005).

However, some reservations must be made, as for example the need for more constant maintenance.

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pp. 165-180

Horizonte, 21p

v. 301, issues 1-4, p. 108–122

York, v. 111, n. 4, 1985. p. 382-398

Perspective. 9th International Conference on Urban Drainage (9 ICUD), Portland,

permeáveis na redução de escoamento superficial. In: Revista Brasileira de Recursos

John; Fewtrell, Lorna; Poole, Tony & Maksimovic, Cedo. 2007. Adaptable Urban Drainage: Addressing Change in Intensity, Occurrence and Uncertainty of

prognoses. The Institute for Environmental Studies, University of Washington: The

Mestrado em Tecnologia Ambiental e Recursos Hídricos, Publicação PTARH.DM-094/06, Departamento de Engenharia Civil e Ambiental, Universidade Brasília,

using Sustainable Drainage in cities. Journal of Water and Climate Change, v.1, n.3,

Wetlands construídos com dez dias de detenção hidráulica na remoção de colífagos e

urbano na microdrenagem, XIII Simpósio Brasileiro de recursos hídricos, Belo

drenagem urbana. 17 f. Tese (Doutorado em Geologia) – Programa de Pós-Graduação

management. Journal of Water Resourses Planning and Management. ASCE. New

### **6. Final considerations**

Like all other drainage systems, the SUDS system has its advantages and disadvantages. Therefore positive and negative points may be cited regarding its use, which may be useful for directing future studies and applications.

Among the different devices presented in this book, diverse positive points become evident, and among them are:


Nevertheless, the challenges that must be overcome for improvement in performance and incentive for application of these systems must be kept in mind. Among the main problems are:


Even so, in a more general way, implementation of some component systems of SUDS do not have high cost; therefore, upon performing an analysis of economic-environmental viability, SUDS presents a good cost-benefit ratio.

The evolution of society and its systems occurs in two manners: first in the search for comfort and better quality of life, and later through the fundamental need for preservation of life. Thus, in the same way that rainwater drainage centered on channeling was of extreme necessity for prevention of diseases and epidemics, a new drainage model is necessary for resolution of conflicts from problems created between urbanization and Earth's water cycle.

In spite of being relatively new compared to the traditional system of urban drainage, SUDS already presents diverse implemented systems in operation as an alternative for improving urban drainage, effectively reducing peak flows of human creation. Although still little applied in Brazil, SUDS is being studied and applied in diverse developed countries, above all in the region of Scandinavia and the United Kingdom.

Therefore, it may be concluded that the application of SUDS systems means evolution in drainage systems, and results in improvement of quality of life for the population involved. It renews the search for sustainable environments in urban areas.

#### **7. References**


Like all other drainage systems, the SUDS system has its advantages and disadvantages. Therefore positive and negative points may be cited regarding its use, which may be useful

Among the different devices presented in this book, diverse positive points become evident,

Retaining of rainwater for later use in less refined activities (watering gardens, flushing

Nevertheless, the challenges that must be overcome for improvement in performance and incentive for application of these systems must be kept in mind. Among the main problems are:

 High cost of implementation when necessary adaptations in pre-existing systems are made; In general, these systems do not support high loads of sediments and present the risk of

Even so, in a more general way, implementation of some component systems of SUDS do not have high cost; therefore, upon performing an analysis of economic-environmental

The evolution of society and its systems occurs in two manners: first in the search for comfort and better quality of life, and later through the fundamental need for preservation of life. Thus, in the same way that rainwater drainage centered on channeling was of extreme necessity for prevention of diseases and epidemics, a new drainage model is necessary for resolution of conflicts from problems created between urbanization and

In spite of being relatively new compared to the traditional system of urban drainage, SUDS already presents diverse implemented systems in operation as an alternative for improving urban drainage, effectively reducing peak flows of human creation. Although still little applied in Brazil, SUDS is being studied and applied in diverse developed countries, above

Therefore, it may be concluded that the application of SUDS systems means evolution in drainage systems, and results in improvement of quality of life for the population involved.

Abbot, C. L. & Comino-Mateos, L. 2003. In-situ hydraulic performance of a permeable

Agra, S. G. Estudo Experimental de Microrreservatórios para Controle do Escoamento

of Water and Environmental Management, v.17, n.3, p. 187–90.

pavement sustainable urban drainage system. Journal of the Chartered Institution

Superficial. Dissertação submetida ao Programa de Pós-Graduação em Recursos Hídricos e Saneamento Ambiental da Universidade Federal do Rio Grande do Sul,

Increase in the infiltration rates and reduction of surface runoff;

Creation of leisure areas and a better landscaping aspect for cities.

toilets in bathrooms, washing sidewalks, etc.);

viability, SUDS presents a good cost-benefit ratio.

all in the region of Scandinavia and the United Kingdom.

It renews the search for sustainable environments in urban areas.

**6. Final considerations** 

and among them are:

colmatation.

Earth's water cycle.

**7. References** 

2001. 104p

for directing future studies and applications.

Need for frequent maintenance;


**Part 2** 

**Subsurface Drainage – Aquifer Management** 


## **Part 2**

## **Subsurface Drainage – Aquifer Management**

72 Drainage Systems

Nascimento, N. O. 1996. Curso: Tecnologias Alternativas em Drenagem Urbana. Escola de

Oliveira, E. W. N. Telhados verdes para habitações de interesse social: retenção das águas

Pereira, L. R. Viabilidade Economico/Ambiental da implantação de um sistema de captação e

Reis, R. P. A.; Oliveira, L. H. & Sales, M. M. Sistemas de drenagem na fonte por poços de

Schlüter, W.; Spitzer, A. & Jefferies, C. Performance of Three Sustainable Urban Drainage

Silva, J. P. Estudos Preliminares para Implantação de Trincheiras de Infiltração. Dissertação de

Silva, L. C. Sistemas de Drenagem Urbana Não-convencionais. Trabalho de Conclusão de

Silveira, A. L. L. Apostila: Drenagem Urbana: aspectos de gestão. 1. Ed. Curso preparado por:

Silveira, G. L. Cobrança pela Drenagem Urbana de Águas Pluviais: incentivo à

Souza, C. F. Mecanismos técnico-institucionais para a sustentabilidade da drenagem urbana,

Souza, V. C. & Goldenfum, J. A. 1999. Trincheiras e infiltração como elemento de controle do

TIM-II - Trabalho de Integralização Multidisciplinar II. Universidade Federal de Minas Gerais,

Urbonas, B. & Stahre, P. 1993. Stormwater Best management Practices and Detention. Prentice

Woods, B. B.; Kellagher, R.; Martin, P.; Jefferies, C.; Bray R. & Shaffer, P. 2007. The SUDS

Zheng, J.; Nanbakhsh, H. & Scholz, M. 2006. Case study: design and operation of sustainable

Zobrist, J.; Müller, S. R.; Ammannm, A.; Bucheli, T. D.; Mottier, V.; Ochs, M.; Schoenenberger,

Brasil. Relatório do Workshop em Goiânia-GO, 2003

Universidade Federal de Goiás, Goiânia, 2005. 228p

Mestrado em Geotecnia. Universidade de Brasília, 2007

Fundo Setorial de Recursos Hídricos (CNPq), 2002

sustentabilidade. Relatório de Pós-Doutorado, 2008

Equipamentos Urbanos: Termo de Referência, 2008. p.25

Recursos Hídricos. Belo Horizonte, 11p

Hall, Englewood Cliffs, New Jersey. 450p

Wat. Res., v.34, n.5, p. 1455-1462

Development – Am. Soc. Civ. Eng. 132, pp. 36–41

Curso. Universidade Anhembi Morumbi. São Paulo, 2004

Construído. v. 8, n. 2, 2008. p. 99-117

pluviais e conforto térmico. Dissertação de mestrado. Rio de Janeiro: UERJ, 2009. 87p Parkinson, J.; Milograna, J.; Campos, L. C. & Campos, R. Drenagem Urbana Sustentável no

aproveitamento de água pluvial em edificação de 100m2 de cobertura. Monografia (Trabalho de Conclusão de Curso) – Pontifícia Universidade Católica de Goiás, 2008 Reis, R. P. A. Proposição de parâmetros de dimensionamento e avaliação de desempenho de

poço de infiltração de água pluvial. Dissertação (Mestrado em Engenharia Civil) –

infiltração de águas pluviais. Associação Nacional de Tecnologia do Ambiente

Systems in East Scotland. 9th International Conference on Urban Drainage (9 ICUD),

Instituto de Pesquisas Hidráulicas, Universidade Federal do Rio Grande do Sul e

2005, 174f. Dissertação (Mestrado) – Universidade Federal do Rio Grande do Sul. Programa de Pós-Graduação em Recursos Hídricos e Saneamento Ambiental, Porto

escoamento superficial: um estudo experimental. XIII Simpósio Brasileiro de

Escola de Engenharia, Curso de Engenharia Civil, Projeto de Infra-Estrutura e

manual (C697). Construction Industry Research and Information Association,

urban infiltration ponds treating storm runoff. Journal of Urban Planning and

R.; Eugster, J. & Boller, M. 2000. Quality of roof runoff for groundwater infiltration.

Engenharia – UFMG

Portland, Oregon

Alegre, 2005

London. 697p

**4** 

*Iran* 

**Common Approximations** 

Homayoon Katibeh1 and Ali Aalianvari2

*1Amirkabir University of Technology 2Hamedan University of Technology* 

**to the Water Inflow into Tunnels** 

Groundwater inflow into hard rock tunnels is very difficult to estimate accurately. In practice, estimates range from grossly low, which then results in large cost overruns and hazardous conditions in the workplace, to grossly high, which leads contractors to ignore them. This chapter looks at some of the reasons why inflow estimates are difficult to make.

There are two main problems with inflow estimates. The first is the lack of simple, realistic equations or models that can be readily applied to hard-rock tunnels. This difficulty may turn out to be unavoidable, and this chapter does not attempt to improve upon the situation. The second difficulty is that the practical range of permeability in fractured rock typically ranges over at least six orders of magnitude, and this range typically repeats again and again over the lengths of long tunnels. This range of permeability, combined with the length of the tunnels, makes hard-rock tunnels very different from well fields, major aquifers, and

This chapter is concerned with hard-rock tunnels in fractured rock that are excavated below groundwater table. These tunnels are commonly constructed under atmospheric pressure using either drill and blast methods or main-beam tunnel boring machines. Lining in these tunnels is typically installed only after excavation is completed, and only where needed. During construction, groundwater flows freely into these tunnels through fractures in the rock. Where the rock is tight and the potentiometric head above the tunnel is low, the inflow will be small. Where the rock contains large, open fractures or where the head is high, the inflow will be substantial. Where the rock contains both large fractures and high head, the

Tunnel designers must determine, and tell the contractor, how much water to expect over both the total length of the tunnel and in the heading area. The total flow is used to design appropriately sized pumping systems and water treatment plants. The inflows in the heading will affect the contractor's construction methods and schedule. Major delays can occur if either is underestimated. Excessive and unnecessary cost can result if either is

In hard-rock tunnels, most of the inflow comes from a few places, some of the inflow comes from many places, and much of the tunnel is dry. The total inflow accumulates over the

It also suggests a few practical ways to get past some of these problems.

**1. Introduction** 

other applications of practical hydrology.

inflows can be catastrophic.

grossly overestimated.

## **Common Approximations to the Water Inflow into Tunnels**

Homayoon Katibeh1 and Ali Aalianvari2

*1Amirkabir University of Technology 2Hamedan University of Technology Iran* 

#### **1. Introduction**

Groundwater inflow into hard rock tunnels is very difficult to estimate accurately. In practice, estimates range from grossly low, which then results in large cost overruns and hazardous conditions in the workplace, to grossly high, which leads contractors to ignore them. This chapter looks at some of the reasons why inflow estimates are difficult to make. It also suggests a few practical ways to get past some of these problems.

There are two main problems with inflow estimates. The first is the lack of simple, realistic equations or models that can be readily applied to hard-rock tunnels. This difficulty may turn out to be unavoidable, and this chapter does not attempt to improve upon the situation. The second difficulty is that the practical range of permeability in fractured rock typically ranges over at least six orders of magnitude, and this range typically repeats again and again over the lengths of long tunnels. This range of permeability, combined with the length of the tunnels, makes hard-rock tunnels very different from well fields, major aquifers, and other applications of practical hydrology.

This chapter is concerned with hard-rock tunnels in fractured rock that are excavated below groundwater table. These tunnels are commonly constructed under atmospheric pressure using either drill and blast methods or main-beam tunnel boring machines. Lining in these tunnels is typically installed only after excavation is completed, and only where needed. During construction, groundwater flows freely into these tunnels through fractures in the rock. Where the rock is tight and the potentiometric head above the tunnel is low, the inflow will be small. Where the rock contains large, open fractures or where the head is high, the inflow will be substantial. Where the rock contains both large fractures and high head, the inflows can be catastrophic.

Tunnel designers must determine, and tell the contractor, how much water to expect over both the total length of the tunnel and in the heading area. The total flow is used to design appropriately sized pumping systems and water treatment plants. The inflows in the heading will affect the contractor's construction methods and schedule. Major delays can occur if either is underestimated. Excessive and unnecessary cost can result if either is grossly overestimated.

In hard-rock tunnels, most of the inflow comes from a few places, some of the inflow comes from many places, and much of the tunnel is dry. The total inflow accumulates over the

Common Approximations to the Water Inflow into Tunnels 77

Well Flow (Q) From Pumping

> Potentiometric Gradient

Horizontal Flow Lines

Vertical Equipotential Lines

Impermeable Confining Layer

Impermeable Confining Layer

infinitely, and at infinity recharge equals well flow.

difference might become significant.

Fig. 1. Thiem equation for radial flow to wells. Equipotential lines are vertical and concentric about the well. Flow lines are horizontal and radial toward the well. The aquifer extends

For convenience, r1 can be the tunnel radius and H1 the potentiometric head at the tunnel radius. If the tunnel is under construction at atmospheric pressure, H1 is the elevation of the tunnel wall. H2 is the head of water some distance r2 from the centerline of the tunnel. Transmissivity, which is the coefficient of proportionality, now has to be oriented

Note that H1 is not a specific point, but ranges between the crown and invert of the tunnel. This difference is trivial for deep tunnels. For large-diameter, shallow tunnels, however, this

"Horizontal transmissivity" (Th) is the coefficient of proportionality for the horizontal Thiem equation. It is placed in quotes because transmissivity is normally considered to represent the vertical thickness of the aquifer, rather than the horizontal length of the tunnel. The concept is important and worthy of indulgence to make a point. The fundamental observation shows that permeability varies over many orders of magnitude along the length of a hard-rock tunnel. This is similar to the horizontal stratification in a sedimentary aquifer

horizontally along the axis of the tunnel, becoming the "horizontal transmissivity."

length of the tunnel and is the sum of all the inflows. This is the fundamental observation from hard rock tunnels, and the root of much of the trouble with estimating inflow using standard hydrologic methods.

There are several analytical expressions in literature to calculate groundwater discharges into tunnels, such as Goodman(1965), Lohman(1972), Zhang(1993), Heuer (1995), Lei(1999), Karlsrud(2001), Raymer(2001) and El Tani (2003). In addition them, Katibeh and Aalianvari (2010) proposed a new method to classified tunnel length with accordance to groundwater flow into tunnels. This chapter provides a summary of analytical methods to calculate groundwater discharges into tunnels.

#### **2. Inflow equations**

Groundwater inflow equations are based on Darcy's Law and conservation of mass. Darcy's Law holds that inflow equals the permeability times the gradient. Conservation of mass holds that the inflow equals the recharge plus the water released from storage.

#### **2.1 Thiem equation**

Darcy's Law is Q = (KA)I, where I is the hydraulic gradient, KA is the permeability (K) across an area (A), and Q is the inflow. In this version of the equation (KA) are taken together in parentheses as a single term to emphasize the fact that actual water flows through a finite volume of rock mass, rather than a theoretical unity.

If Darcy's Law is configured for cylindrical coordinates around a vertical well, then the Thiem equation from well hydraulics results (Figure 1):

$$\mathbf{Q} = 2\pi \Gamma \left( \mathbf{H}\_2 - \mathbf{H}\_1 \right) / \ln(\mathbf{r}\_2/\mathbf{r}\_1) \tag{1}$$

where the gradient is expressed as (H2-H1)/ln(r2/r1). H1 and H2 are the potentiometric heads in the aquifer at two arbitrary points having radial distances r1 and r2 from the center of the well. The hydraulic conductivity (K) and unit area (A) are handled together in the term 2T, where T is the transmissivity. Provided that the rock is uniformly permeable, then T=Kb, where b is the vertical thickness of the aquifer. The Thiem equation (as shown above) is based on the following assumptions:


The Thiem equation can be applied to tunnels by turning the well on its side. The axis of the well is now the centerline of the tunnel. As with a well, the cone of depression is radial around the tunnel. Unlike a well, the potentiometric surface is a bit more abstract, and will look like a trough along the axis of the tunnel if measured at springline (or any constant elevation).

length of the tunnel and is the sum of all the inflows. This is the fundamental observation from hard rock tunnels, and the root of much of the trouble with estimating inflow using

There are several analytical expressions in literature to calculate groundwater discharges into tunnels, such as Goodman(1965), Lohman(1972), Zhang(1993), Heuer (1995), Lei(1999), Karlsrud(2001), Raymer(2001) and El Tani (2003). In addition them, Katibeh and Aalianvari (2010) proposed a new method to classified tunnel length with accordance to groundwater flow into tunnels. This chapter provides a summary of analytical methods to calculate

Groundwater inflow equations are based on Darcy's Law and conservation of mass. Darcy's Law holds that inflow equals the permeability times the gradient. Conservation of mass

Darcy's Law is Q = (KA)I, where I is the hydraulic gradient, KA is the permeability (K) across an area (A), and Q is the inflow. In this version of the equation (KA) are taken together in parentheses as a single term to emphasize the fact that actual water flows

If Darcy's Law is configured for cylindrical coordinates around a vertical well, then the

where the gradient is expressed as (H2-H1)/ln(r2/r1). H1 and H2 are the potentiometric heads in the aquifer at two arbitrary points having radial distances r1 and r2 from the center of the well. The hydraulic conductivity (K) and unit area (A) are handled together in the term 2T, where T is the transmissivity. Provided that the rock is uniformly permeable, then T=Kb, where b is the vertical thickness of the aquifer. The Thiem equation (as shown above) is

Flow is radial toward the well and non-turbulent. The well produces from the full

 The well has reached steady-state flow, meaning that the cone of depression around the well has encountered a supply of water sufficient to replenish the water produced from the well. At this point, the cone of depression stops expanding and water is no longer

The Thiem equation can be applied to tunnels by turning the well on its side. The axis of the well is now the centerline of the tunnel. As with a well, the cone of depression is radial around the tunnel. Unlike a well, the potentiometric surface is a bit more abstract, and will look like a trough along the axis of the tunnel if measured at springline (or any constant

Q = 2T (H2 – H1) / ln(r2/r1) (1)

holds that the inflow equals the recharge plus the water released from storage.

through a finite volume of rock mass, rather than a theoretical unity.

Thiem equation from well hydraulics results (Figure 1):

based on the following assumptions:

being released from storage.

elevation).

thickness of the aquifer.

standard hydrologic methods.

groundwater discharges into tunnels.

**2. Inflow equations** 

**2.1 Thiem equation** 

Fig. 1. Thiem equation for radial flow to wells. Equipotential lines are vertical and concentric about the well. Flow lines are horizontal and radial toward the well. The aquifer extends infinitely, and at infinity recharge equals well flow.

For convenience, r1 can be the tunnel radius and H1 the potentiometric head at the tunnel radius. If the tunnel is under construction at atmospheric pressure, H1 is the elevation of the tunnel wall. H2 is the head of water some distance r2 from the centerline of the tunnel. Transmissivity, which is the coefficient of proportionality, now has to be oriented horizontally along the axis of the tunnel, becoming the "horizontal transmissivity."

Note that H1 is not a specific point, but ranges between the crown and invert of the tunnel. This difference is trivial for deep tunnels. For large-diameter, shallow tunnels, however, this difference might become significant.

"Horizontal transmissivity" (Th) is the coefficient of proportionality for the horizontal Thiem equation. It is placed in quotes because transmissivity is normally considered to represent the vertical thickness of the aquifer, rather than the horizontal length of the tunnel. The concept is important and worthy of indulgence to make a point. The fundamental observation shows that permeability varies over many orders of magnitude along the length of a hard-rock tunnel. This is similar to the horizontal stratification in a sedimentary aquifer

Common Approximations to the Water Inflow into Tunnels 79

measured inflows range from 90 percent lower to 30 percent higher than predicted by Eq. 2. Heuer's (1995) work indicates that inflows from his projects have tended to be about one eighth (87.5 percent) lower than predicted by Eq. 2. My own experience from fairly shallow tunnels (typically less than 100 m) is in rough agreement with Heuer's. Other colleagues of mine report that inflows from deeper tunnels increase toward and then pass the inflows

Freeze and Cheery (1979) further modified Goodman's (1965) solution by replacing z with H0. In this solution, the water table is modeled as an infinite recharge boundary. Freeze and Cherry's (1979) solution will give minimally lower estimates than Goodman's because H0 is greater than z and both terms are in the logarithm. In a real tunnel, however, it is unlikely that recharge to the water table from precipitation could keep up with the yield from the larger fractures. This will serve to draw down the water table substantially around the tunnel and thus lower the head (H0) to a point where recharge can keep up with the reduced

Goodman's model is based on some major simplifying assumptions. First, the tunnel is infinitely long and the water table will never be drawn down close to the crown of the tunnel. Second, at some height z above the tunnel, there is an infinite reservoir of water, such as a lake or river that cannot be depleted by inflow to the tunnel. The head (H0) must be at least as high as the base of this reservoir (z) above the tunnel. Third, the hydraulic conductivity (K) of the ground between the tunnel and the base of the reservoir is the only factor limiting the rate at which this infinite supply of water drains into the tunnel. Fourth, the flow is non-turbulent and the ground is homogeneous and isotropic, such as a uniform

Goodman's assumption of an infinite reservoir above the tunnel is probably somewhat reasonable in many hard-rock tunnel situations in the eastern United States, including the Chattahoochee Tunnel. It is not necessary that this reservoir be a lake or a river: merely that it be a thick, saturated zone that is much more porous and permeable than the underlying bedrock that contains the tunnel. This overlying saturated zone must receive more than enough recharge from rivers, rainfall, or overlying formations to offset leakage through the bedrock zone and into the tunnel. The transition and soil zones of the Chattahoochee Tunnel

Goodman's assumption of a homogeneous, isotropic aquifer is unrealistic for hard-rock tunnels but is believed to be accounted for by Heuer's empirical reduction factor of 1/8. While Heuer's reduction factor has not been worked out mathematically, it seems reasonably consistent with the reduction in flow predicted by fracture-flow equations as opposed to porous-media equations, such as Goodman's. Further work needs to be done in

The variables in Eq. 2 have practical ranges for tunnels. These practical ranges give insight into which are more important and which are less. In summary, K is the most important

are considered adequate to meet this requirement for the purpose of this analysis.

predicted by Eq. 2 as the tunnels become deeper.

inflow.

this area.

**2.2.1 Assumptions** 

sand or silt without fractures.

**2.2.2 Practical ranges of variables** 

penetrated by a vertical well. The "horizontal transmissivity" requires that the average permeability (Kavg) be considered when calculating inflow, rather than the idealized value of hydraulic conductivity. The average hydraulic conductivity is Kavg =Th/L, where L is the length of the tunnel.

The assumptions of the Thiem equation still have to apply for tunnels. Flow has to be radial toward the tunnel. The tunnel has to be long, such that that non-radial flow around the ends of the tunnel is negligible compared to the total inflow. The water table has to be high above the tunnel and not draw down close to the tunnel. The cone of depression has to have room to expand radially to a point where the water captured is large enough to provide for the inflow, even if an infinite supply of water is never encountered. These assumptions are reasonable for tunnels as long as the rock is nearly tight, the inflows very small, and the tunnel deep below the water table. In practice, tunnels that meet these conditions are less likely to have groundwater problems because the inflow rates will have to be very small.

#### **2.2 Goodman's equation**

Goodman (1965) considered the question of a tunnel lying beneath a lake or large river. He considered this lake or river to be an infinite source of water and applied the method of images (Lohman, 1972) to derive the following equation (Figure 2):

$$\mathbf{Q}\_{\rm l.} = 2\pi \mathbf{K} \mathbf{H}\_0 \,/\, \ln(2\mathbf{z}/\mathbf{r})\tag{2}$$

where H0 is the head of water above the tunnel, and z is the distance from the tunnel to the bottom of the lake. Goodman also divided T by the length of the tunnel to put the equation in terms of hydraulic conductivity (K) and inflow per unit length of tunnel (QL). This equation only applies to steady-state inflow along the length of the tunnel. The inflow is steady state because the lake acts as an infinite recharge boundary, which causes the cone of depression to stop expanding.

Fig. 2. Goodman's (1965) model for tunnels beneath a large water body. z is distance from centerline to top of rock. H0 is initial head between water surface and centerline.

Workers who have tried to apply this equation commonly report that actual inflows deviate greatly from the inflows predicted by this equation. Zhang and Franklin (1993) report that measured inflows range from 90 percent lower to 30 percent higher than predicted by Eq. 2. Heuer's (1995) work indicates that inflows from his projects have tended to be about one eighth (87.5 percent) lower than predicted by Eq. 2. My own experience from fairly shallow tunnels (typically less than 100 m) is in rough agreement with Heuer's. Other colleagues of mine report that inflows from deeper tunnels increase toward and then pass the inflows predicted by Eq. 2 as the tunnels become deeper.

Freeze and Cheery (1979) further modified Goodman's (1965) solution by replacing z with H0. In this solution, the water table is modeled as an infinite recharge boundary. Freeze and Cherry's (1979) solution will give minimally lower estimates than Goodman's because H0 is greater than z and both terms are in the logarithm. In a real tunnel, however, it is unlikely that recharge to the water table from precipitation could keep up with the yield from the larger fractures. This will serve to draw down the water table substantially around the tunnel and thus lower the head (H0) to a point where recharge can keep up with the reduced inflow.

#### **2.2.1 Assumptions**

78 Drainage Systems

penetrated by a vertical well. The "horizontal transmissivity" requires that the average permeability (Kavg) be considered when calculating inflow, rather than the idealized value of hydraulic conductivity. The average hydraulic conductivity is Kavg =Th/L, where L is the

The assumptions of the Thiem equation still have to apply for tunnels. Flow has to be radial toward the tunnel. The tunnel has to be long, such that that non-radial flow around the ends of the tunnel is negligible compared to the total inflow. The water table has to be high above the tunnel and not draw down close to the tunnel. The cone of depression has to have room to expand radially to a point where the water captured is large enough to provide for the inflow, even if an infinite supply of water is never encountered. These assumptions are reasonable for tunnels as long as the rock is nearly tight, the inflows very small, and the tunnel deep below the water table. In practice, tunnels that meet these conditions are less likely to have groundwater problems because the inflow rates will have to be very small.

Goodman (1965) considered the question of a tunnel lying beneath a lake or large river. He considered this lake or river to be an infinite source of water and applied the method of

 QL = 2KH0 / ln(2z/r) (2) where H0 is the head of water above the tunnel, and z is the distance from the tunnel to the bottom of the lake. Goodman also divided T by the length of the tunnel to put the equation in terms of hydraulic conductivity (K) and inflow per unit length of tunnel (QL). This equation only applies to steady-state inflow along the length of the tunnel. The inflow is steady state because the lake acts as an infinite recharge boundary, which causes the cone of

Large Water Body

z

Fig. 2. Goodman's (1965) model for tunnels beneath a large water body. z is distance from

Workers who have tried to apply this equation commonly report that actual inflows deviate greatly from the inflows predicted by this equation. Zhang and Franklin (1993) report that

centerline to top of rock. H0 is initial head between water surface and centerline.

H0

images (Lohman, 1972) to derive the following equation (Figure 2):

Uniform Permeability

length of the tunnel.

**2.2 Goodman's equation** 

depression to stop expanding.

Goodman's model is based on some major simplifying assumptions. First, the tunnel is infinitely long and the water table will never be drawn down close to the crown of the tunnel. Second, at some height z above the tunnel, there is an infinite reservoir of water, such as a lake or river that cannot be depleted by inflow to the tunnel. The head (H0) must be at least as high as the base of this reservoir (z) above the tunnel. Third, the hydraulic conductivity (K) of the ground between the tunnel and the base of the reservoir is the only factor limiting the rate at which this infinite supply of water drains into the tunnel. Fourth, the flow is non-turbulent and the ground is homogeneous and isotropic, such as a uniform sand or silt without fractures.

Goodman's assumption of an infinite reservoir above the tunnel is probably somewhat reasonable in many hard-rock tunnel situations in the eastern United States, including the Chattahoochee Tunnel. It is not necessary that this reservoir be a lake or a river: merely that it be a thick, saturated zone that is much more porous and permeable than the underlying bedrock that contains the tunnel. This overlying saturated zone must receive more than enough recharge from rivers, rainfall, or overlying formations to offset leakage through the bedrock zone and into the tunnel. The transition and soil zones of the Chattahoochee Tunnel are considered adequate to meet this requirement for the purpose of this analysis.

Goodman's assumption of a homogeneous, isotropic aquifer is unrealistic for hard-rock tunnels but is believed to be accounted for by Heuer's empirical reduction factor of 1/8. While Heuer's reduction factor has not been worked out mathematically, it seems reasonably consistent with the reduction in flow predicted by fracture-flow equations as opposed to porous-media equations, such as Goodman's. Further work needs to be done in this area.

#### **2.2.2 Practical ranges of variables**

The variables in Eq. 2 have practical ranges for tunnels. These practical ranges give insight into which are more important and which are less. In summary, K is the most important

Common Approximations to the Water Inflow into Tunnels 81

Fig. 3. Relationship between steady state flow and equivalent permeability (Heuer1995).

term and hardest to estimate, H0 is less important and easy to estimate, and ln(2z/r) is of minor importance and easy to estimate.

*H0:* In most situations, the maximum for the static head (H0) is the elevation difference between the tunnel and highest water table around the tunnel. The minimum is the elevation of the lowest water table around the tunnel. These values can be estimated readily from topographic maps and piezometers.

*ln(2z/r):* The rock cover above the tunnel should be known from borings. The tunnel diameter should be known from the design. Since both terms are in a logarithm, the practical range is quite small. For a 2 meter tunnel at 1000 meters deep, ln(2z/r) = 6.9. For a 10 meter tunnel 30 meters deep, ln(2z/r) = 1.8. This gives an extreme range between about 2 and 7.

*K:* In fractured rock, permeability ranges over many orders of magnitude within a given rock mass. This variability is difficult to predict. The practical minimum for tunnels is around 10-6 cm/s, because even with large heads over long distances, the amount of inflow is very small. The practical maximum, however, can range up to 0.1 cm/s or higher, depending on the rock conditions.

#### **2.3 Heuer method**

Heuer (1995, 2005) found that the actual water inflow into tunnel is generally significantly lower than the predicted water inflow using analytical equations and proposed an adjustment factor, on the basis of actual inflow measurements in various tunnels. The adjustment inflow rate is about one-eight of the inflow rate predicted from analytical solutions.

Although this factor is a significant improvement, it cannot be indiscriminately applied to tunnels under a range of conditions and needs to be modified to take into account the effect of depth, hydro mechanical interaction along rock mass discontinuities and other key geological features affecting the tunnel inflow rate

#### **2.4 Lei method**

Lei in 1999, derived analytical expression for hydraulic head, the stream function and the inflow rate of the two-dimensional, steady ground water flow near a horizontal tunnel in a fully saturated , homogeneous, isotropic and semi- infinite porous aquifer for a constant hydraulic head condition at the tunnel perimeter.

$$\mathbf{Q} = (\frac{2\pi \mathbf{K} \mathbf{h}}{\ln(\frac{\mathbf{h}}{\mathbf{r}} + \sqrt{\left(\frac{\mathbf{h}}{\mathbf{r}}\right)^2 - 1})}) \tag{3}$$

Where Q is the groundwater flow, h is the head of water above the tunnel, K is the equivalent permeability and r is the radius of tunnel.(Fig.4)

Fig. 3. Relationship between steady state flow and equivalent permeability (Heuer1995).

term and hardest to estimate, H0 is less important and easy to estimate, and ln(2z/r) is of

*H0:* In most situations, the maximum for the static head (H0) is the elevation difference between the tunnel and highest water table around the tunnel. The minimum is the elevation of the lowest water table around the tunnel. These values can be estimated readily

*ln(2z/r):* The rock cover above the tunnel should be known from borings. The tunnel diameter should be known from the design. Since both terms are in a logarithm, the practical range is quite small. For a 2 meter tunnel at 1000 meters deep, ln(2z/r) = 6.9. For a 10 meter tunnel 30 meters deep, ln(2z/r) = 1.8. This gives an extreme range between about 2

*K:* In fractured rock, permeability ranges over many orders of magnitude within a given rock mass. This variability is difficult to predict. The practical minimum for tunnels is around 10-6 cm/s, because even with large heads over long distances, the amount of inflow is very small. The practical maximum, however, can range up to 0.1 cm/s or higher,

Heuer (1995, 2005) found that the actual water inflow into tunnel is generally significantly lower than the predicted water inflow using analytical equations and proposed an adjustment factor, on the basis of actual inflow measurements in various tunnels. The adjustment inflow rate is about one-eight of the inflow rate predicted from analytical

Although this factor is a significant improvement, it cannot be indiscriminately applied to tunnels under a range of conditions and needs to be modified to take into account the effect of depth, hydro mechanical interaction along rock mass discontinuities and other key

Lei in 1999, derived analytical expression for hydraulic head, the stream function and the inflow rate of the two-dimensional, steady ground water flow near a horizontal tunnel in a fully saturated , homogeneous, isotropic and semi- infinite porous aquifer for a constant

> 2 Kh Q ( ) h h ln( ( ) 1) r r

Where Q is the groundwater flow, h is the head of water above the tunnel, K is the

2

( 3)

minor importance and easy to estimate.

from topographic maps and piezometers.

depending on the rock conditions.

geological features affecting the tunnel inflow rate

hydraulic head condition at the tunnel perimeter.

equivalent permeability and r is the radius of tunnel.(Fig.4)

**2.3 Heuer method** 

solutions.

**2.4 Lei method** 

and 7.

Common Approximations to the Water Inflow into Tunnels 83

Katibeh and Aalianvari(2009) using the experiments due to ten tunnels in Iran have been proposed a new qualitative and quantitative method for rating the tunnel sites in groundwater hazard point of view, named " Site Groundwater Rating" (SGR). In this method, the tunnel site, according to the preliminary investigations of engineering geological and hydrogeological properties, is categorized into six rates as follow: No Risk, Low Risk, Moderate Risk, Risky, High Risk and Critical. Considered parameters in this method are: joint frequency, joint aperture, karstification, crashed zone, schistosity, head of

In SGR method, after scoring each parameter, the SGR factor of the site is computed and according to this factor the tunnel site is divided into six categories. One of the advantages of this method is helping the engineers and contractors to design more suitable drainage systems and choosing the suitable drilling methods, according to the potential of the

In general, tunnel site are divided into two parts: tunnels in saturated zones and tunnels in unsaturated zones. Also with respect to the site lithology, tunnel sites are divided into rock

where parameters S1 to S7 respecting to the affecting parameters in groundwater inflow, will

Massive rocks in tunnels alignment include one or more joint sets and tunnels cut them. Amount of water inflow into tunnels depends on joint frequency and joint aperture, so the

> i 1 ge S 25 ( a) <sup>12</sup>

where: λi, the joint frequency (1/m), ei, the mean hydraulic joint aperture (m), g, the earth gravity (m/s2), , the kinematic viscosity of water (m2/s), a, the unit factor (s/m)

The constant coefficient in Eq.6, 25, is obtained according to the experiments to normalize

The joint hydraulic aperture, eh, in Eq.7, is different from the joint aperture estimated in surface. Cheng (1994) suggested the following equation to calculate joint hydraulic aperture

where, E is average joint hydraulic aperture in surface (mm) and ΔVj is calculated using the

1

n 2 i i

SGR (S S S S ) S S S 1 2 3 4 5 67 (5)

(6)

<sup>h</sup> <sup>j</sup> eEV (7)

**3. Tunnel site rating from groundwater hazard point of view(SGR)** 

water above tunnel, soil permeability and annual raining.

sites and soil sites. The equation to compute the SGR factor is:

**3.1 Score of frequency and aperture of joints, S1**

representative parameter, S1, is calculated using Eq.6:

converting S1 to dimensionless form.

the parameter S1.

following equation:

in depth:

groundwater inflow, calculated in SGR.

be described as below.

Fig. 4. Circular tunnel in a semi-infinite aquifer with a horizontal water table.

This method deals with an ideal situation. And valid only for cases under the given assumptions. For more complicated scenarios, a numerical model would be more flexible.

#### **2.5 El-Tani method**

The steady gravity flow that is generated by a circular tunnel disturbing the hydrostatic state of a semi-infinite, homogeneous and isotropic aquifer is solved exactly. Many aspects of the flow are found in closed analytical forms such as the water inflow, pressure, leakage and recharging infiltration, which give a complete view of the aquifer in the drained steady state.

$$\mathbf{Q} = 2\pi \text{kh} (\frac{1 - 3(\frac{\mathbf{r}}{2\mathbf{h}})^2}{\left[1 - (\frac{\mathbf{r}}{2\mathbf{h}})^2\right] \ln \frac{2\mathbf{h}}{\mathbf{r}} - (\frac{\mathbf{r}}{2\mathbf{h}})^2} \tag{4}$$

Where Q is the groundwater flow, h is the head of water above the tunnel, K is the equivalent permeability and r is the radius of tunnel.

It is found that the maximum value of the recharging infiltration does not exceed the hydraulic conductivity allowing stating criteria for recharge intervention to ensure the stability of the aquifer. In addition to the main results, two aspects of the water inflow are treated. These are the necessary modifications that are to be considered in the case of an inclined water table and in the case of a lined tunnel that develops a constant internal pressure. It is also found that under an inclined water table a tunnel may cease to drain on its complete circumferential edge and a limiting condition is stated. Furthermore, the Muskat–Goodman and other water inflow predictions are compared to the exact gravity water inflow.

In this method The gravity flow that isgenerated by a circular tunnel is solved exactly. Other cases need to be obtained in closed forms such as the flow generated by non-circular tunnels in non-homogeneous and bounded aquifers. The integral formulation will probably be useful if it is adequately extended to these cases and to others in the three-dimensional space.

Fig. 4. Circular tunnel in a semi-infinite aquifer with a horizontal water table.

**2.5 El-Tani method** 

state.

water inflow.

space.

This method deals with an ideal situation. And valid only for cases under the given assumptions. For more complicated scenarios, a numerical model would be more flexible.

The steady gravity flow that is generated by a circular tunnel disturbing the hydrostatic state of a semi-infinite, homogeneous and isotropic aquifer is solved exactly. Many aspects of the flow are found in closed analytical forms such as the water inflow, pressure, leakage and recharging infiltration, which give a complete view of the aquifer in the drained steady

Q 2 kh( 2h ) r 2h r 1 ( ) ln ( ) 2h r 2h

Where Q is the groundwater flow, h is the head of water above the tunnel, K is the

It is found that the maximum value of the recharging infiltration does not exceed the hydraulic conductivity allowing stating criteria for recharge intervention to ensure the stability of the aquifer. In addition to the main results, two aspects of the water inflow are treated. These are the necessary modifications that are to be considered in the case of an inclined water table and in the case of a lined tunnel that develops a constant internal pressure. It is also found that under an inclined water table a tunnel may cease to drain on its complete circumferential edge and a limiting condition is stated. Furthermore, the Muskat–Goodman and other water inflow predictions are compared to the exact gravity

In this method The gravity flow that isgenerated by a circular tunnel is solved exactly. Other cases need to be obtained in closed forms such as the flow generated by non-circular tunnels in non-homogeneous and bounded aquifers. The integral formulation will probably be useful if it is adequately extended to these cases and to others in the three-dimensional

 

equivalent permeability and r is the radius of tunnel.

2

<sup>r</sup> 1 3( )

2 2

(4)

#### **3. Tunnel site rating from groundwater hazard point of view(SGR)**

Katibeh and Aalianvari(2009) using the experiments due to ten tunnels in Iran have been proposed a new qualitative and quantitative method for rating the tunnel sites in groundwater hazard point of view, named " Site Groundwater Rating" (SGR). In this method, the tunnel site, according to the preliminary investigations of engineering geological and hydrogeological properties, is categorized into six rates as follow: No Risk, Low Risk, Moderate Risk, Risky, High Risk and Critical. Considered parameters in this method are: joint frequency, joint aperture, karstification, crashed zone, schistosity, head of water above tunnel, soil permeability and annual raining.

In SGR method, after scoring each parameter, the SGR factor of the site is computed and according to this factor the tunnel site is divided into six categories. One of the advantages of this method is helping the engineers and contractors to design more suitable drainage systems and choosing the suitable drilling methods, according to the potential of the groundwater inflow, calculated in SGR.

In general, tunnel site are divided into two parts: tunnels in saturated zones and tunnels in unsaturated zones. Also with respect to the site lithology, tunnel sites are divided into rock sites and soil sites. The equation to compute the SGR factor is:

$$\text{GGR} = \left[ \left( \mathbf{S}\_1 + \mathbf{S}\_2 + \mathbf{S}\_3 + \mathbf{S}\_4 \right) + \mathbf{S}\_5 \right] \mathbf{S}\_6 \text{ S}\_7 \tag{5}$$

where parameters S1 to S7 respecting to the affecting parameters in groundwater inflow, will be described as below.

#### **3.1 Score of frequency and aperture of joints, S1**

Massive rocks in tunnels alignment include one or more joint sets and tunnels cut them. Amount of water inflow into tunnels depends on joint frequency and joint aperture, so the representative parameter, S1, is calculated using Eq.6:

$$\mathbf{S}\_1 = 25 \times \left(\sum\_{i=1}^n \frac{\lambda\_i \,\mathrm{ge}\_i^2}{12\,\mathrm{v}} \mathbf{a}\right) \tag{6}$$

where: λi, the joint frequency (1/m), ei, the mean hydraulic joint aperture (m), g, the earth gravity (m/s2), , the kinematic viscosity of water (m2/s), a, the unit factor (s/m) converting S1 to dimensionless form.

The constant coefficient in Eq.6, 25, is obtained according to the experiments to normalize the parameter S1.

The joint hydraulic aperture, eh, in Eq.7, is different from the joint aperture estimated in surface. Cheng (1994) suggested the following equation to calculate joint hydraulic aperture in depth:

$$\mathbf{e}\_{\mathbf{h}} = \mathbf{E} - \Delta \mathbf{V}\_{\mathbf{j}} \tag{7}$$

where, E is average joint hydraulic aperture in surface (mm) and ΔVj is calculated using the following equation:

Common Approximations to the Water Inflow into Tunnels 85

Crashed zones in both saturated and unsaturated zones are suitable paths for groundwater

Karstification is the geologic process of chemical and mechanical erosion by water on soluble bodies of rock, such as limestone, dolomite, gypsum, or salt, at or near the earth's surface. Karstification is exhibited best on thick, fractured, and pure limestone in a humid environment in which the subsurface and surface are being modified simultaneously. The resulting karst morphology is usually characterized by some types of cavities and a complex subsurface drainage system. So these cavities can conduct groundwater into tunnels. Groundwater inflow into tunnels can be very sudden and so dangerous. According to the

Parameters S1 to S4 are related to rock tunnels but if tunnel is excavated in soil, parameters S1 to S4 are automatically equal to zero. In SGR soil permeability is very important factor which is scored in S5. The permeability of a clay layer can be as low as 10-10 m/s, of a weakly

Because of the direct relation between soil permeability and rate of groundwater inflow, in

where, K is the soil permeability (m/day), c is the unit factor (day/m) converting S5 to

Head of water (H) above tunnel is one of the most effective parameters on groundwater inflow into tunnels. The inflow equations such as Muskat–Goodman, Rat–Schleiss–Lei, Karlsrud and Lombardi indicate that groundwater inflow into tunnel has linear relation

<sup>H</sup> S d

where, H is water head above tunnel and d is the unit factor (1/m) converting S6 to

Just when tunnel is excavated in unsaturated zones, annual raining is effective on groundwater inflow into tunnels. In such case infiltrated water rain can seep into tunnel through fractures and faults. However, in such case groundwater inflow is not permanent like tunneling in saturated zones. Related to the tunnel depth, overburden permeability and length of water channel from discharging area up to tunnel, the time of reaching surface

with H/Ln(H), so the representative parameter S6, is calculated using Eq.12:

6

dimensionless form. When tunnel is excavated above water table S6 is equal to unit.

<sup>5</sup> S Kc (11)

Ln(H d) (12)

flow, thus, crashed zones are of most importance in SGR.

degree of karstification, S4 is estimated between 10 to 100.

permeable layer 10-6 m/s and of a highly permeable layer 10-2 m/s.

SGR, the score of soil permeability, S5 is calculated as follow:

**3.4 Karstification, S4**

**3.5 Soil permeability, S5** 

dimensionless form.

**3.7 Annual raining, S7**

**3.6 Water head above tunnel, S6**

$$
\Delta \mathbf{V\_{j}} = \frac{\sigma\_{\rm n} \mathbf{V\_{m}}}{\mathbf{K\_{ni}} \mathbf{V\_{m}} + \sigma\_{\rm n} \mathbf{V\_{m}}} \tag{8}
$$

where, Cheng (1994) suggested <sup>n</sup> =0.027Z, according to his experiments, in which Z is overburden thickness. Moreover, analyses by Bandis et al. of experimental data indicated that the following relation was appropriate

$$\mathbf{V\_m} = \mathbf{A} + \mathbf{B(JRC)} + \mathbf{C(\frac{JCS}{E})^D} \tag{9}$$

in which constants A, B, C, and D, according to the Priest's experimental researches are: A= -0.2960, B= -0.0056, C= 2.241, D=-0.2450

JRC is joint roughness coefficient, JCS is joint wall strength and Kni is computed using Eq. 10.

$$\text{K}\_{\text{ni}} = 0.02(\frac{\text{JCS}}{\text{E}}) + 1.75 \text{JRC} - 7.15 \tag{10}$$

Finally, S1 is calculated in dimensionless form. If the joint is filled with some materials such as clay, calcite, etc, then ei (Eq. 6) will be equal to zero. However, the caution must be taken for the joints filled with washable materials such as some clay types. Joints with washable materials can be identified in the supplementary site investigation during Lugeon tests.

#### **3.2 Schistosity, S2**

Commonly, clay-base rocks are supposed to schistosity during tectonic processes, so that water can flow through schist planes. However, the relevant permeability is very less compared to the other discontinuities. In spite of low permeability, in SGR, the parameter S2, representative of schistosity, is supposed in the range of 1 to 5, depending on the degree of schistosity.

#### **3.3 Crashed zone, S3**

Crashed zones are the major path of groundwater flow through rock. Crashed zones considerably increase rock permeability; however this increase depends on the rock type. In clay-base rocks such as marl, shale, schist etc, clay minerals fill fractures and discontinuities resulting in considerable decrease in the permeability of crashed zone, but in the other rock types such as limestone, the permeability in crashed zone is very high. Moreover, the groundwater flow rate through crashed zones is related to the rock type and the crashed zone width. Considering rock type and crashed zone width, table 1 shows the equations to calculate S3 in different rocks type in SGR.


\* b is the unit factor (1/m),

\*\*Czw is the crash zone width (m)

Table.1. Method to estimate S3 in crashed zones.

Crashed zones in both saturated and unsaturated zones are suitable paths for groundwater flow, thus, crashed zones are of most importance in SGR.

#### **3.4 Karstification, S4**

84 Drainage Systems

n m <sup>j</sup>

where, Cheng (1994) suggested <sup>n</sup> =0.027Z, according to his experiments, in which Z is overburden thickness. Moreover, analyses by Bandis et al. of experimental data indicated

JCS V A B(JRC) C( ) <sup>E</sup>

in which constants A, B, C, and D, according to the Priest's experimental researches are:

JRC is joint roughness coefficient, JCS is joint wall strength and Kni is computed using Eq. 10.

JCS K 0.02( ) 1.75JRC 7.15 <sup>E</sup>

Finally, S1 is calculated in dimensionless form. If the joint is filled with some materials such as clay, calcite, etc, then ei (Eq. 6) will be equal to zero. However, the caution must be taken for the joints filled with washable materials such as some clay types. Joints with washable materials can be identified in the supplementary site investigation during Lugeon tests.

Commonly, clay-base rocks are supposed to schistosity during tectonic processes, so that water can flow through schist planes. However, the relevant permeability is very less compared to the other discontinuities. In spite of low permeability, in SGR, the parameter S2, representative of schistosity, is supposed in the range of 1 to 5, depending on the degree of

Crashed zones are the major path of groundwater flow through rock. Crashed zones considerably increase rock permeability; however this increase depends on the rock type. In clay-base rocks such as marl, shale, schist etc, clay minerals fill fractures and discontinuities resulting in considerable decrease in the permeability of crashed zone, but in the other rock types such as limestone, the permeability in crashed zone is very high. Moreover, the groundwater flow rate through crashed zones is related to the rock type and the crashed zone width. Considering rock type and crashed zone width, table 1 shows the equations to

**Type of rock Crashed zone width S3**

Clay base rocks Czw 2×Log(10Czw× b\*) Other rock type Czw 100×Log(10Czw\*\*×b)

<sup>V</sup> <sup>V</sup>

m

ni

that the following relation was appropriate

A= -0.2960, B= -0.0056, C= 2.241, D=-0.2450

**3.2 Schistosity, S2**

**3.3 Crashed zone, S3**

\* b is the unit factor (1/m), \*\*Czw is the crash zone width (m)

calculate S3 in different rocks type in SGR.

Table.1. Method to estimate S3 in crashed zones.

schistosity.

ni m n m

D

(9)

(10)

(8)

KV V

Karstification is the geologic process of chemical and mechanical erosion by water on soluble bodies of rock, such as limestone, dolomite, gypsum, or salt, at or near the earth's surface. Karstification is exhibited best on thick, fractured, and pure limestone in a humid environment in which the subsurface and surface are being modified simultaneously. The resulting karst morphology is usually characterized by some types of cavities and a complex subsurface drainage system. So these cavities can conduct groundwater into tunnels. Groundwater inflow into tunnels can be very sudden and so dangerous. According to the degree of karstification, S4 is estimated between 10 to 100.

#### **3.5 Soil permeability, S5**

Parameters S1 to S4 are related to rock tunnels but if tunnel is excavated in soil, parameters S1 to S4 are automatically equal to zero. In SGR soil permeability is very important factor which is scored in S5. The permeability of a clay layer can be as low as 10-10 m/s, of a weakly permeable layer 10-6 m/s and of a highly permeable layer 10-2 m/s.

Because of the direct relation between soil permeability and rate of groundwater inflow, in SGR, the score of soil permeability, S5 is calculated as follow:

$$\mathbf{S}\_{\mathfrak{S}} = \mathbf{K} \times \mathbf{c} \tag{11}$$

where, K is the soil permeability (m/day), c is the unit factor (day/m) converting S5 to dimensionless form.

#### **3.6 Water head above tunnel, S6**

Head of water (H) above tunnel is one of the most effective parameters on groundwater inflow into tunnels. The inflow equations such as Muskat–Goodman, Rat–Schleiss–Lei, Karlsrud and Lombardi indicate that groundwater inflow into tunnel has linear relation with H/Ln(H), so the representative parameter S6, is calculated using Eq.12:

$$\mathbf{S}\_{\delta} = \frac{\mathbf{H}}{\text{Ln(H} \times \text{d)}} \times \mathbf{d} \tag{12}$$

where, H is water head above tunnel and d is the unit factor (1/m) converting S6 to dimensionless form. When tunnel is excavated above water table S6 is equal to unit.

#### **3.7 Annual raining, S7**

Just when tunnel is excavated in unsaturated zones, annual raining is effective on groundwater inflow into tunnels. In such case infiltrated water rain can seep into tunnel through fractures and faults. However, in such case groundwater inflow is not permanent like tunneling in saturated zones. Related to the tunnel depth, overburden permeability and length of water channel from discharging area up to tunnel, the time of reaching surface

Common Approximations to the Water Inflow into Tunnels 87

 El Tani (2003) compared the results of above mentioned methods with the observed seepage into tunnels, for different values of r/h. Table 1 contains a listing of diverse approximations of the water inflow including Muskat–Goodman, Rat–Schleiss–Lei, Karlsrud, Lombardi and El Tani methods. The relative differences of the diverse formula of table 1 with the

> Q Q ap Q

**Goodman** 

**Karlsrud** 

Fig. 5. Relative difference of the diverse approximations in Table 1with the exact water

**Heuer** 

**Lee** 

<sup>h</sup> Q 2K 2z ln( )

2 KH <sup>Q</sup> 2H ln( )

<sup>o</sup> <sup>L</sup> 2 KH <sup>1</sup> <sup>Q</sup> 2z <sup>8</sup> ln( ) r

<sup>h</sup> Q 2K h h ln( ( ) 1)

Q 2K 2h

r r

<sup>r</sup> 1 3( )

r 2h r [1 ( ) ]ln( ( ) 2h r 2h

r

o o

2

2

2 2

r

exact (observed) water inflow (Q) are shown in Fig. 2 and are computed with:

in which, Qap is a water inflow approximation.

**El Tani** 

Table 3. Diverse approximations for the water inflow.

inflow.

water to tunnel is different. In unsaturated zones quantity and intensity of raining affect the groundwater inflow into tunnels, but here only annual raining is considered. S7 for unsaturated tunnels is calculated using Eq. 13:

$$\mathbf{S}\_7 = \frac{\mathbf{P}\_\mathbf{y}}{5000} \qquad \mathbf{S}\_7 \le 1 \tag{13}$$

where Py is annual raining (mm).

Maximum value of S7 is when annual raining is equal to 5000 mm or more. When tunneling in saturated zone, S7 =1.

#### **3.8 SGR factor**

After calculating all the parameters, S1 – S7, SGR factor of the site is computed by means of Eq.5, then according to the value of SGR and using table 2, the tunnel site category can be found in six cases as: No Danger, Low Danger, Relatively Dangerous, Dangerous, Highly Dangerous, and Critical.


Table 2. SGR rating for groundwater inflow into tunnels.

Experiments due to 10 tunnels show that there are direct correlations between SGR factor and groundwater inflow rate into tunnels. In case of high SGR factor (more than 700), mixture of mud and groundwater is probable to rush into tunnel, endangering persons and equipments.

In the other hand, with attention to SGR factor, groundwater inflow into tunnel can be predicted, which help to plan suitable drainage systems and even to choose the best drilling method.

#### **4. Discussion**

This chapter is concerned with groundwater flow approximation methods into hard-rock tunnels in fractured rock that are excavated below the water table. Several analytical equations to calculate groundwater discharges into tunnels, including Goodman(1965), Lohman(1972), Zhang(1993), Heuer (1995), Lei(1999), Karlsrud(2001), Raymer(2001) and El Tani (2003) were introduced here, along with SGR method.

water to tunnel is different. In unsaturated zones quantity and intensity of raining affect the groundwater inflow into tunnels, but here only annual raining is considered. S7 for

y

Maximum value of S7 is when annual raining is equal to 5000 mm or more. When tunneling

After calculating all the parameters, S1 – S7, SGR factor of the site is computed by means of Eq.5, then according to the value of SGR and using table 2, the tunnel site category can be found in six cases as: No Danger, Low Danger, Relatively Dangerous, Dangerous, Highly

1000 Highly Dangerous V Q>0.28 ،Inflow of groundwater and mud from crashed

1000< Critical VI Inflow of groundwater and mud is highly probable.

Experiments due to 10 tunnels show that there are direct correlations between SGR factor and groundwater inflow rate into tunnels. In case of high SGR factor (more than 700), mixture of mud and groundwater is probable to rush into tunnel, endangering persons and

In the other hand, with attention to SGR factor, groundwater inflow into tunnel can be predicted, which help to plan suitable drainage systems and even to choose the best drilling

This chapter is concerned with groundwater flow approximation methods into hard-rock tunnels in fractured rock that are excavated below the water table. Several analytical equations to calculate groundwater discharges into tunnels, including Goodman(1965), Lohman(1972), Zhang(1993), Heuer (1995), Lei(1999), Karlsrud(2001), Raymer(2001) and El

**SGR Tunnel Rating Class Probable conditions for groundwater** 

Dangerous III 0.1-0.16

0-100 No Danger Ι 0-0.04 100-300 Low Danger II 0.04-0.1

500-700 Dangerous IV 0.16-0.28

Table 2. SGR rating for groundwater inflow into tunnels.

Tani (2003) were introduced here, along with SGR method.

<sup>5000</sup> S7 1 (13)

**inflow into tunnel (Lit/s/m)** 

zones is probable.

P

7

S

unsaturated tunnels is calculated using Eq. 13:

where Py is annual raining (mm).

in saturated zone, S7 =1.

Dangerous, and Critical.

300-500 Relatively

700-

equipments.

method.

**4. Discussion** 

**3.8 SGR factor** 

 El Tani (2003) compared the results of above mentioned methods with the observed seepage into tunnels, for different values of r/h. Table 1 contains a listing of diverse approximations of the water inflow including Muskat–Goodman, Rat–Schleiss–Lei, Karlsrud, Lombardi and El Tani methods. The relative differences of the diverse formula of table 1 with the exact (observed) water inflow (Q) are shown in Fig. 2 and are computed with:

$$
\Delta = \frac{\mathbf{Q}\_{\text{ap}} - \mathbf{Q}}{\mathbf{Q}}
$$

in which, Qap is a water inflow approximation.

Table 3. Diverse approximations for the water inflow.

Fig. 5. Relative difference of the diverse approximations in Table 1with the exact water inflow.

**5** 

**Drainage of Bank Storage** 

*1LRGCU Amar Telidji, Laghouat,* 

*2Ploytechnique, Sofia,* 

*1Algeria 2Bulgaria* 

**in Shallow Unconfined Aquifers** 

Abdelkader Djehiche1, Mustapha Gafsi1 and Konstantin Kotchev2

The present work concerns subsurface drainage systems. The problems of surface and subsurface draining excess water from the canal or river are the major preoccupation of many researchers for at least 50 years; therefore we devoted this study to find appropriate solutions for problems encountered in the drainage of bank storage in shallow unconfined

It is necessary to develop special processes such as the drains, the filters and to choose the type of the most effective drain to drain excess water from the canal. We have performed a study on a reduced model, of a homogeneous soil with trench drain on an impervious foundation, and we have proposed a correlation to determine the best position of the trench drain in the homogeneous soil. The water level in the trench drains can be directly determined for a given head of water in the canal, slope of the canal and the permeability coefficient, so that the seepage analysis is simplified to a certain degree and the accuracy is also satisfied based on the new approach. Finally comparative studies between experimental

In this section, we discuss the flow of groundwater to trench drains under steady state conditions. The steady-state theory is based on the assumption that the rate of recharge to

To describe the flow of groundwater to the trench drains, we have to make the following


Figure 1 shows a typical cross-section of a drainage system under this condition.

and numerical results using [SEEP] software were carried out.

**2.1 Steady and parallel flow in unconfined aquifers** 

the groundwater and evaporation is null.

**1. Introduction** 

**2. Horizontal drainage** 

assumptions:

aquifers.

As the Fig. 5 shows, with decreasing r/h, water inflow approximations converge each other and converge to the exact water inflow. For r/h less than 0.3, the relative differences are negligible (El Tani, 2003). For large values of r/h, means tunnels near to the Groundwater table, Lombardi and El Tani approximations are more close to the exact water inflow, while, the relative differences of other equations are considerable in this case (Fig. 5).

A new qualitative and quantitative method for tunnel site rating in groundwater hazard point of view (SGR), was introduced in this chapter. In this method, the tunnel site, according to the preliminary investigations of engineering geological and hydrogeological properties, is categorized into six rates as follow: No Danger, Low Danger, Relatively Dangerous, Dangerous, Highly Dangerous, and Critical. (Katibeh, Aalianvari, 2009). Using SGR factor, groundwater inflow into tunnel can be estimated, which helps to predict suitable drainage system and to choose the best drilling method.

#### **5. References**


## **Drainage of Bank Storage in Shallow Unconfined Aquifers**

Abdelkader Djehiche1, Mustapha Gafsi1 and Konstantin Kotchev2

*1LRGCU Amar Telidji, Laghouat, 2Ploytechnique, Sofia, 1Algeria 2Bulgaria* 

### **1. Introduction**

88 Drainage Systems

As the Fig. 5 shows, with decreasing r/h, water inflow approximations converge each other and converge to the exact water inflow. For r/h less than 0.3, the relative differences are negligible (El Tani, 2003). For large values of r/h, means tunnels near to the Groundwater table, Lombardi and El Tani approximations are more close to the exact water inflow, while, the

A new qualitative and quantitative method for tunnel site rating in groundwater hazard point of view (SGR), was introduced in this chapter. In this method, the tunnel site, according to the preliminary investigations of engineering geological and hydrogeological properties, is categorized into six rates as follow: No Danger, Low Danger, Relatively Dangerous, Dangerous, Highly Dangerous, and Critical. (Katibeh, Aalianvari, 2009). Using SGR factor, groundwater inflow into tunnel can be estimated, which helps to predict

El Tani, M.; 2003; "Circular tunnel in a semi-infinite aquifer", J. of Tunneling and

Freeze, R.A.; Cherry, J.A. (1979) "Groundwater Englewood", New Jersey, Prentice-Hall Inc,

Goodman, R., D. Moye, A. Schalkwyk, and I. Javendel.1965. "Groundwater inflow during

Heuer, R.E. 1995. "Estimating rock-tunnel water inflow". Proceeding of the Rapid

Katibeh, H., Aalianvari, A.; 2009; "Development of a new method for tunnel site rating from groundwater hazard point of view", Journal of Applied Sciences, Vol 9, 1496-1502. Karlsrud, K., 2001. Water control when tunnelling under urban areas in the Olso region.

Lei, S., 1999. An analytical solution for steady flow into a tunnel. Ground Water 37, 23–26. Raymer, J.H.,(2003), "Predicting groundwater inflow into hard-rock tunnels : Estimating the

high- end of the permeability disterbution",RETC. Pp. 201-217

relative differences of other equations are considerable in this case (Fig. 5).

suitable drainage system and to choose the best drilling method.

Underground Space Technology, Vol. 18, PP. 49-55.

Excavation and Tunneling Conference, June 18-21.

NFF publication No. 12, 4, 27–33, NFF.

tunnel driving", Engineering Geology vol.1 , pp 150-162.

**5. References** 

TIC 217571.

The present work concerns subsurface drainage systems. The problems of surface and subsurface draining excess water from the canal or river are the major preoccupation of many researchers for at least 50 years; therefore we devoted this study to find appropriate solutions for problems encountered in the drainage of bank storage in shallow unconfined aquifers.

It is necessary to develop special processes such as the drains, the filters and to choose the type of the most effective drain to drain excess water from the canal. We have performed a study on a reduced model, of a homogeneous soil with trench drain on an impervious foundation, and we have proposed a correlation to determine the best position of the trench drain in the homogeneous soil. The water level in the trench drains can be directly determined for a given head of water in the canal, slope of the canal and the permeability coefficient, so that the seepage analysis is simplified to a certain degree and the accuracy is also satisfied based on the new approach. Finally comparative studies between experimental and numerical results using [SEEP] software were carried out.

#### **2. Horizontal drainage**

#### **2.1 Steady and parallel flow in unconfined aquifers**

In this section, we discuss the flow of groundwater to trench drains under steady state conditions. The steady-state theory is based on the assumption that the rate of recharge to the groundwater and evaporation is null.

Figure 1 shows a typical cross-section of a drainage system under this condition.

To describe the flow of groundwater to the trench drains, we have to make the following assumptions:


$$\frac{K}{2} \left[ \frac{\vartheta^2(h)^2}{\vartheta x^2} + \frac{\vartheta^2(h)^2}{\vartheta y^2} \right] \pm q = 0 \tag{1}$$

$$\frac{d^2(h)^2}{dx^2} = 0\tag{2}$$

$$h^2 = \mathcal{C}\_1 \mathfrak{x} + \mathcal{C}\_2 \tag{3}$$

$$\mathcal{C}\_1 = \frac{H\_1^2 - H\_2^2}{E}, \quad \mathcal{C}\_2 = H\_1^2 \tag{4}$$

$$h^2 = H\_1^2 - (H\_1^2 - H\_2^2)\frac{\chi}{\pi} \tag{5}$$

$$Q = -V.S = -K.I.h.1 = -Kh\frac{\partial h}{\partial x} = -\frac{K}{2}\frac{\partial (h^2)}{\partial x} \tag{6}$$

$$Q = \frac{K\left(H\_1^2 - H\_2^2\right)}{2E} \tag{7}$$

$$\frac{\kappa}{2} \frac{d^2(h^2)}{dx^2} + q = 0\tag{8}$$

$$h^2 = -\frac{q}{\kappa} \mathfrak{x}^2 + \mathcal{C}\_1 \mathfrak{x} + \mathcal{C}\_2 \tag{9}$$

$$h^2 = H\_1^2 - \left(H\_2^2 - H\_1^2\right)\frac{\chi}{E} + \frac{q}{K}\chi(E-\chi) \tag{10}$$

$$Q = \frac{\kappa \left(H\_1^2 - H\_2^2\right)}{2E} + q\left(\varkappa - \frac{E}{2}\right) \tag{11}$$

$$Q = \frac{K\{H\_1^2 - H\_2^2\}}{2E} + q\left(x - \frac{E}{2}\right)^2$$

$$\begin{array}{ll} \text{a.} \quad \chi = 0; \rightarrow Q\_0 = \frac{2(5^2 - 0)}{2.200} + 0.01 \left( 0 - \frac{200}{2} \right) = -0.875 \frac{m^3}{d.ml} \\\text{b.} \quad \chi = \mathbf{E}; \rightarrow Q\_0 = \frac{50}{400} + 0.01 \left( 200 - \frac{200}{2} \right) = 1,125 \frac{m^3}{d.ml} \end{array}$$

$$
\Sigma \ Q = Q.B: \Sigma \ Q\_0 = -0.875.500 = -437,5 \frac{m^3}{d} = -5,06 \text{ l/s}
$$

$$
\Sigma \ Q\_E = \ 1,125.500 = \ 562,5 \frac{m^3}{d} = \ 6,51 \text{ l/s}
$$

$$Q = \frac{K(H\_1^2 - H\_2^2)}{2E}$$

$$Q = \frac{2(5^2 - 0)}{2.200} = 0.125 \frac{m^3}{d.ml^3}$$

$$
\sum Q = Q.B: \sum Q = 0.125.500 = \ 62.5 \frac{m^3}{d} = \ 0.72 \text{ l/s}
$$

$$K = \frac{2QE}{(H\_1^2 - H\_2^2)} = \frac{2.0,200.200}{(5^2 - 0)} = \frac{60}{25} = 3,2 \frac{m^3}{d}$$

$$Q = \frac{\Sigma \, Q}{B} = \frac{100}{500} = 0.2 \frac{m^3}{d.ml}$$

$$q = \frac{K}{r} (H - 0.27h\_0) (H^2 - h\_0^2) \tag{12}$$

$$h\_d = h\_0 \left[ \frac{c\_1 c\_2}{r} (H - h\_0) + 1 \right] \tag{13}$$

$$q = \frac{K}{r} \left( H - 0.27h\_0 \right) \left( H^2 - h\_0^2 \right)$$

$$q = \frac{9}{50} (8 - 0.27.5.5) \left( 8^2 - 5.5^2 \right) = 4.95 \frac{m^2}{d.m}$$

$$\frac{a}{h\_0} = \frac{10}{8} = 1,25 \to \mathcal{C}\_1 = 0,93$$

$$\frac{B}{H} = \frac{0,8}{8} = 0,1 \to \mathcal{C}\_2 = 0,6$$

$$h\_d = h\_0 \left[ \frac{\mathcal{C}\_1 \mathcal{C}\_2}{r} (H - h\_0) + 1 \right]^2$$

$$h\_d = 5.5 \left[ \frac{0.93.0,6}{50} (8 - 5.5) + 1 \right] = 5.65 m$$

$$H - h\_d = 8 - 5.65 = 2.35m$$

$$H\_0^2 - H\_p^2 = \frac{q}{\pi \kappa} \ln \frac{r}{r\_p} \tag{14}$$

Drainage of Bank Storage in Shallow Unconfined Aquifers 99

Unconfined aquifers are associated with the presence of a free water table, therefore the groundwater can flow in any direction: horizontal, vertical, or intermediate between them. Shallow unconfined aquifers have a shallow impermeable layer (say at 0.5 to 2 m below the soil surface). The flow of groundwater to subsurface drains above a shallow impermeable layer is mainly horizontal and occurs mostly above drain level (Fig. 11). In shallow unconfined aquifers, it is usually sufficient to measure the horizontal hydraulic conductivity of the soil above drain level (i.e. Ka). The recharge of water to a shallow aquifer occurs only as the percolation of rain or irrigation water; there is neither upward seepage of groundwater nor any natural drainage. Since the transmissivity of a shallow aquifer is small, the horizontal flow in the absence of subsurface drains is usually neglected (from

Fig. 11. Flow of groundwater to subsurface drains in shallow unconfined aquifers (from

A large number of procedures have been used to solve seepage problems through porous medium, graphical, analytical, experimental and numerical methods were introduced in literatures to determine the hydraulic parameters of seepage through homogeneous soil.

The governing steady flow which can be described by the Laplace equation (Equation 17) is developed from application of the law of mass conservation with Darcy's Law can be solved by a graphical construction of a flow net. A flow net is a network of curves called streamlines and equipotential lines. A streamline is an imaginary line that traces the path that a particle of groundwater would follow as it flows through an aquifer. In an isotropic

**5. Drainage of bank storage in shallow unconfined aquifers** 

**5.1 Shallow unconfined aquifers** 

Oosterbaan, R.J. & Nijland, H.J. (1994)).

Oosterbaan, R.J. & Nijland, H.J. (1994)).

For isotropic soil the Laplace equation is:

**5.2.1 Introduction** 

**5.2 Methods for solving unconfined drainage** 

aquifer, streamlines are perpendicular to equipotential lines.

#### **4. Single horizontal drainage in semi-captive aquifers**

The pumping rate is estimated by the flowing formula (Leonards, 1968):

$$q = \frac{2KD(H - h\_0)}{l + \lambda D} \tag{16}$$

where: � = coefficient given by the curve of the figure 10.

Fig. 9. Single horizontal drainage in semi-Captive aquifers.

where r =radius of influence

Fig. 10. Values of � (from Cassan, M. (1994)).

### **5. Drainage of bank storage in shallow unconfined aquifers**

#### **5.1 Shallow unconfined aquifers**

98 Drainage Systems

���(����)

���� (16)

**4. Single horizontal drainage in semi-captive aquifers** 

where: � = coefficient given by the curve of the figure 10.

Fig. 9. Single horizontal drainage in semi-Captive aquifers.

where r =radius of influence

Fig. 10. Values of � (from Cassan, M. (1994)).

The pumping rate is estimated by the flowing formula (Leonards, 1968):

� �

Unconfined aquifers are associated with the presence of a free water table, therefore the groundwater can flow in any direction: horizontal, vertical, or intermediate between them. Shallow unconfined aquifers have a shallow impermeable layer (say at 0.5 to 2 m below the soil surface). The flow of groundwater to subsurface drains above a shallow impermeable layer is mainly horizontal and occurs mostly above drain level (Fig. 11). In shallow unconfined aquifers, it is usually sufficient to measure the horizontal hydraulic conductivity of the soil above drain level (i.e. Ka). The recharge of water to a shallow aquifer occurs only as the percolation of rain or irrigation water; there is neither upward seepage of groundwater nor any natural drainage. Since the transmissivity of a shallow aquifer is small, the horizontal flow in the absence of subsurface drains is usually neglected (from Oosterbaan, R.J. & Nijland, H.J. (1994)).

Fig. 11. Flow of groundwater to subsurface drains in shallow unconfined aquifers (from Oosterbaan, R.J. & Nijland, H.J. (1994)).

#### **5.2 Methods for solving unconfined drainage**

#### **5.2.1 Introduction**

A large number of procedures have been used to solve seepage problems through porous medium, graphical, analytical, experimental and numerical methods were introduced in literatures to determine the hydraulic parameters of seepage through homogeneous soil.

The governing steady flow which can be described by the Laplace equation (Equation 17) is developed from application of the law of mass conservation with Darcy's Law can be solved by a graphical construction of a flow net. A flow net is a network of curves called streamlines and equipotential lines. A streamline is an imaginary line that traces the path that a particle of groundwater would follow as it flows through an aquifer. In an isotropic aquifer, streamlines are perpendicular to equipotential lines.

For isotropic soil the Laplace equation is:

Drainage of Bank Storage in Shallow Unconfined Aquifers 101

equations with N unknown values of head are developed (N equals number of nodes). Normally, N is large and relaxation methods involving iterations and the use of a

This method is also based on grid pattern (not necessarily rectangular) which divides the flow region into discrete elements and provides N equations with N unknowns. Material properties, such as permeability, are specified for each element and boundary conditions (heads and flow rates) are set. A system of equations is solved to compute heads at nodes

The finite element has several advantages over the finite difference method for more

The graphical method can be used to solve a wider class of problems than analytical method. Its advantage is highly remarkable in case of potential flow through domains with irregular boundaries. Other types of flow such as through two dimensional anisotropic

Flow nets are one of the most useful and accepted methods for solution of Laplace's equation (Casagrande, 1937). If boundary conditions and geometry of a flow region are known and can be displayed two dimensionally, a flow net can provide a strong visual

To draw the flow net, the following conditions are to be satisfied as follows (Harry, 1989);

Using the previous conditions, it is recommended to start the flow net construction by drawing the streamlines taking the advantage of the existing impermeable surfaces in the domain of flow and making sure that they meet water bodies at right angles. However, the graphical method requires a lot of experience and many trial and error works before

Experimental methods are considered useful for simulating the flow of water by models in laboratory. There are two types of models, electrical model, which analogous the flow of

sense of what is happening (pressures and flow quantities) in the flow region.

a. Complex geometry including sloping layers of material can be easily accommodated. b. By varying the size of elements, zones where seepage gradients or velocity are high can

given node is the average of the surrounding nodes, a set of N linear algebraic

2. The finite element method is a second way of numerical solution.

complex seepage problems. These include (Radhakrishnan, 1978):

homogeneous soil or multilayers can also be treated graphically.

2. all water bodies are lines of constant head (equipotential lines),

computer must be applied.

and flows in the elements.

be accurately modeled.

**5.2.4 Graphical method** 

c. Pockets of material in a layer can be modeled.

1. all impermeable boundaries are streamlines,

reaching a solution with reasonable accuracy.

**5.2.5 Experimental model** 

3. streamlines meet equipotential lines at right angles, 4. streamlines do not intersect one another, and 5. equipotential lines do not intersect one another.

$$\nabla^2 h = \frac{\partial^2 h}{\partial \mathbf{x}^2} + \frac{\partial^2 h}{\partial y^2} = \mathbf{0} \tag{17}$$

Where h is the total fluid head.

#### **5.2.2 Analytical methods**

Flow problems may be solved by analytical, experimental means or a combination of the two. Some analytical solutions are available for seepage flow problems. In a few cases, analytical expressions can be obtained by direct integration of the appropriate differential equation. Harr (1962) explains the use of transformations and mapping to transfer the geometry of a seepage problem from one complex plane to another. Conformal transformation techniques (conformal mapping) and velocity hodograph can also analyze a range of problems (Abd El Razek , & Nasr, 1993).

Pavlovsky (1936, 1956) developed an approximate method which allows the piecing together of flow net fragments to develop a flow net for the total seepage problem. This method, termed the method of fragments, allows rather complicated seepage problems to be resolved by breaking them into parts, analyzing flow patterns for each, and reassembling the parts to provide an overall solution.

In 1931, Kozeny (Abd El Razek , & Nasr, 1993) studied the problem of seepage through an earth dam on an impervious base with a parabolic upstream face and a horizontal underdrain. Using conformal mapping, he obtained a parabola for the free surface.

#### **5.2.3 Numerical methods**

The flow through porous media occurs usually in domain shapes that make the possibility of obtaining an analytical solution highly improbable. The nonhomogenity of the soil, the complexity of the boundaries and boundary conditions make the situation even more difficult (Hayder Hassan Al.Jairry, 2010).

The numerical solution of boundary value problems is a very old subject. In the past, the difficulty lied in the huge number of the obtained simultaneous algebraic equations, which have to be solved to reach the solution. The development of strong numerical methods can be applied to almost all types of problems of flow through porous media. These lead to the production of high quality easy to use software that can solve complicated problems and present the results in most convenient forms

Computer models are used to make acceptable approximations for the Laplace equation in complex flow conditions.

The two primary methods of numerical solution are finite difference and finite element. Both methods can be used in one-, two-, or three-dimensional modeling.

1. The finite difference method solves the Laplace equations by approximating them with a set of linear algebraic equations. The flow region is divided into a discrete rectangular grid with nodal points which are assigned values of head (known head values along fixed head boundaries or points, estimated heads for nodal points that do not have initially known head values). Using Darcy's law and the assumption that the head at a

given node is the average of the surrounding nodes, a set of N linear algebraic equations with N unknown values of head are developed (N equals number of nodes). Normally, N is large and relaxation methods involving iterations and the use of a computer must be applied.

2. The finite element method is a second way of numerical solution.

This method is also based on grid pattern (not necessarily rectangular) which divides the flow region into discrete elements and provides N equations with N unknowns. Material properties, such as permeability, are specified for each element and boundary conditions (heads and flow rates) are set. A system of equations is solved to compute heads at nodes and flows in the elements.

The finite element has several advantages over the finite difference method for more complex seepage problems. These include (Radhakrishnan, 1978):


#### **5.2.4 Graphical method**

100 Drainage Systems

2 2

2 2 <sup>0</sup> *h h <sup>h</sup> x y* 

Flow problems may be solved by analytical, experimental means or a combination of the two. Some analytical solutions are available for seepage flow problems. In a few cases, analytical expressions can be obtained by direct integration of the appropriate differential equation. Harr (1962) explains the use of transformations and mapping to transfer the geometry of a seepage problem from one complex plane to another. Conformal transformation techniques (conformal mapping) and velocity hodograph can also analyze a

Pavlovsky (1936, 1956) developed an approximate method which allows the piecing together of flow net fragments to develop a flow net for the total seepage problem. This method, termed the method of fragments, allows rather complicated seepage problems to be resolved by breaking them into parts, analyzing flow patterns for each, and reassembling

In 1931, Kozeny (Abd El Razek , & Nasr, 1993) studied the problem of seepage through an earth dam on an impervious base with a parabolic upstream face and a horizontal

The flow through porous media occurs usually in domain shapes that make the possibility of obtaining an analytical solution highly improbable. The nonhomogenity of the soil, the complexity of the boundaries and boundary conditions make the situation even more

The numerical solution of boundary value problems is a very old subject. In the past, the difficulty lied in the huge number of the obtained simultaneous algebraic equations, which have to be solved to reach the solution. The development of strong numerical methods can be applied to almost all types of problems of flow through porous media. These lead to the production of high quality easy to use software that can solve complicated problems and

Computer models are used to make acceptable approximations for the Laplace equation in

The two primary methods of numerical solution are finite difference and finite element.

1. The finite difference method solves the Laplace equations by approximating them with a set of linear algebraic equations. The flow region is divided into a discrete rectangular grid with nodal points which are assigned values of head (known head values along fixed head boundaries or points, estimated heads for nodal points that do not have initially known head values). Using Darcy's law and the assumption that the head at a

Both methods can be used in one-, two-, or three-dimensional modeling.

underdrain. Using conformal mapping, he obtained a parabola for the free surface.

(17)

2

Where h is the total fluid head.

range of problems (Abd El Razek , & Nasr, 1993).

the parts to provide an overall solution.

difficult (Hayder Hassan Al.Jairry, 2010).

present the results in most convenient forms

**5.2.3 Numerical methods** 

complex flow conditions.

**5.2.2 Analytical methods** 

The graphical method can be used to solve a wider class of problems than analytical method. Its advantage is highly remarkable in case of potential flow through domains with irregular boundaries. Other types of flow such as through two dimensional anisotropic homogeneous soil or multilayers can also be treated graphically.

Flow nets are one of the most useful and accepted methods for solution of Laplace's equation (Casagrande, 1937). If boundary conditions and geometry of a flow region are known and can be displayed two dimensionally, a flow net can provide a strong visual sense of what is happening (pressures and flow quantities) in the flow region.

To draw the flow net, the following conditions are to be satisfied as follows (Harry, 1989);


Using the previous conditions, it is recommended to start the flow net construction by drawing the streamlines taking the advantage of the existing impermeable surfaces in the domain of flow and making sure that they meet water bodies at right angles. However, the graphical method requires a lot of experience and many trial and error works before reaching a solution with reasonable accuracy.

#### **5.2.5 Experimental model**

Experimental methods are considered useful for simulating the flow of water by models in laboratory. There are two types of models, electrical model, which analogous the flow of

Drainage of Bank Storage in Shallow Unconfined Aquifers 103

where Q = quantity of discharge; H1 = the head of water upstream; H2 = the head of water downstream; L = the length of the sample; b = the width of the sample; Kh = coefficient of

The best position of a trench drain in a homogeneous soil (fig.12.) can be determined according to the maximum head of water in the canal, the slope of the canal and the critical hydraulic gradient of the soil, for the case of fine sand, Icr=0,38 (Volkov, 1986). Assuming that the curve of saturation (phreatic line) has a linear shape, we proposed the following

�� � ��� <sup>+</sup> �����

where Hm = maximum head of water in the canal; hd = imposed head of water in the trench drain; Icr = critical gradient of material used; n = slope of the canal; Ld = position of the

The water level in the trench drain can be determined for a given head of water in the canal by using the two following relationships (Eq.24 and Eq.25). For the first relationship (Eq.24), we assume that the curve of saturation (phreatic line) has a linear shape, and the critical

�����

hydraulic gradient material of the soil is under the following condition:

��� ������� and � � �����

*Iadm* - allowed infiltration gradient (Volkov, 1986).

���

(20)

relationship (Djehiche, 1993, Djehiche et al., 2006, Djehiche & Kotchev, 2008).

horizontal permeability. We obtain Kh= 43.2 (m/day) = 5.10-4(m/s).

**7. Trench drain** 

trench drain.

**7.1 Position of the trench drain** 

Fig. 12. The position of the trench drains.

**7.2 Water level in the trench drain** 

water by a flow of current and physical models such as sandbox model and viscous flow model (Hele-Shaw model). These methods have some inconvenient such as the complicated construction and operation. In Hele-Shaw model, the viscosity of the fluid varies with temperature, and sandbox model suffers from the difficulty of representing the correct permeability of the soil and because of the difficulties caused by capillarity. In this study we have used a sandbox model.

#### **5.2.5.1 Sand-box model**

Sand models which may use prototype materials can provide information about flow paths and head at particular points in the aquifer. We have constructed a scale model (generally sand) of the prototype in a sandbox equipped from perforated front and which allow the passage of water. When steady-state flow is reached, the flow can be traced by dye injection at various points along the upstream boundary close to the transparent wall to form the traces of streamlines, and heads determined by small piezometers (El-Masry, 1995; Khalaf Allah, 2005).

A small-scale model was built; which is geometrically similar to the real system. This model represents a homogeneous soil (bank storage in shallow unconfined aquifers) with a trench drain on an impervious foundation. Sand has been used as a permeable medium for the body of the soil, provided that its permeability is such as the flow remains laminar and that there is not any effect of distortion by capillarity (the grains should not be lower than 0,7 mm) (Mallet & Pacouant, 1951) and of gravel for the trench drain. The piezometric prickings laid out on the two zones with dimensions of the tank make it possible to know the actual values of the head of water along the trajectory of flow and highlight the burden-sharing of water in the seepages (Bear, 1972; Casagrande, 1973; Harr, 1962).

#### **6. Reduced model of bank storage in shallow unconfined aquifers**

#### **6.1 Determination of the material characteristics**

The characteristics of materials used in this model have been determined (sand for the soil and gravel for the drain) such as the vertical and horizontal permeability

#### **6.2 Vertical permeability**

It is given according to the Darcy' law:

$$Q = K\_{\nu}.SI \tag{18}$$

where Q = quantity of discharge; S = cross-sectional area of flow; I = hydraulic gradient; Kv = coefficient of vertical permeability.

We obtain,ܭ௩= 4.9(m/day) = 5, 67.10-5 (m/s),

#### **6.3 Horizontal permeability**

This permeability is given according to the formula of Dupuit:

$$Q = \frac{\kappa\_h \left(H\_1^2 - H\_2^2\right)}{2L} \tag{19}$$

where Q = quantity of discharge; H1 = the head of water upstream; H2 = the head of water downstream; L = the length of the sample; b = the width of the sample; Kh = coefficient of horizontal permeability. We obtain Kh= 43.2 (m/day) = 5.10-4(m/s).

#### **7. Trench drain**

102 Drainage Systems

water by a flow of current and physical models such as sandbox model and viscous flow model (Hele-Shaw model). These methods have some inconvenient such as the complicated construction and operation. In Hele-Shaw model, the viscosity of the fluid varies with temperature, and sandbox model suffers from the difficulty of representing the correct permeability of the soil and because of the difficulties caused by capillarity. In this study we

Sand models which may use prototype materials can provide information about flow paths and head at particular points in the aquifer. We have constructed a scale model (generally sand) of the prototype in a sandbox equipped from perforated front and which allow the passage of water. When steady-state flow is reached, the flow can be traced by dye injection at various points along the upstream boundary close to the transparent wall to form the traces of streamlines, and heads determined by small piezometers (El-Masry, 1995; Khalaf

A small-scale model was built; which is geometrically similar to the real system. This model represents a homogeneous soil (bank storage in shallow unconfined aquifers) with a trench drain on an impervious foundation. Sand has been used as a permeable medium for the body of the soil, provided that its permeability is such as the flow remains laminar and that there is not any effect of distortion by capillarity (the grains should not be lower than 0,7 mm) (Mallet & Pacouant, 1951) and of gravel for the trench drain. The piezometric prickings laid out on the two zones with dimensions of the tank make it possible to know the actual values of the head of water along the trajectory of flow and highlight the burden-sharing of

The characteristics of materials used in this model have been determined (sand for the soil

where Q = quantity of discharge; S = cross-sectional area of flow; I = hydraulic gradient; Kv

మିுమ మ൯

(18) ܫܵ ௩Ǥܭൌܳ

ଶ (19)

water in the seepages (Bear, 1972; Casagrande, 1973; Harr, 1962).

**6.1 Determination of the material characteristics** 

**6.2 Vertical permeability** 

It is given according to the Darcy' law:

= coefficient of vertical permeability.

**6.3 Horizontal permeability** 

We obtain,ܭ௩= 4.9(m/day) = 5, 67.10-5 (m/s),

This permeability is given according to the formula of Dupuit:

ܳ ൌ ൫ுభ

**6. Reduced model of bank storage in shallow unconfined aquifers** 

and gravel for the drain) such as the vertical and horizontal permeability

have used a sandbox model.

**5.2.5.1 Sand-box model** 

Allah, 2005).

#### **7.1 Position of the trench drain**

The best position of a trench drain in a homogeneous soil (fig.12.) can be determined according to the maximum head of water in the canal, the slope of the canal and the critical hydraulic gradient of the soil, for the case of fine sand, Icr=0,38 (Volkov, 1986). Assuming that the curve of saturation (phreatic line) has a linear shape, we proposed the following relationship (Djehiche, 1993, Djehiche et al., 2006, Djehiche & Kotchev, 2008).

$$L\_d = nH\_m + \frac{H\_m - H\_d}{l\_{cr}} \tag{20}$$

where Hm = maximum head of water in the canal; hd = imposed head of water in the trench drain; Icr = critical gradient of material used; n = slope of the canal; Ld = position of the trench drain.

Fig. 12. The position of the trench drains.

#### **7.2 Water level in the trench drain**

The water level in the trench drain can be determined for a given head of water in the canal by using the two following relationships (Eq.24 and Eq.25). For the first relationship (Eq.24), we assume that the curve of saturation (phreatic line) has a linear shape, and the critical hydraulic gradient material of the soil is under the following condition:

$$I\_{cr} \le I \le I\_{adm} \qquad \text{and} \qquad I = \frac{0.82H}{L\_d - nH}$$

*Iadm* - allowed infiltration gradient (Volkov, 1986).

$$
\tan \beta = \frac{H}{L\_1} = \frac{1}{n} \Rightarrow L\_1 = nH \tag{21}
$$

$$\tan a = \frac{H - h}{L\_2} = I\_{cr} \Rightarrow L\_2 = \frac{H - h \text{III}}{l\_{cr}} \tag{22}$$

$$L\_d = L\_1 + L\_2 = nH + \frac{H - h}{l\_{cr}} \tag{23}$$

$$h = H - (L\_d - nH)I\_{cr} \tag{24}$$

$$\text{(a) n=3,0}$$

$$\begin{aligned} \dots & \le \frac{K\_h}{K\_v} \le 30 \\\\ & \left[ \frac{^{0.10791 H \left( \frac{K\_h}{K\_v} \right)^{0.3}} \cdot \frac{^{3.3111} \sqrt{K\_h}}{n^{1.2}}}{n^{1.2}} \right] \\\\ & = e \end{aligned} $$

Drainage of Bank Storage in Shallow Unconfined Aquifers 109

Bear, J.; (1972). *Dynamics of Fluids in Porous Media*, Elsevier, ISBN 0-444-00114-X, New York

Chu , J.; Bo, M. W.; & Choa, V. (2004). Practical considerations for using vertical drains in

Djehiche, A. (1993). *Comportement des barrages en terre avec cheminée filtrante sous l'action de* 

Djehiche, A.; Derriche, Z. & Kotchev, K. (2006). *Control of water head in the vertical drain.* 

Djehiche, A.; & Kotchev, K.; (2008). *Control of seepage in earth dams with a vertical drain.* 

Duncan, J. M. (1970). SEEP, A computer for seepage with a free surface or confined steady

Dunglas, J. & Loudiere, D. (1973). Nouvelle conception des drains dans les barrages en terre

El-Masry A. A., (1995). Unconfined Seepage through Earth Dams with Chimney Drain by

Harr, M. E.; (1962). *Groundwater and Seepage*, McGraw-Hill Book Company, ISBN 0-486-

Harry R. Cedergren, (1989). *Seepage, drainage, and flow nets*. John Wiley & Sons, Inc., New

Hayder Hassan Al.Jairry (2010) 2D-Flow Analysis Through Zoned Earth Dam Using Finite

Kahlown M. A. & Khan A.D. (2004). *Tile drainage manual*. Khyaban-e-Johar, H-8/1,

Khalaf Allah S., (2005). *Seepage through Earth dams with Filters*, M. Sc thesis, Dept. of

Leonards, G.A., (1968), *Les Fondations* (traduction de "Foundation Engineering". McGraw-

Loudiere, D. (1972). Elément théorique sur le drainage dans les barrages en terre

Oosterbaan, R.J. & Nijland, H.J. (1994). Determining the saturated hydraulic conductivity.

Ritzema, H.P. ; (1994). Subsurface Flow to Drains. *Drainage Principles and Applications*.

revised edition, Wageningen, The Netherlands. ISBN 90 70754 3 39

Hill New York 1962 par un groupe d'ingénieurs des Laboratoires des Ponts et

*Drainage Principles and Applications*. International Institute for Land Reclamation and Improvement ( ILRI), Chapter 12 in: H.P.Ritzema (Ed.) Publication 16, second

International Institute for Land Reclamation and Improvement ( ILRI), Chapter 8 in: Publication 16, second revised edition, Wageningen, The Netherlands. ISBN 90

*l'infiltration*. Thèse Magister, Algeria: USTO, pp 121 (in Arabic).

soil improvement projects, *Geotextiles and Geomembranes* , N° 22: pp 101–117, ISSN

Proceedings of Dams and Reservoirs, Societies and Environment in the 21st

Chinese Journal of Geotechnical Engineering, pp 1657-1660, Vol.30, Nov (2008),

homogènes de petite et moyenne dimensions. *La Houille Blanche*, 5(6): pp. 461-465,

Boundary Element Method", Proceeding of First Engineering conference,

Casagrande,A. (1973). *Seepage control in earth dams*. J. Wiley & Sone.

Century*,* Vol.1, pp 913-916, ISBN-10: 0-415-40423-1.

flow. University of California: Berkeley.

Mansoura, March 1995, Vol. III. pp. 357-365.

Islamabad – Pakistan ISBN 969-8469-13-3

Chaussées). Dunod, Paris, 1106 p

homogènes. C.T.G.R.E.F., Nov,

Element Approach, *Eng. & Tech. Journal* ,Vol.28, No.21,

Mallet, Ch. & Pacouant, J. ; (1951). *Les barrages en terre*. Edition Eyrolles.

Irrigation and Hydraulics Eng. Mansoura university , Egypt.

0266-1144

ISSN *1000-4548*.

ISSN 0018-6368.

66881-9, New York.

York, NY.

70754 3 39

Fig. 15. The lozenge represents the experimental results of the tests, the triangle represents the results obtained with equation (25), and the square represents the numerical results: (a) n=3,0; (b) n=2,5; (c) n=2,0.

#### **7.2.2 Discussion**

We observe a good agreement between the curves obtained by the three procedures the empirical formula (25), the experimental data and the numerical results obtained with "SEEP" (Duncan, 1970).

#### **8. Conclusion**

The models developed in this study enable us to design the most effective position of the trench drains in the drainage of bank storage in shallow unconfined aquifers. The water level in the trench drains can be directly determined for a given head of water in the canal, slope of the canal and the permeability coefficient, therefore the seepage analysis is simplified to a certain degree and the accuracy is also satisfied based on the new approach. Moreover, these equations are simple to apply and can be used to design and analyze any homogeneous soil with a trench drains in the drainage of bank storage in shallow unconfined aquifers. These very encouraging results enable us also to extrapolated these results in the field of a network of drains in a drainage system and consider the prediction of the infiltrations through the earth dams as well as the piping phenomena which are often at the origin of many dramatic accidents.

#### **9. References**

Abd El Razek M., & Nasr R. I., (1993). Evaluation of the Minimum Length of Filter in Earth Dams, Journal *of Alexandria Engineering*, Vol. 32, No. 4, October 1993, ISSN 1110- 0168.

**n=2,0**

(c) Fig. 15. The lozenge represents the experimental results of the tests, the triangle represents the results obtained with equation (25), and the square represents the numerical results: (a)

14 19 24 29

**H(cm)**

We observe a good agreement between the curves obtained by the three procedures the empirical formula (25), the experimental data and the numerical results obtained with

The models developed in this study enable us to design the most effective position of the trench drains in the drainage of bank storage in shallow unconfined aquifers. The water level in the trench drains can be directly determined for a given head of water in the canal, slope of the canal and the permeability coefficient, therefore the seepage analysis is simplified to a certain degree and the accuracy is also satisfied based on the new approach. Moreover, these equations are simple to apply and can be used to design and analyze any homogeneous soil with a trench drains in the drainage of bank storage in shallow unconfined aquifers. These very encouraging results enable us also to extrapolated these results in the field of a network of drains in a drainage system and consider the prediction of the infiltrations through the earth dams as well as the piping phenomena which are often at

Abd El Razek M., & Nasr R. I., (1993). Evaluation of the Minimum Length of Filter in Earth

Dams, Journal *of Alexandria Engineering*, Vol. 32, No. 4, October 1993, ISSN 1110-

n=3,0; (b) n=2,5; (c) n=2,0.

0

2

4

6

**h(cm)**

8

10

12

"SEEP" (Duncan, 1970).

the origin of many dramatic accidents.

**7.2.2 Discussion** 

**8. Conclusion** 

**9. References** 

0168.


**6** 

**A Study of Subsurface Drainage and Water** 

**Central Arabian Shield, Saudi Arabia** 

*Faculty of Earth Sciences, King Abdulaziz University, Jeddah,* 

Mohammed Amin M. Sharaf

*Saudi Arabia* 

**Quality in Jeddah-Makkah Aquifer Zone, West** 

In arid regions where average annual rainfall is less than 200 mm, recharge to local and regional aquifers is mostly indirect, very limited and insignificant (Lloyd 1999). Apart from the limited groundwater in shallow alluvial aquifers, most of the stored groundwater in local and regional sedimentary aquifers is non-renewable fossil water with varying ages between about 10,000–32,000 years.. The extensive use of groundwater, including the nonrenewable part, has been heavily practiced in several countries such as USA, Australia, Spain, India, Jordan, Oman, Libya, Bahrain, UAE, Egypt and Saudi Arabia, to support, agricultural and domestic activities. Saudi Arabia's intensive use of groundwater, including non-renewable fossil water, especially after the increase in its oil revenues in 1974, is an example for intensive utilization of groundwater for irrigated agriculture to support

Groundwater in Saudi Arabia is found almost entirely in the many thick, highly permeable aquifers of large sedimentary basins to the north, east, and groundwater occurs in the fractured, Precambrian crystalline rocks of the Arabian Shield, which is more significant in providing extensive, higher, relatively impermeable areas for surface runoff, and localised, shallow wadi underflow (Burden, 1982). While the major aquifers in the north of the country consist of multiple, Early Palaeozoic clastic permeable formations with interdigitated impermeable argillaceous strata, those in the eastern part include both karstified Tertiary carbonates and Mesozoic to basal Palaeozoic clastic formations. To the south of the Arabian Shelf, a single thick basal Early Palaeozoic sandstone formation constitutes a high yield aquifer. Groundwater is stored in more than 20- layered principal and secondary aquifers of

The Arabian Shelf includes the deep sedimentary aquifers, which are formed mostly of limestone and sandstone that overlay the basement rocks and covers about two thirds of Saudi Arabia or 1,485,000 km2 (MAW 1984). The total thickness varies between a few hundred to more than 5,000 m (MAW 1984). The principal aquifers are: Saq, Wajid, Tabuk, Minjur, Dhruma, Biyadh, Wasia, Dammam, Umm Er Radhuma and Neogene. The secondary aquifers are: Al-Jauf, Al-Khuf, Al-Jilh, the Upper Jurassic, Sakaka, the Lower

**1. Introduction** 

**1.1 Ground water in Saudi Arabia** 

socioeconomic developments of natural communities.

different geological ages (Fig. 1) (MAW 1984).


### **A Study of Subsurface Drainage and Water Quality in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia**

Mohammed Amin M. Sharaf *Faculty of Earth Sciences, King Abdulaziz University, Jeddah, Saudi Arabia* 

#### **1. Introduction**

110 Drainage Systems

Thieu N.T. M., Fredlund D. G., Fredlund M. D. & Hung V. Q. (2001). *Seepage Modeling in a* 

Zhang J., Xu Q. & Chen Z.,( 2001). Seepage Analysis Based on the Unified Unsaturated Soil Theory, Mechanics Research Communications, , 28, No 1:pp 107-112,

Land and Water Resources, MLWR, October 20-22, Hanoi, Vietnam. Cassan, M. (1994). *Aide-Memoire D'hydraulique Souterraine.* Presses de l'école nationale des Ponts et Chaussées (ENPC) - 2ème Édition, France. ISBN-10: 2-85978-208-7 Volkov, V. (1986). *Ouvrages hydrauliques*. Guide de Thèse, ENSH, Blida, Algeria, pp 120-128. Xu Y.-Q., Unami K. & Kawachi T. (2003). Optimal hydraulic design of earth dam cross

Resources, 26: pp 1–7

*saturated/unsaturated Soil System*. International Conference on Management of the

section using saturated–unsaturated seepage flow model, Advances in Water

#### **1.1 Ground water in Saudi Arabia**

In arid regions where average annual rainfall is less than 200 mm, recharge to local and regional aquifers is mostly indirect, very limited and insignificant (Lloyd 1999). Apart from the limited groundwater in shallow alluvial aquifers, most of the stored groundwater in local and regional sedimentary aquifers is non-renewable fossil water with varying ages between about 10,000–32,000 years.. The extensive use of groundwater, including the nonrenewable part, has been heavily practiced in several countries such as USA, Australia, Spain, India, Jordan, Oman, Libya, Bahrain, UAE, Egypt and Saudi Arabia, to support, agricultural and domestic activities. Saudi Arabia's intensive use of groundwater, including non-renewable fossil water, especially after the increase in its oil revenues in 1974, is an example for intensive utilization of groundwater for irrigated agriculture to support socioeconomic developments of natural communities.

Groundwater in Saudi Arabia is found almost entirely in the many thick, highly permeable aquifers of large sedimentary basins to the north, east, and groundwater occurs in the fractured, Precambrian crystalline rocks of the Arabian Shield, which is more significant in providing extensive, higher, relatively impermeable areas for surface runoff, and localised, shallow wadi underflow (Burden, 1982). While the major aquifers in the north of the country consist of multiple, Early Palaeozoic clastic permeable formations with interdigitated impermeable argillaceous strata, those in the eastern part include both karstified Tertiary carbonates and Mesozoic to basal Palaeozoic clastic formations. To the south of the Arabian Shelf, a single thick basal Early Palaeozoic sandstone formation constitutes a high yield aquifer. Groundwater is stored in more than 20- layered principal and secondary aquifers of different geological ages (Fig. 1) (MAW 1984).

The Arabian Shelf includes the deep sedimentary aquifers, which are formed mostly of limestone and sandstone that overlay the basement rocks and covers about two thirds of Saudi Arabia or 1,485,000 km2 (MAW 1984). The total thickness varies between a few hundred to more than 5,000 m (MAW 1984). The principal aquifers are: Saq, Wajid, Tabuk, Minjur, Dhruma, Biyadh, Wasia, Dammam, Umm Er Radhuma and Neogene. The secondary aquifers are: Al-Jauf, Al-Khuf, Al-Jilh, the Upper Jurassic, Sakaka, the Lower

A Study of Subsurface Drainage and Water Quality

**1.2 Water supply sources in Saudi Arabia** 

**1.3 General climates and geology of the study area** 

suitability for different purposes.

and Al-Rehaili, 1989).

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 113

that can be utilized or may create serious problems for domestic, agriculture and other activities. Therefore, there is a growing need to study the groundwater chemistry that include evaluation of major ions and trace elements concentrations and their effects on its

The dependence on non-renewable groundwater resources has increased with time due to higher dependence of domestic and industrial water use on renewable groundwater in addition to desalination processes. The domestic and industrial water use depends mainly on desalination plants and renewable groundwater, while non-renewable groundwater water has been a secondary supplier to meet these demands. This study dealt with the hydrogeology and hydrochemistry of the groundwater aquifers in Jeddah- Makkah Al Mukarramah District, West Central Saudi Arabia. The study is based mainly on field

The study area lies within the western province of Saudi Arabia between latitudes 20o 54 00\ and 21o 57 23\ N and longitudes 39o 17 09\ and 40o 00 57\ E (Fig. 2). The present study will involve the three major drainage basins and their main tributaries. These are as follow: 1) Usfan, including, Haddat Ash Sham, Al Baydah-Mudsus, Ash Shamiyah and As Suqah sub-basins, 2) An Numan, including, Dayqah, Rahjan, Arar, Yarij and Uranah sub- basins, and 3) Fatimah, including, Al Sail Al Kabir, Al Yammaniyyah, Al Shamiyyah, Hawarah, Alaf, Bani Omair-Al Rayan and Al Jumum-Bahrah. All the basins lying partially within the

Several hydrogeological research activities were carried out in the study area since the early seventies. Most of these works were concerned with the groundwater condition, aquifer characteristics and the groundwater quality in the wadi sediments (e.g. Italconsult, 1976; Al-Khatib, 1977; Al-Hajeri, 1977; Jamman, 1978; Al-Nujaidi, 1978; Al-Gamal and Sen, 1983; Mansour, 1984; Sharaf et al. 1988; Al Kabir, 1985; Basmci and Al-Kabir, 1988; Alyamani and Hussein, 1995; Alyamani et al. 1996; and Alyamani, 1999). A few studies concerned with the trace elements concentrations such as Mn, Pb, Si, Al, F and B in the groundwater are available .i.e. Bazuhair et al. (1992) outlined comprehensive investigations on groundwater condition included water chemistry within Khulais basin. Detailed hydrogeological and hydrochemical studies were carried out in Wadi Usfan by Sharaf et al. (2002). Several detailed studies regarding geological and geomorphological characteristics of the area around An Numan basin are available (e.g. Brown et al. 1963; Zaidi, 1983 and 1984; Moore

The climatic conditions all over the study area may play an important role in defining the hydraulic response of the watersheds and groundwater quality existing in the region. Generally, the climate is typically arid and the rainfall is irregular and has torrential nature. The rainfall occurs during winter season, while in the autumn and spring the area is subjected to isolated events. The average annual rainfall is about 60 mm in the lowland areas. Where, moving towards the eastern direction the rainfall increases to more than 170 mm/year. Such variation in the rainfall amount can be attributed to the orographic effects of

observations and measurements augmented by may laboratory techniques.

Arabian Shield, while their lower parts are on the Red Sea coastal plain.

Cretaceous, Aruma, Basalts and Wadi Sediments (Fig. 1). The groundwater quality varies between sites and among aquifers. The isotopic analyses showed that the fossil groundwater in the above aquifers is 10,000–32,000 years old. Large volumes of groundwater are stored in the sedimentary aquifers (KFUPM/RI 1988). The estimated groundwater reserves to a depth of 300 meters below ground surface is about 2,185 km3, with a total annual recharge of 2,762 Mm3 based on several hydrogeological studies as given in KFUPM/RI (1988) and Alawi & bdulrazzak (1994).

Fig. 1. The extension of the outcrop area of principle and secondary aquifers in agriculture regions in Saudi Arabia.

In arid regions, the irregularity of recharge leads to significant variations in quality of the groundwater from place to place and from time to time. The groundwater quality depends widely on such factors as the chemical composition of the water-bearing formation as well as residence with the aquifer.

For the planning of water resources management it is necessary to define water quality from the areal distribution and the genetic aspects, in order to establish as far as possible the qualitative effects of natural and human influence factors on the water quality. Hence, any fall off in groundwater quality may result in a big reduction in the percentage of resources that can be utilized or may create serious problems for domestic, agriculture and other activities. Therefore, there is a growing need to study the groundwater chemistry that include evaluation of major ions and trace elements concentrations and their effects on its suitability for different purposes.

#### **1.2 Water supply sources in Saudi Arabia**

112 Drainage Systems

Cretaceous, Aruma, Basalts and Wadi Sediments (Fig. 1). The groundwater quality varies between sites and among aquifers. The isotopic analyses showed that the fossil groundwater in the above aquifers is 10,000–32,000 years old. Large volumes of groundwater are stored in the sedimentary aquifers (KFUPM/RI 1988). The estimated groundwater reserves to a depth of 300 meters below ground surface is about 2,185 km3, with a total annual recharge of 2,762 Mm3 based on several hydrogeological studies as given in KFUPM/RI (1988) and Alawi &

Fig. 1. The extension of the outcrop area of principle and secondary aquifers in agriculture

In arid regions, the irregularity of recharge leads to significant variations in quality of the groundwater from place to place and from time to time. The groundwater quality depends widely on such factors as the chemical composition of the water-bearing formation as well

For the planning of water resources management it is necessary to define water quality from the areal distribution and the genetic aspects, in order to establish as far as possible the qualitative effects of natural and human influence factors on the water quality. Hence, any fall off in groundwater quality may result in a big reduction in the percentage of resources

bdulrazzak (1994).

regions in Saudi Arabia.

as residence with the aquifer.

The dependence on non-renewable groundwater resources has increased with time due to higher dependence of domestic and industrial water use on renewable groundwater in addition to desalination processes. The domestic and industrial water use depends mainly on desalination plants and renewable groundwater, while non-renewable groundwater water has been a secondary supplier to meet these demands. This study dealt with the hydrogeology and hydrochemistry of the groundwater aquifers in Jeddah- Makkah Al Mukarramah District, West Central Saudi Arabia. The study is based mainly on field observations and measurements augmented by may laboratory techniques.

#### **1.3 General climates and geology of the study area**

The study area lies within the western province of Saudi Arabia between latitudes 20o 54 00\ and 21o 57 23\ N and longitudes 39o 17 09\ and 40o 00 57\ E (Fig. 2). The present study will involve the three major drainage basins and their main tributaries. These are as follow: 1) Usfan, including, Haddat Ash Sham, Al Baydah-Mudsus, Ash Shamiyah and As Suqah sub-basins, 2) An Numan, including, Dayqah, Rahjan, Arar, Yarij and Uranah sub- basins, and 3) Fatimah, including, Al Sail Al Kabir, Al Yammaniyyah, Al Shamiyyah, Hawarah, Alaf, Bani Omair-Al Rayan and Al Jumum-Bahrah. All the basins lying partially within the Arabian Shield, while their lower parts are on the Red Sea coastal plain.

Several hydrogeological research activities were carried out in the study area since the early seventies. Most of these works were concerned with the groundwater condition, aquifer characteristics and the groundwater quality in the wadi sediments (e.g. Italconsult, 1976; Al-Khatib, 1977; Al-Hajeri, 1977; Jamman, 1978; Al-Nujaidi, 1978; Al-Gamal and Sen, 1983; Mansour, 1984; Sharaf et al. 1988; Al Kabir, 1985; Basmci and Al-Kabir, 1988; Alyamani and Hussein, 1995; Alyamani et al. 1996; and Alyamani, 1999). A few studies concerned with the trace elements concentrations such as Mn, Pb, Si, Al, F and B in the groundwater are available .i.e. Bazuhair et al. (1992) outlined comprehensive investigations on groundwater condition included water chemistry within Khulais basin. Detailed hydrogeological and hydrochemical studies were carried out in Wadi Usfan by Sharaf et al. (2002). Several detailed studies regarding geological and geomorphological characteristics of the area around An Numan basin are available (e.g. Brown et al. 1963; Zaidi, 1983 and 1984; Moore and Al-Rehaili, 1989).

The climatic conditions all over the study area may play an important role in defining the hydraulic response of the watersheds and groundwater quality existing in the region. Generally, the climate is typically arid and the rainfall is irregular and has torrential nature. The rainfall occurs during winter season, while in the autumn and spring the area is subjected to isolated events. The average annual rainfall is about 60 mm in the lowland areas. Where, moving towards the eastern direction the rainfall increases to more than 170 mm/year. Such variation in the rainfall amount can be attributed to the orographic effects of

A Study of Subsurface Drainage and Water Quality

another.

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 115

the upper levels of both the basement complex and the sedimentary rocks; the lavas are either rest on peneplain or infilled ancient wadis. They are preserved in three northnorthwest trending, asymmetric depositional troughs which are the Sham, Suqah and Shumaysi troughs. These troughs are bounded in the north by faults downthrown to the

Quaternary deposits cover large parts of the study area. They principally occur in the large drainage basins of Haddat Ash Sham. The principle units of the Quaternary rocks are the terrace gravel, alluvial fan deposits, tallus deposits, alluvial sands and gravels of wadi beds and some eolian edifices. The thickness of these deposits varies widely from one place to

Fig. 3. Geologic map of Makkah district including Wadi Usfan, Wadi Fatimah and wadi An

Numan (Petter Johnson, 2006).

west and in the west by an unconformity at the base of the easterly dipping strata.

the Red Sea escarpment. Rainfall distribution over the study area was characterized in time and space. Data from the five rainfall gauges were used to establish the rainfall distribution. The variation of rainfall in the spatial dimension reflects the topographic effects, since the highest values were recorded at the highest stations. The average monthly rainfall was computed in order to give an approximate idea of the seasonal variation in the local rainfall patterns. All effective rainfall is concentrated between November and April (with very minor exceptions in early May).

From the geologic points of views, the study area comprises Precambrian-Cambrian basement complex, Cretaceous-Tertiary sedimentary succession, the Tertiary- Quaternary basaltic lava flows, and the Quaternary-Recent alluvial deposits (Fig. 3). The Precambrian rock units in the study area consist of Late-Proterozoic basaltic to rhyolitic volcanic and volcanoclastic and epiclastics of primitive island-arc type, that have been multiply deformed and metamorphosed and injected by intrusive bodies of different ages and compositions. These rock units are divided into Zibarah, Samran, and Fatimahh groups (sedimentary rocks). Plutonic rock units are gabbro, diorite, tonalite and granodiorite to monzonite of probably early Cambrian ages.

The Cretaceous-Tertiary sedimentary succession is exposed beneath a cover of flat-lying lavas and Quaternary deposits in the study area. This succession is subdivided into the Haddat Ash Sham, Shumaysi, Khulays, and Buraykah formations. It consists of clastic rocks dominated by sandstones, shale, mudstones, oolitic ironstones, and occasionally conglomerates. A middle Cretaceous age has been assigned to Haddat As Sham Formation. Basalt lava flows form discontinuous caps overlying

Fig. 2. Satellite image of the study area.

the Red Sea escarpment. Rainfall distribution over the study area was characterized in time and space. Data from the five rainfall gauges were used to establish the rainfall distribution. The variation of rainfall in the spatial dimension reflects the topographic effects, since the highest values were recorded at the highest stations. The average monthly rainfall was computed in order to give an approximate idea of the seasonal variation in the local rainfall patterns. All effective rainfall is concentrated between November and April (with very

From the geologic points of views, the study area comprises Precambrian-Cambrian basement complex, Cretaceous-Tertiary sedimentary succession, the Tertiary- Quaternary basaltic lava flows, and the Quaternary-Recent alluvial deposits (Fig. 3). The Precambrian rock units in the study area consist of Late-Proterozoic basaltic to rhyolitic volcanic and volcanoclastic and epiclastics of primitive island-arc type, that have been multiply deformed and metamorphosed and injected by intrusive bodies of different ages and compositions. These rock units are divided into Zibarah, Samran, and Fatimahh groups (sedimentary rocks). Plutonic rock units are gabbro, diorite, tonalite and granodiorite to monzonite of

The Cretaceous-Tertiary sedimentary succession is exposed beneath a cover of flat-lying lavas and Quaternary deposits in the study area. This succession is subdivided into the Haddat Ash Sham, Shumaysi, Khulays, and Buraykah formations. It consists of clastic rocks dominated by sandstones, shale, mudstones, oolitic ironstones, and occasionally conglomerates. A middle Cretaceous age has been assigned to Haddat As Sham Formation.

minor exceptions in early May).

probably early Cambrian ages.

Basalt lava flows form discontinuous caps overlying

Fig. 2. Satellite image of the study area.

the upper levels of both the basement complex and the sedimentary rocks; the lavas are either rest on peneplain or infilled ancient wadis. They are preserved in three northnorthwest trending, asymmetric depositional troughs which are the Sham, Suqah and Shumaysi troughs. These troughs are bounded in the north by faults downthrown to the west and in the west by an unconformity at the base of the easterly dipping strata.

Quaternary deposits cover large parts of the study area. They principally occur in the large drainage basins of Haddat Ash Sham. The principle units of the Quaternary rocks are the terrace gravel, alluvial fan deposits, tallus deposits, alluvial sands and gravels of wadi beds and some eolian edifices. The thickness of these deposits varies widely from one place to another.

Fig. 3. Geologic map of Makkah district including Wadi Usfan, Wadi Fatimah and wadi An Numan (Petter Johnson, 2006).

A Study of Subsurface Drainage and Water Quality

sometimes appear as small knobs.

**1.4 Data of recharge area** 

**STATION NAME**

**Alhada (1980-1992)**

**AlsailAlkabir**

**Bahrah (1966-1997)**

**Barzah**

**Medrakah**

NE sets.

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 117

Three main sets of faults: NW, NE and N (Fig. 4). The NW faults are the oldest and seem to have controlled the depositional troughs in the study area, mainly those of Haddat Ash Sham and As Suqah. They are mostly normal faults dipping steeply to the southwest. The NE faults displace the NW set and seem to be second component in block faulting. The N trending faults are shear faults with lateral displacement for the above mentioned NW and

Three distinctive geomorphologic zones in the study area are present, namely the mountainous region in the extreme east, the pediment region and the coastal plain (Fig. 5). The mountainous region comprises mostly folded and faulted Precambrian rocks (Hijaz Highlands) and Tertiary lave flows (Harrat Rahat). They form a longitudinal block that extends from the north to the south. The pediments bound the mountainous region from the west and are marked by their elongated features, which trend in a westerly direction and

The pediments are marked by thin layer of alluvial and aeolian sediments resting on highly weathered surface of Precambrian rocks. The mountainous region is mainly a recharge area,

The rainfall data collected from five rain gauges stations; these are Alhada, Alsail Alkabir, Bahrah, Barzah, and Medrakah. The collected data are in the form of daily rainfall for different number of years. These data were collected from the Hydrology section of the Ministry of Agriculture and Water (MAW) and from Meteorology and Environmental Protection Administration (MEPA). A total of 400 groundwater samples were collected from the privately owned drilled wells within the studied basins. Most of the groundwater samples were taken from intensively pumped wells in order to avoid any local contamination or change in chemistry caused by evaporation or gas exchange in the well

**Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Elevation**

**22.4 7.0 18.3 19.6 30.4 2.5 0 8.0 7.6 14.4 21.2 36.7 1940**

**18.0 4.0 1.5 4.2 1.2 0 0 2.0 1.5 0.9 11.4 18.0 116**

**(1982-1993) 5.3 0.4 5.7 17.7 12.0 1.6 0.2 0.9 2.6 1.7 7.6 10.8 1230**

**(1976-1997) 8.5 3.9 7.0 7.0 0.8 1.9 0.7 2.7 5.5 1.1 18.0 15.0 350**

**(1966-1996) 16.6 3.9 7.7 23.2 9.0 1.1 4.0 3.5 13.6 7.9 12.9 7.1 710**

Table 1. Average monthly rainfall for different rain gauges (mm) (Sharaf, 2011a).

**m.a.s.l**

while the pediment region may be considered as an area of surface flow.

Fig. 4. General structural geologic map of Makkah district including W. As Suqah area (after Sharaf, 2011b).

Fig. 5. Drainage basin map of the studied basins (Sharaf, 2011a).

Three main sets of faults: NW, NE and N (Fig. 4). The NW faults are the oldest and seem to have controlled the depositional troughs in the study area, mainly those of Haddat Ash Sham and As Suqah. They are mostly normal faults dipping steeply to the southwest. The NE faults displace the NW set and seem to be second component in block faulting. The N trending faults are shear faults with lateral displacement for the above mentioned NW and NE sets.

Three distinctive geomorphologic zones in the study area are present, namely the mountainous region in the extreme east, the pediment region and the coastal plain (Fig. 5). The mountainous region comprises mostly folded and faulted Precambrian rocks (Hijaz Highlands) and Tertiary lave flows (Harrat Rahat). They form a longitudinal block that extends from the north to the south. The pediments bound the mountainous region from the west and are marked by their elongated features, which trend in a westerly direction and sometimes appear as small knobs.

The pediments are marked by thin layer of alluvial and aeolian sediments resting on highly weathered surface of Precambrian rocks. The mountainous region is mainly a recharge area, while the pediment region may be considered as an area of surface flow.

#### **1.4 Data of recharge area**

116 Drainage Systems

Fig. 4. General structural geologic map of Makkah district including W. As Suqah area

Fig. 5. Drainage basin map of the studied basins (Sharaf, 2011a).

(after Sharaf, 2011b).

The rainfall data collected from five rain gauges stations; these are Alhada, Alsail Alkabir, Bahrah, Barzah, and Medrakah. The collected data are in the form of daily rainfall for different number of years. These data were collected from the Hydrology section of the Ministry of Agriculture and Water (MAW) and from Meteorology and Environmental Protection Administration (MEPA). A total of 400 groundwater samples were collected from the privately owned drilled wells within the studied basins. Most of the groundwater samples were taken from intensively pumped wells in order to avoid any local contamination or change in chemistry caused by evaporation or gas exchange in the well


Table 1. Average monthly rainfall for different rain gauges (mm) (Sharaf, 2011a).

A Study of Subsurface Drainage and Water Quality

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 119

the absolute depth to the water while the values of the contour lines showing the flow

In Usfan basin, the geological and geophysical exploration for groundwater is based mainly on integrated electro-resistivity (VES, Fig. 9), and four drilled test wells (Fig. 10) and seismic and magnetic geophysical tools. The results of theses exploration tools revealed the following conclusions: 1) Groundwater occurs mainly in two water-bearing horizons, the alluvial deposits and within the clastic sedimentary rocks of Haddat Ash Sham and Ash Shumaysi formations. The shallow zone is characterized with a saturated thickness of 3- 20 m and water is found under confined to semi-confined conditions, 2) Water levels were encountered at depths varying from 3-16m in the alluvial wadi deposits, and from 18-62 m in the sedimentary succession, 3) Groundwater movement is towards the west and northwest, following the general surface drainage system, and 4) Hydraulic gradient varies greatly from one point to another depending on the pumping rates and cross-sectional area

The locations of the water wells of wadi Usfan (Fig. 7A) show the localization of these wells in the southeastern (upstream) part of the wadi. The cation composition varies between almost exclusively Na+ to dominantly Ca2+ and Mg2+ with relatively lesser amount of K+.

rather uniform distribution. The ionic concentration of the groundwater samples has the

Na+ > Ca2+ > Mg2+ > K+ and Cl- > SO42- > HCO3- On the other hand, the spatial distributions of the major ions shown that the major

The chemical analyses of the trace elements shown that, each element has its own dispersion in the area without any general trend of distribution. Such pattern occurred reflecting that

constituents followed the general trend of the groundwater salinity (EC) in the basin.

is dominant. They also reflect that HCO3- and K+ ions seem to be

direction in Fig. 7 represents the water depth above sea level (a. s. l.).

Fig. 6. Simplified geologic map of Usfan basin (Sharaf, 2011b).

of the aquifer in addition to its transmissivity.

Among the anions, Cl-

following general pattern:

itself rainfall distribution over the study area was characterized in time and space. Data from the five rainfall gauges (Fig. 5 & Tab. 1) were used to establish the rainfall distribution. This table shows that the variation of rainfall in the spatial dimension reflects the topographic effects, since the highest values were recorded at the highest stations (Medrakah, Alsail Alkabir, and Alhada, Fig. 5). The average monthly rainfall was computed in order to give an approximate idea of the seasonal variation in the local rainfall patterns. All effective rainfall is concentrated between November and April (with very minor exceptions in early May).

### **2. Wadi Usfan**

From the geologic point of view, the study area comprises Precambrian-Cambrian basement rocks, Cretaceous-Tertiary sedimentary succession, the Tertiary- Quaternary basaltic lava flows, and the Quaternary-Recent alluvial deposits. Wadi As Suqah is a NW-SE low lands surrounded from the west by Precambrian rocks overlain by black basaltic lava flows (Harrat, Fig. 6, 7).

Precambrian rocks of wadi Usfan have been classified by Moore and Al-Reheili (1989) into Late- Proterozoic basaltic to rhyolitic volcanic and volcanoclastic and epiclastics of primitive island-arc type, that have been deformed and metamorphosed during many times and injected by intrusive bodies of different ages and compositions.

Sedimentary rock units of Usfan basin have been classified by Petter Johnson (2006) into: 1- The Cryogenian layered rocks which are represented by the Samran Group (sa), 2- The Cryogenian intrusive rocks which are represented by The Hishash granite (ig) which intrudes the Kamil Suite and Samran Group and composed of monzogranite and subordinate granodiorite (Moore and Al-Rehaili, 1989) and the Kamil Suite (km) which consists of mafic, intermediate, and felsic plutonic rocks of calc-alkalic and locally trondhjemitic affinities and, 3- The Edicarian layered rocks are represented by Shayma Nasir Group (Sn), which includes polymict conglomerate; basaltic, andesitic, dacitic, and rhyolitic lava, tuff, and agglomerate; and red-brown arkosic, volcaniclastic, and calcareous sandstone.

Cenozoic rock units of Usfan Basin (CS) are exposed beneath a cover of flat-lying lavas and Quaternary deposits. Brown and others (1963) introduced the names Shumaysi and Usfan formations to these sedimentary sequences after Karpoff (1958). Spincer and Vincent (1984) divided the Shumaysi Formation into the Haddat Ash Sham, Shumaysi, Khulays, and Buraykah formations.

Sharaf (2009 a and b) carried out a geophysical and hydrochemical study on Haddat Ash Sham and Ash Shamiyah areas and concluded that, the groundwater is mainly present in the Quaternary alluvial deposits and the Tertiary sandstones and conglomerates of Haddat Ash Sham and Ash Shumaysi Formations. In As Suqah area (Fig. 6), the groundwater is present within two main water-bearing units: the alluvium of the Wadi system under unconfined conditions and within the clastic layers of the Cretaceous sedimentary succession. The general groundwater flow in the aquifer system follows the surface drainage towards the northwest to Usfan city; it takes place from areas of high potential to areas of low potential (Fig. 8). Both the elevation and pressure heads define the direction of groundwater flow towards northwest. The values of the depth to water in Table 1 represent

itself rainfall distribution over the study area was characterized in time and space. Data from the five rainfall gauges (Fig. 5 & Tab. 1) were used to establish the rainfall distribution. This table shows that the variation of rainfall in the spatial dimension reflects the topographic effects, since the highest values were recorded at the highest stations (Medrakah, Alsail Alkabir, and Alhada, Fig. 5). The average monthly rainfall was computed in order to give an approximate idea of the seasonal variation in the local rainfall patterns. All effective rainfall is concentrated between November and April (with very minor

From the geologic point of view, the study area comprises Precambrian-Cambrian basement rocks, Cretaceous-Tertiary sedimentary succession, the Tertiary- Quaternary basaltic lava flows, and the Quaternary-Recent alluvial deposits. Wadi As Suqah is a NW-SE low lands surrounded from the west by Precambrian rocks overlain by black basaltic lava flows

Precambrian rocks of wadi Usfan have been classified by Moore and Al-Reheili (1989) into Late- Proterozoic basaltic to rhyolitic volcanic and volcanoclastic and epiclastics of primitive island-arc type, that have been deformed and metamorphosed during many times and

Sedimentary rock units of Usfan basin have been classified by Petter Johnson (2006) into: 1- The Cryogenian layered rocks which are represented by the Samran Group (sa), 2- The Cryogenian intrusive rocks which are represented by The Hishash granite (ig) which intrudes the Kamil Suite and Samran Group and composed of monzogranite and subordinate granodiorite (Moore and Al-Rehaili, 1989) and the Kamil Suite (km) which consists of mafic, intermediate, and felsic plutonic rocks of calc-alkalic and locally trondhjemitic affinities and, 3- The Edicarian layered rocks are represented by Shayma Nasir Group (Sn), which includes polymict conglomerate; basaltic, andesitic, dacitic, and rhyolitic lava, tuff, and agglomerate; and red-brown arkosic, volcaniclastic, and calcareous

Cenozoic rock units of Usfan Basin (CS) are exposed beneath a cover of flat-lying lavas and Quaternary deposits. Brown and others (1963) introduced the names Shumaysi and Usfan formations to these sedimentary sequences after Karpoff (1958). Spincer and Vincent (1984) divided the Shumaysi Formation into the Haddat Ash Sham, Shumaysi, Khulays, and

Sharaf (2009 a and b) carried out a geophysical and hydrochemical study on Haddat Ash Sham and Ash Shamiyah areas and concluded that, the groundwater is mainly present in the Quaternary alluvial deposits and the Tertiary sandstones and conglomerates of Haddat Ash Sham and Ash Shumaysi Formations. In As Suqah area (Fig. 6), the groundwater is present within two main water-bearing units: the alluvium of the Wadi system under unconfined conditions and within the clastic layers of the Cretaceous sedimentary succession. The general groundwater flow in the aquifer system follows the surface drainage towards the northwest to Usfan city; it takes place from areas of high potential to areas of low potential (Fig. 8). Both the elevation and pressure heads define the direction of groundwater flow towards northwest. The values of the depth to water in Table 1 represent

injected by intrusive bodies of different ages and compositions.

exceptions in early May).

**2. Wadi Usfan** 

(Harrat, Fig. 6, 7).

sandstone.

Buraykah formations.

the absolute depth to the water while the values of the contour lines showing the flow direction in Fig. 7 represents the water depth above sea level (a. s. l.).

Fig. 6. Simplified geologic map of Usfan basin (Sharaf, 2011b).

In Usfan basin, the geological and geophysical exploration for groundwater is based mainly on integrated electro-resistivity (VES, Fig. 9), and four drilled test wells (Fig. 10) and seismic and magnetic geophysical tools. The results of theses exploration tools revealed the following conclusions: 1) Groundwater occurs mainly in two water-bearing horizons, the alluvial deposits and within the clastic sedimentary rocks of Haddat Ash Sham and Ash Shumaysi formations. The shallow zone is characterized with a saturated thickness of 3- 20 m and water is found under confined to semi-confined conditions, 2) Water levels were encountered at depths varying from 3-16m in the alluvial wadi deposits, and from 18-62 m in the sedimentary succession, 3) Groundwater movement is towards the west and northwest, following the general surface drainage system, and 4) Hydraulic gradient varies greatly from one point to another depending on the pumping rates and cross-sectional area of the aquifer in addition to its transmissivity.

The locations of the water wells of wadi Usfan (Fig. 7A) show the localization of these wells in the southeastern (upstream) part of the wadi. The cation composition varies between almost exclusively Na+ to dominantly Ca2+ and Mg2+ with relatively lesser amount of K+. Among the anions, Cl is dominant. They also reflect that HCO3- and K+ ions seem to be rather uniform distribution. The ionic concentration of the groundwater samples has the following general pattern:

$$\text{Na} \succ \text{Ca}^{2+} \succ \text{Mg}^{2+} \succ \text{K}^{\cdot} \text{ and } \quad \text{Cl} \succ \text{SO}\_{4}{\text{-}} \succ \text{HCO}\_{3}{\text{-}}$$

On the other hand, the spatial distributions of the major ions shown that the major constituents followed the general trend of the groundwater salinity (EC) in the basin.

The chemical analyses of the trace elements shown that, each element has its own dispersion in the area without any general trend of distribution. Such pattern occurred reflecting that

A Study of Subsurface Drainage and Water Quality

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 121

Fig. 7. A= Well locations in wadi Usfan; B= EC; and C= SO4 content of the groundwater of

wadi Usfan.

most of these elements are probably locally affected as a result of chemical reactions between groundwater and the parent rocks. However, the majority of these elements were marked in As Suqah and Ash Shamiyah regions, such as B, As, Al, Mn, Li, Cd, Ba, Cr, and Mo. The high concentrations of these elements is almost present adjacent to the basaltic lava in the middle part of the study area, reflecting that the chemical weathering of basalt may consider as a source of them. Haddat Ash Sham, on the other hand, characterized by high contents of Hg, Cu, Co, F and PO4.

In Wadi Usfan, the water quality is highly variable. The groundwater salinity is nonuniform aerially, and there are wide differences among the individual wells as well as the sub-areas. Mean values and ranges of the EC measurements for each sub-area (i.e. Haddat Ash Sham, Ash Shamiyah, Al Baydah-Mudsus and As Suqah) are shown in Table 2. Both Haddat Ash Sham and Ash Shamiyah sub-basins are characterized by relatively low saline water, whereas, highly mineralized water almost marked Wadi As Suqah sub-basin where the groundwater salinity reached up to 30,000 µS/cm with an average of about 18800 µS/cm. The EC measurements of the groundwater within Haddat Ash Sham and Ash Shamiyah sub-basins indicated that few wells yield relatively low saline water (< 1500 µS/cm). These are distributed randomly and are often near wells providing moderately mineralized water. It also observed that within these two areas, the groundwater from wells drilled in the center of the wadi alluvium are not as mineralized as the waters extracted from wells located along the edges of the wadi channel. The EC and SO4 (Fig. 7B, C respectively) distribution shows that the groundwater salinity almost increased towards the downstream part of the wadi, which probably matches the general flow of the groundwater.

The dominant water types are NaCl and CaCl2. On the other hand, a few wells yield medium to high saline water. Those are concentrated in Wadi Haddat Ash Sham, Ash Shamiyah and Al Baydah-Mudsus sub-basins. These are fallen within the satisfactory limits and can be used safely for agricultural practices. In contrast, Wadi As Suqah sub-basin shown highly saline water, although they reflected low to high SAR values. Under this condition, the groundwater tends to restrict its utilization for agricultural activities. The concentration of NO3- ions is relatively high. The major sources of NO3- probably as a result of intensive use of chemical fertilizers in these regions. Poultries may also considered as another source of NO3- particularly in the upper part of Wadi Ash Shamiyah in Usfan basin. The concentration of NO3 - ions is relatively high. The major sources of NO3- probably as a result of intensive use of chemical fertilizers in these regions. Poultries may also considered as another source of NO3- particularly in the upper part of Wadi Ash Shamiyah in Usfan basin.


Table 2. Average groundwater salinity in Usfan sub-basins.

most of these elements are probably locally affected as a result of chemical reactions between groundwater and the parent rocks. However, the majority of these elements were marked in As Suqah and Ash Shamiyah regions, such as B, As, Al, Mn, Li, Cd, Ba, Cr, and Mo. The high concentrations of these elements is almost present adjacent to the basaltic lava in the middle part of the study area, reflecting that the chemical weathering of basalt may consider as a source of them. Haddat Ash Sham, on the other hand, characterized by high

In Wadi Usfan, the water quality is highly variable. The groundwater salinity is nonuniform aerially, and there are wide differences among the individual wells as well as the sub-areas. Mean values and ranges of the EC measurements for each sub-area (i.e. Haddat Ash Sham, Ash Shamiyah, Al Baydah-Mudsus and As Suqah) are shown in Table 2. Both Haddat Ash Sham and Ash Shamiyah sub-basins are characterized by relatively low saline water, whereas, highly mineralized water almost marked Wadi As Suqah sub-basin where the groundwater salinity reached up to 30,000 µS/cm with an average of about 18800 µS/cm. The EC measurements of the groundwater within Haddat Ash Sham and Ash Shamiyah sub-basins indicated that few wells yield relatively low saline water (< 1500 µS/cm). These are distributed randomly and are often near wells providing moderately mineralized water. It also observed that within these two areas, the groundwater from wells drilled in the center of the wadi alluvium are not as mineralized as the waters extracted from wells located along the edges of the wadi channel. The EC and SO4 (Fig. 7B, C respectively) distribution shows that the groundwater salinity almost increased towards the downstream part of the wadi, which probably matches the general

The dominant water types are NaCl and CaCl2. On the other hand, a few wells yield medium to high saline water. Those are concentrated in Wadi Haddat Ash Sham, Ash Shamiyah and Al Baydah-Mudsus sub-basins. These are fallen within the satisfactory limits and can be used safely for agricultural practices. In contrast, Wadi As Suqah sub-basin shown highly saline water, although they reflected low to high SAR values. Under this condition, the groundwater tends to restrict its utilization for agricultural activities. The concentration of NO3- ions is relatively high. The major sources of NO3- probably as a result of intensive use of chemical fertilizers in these regions. Poultries may also considered as another source of NO3- particularly in the upper part of Wadi Ash Shamiyah in Usfan basin. The concentration of NO3- ions is relatively high. The major sources of NO3- probably as a result of intensive use of chemical fertilizers in these regions. Poultries may also considered as another source of NO3- particularly in the upper part of Wadi Ash Shamiyah in Usfan

**Basin Name Sub-Basin Name Maximum Minimum Mean** 

Haddat Ash Sham 8600 875 3699 Ash Shamiyyah 10890 1808 6482 Mudsus-Al Baydah 11940 2200 5504 As Suqah 30800 7720 18837

contents of Hg, Cu, Co, F and PO4.

flow of the groundwater.

basin.

**WADI USFAN** 

Table 2. Average groundwater salinity in Usfan sub-basins.

Fig. 7. A= Well locations in wadi Usfan; B= EC; and C= SO4 content of the groundwater of wadi Usfan.

A Study of Subsurface Drainage and Water Quality

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 123

Fig. 9. Haddat Ash Sham (Usfan Basin) geo-electrical cross-section (Sharaf, 2011b).

Fig. 10. Stratigraphic logs of the drilled test wells in Usfan basin (Modified from Sharaf,

2010a, b and 2011b).

Fig. 8. Detailed geologic map showing the locations of the studied boreholes of As Suqah area (Sharaf, 2011d).

Fig. 8. Detailed geologic map showing the locations of the studied boreholes of As Suqah

area (Sharaf, 2011d).

Fig. 9. Haddat Ash Sham (Usfan Basin) geo-electrical cross-section (Sharaf, 2011b).

Fig. 10. Stratigraphic logs of the drilled test wells in Usfan basin (Modified from Sharaf, 2010a, b and 2011b).

A Study of Subsurface Drainage and Water Quality

channel of wadi An Numan is about 39m.

**3.1.1 Sampling and analytical methods** 

Na+, K+, Ca2+, Mg2+ and the anions HCO3- , CO3

**3.1.2 Description of the groundwater chemistry** 

water.

**3.1.2.1 Durov diagram** 

**3.1.2.2 Trilinear diagram** 

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 125

the alluvial deposits are thin, while in the downstream parts, they are thick and composed of moderately well sorted gravel and medium to fine sand. The water depth maps of wadi An Numan shows that, the wells in the uppermost (recharge areas) tributaries are nearly shallow while the wells within the main channel of wadi An Numan are deeper. The lowest water depth is 25m while the highest water depth within the downstream of the main

A total of 65 groundwater samples were collected from the privately owned drilled wells within Wadi An Numan basin. During the field survey and sample collection, groundwater temperature, electrical conductivity (EC) and pH were measured at the well sites. Most of the groundwater samples were taken from intensively pumped wells in order to avoid any local contamination or change in chemistry caused by evaporation or gas exchange in the well itself. These water samples were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in the laboratories of the Faculty of Earth Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. The chemical analyses were performed for the cations

In Wadi An Numan, the groundwater salinity is rather low with EC ranged from 542 to 5400 µS/cm with an average of about 1539 µS/cm (Table 3). The dominant water types are NaCl and CaCl2. The rare and trace elements of the groundwater samples were determined. These are As, Mo, Zn, P, Pb, Co, Cd, Ni, Ba, Fe, B, Si, Hg, Mn, Cr, V, Bi, Cu, U, Al, Li, Rb, Au, Cr, Sr, F and NH4. The chemical analyses show that, the groundwater is enriched with nitrate (NO3) ions and most of the groundwater is very hard for use as a drinking water supply. In addition, a few trace elements showed an increase in their contents and exceed the maximum acceptable limits of the standards that restricted to its utilization for drinking

The main purpose of the Durov diagram is to show clustering of data points to indicate samples that have similar compositions (Hem, 1989). The durov diagram of the chemical analyses of the water samples of the different areas (Fig. 12) revealed that, the water types of wadi Dayqah sub-basin are mainly of CaCl2 types except some analyses which are of calcium bicarbonate types. Analyses no. 5, 7, 9, 10 are of calcium sulphate types. The chemical analyses of the main channel of wadi An Numan sub-basin are of calcium chloride and calcium sulphate types with less frequent calcium bicarbonate types. Some analyses are of NaCl and others are of sodium sulphate water type. In wadi Arar sub-basin the water types are mainly calcium chloride, calcium sulphate and calcium bicarbonate. In wadi Rahjan sub-basin the water types are of calcium chloride and calcium sulphate with less frequent Na and Ca bicarbonates and Ca sulphates. From the Durov diagram we notice that,

The plotting of the analyses of the different sub-basins on the trilinear diagram (Fig. 13) revealed that, the groundwater within the study area is predominantly a mixture of

the analyses of the main channel of wadi An Numan are enriched in Cl and SO4.

2-, SO42-, Cl-

, NO3- .

#### **3. Wadi An Numan**

An Numan basin mainly originate in the Hijaz Highlands (Fig. 11). The drainage of the basins is generally well developed and the pattern is typically dendritic (Fig. 5). Three distinctive geomorphologic zones in the study area are present, namely the mountainous region in the extreme east, the pediment region and the coastal plain. The mountainous region comprises mostly folded and faulted Precambrian rocks (Hijaz Highlands) and Tertiary lave flows (Harrat Rahat). They form a longitudinal block that extends from the north to the south. The pediments bound the mountainous region from the west and are marked by their elongated features, which trend in a westerly direction and sometimes appear as small knobs. The pediments are marked by thin layer of alluvial and aeolian sediments resting on highly weathered surface of Precambrian rocks. The mountainous region is mainly a recharge area, while the pediment region may be considered as an area of surface flow.

Fig. 11. Geologic map of the study area (Modified after Johnson, 2006 by Sharaf, 2011a).

#### **3.1 Water hydrochemistry**

The groundwater aquifer in wadi An Numan basin and related sub-basins is present in the Quaternary wadi fill deposits as well as in the weathered fractured crystalline Precambrian bed rocks. The Quaternary alluvial deposits consist of well rounded pebble to boulder size conglomerate. These deposits are essentially recorded in steep-sided wadis. In these areas, the alluvial deposits are thin, while in the downstream parts, they are thick and composed of moderately well sorted gravel and medium to fine sand. The water depth maps of wadi An Numan shows that, the wells in the uppermost (recharge areas) tributaries are nearly shallow while the wells within the main channel of wadi An Numan are deeper. The lowest water depth is 25m while the highest water depth within the downstream of the main channel of wadi An Numan is about 39m.

#### **3.1.1 Sampling and analytical methods**

124 Drainage Systems

An Numan basin mainly originate in the Hijaz Highlands (Fig. 11). The drainage of the basins is generally well developed and the pattern is typically dendritic (Fig. 5). Three distinctive geomorphologic zones in the study area are present, namely the mountainous region in the extreme east, the pediment region and the coastal plain. The mountainous region comprises mostly folded and faulted Precambrian rocks (Hijaz Highlands) and Tertiary lave flows (Harrat Rahat). They form a longitudinal block that extends from the north to the south. The pediments bound the mountainous region from the west and are marked by their elongated features, which trend in a westerly direction and sometimes appear as small knobs. The pediments are marked by thin layer of alluvial and aeolian sediments resting on highly weathered surface of Precambrian rocks. The mountainous region is mainly a recharge area, while the pediment region may be considered as an area of

Fig. 11. Geologic map of the study area (Modified after Johnson, 2006 by Sharaf, 2011a).

The groundwater aquifer in wadi An Numan basin and related sub-basins is present in the Quaternary wadi fill deposits as well as in the weathered fractured crystalline Precambrian bed rocks. The Quaternary alluvial deposits consist of well rounded pebble to boulder size conglomerate. These deposits are essentially recorded in steep-sided wadis. In these areas,

**3. Wadi An Numan** 

surface flow.

**3.1 Water hydrochemistry** 

A total of 65 groundwater samples were collected from the privately owned drilled wells within Wadi An Numan basin. During the field survey and sample collection, groundwater temperature, electrical conductivity (EC) and pH were measured at the well sites. Most of the groundwater samples were taken from intensively pumped wells in order to avoid any local contamination or change in chemistry caused by evaporation or gas exchange in the well itself. These water samples were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) in the laboratories of the Faculty of Earth Sciences, King Abdulaziz University, Jeddah, Saudi Arabia. The chemical analyses were performed for the cations Na+, K+, Ca2+, Mg2+ and the anions HCO3- , CO3 2-, SO42-, Cl- , NO3- .

In Wadi An Numan, the groundwater salinity is rather low with EC ranged from 542 to 5400 µS/cm with an average of about 1539 µS/cm (Table 3). The dominant water types are NaCl and CaCl2. The rare and trace elements of the groundwater samples were determined. These are As, Mo, Zn, P, Pb, Co, Cd, Ni, Ba, Fe, B, Si, Hg, Mn, Cr, V, Bi, Cu, U, Al, Li, Rb, Au, Cr, Sr, F and NH4. The chemical analyses show that, the groundwater is enriched with nitrate (NO3) ions and most of the groundwater is very hard for use as a drinking water supply. In addition, a few trace elements showed an increase in their contents and exceed the maximum acceptable limits of the standards that restricted to its utilization for drinking water.

#### **3.1.2 Description of the groundwater chemistry**

#### **3.1.2.1 Durov diagram**

The main purpose of the Durov diagram is to show clustering of data points to indicate samples that have similar compositions (Hem, 1989). The durov diagram of the chemical analyses of the water samples of the different areas (Fig. 12) revealed that, the water types of wadi Dayqah sub-basin are mainly of CaCl2 types except some analyses which are of calcium bicarbonate types. Analyses no. 5, 7, 9, 10 are of calcium sulphate types. The chemical analyses of the main channel of wadi An Numan sub-basin are of calcium chloride and calcium sulphate types with less frequent calcium bicarbonate types. Some analyses are of NaCl and others are of sodium sulphate water type. In wadi Arar sub-basin the water types are mainly calcium chloride, calcium sulphate and calcium bicarbonate. In wadi Rahjan sub-basin the water types are of calcium chloride and calcium sulphate with less frequent Na and Ca bicarbonates and Ca sulphates. From the Durov diagram we notice that, the analyses of the main channel of wadi An Numan are enriched in Cl and SO4.

#### **3.1.2.2 Trilinear diagram**

The plotting of the analyses of the different sub-basins on the trilinear diagram (Fig. 13) revealed that, the groundwater within the study area is predominantly a mixture of

A Study of Subsurface Drainage and Water Quality

the formation of saline and brakish waters of HCO3-

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 127

calcium-sodium ions and the upper tributaries of Wadi Numan contains fresh water while downstream (main channel of wadi An Numan, Wadi Rahjan and wadi Arar) waters are brackish. This is due to the very slow interaction between the fractured crystalline rocks and the rainfall waters in the upstream (fresh water) while in the downstream, the water is interacted with the alluvial sediments as well as the highly weathered and fractured bed rocks which lead to the addition of CO3, Na, Ca, K and Mg to the water with time leading to

Fig. 13. Trilinear diagram of the chemical analyses of the ground water samples of the

There are many factors that determine whether groundwater is suitable for irrigation use, which include: 1) the total salt concentration of the water, 2) the concentration of certain ions that may be toxic to plants or that have an unfavorable effect on crop quality; and 3) the concentration of cations such as Na+, Ca2+ and Mg2+ that can cause deflocculation of the clay in the soil and resulting damage to soil structure and declines in infiltration rate. The

different sub-basins of wadi An Numan (Sharaf, 2011a).

**3.2 Suitability of groundwater** 

**3.2.1 Irrigation water** 



Table 3. Statistics of the chemical analyses (65 samples, concentrations in mg/l) (Sharaf, 2011a).

Fig. 12. Durov Diagram of the chemical analyses of the water samples of the different subbasins of wadi An Numan (Sharaf, 2011a).

Table 3. Statistics of the chemical analyses (65 samples, concentrations in mg/l) (Sharaf,

Fig. 12. Durov Diagram of the chemical analyses of the water samples of the different sub-

basins of wadi An Numan (Sharaf, 2011a).

2011a).

Item Minimum Maximum Average St. Dev. Ca 66 432 154.766 72.155 Mg 3.26 160 36.893 27.756 Na 37.2 500 101.466 77.288 K 2.57 14.5 6.753 1.735 HCO3 127.9 392.5 214.36 54.221 SO4 89.0 1350 262.252 205.664 SO3 74.2 1125 219.007 171.415 NO3 6 560 78.32 83.5 Cl 44 1085.8 205.075 173.17 Sum Cations 5.943 55.894 15.344 8.814 Sum Anions ◌ِ 5.579 55.945 14.758 9.099 Alkalinity 11.74 36.028 19.676 4.977

calcium-sodium ions and the upper tributaries of Wadi Numan contains fresh water while downstream (main channel of wadi An Numan, Wadi Rahjan and wadi Arar) waters are brackish. This is due to the very slow interaction between the fractured crystalline rocks and the rainfall waters in the upstream (fresh water) while in the downstream, the water is interacted with the alluvial sediments as well as the highly weathered and fractured bed rocks which lead to the addition of CO3, Na, Ca, K and Mg to the water with time leading to the formation of saline and brakish waters of HCO3- -Ca2 +- Na+ -SO4 2- - Cl -Ca2+ type.

Fig. 13. Trilinear diagram of the chemical analyses of the ground water samples of the different sub-basins of wadi An Numan (Sharaf, 2011a).

#### **3.2 Suitability of groundwater**

#### **3.2.1 Irrigation water**

There are many factors that determine whether groundwater is suitable for irrigation use, which include: 1) the total salt concentration of the water, 2) the concentration of certain ions that may be toxic to plants or that have an unfavorable effect on crop quality; and 3) the concentration of cations such as Na+, Ca2+ and Mg2+ that can cause deflocculation of the clay in the soil and resulting damage to soil structure and declines in infiltration rate. The

A Study of Subsurface Drainage and Water Quality

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 129

1.85. Wadi An Numan groundwater samples are of SAR values between values 1 and 3 and EC values between 1000 and 3000 (Fig. 14). Most of the samples are located within the C3-S1

The RSC values for the different sub-basins of wadi An Numan are negative (< 1.25). This is

However, the RSC values in the range found can be used safely for irrigation purposes (Lloyd and Heathcote, 1985). The magnesium hazard (MH) values are > 50 which are considered to be harmful. In Wadi An Numan, all the groundwater samples are fall within accepted limits which in turn the water can be used safely. Boron is essential for growth of plants in very small concentrations, and becomes of toxic effect when present above the optimum level. Boron in Wadi An Numan groundwater is fallen with satisfactory limits.

Although evaporation probably has the greatest influence on the total dissolved solids (TDS) in the investigated regions, the actual chemical composition is also influenced by other factors. These include the net addition of the major constituents such as Ca2+, Mg2+, K, HCO3 and trace elements by weathering of silicate minerals. The Precambrian and intrusive rocks commonly contain the major rock-forming minerals such as hornblende and biotite that enrich in Ca2+ , Mg2+ , K+ and Fe. Na+ is added by this means but not that much of these ions. Oxidation and dissolution rocks of gabbroic composition will contribute trace elements such as Ni, Co, Cu, Zn, Cr, Li, Cd, V and Mn. The source of these trace elements will be associated with the major cations such as Ca2+, Mg2+, Fe, Na+, Al and Si which are considered the major cations in the rocks of gabbroic composition. Whereas, in the weathering granitic rocks will contribute trace elements of Cu, Ba, Rb, Pb, As, Mo, U and Br. These elements will be associated with the major ions such as Na+, K+, Al and Si. However, the released trace elements almost occur as lattice substitutes impurities or in solid solution. Evaporation, recycling of irrigation water and chemical weathering reactions of silicate minerals are the dominate processes affecting the groundwater's chemical composition. The first two processes possibly worked collectively and lead to precipitate evaporitic salts in the irrigated fields around the production wells. Calcite, dolomite and gypsum are the dominant evaporitic salts. The groundwater in the study area seems to be suitable when compared with FAO quality criteria for irrigation. The calculated values of SAR, RSC, and

Magnesium hazard indicate well to permissible use of ground water for this aim.

Wadi Fatimah is shallow alluvial and fracture bedrock aquifer in western part of Saudi Arabia, and considered as one of the major source of water supplies in the area. Because of the rapid growth of population, long time of aridity and intensive exploitation of groundwater resources from this wadi has led to concern about potential water quality impacts. Alyamani (2007) studied the nitrate concentration in the upper reaches of Wadi Fatimah. His study shows that the nitrate concentration in the groundwater exceeded the maximum contaminant level due to the effects of cesspool system in the upper reach of the

Wadi Fatimah basin comprises the most important drainage system in the western province of Saudi Arabia (Fig. 5). It considered the major important sources of groundwater to the cities of Makkah, Jeddah and the surrounding villages and towns. The Red Sea escarpment

**4. Wadi Fatimah** 

basin.

2- in the groundwater.

and C4-S1. Less frequent samples are present in the fields C2-S1 and C4-S2.

because HCO3- is not an important anion compared to Cl- and SO4

quality requirements of irrigation water or universal standards for it cannot be formulated, and what might be a poor water at one place could be quite acceptable somewhere else.

Fig. 14. US Salinity classification of wadi An Numan groundwater for irrigation (USLL, 1954) (Sharaf, 2011a).

Most of the groundwater in Wadi An Numan are fallen within the satisfactory limits. The calculated values of SAR for the groundwater in Wadi An Numan are low according to the recommended water classification for SAR (Lloyd and Heathcote, 1985). The minimum SAR values of wadi An Numan groundwater is 0.8 while the maximum is 5.28 and the average is 1.85. Wadi An Numan groundwater samples are of SAR values between values 1 and 3 and EC values between 1000 and 3000 (Fig. 14). Most of the samples are located within the C3-S1 and C4-S1. Less frequent samples are present in the fields C2-S1 and C4-S2.

The RSC values for the different sub-basins of wadi An Numan are negative (< 1.25). This is because HCO3- is not an important anion compared to Cl- and SO4 2- in the groundwater. However, the RSC values in the range found can be used safely for irrigation purposes (Lloyd and Heathcote, 1985). The magnesium hazard (MH) values are > 50 which are considered to be harmful. In Wadi An Numan, all the groundwater samples are fall within accepted limits which in turn the water can be used safely. Boron is essential for growth of plants in very small concentrations, and becomes of toxic effect when present above the optimum level. Boron in Wadi An Numan groundwater is fallen with satisfactory limits.

Although evaporation probably has the greatest influence on the total dissolved solids (TDS) in the investigated regions, the actual chemical composition is also influenced by other factors. These include the net addition of the major constituents such as Ca2+, Mg2+, K, HCO3 and trace elements by weathering of silicate minerals. The Precambrian and intrusive rocks commonly contain the major rock-forming minerals such as hornblende and biotite that enrich in Ca2+ , Mg2+ , K+ and Fe. Na+ is added by this means but not that much of these ions. Oxidation and dissolution rocks of gabbroic composition will contribute trace elements such as Ni, Co, Cu, Zn, Cr, Li, Cd, V and Mn. The source of these trace elements will be associated with the major cations such as Ca2+, Mg2+, Fe, Na+, Al and Si which are considered the major cations in the rocks of gabbroic composition. Whereas, in the weathering granitic rocks will contribute trace elements of Cu, Ba, Rb, Pb, As, Mo, U and Br. These elements will be associated with the major ions such as Na+, K+, Al and Si. However, the released trace elements almost occur as lattice substitutes impurities or in solid solution.

Evaporation, recycling of irrigation water and chemical weathering reactions of silicate minerals are the dominate processes affecting the groundwater's chemical composition. The first two processes possibly worked collectively and lead to precipitate evaporitic salts in the irrigated fields around the production wells. Calcite, dolomite and gypsum are the dominant evaporitic salts. The groundwater in the study area seems to be suitable when compared with FAO quality criteria for irrigation. The calculated values of SAR, RSC, and Magnesium hazard indicate well to permissible use of ground water for this aim.

### **4. Wadi Fatimah**

128 Drainage Systems

quality requirements of irrigation water or universal standards for it cannot be formulated, and what might be a poor water at one place could be quite acceptable somewhere else.

Fig. 14. US Salinity classification of wadi An Numan groundwater for irrigation (USLL,

Most of the groundwater in Wadi An Numan are fallen within the satisfactory limits. The calculated values of SAR for the groundwater in Wadi An Numan are low according to the recommended water classification for SAR (Lloyd and Heathcote, 1985). The minimum SAR values of wadi An Numan groundwater is 0.8 while the maximum is 5.28 and the average is

1954) (Sharaf, 2011a).

Wadi Fatimah is shallow alluvial and fracture bedrock aquifer in western part of Saudi Arabia, and considered as one of the major source of water supplies in the area. Because of the rapid growth of population, long time of aridity and intensive exploitation of groundwater resources from this wadi has led to concern about potential water quality impacts. Alyamani (2007) studied the nitrate concentration in the upper reaches of Wadi Fatimah. His study shows that the nitrate concentration in the groundwater exceeded the maximum contaminant level due to the effects of cesspool system in the upper reach of the basin.

Wadi Fatimah basin comprises the most important drainage system in the western province of Saudi Arabia (Fig. 5). It considered the major important sources of groundwater to the cities of Makkah, Jeddah and the surrounding villages and towns. The Red Sea escarpment

A Study of Subsurface Drainage and Water Quality

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 131

**As** 0.09 0.00026 0.015 0.023 1.98 1.55 **Zn** 0.36 0.0001 0.044 0.069 3.32 1.59 **P** 4.16 0.046 0.626 0.540 3.35 0.86 **Pb** 0.07 0.001 0.020 0.020 1.41 1.00 **Ba** 0.56 0.037 0.208 0.088 0.64 0.42 **B** 8.54 0.372 1.612 1.390 2.45 0.86 **Si** 25.06 4.89 9.832 3.004 2.07 0.31 **Al** 0.90 0.00256 0.062 0.152 3.25 2.46 **Li** 0.60 0.002 0.089 0.145 2.35 1.62 **Cu** 0.06 0.0013 0.021 0.012 0.64 0.58 **Fe** 0.32 0.005 0.032 0.054 4.42 1.68 **Hg** 0.17 0 0.018 0.038 3.05 2.10 **Mn** 0.28 0.001 0.020 0.037 5.10 1.84 **Cd** 0.02 0.0001 0.004 0.004 1.71 1.06 **V** 0.70 0.00213 0.213 0.196 0.19 0.92 **Rb** 0.16 0.0046 0.097 0.055 -0.42 0.57 **Ph** 7.90 7.1 7.487 0.205 0.36 0.03

Table 4. Statistical summary for trace elements (mg/l) (Sharfa & Subyani, 2011e).

the problems of stain and blockage are many times worse.

form. The average cupper content of wadi Fatimah is 0.021 mg/l which is very low when compared with that of WHO (2 mg/l). The average Fe content is 0.032 mg/l which is lower than the recommended WHO iron level (< 0.3mg/l). Iron dissolved in groundwater is in the reduced ferrous iron form. This form is soluble and normally does not cause any problems by itself. Ferrous iron is oxidized into ferric iron on contact with oxygen in the air or by the action of iron related bacteria. Ferric iron forms insoluble hydroxides in water. These are rusty red and cause staining and blockage of screens, pumps, pipes, reticulation systems etc. If the iron hydroxide deposits are produced by iron bacteria then they are also sticky and

**Max Min Mean St.Dev. Skew Co.Var.** 

(Hijaz Highlands) and Harrat Rahat are considered the recharge areas of these basins. Generally, the main course of the basin follow westerly to southwesterly directions towards the Red Sea coast. The drainage of the basins generally is well developed and the pattern is typically dendritic (Fig. 5). Although the local relief generally less than 400 meters above the wadi floor, the wadi networks have many small and large tributaries. They are deep and narrow and their longitudinal profiles are rather gentle and in some areas become irregular. They almost follow N-S, NW-SE and SE-NW directions, which probably controlled by major structures, and smaller faults that commonly control lesser drainage channels. The upper stream parts of the basin is rather narrow, where the width of the main wadi course vary from less than 100 m to more than 1.5 km further downstream, where the alluvium deposits are widespread and rather thicker.

Groundwater samples of the main stream were taken from the alluvial and fracture aquifer in winter, 2004. Trace elements were analyzed in each sample for a total of 17 water quality descriptors (variables), these elements are: As, Zn, P, Pb, Ba, B, Si, Al, Li, Cu, Fe, Hg, Mn, Cd, V, and Rb. Among these, only pH was measured in the field. Samples were analyzed in the laboratories of the Faculty of Earth Sciences, Saudi Arabia. The accuracy of this analytical technique was controlled using appropriate standards. Statistical summary including the mean, standard deviation, coefficient of variation, and skewness of trace elements are shown in Table 4.

The analysed trace elements of wadi Fatimah (Table 4) show the following distribution: In the study area, according to Sharaf and Subyani (2011) the average Al content is 0.062mg/l which is very low when compared with WHO guideline of Al (0.2 mg/l). The concentration of Al will depend on the availability and extent of weathering of the aluminosilicates such as clays, pyrophyllites, feldspars, micas and other related minerals. High concentration of Al in soils and groundwater may also be attributed to a number of factors including the availability of dissolved organic matter and fluoride (Edmunds et al., 1992). Arsenic (As): which is the most important element affecting the groundwater quality. The average value of arsenic is 0.015 mg/l which similar to that recommended by the WHO. The average barium content of wadi Fatimah area is 0.208mg/l which is similar to the WHO (0.3 mg/l). The maximum value of boron is 8.54 mg/l while its minimum value is 0.372 and the average is 1.6126mg/l which is higher than that recorded in the normal groundwater and also higher than the WHO (1993) recommended values (0.3 mg/l). The toxic effect for B in humans is found to occur above 20 mg /l-1 (Bolt and Bruggenwert, 1978). Boron usually occurs as a nonionized form as H3BO3 in soils at pH less than 8.5, but above this pH, it exists as an anion, B(OH)4 -1. It is very soluble in soils and can be leached especially in sandy soils (Brady, 1974). It is also dispersed in the environment through fertilizer application. Since the pH was less than 8.5 for all the samples, it is more likely that B would be in the non ionized than the ionized state.

The cadmium in wadi Fatimah groundwater is higher than that recommended by the WHO guideline. The average of Cd is 0.004 mg/l. Cadmium is used normally as a coating material, paint pigment, in plastics, fungicide and is a constituent of some fertilizers. Copper, Cd and Zn exist in aqueous form in the predominately +2 state. Generally, Zn exists as Zn2+ state in pH below 7.7 (Liptrot, 1989). Cadmium (II) oxide occurs in some Zn ores which suggests that the two have identical properties such as that both have the + 2 being the most stable oxidation state (Liptrot, 1989).In natural waters, Cu, Cd and Zn occur in the +2

(Hijaz Highlands) and Harrat Rahat are considered the recharge areas of these basins. Generally, the main course of the basin follow westerly to southwesterly directions towards the Red Sea coast. The drainage of the basins generally is well developed and the pattern is typically dendritic (Fig. 5). Although the local relief generally less than 400 meters above the wadi floor, the wadi networks have many small and large tributaries. They are deep and narrow and their longitudinal profiles are rather gentle and in some areas become irregular. They almost follow N-S, NW-SE and SE-NW directions, which probably controlled by major structures, and smaller faults that commonly control lesser drainage channels. The upper stream parts of the basin is rather narrow, where the width of the main wadi course vary from less than 100 m to more than 1.5 km further downstream, where the alluvium deposits

Groundwater samples of the main stream were taken from the alluvial and fracture aquifer in winter, 2004. Trace elements were analyzed in each sample for a total of 17 water quality descriptors (variables), these elements are: As, Zn, P, Pb, Ba, B, Si, Al, Li, Cu, Fe, Hg, Mn, Cd, V, and Rb. Among these, only pH was measured in the field. Samples were analyzed in the laboratories of the Faculty of Earth Sciences, Saudi Arabia. The accuracy of this analytical technique was controlled using appropriate standards. Statistical summary including the mean, standard deviation, coefficient of variation, and skewness of trace

The analysed trace elements of wadi Fatimah (Table 4) show the following distribution: In the study area, according to Sharaf and Subyani (2011) the average Al content is 0.062mg/l which is very low when compared with WHO guideline of Al (0.2 mg/l). The concentration of Al will depend on the availability and extent of weathering of the aluminosilicates such as clays, pyrophyllites, feldspars, micas and other related minerals. High concentration of Al in soils and groundwater may also be attributed to a number of factors including the availability of dissolved organic matter and fluoride (Edmunds et al., 1992). Arsenic (As): which is the most important element affecting the groundwater quality. The average value of arsenic is 0.015 mg/l which similar to that recommended by the WHO. The average barium content of wadi Fatimah area is 0.208mg/l which is similar to the WHO (0.3 mg/l). The maximum value of boron is 8.54 mg/l while its minimum value is 0.372 and the average is 1.6126mg/l which is higher than that recorded in the normal groundwater and also higher than the WHO (1993) recommended values (0.3 mg/l). The toxic effect for B in humans is found to occur above 20 mg /l-1 (Bolt and Bruggenwert, 1978). Boron usually occurs as a nonionized form as H3BO3 in soils at pH less than 8.5, but above this pH, it exists as an anion, B(OH)4 -1. It is very soluble in soils and can be leached especially in sandy soils (Brady, 1974). It is also dispersed in the environment through fertilizer application. Since the pH was less than 8.5 for all the samples, it is more likely that B would be in the non ionized

The cadmium in wadi Fatimah groundwater is higher than that recommended by the WHO guideline. The average of Cd is 0.004 mg/l. Cadmium is used normally as a coating material, paint pigment, in plastics, fungicide and is a constituent of some fertilizers. Copper, Cd and Zn exist in aqueous form in the predominately +2 state. Generally, Zn exists as Zn2+ state in pH below 7.7 (Liptrot, 1989). Cadmium (II) oxide occurs in some Zn ores which suggests that the two have identical properties such as that both have the + 2 being the most stable oxidation state (Liptrot, 1989).In natural waters, Cu, Cd and Zn occur in the +2

are widespread and rather thicker.

elements are shown in Table 4.

than the ionized state.


Table 4. Statistical summary for trace elements (mg/l) (Sharfa & Subyani, 2011e).

form. The average cupper content of wadi Fatimah is 0.021 mg/l which is very low when compared with that of WHO (2 mg/l). The average Fe content is 0.032 mg/l which is lower than the recommended WHO iron level (< 0.3mg/l). Iron dissolved in groundwater is in the reduced ferrous iron form. This form is soluble and normally does not cause any problems by itself. Ferrous iron is oxidized into ferric iron on contact with oxygen in the air or by the action of iron related bacteria. Ferric iron forms insoluble hydroxides in water. These are rusty red and cause staining and blockage of screens, pumps, pipes, reticulation systems etc. If the iron hydroxide deposits are produced by iron bacteria then they are also sticky and the problems of stain and blockage are many times worse.

A Study of Subsurface Drainage and Water Quality

King Abdulaziz University (KAU), Saudi Arabia.

water.

for irrigation.

**7. References** 

Arabia.

University.

178.

**6. Acknowledgment** 

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 133

and CaCl2. The chemical analyses show that, the groundwater is enriched with nitrate (NO3) ions and most of the groundwater is very hard for use as a drinking water supply. In addition, a few trace elements showed an increase in their contents and exceed the maximum acceptable limits of the standards that restricted to its utilization for drinking

In Wadi Fatimah the groundwater salinity ranged between 969 to 26.500 µS/cm. Highly mineralized water zone almost found marked the lower part of the wadi e.g. Al Jumum–Bahrah area, where the groundwater salinity reached up to 26.500 µS/cm with an average of about 9500 µS/cm. Based on the irrigation indices (e.g. EC, SAR, RSC, B, MH and chloride hazard), it can be concluded that the groundwater within with exception of those located in the Al Jumum-Bahrah region in Wadi Fatimah basin, although its salinity ranged from medium to high, the groundwater can be safely used

The author would like to thank the staff members of the geophysical team of the project NO. AT, 16–20 funded by the King Abdulaziz City for Science and Technology (KACST). He also introduce deep thanks for the Deanship of Scientific Research and post graduate studies of

Al Kabir, M. A.(1985) Recharge characteristics of groundwater aquifers in Jeddah-Makkah-

Alawi, J. and Abdulrazzak, M. 1993. Water in the Arabian Peninsula: Problems and

Al-Gamal,S.A., and Sen,Z.(1983) Quantitative analysis of groundwater quality in Western

Al-Hageri, F.Y., 1977. Groundwater studies of Wadi Qudaid. Institute of applied geology,

Al-Khatib,E.A.B.(1977) Hydrogeology of Usfan District. M.Sc. Thesis, Institute of Applied

Al-Nujaidi,H,A.(1978) Hydrogeology of Wade Murawani- Khulais. M.Sc.Thesis, Institute of

Alyaamani, MS., and Hussein,M.T.(1995) Hydrochemical study of groundwater in recharge

Alyamani, M. (2007) Effects of cesspool system on groundwater quality of shallow bedrock

aquifers in the recharge area of Wadi Fatimah, Western Arabian Shield, Saudi

Saudi Arabia. Proc. Int. Symp. Noordwijkuhout.

Geology, King Abdulaziz Uni., Jeddah, Saudi Arabia.

Arabia. J. Env. Hydrology, vol. 15, paper 8.

Applied Geology, King Abdulaziz Uni., Jeddah, Saudi Arabia.

area, Wade Fatimah basin, Saudi Arabia. Geo Journal, 37.1, p:81-89.

Taif area. M.Sc. Thesis, Faculty of Earth Sci., King Abdulaziz Uni., Jeddah, Saudi

Prospective. In P. Rogers, and P. Lydon (eds), Water in the Arab World Perspectives and Prognoses:171-202. Division of Applied Sciences: Harvard

King Abdulaziz University, Jeddah, Saudi Arabia. Research series no. 2. 132-

Lead (average 0.001 mg/l) and it is relatively higher than the WHO (0.01). Lead on the other hand is used in automobile industries in form of tetramethyllead and tetraethyllead. Manganese (Mn) is present in wadi Fatimah by very low content (average 0.020 mg/l) and it is relatively lower than the WHO (0.01). Mercury (Hg) is important for the water quality. The average Hg in wadi Fatimah area is 0.018mg/l (Table 3) which is relatively higher than the WHO values.

Oxidation and dissolution rocks of gabbroic composition will contribute trace elements such as, Cu, Zn, Li, Cd, V and Mn. The source of these trace elements will be associated with the major cations such as Ca2+, Mg2+, Fe, Na+, Al and Si which are considered the major cations in the rocks of gabbroic composition. Whereas, in the weathering granitic rocks will contribute trace elements of Cu, Ba, Rb, Pb and As, These elements will be associated with the major ions such as Na+, K+, Al and Si.

In Wadi Fatimah the groundwater salinity ranged between 969 to 26.500 µS/cm. All the subbasins are characterized by a relatively low to medium saline water. Highly mineralized water zone almost found marked the lower part of the wadi e.g. Al Jumum–Bahrah area, where the groundwater salinity reached up to 26.500 µS/cm with an average of about 9500 µS/cm.

Based on the irrigation indices (e.g. EC, SAR, RSC, B, MH and chloride hazard), it can be concluded that the groundwater within with exception of those located in the Al Jumum-Bahrah region in Wadi Fatimah basin, although its salinity ranged from medium to high, the groundwater can be safely used for irrigation.

For domestic purposes, the groundwater can be used safely in Fatimah basins. Within Wadi Fatimah, the analyses showed most of the groundwater to be too mineralized and very hard for use as a drinking water supply. In addition, a few trace elements showed increases in their contents and exceed the maximum acceptable limits which restricted to its utilization for drinking water, such as As, B and Mo.

#### **5. Conclusions**

The results of this study revealed that most of the water resources in Jeddah-Makkah area are present within the underground aquifers. These aquifers are of two main types: 1) shallow aquifers within the Quaternary alluvial deposits, and 2) The Oligo-Miocene siliciclastic succession of Ash Shumaysi and Haddat Ash Sham formations. In wadi Usfan, The results of theexploration tools revealed the following conclusions: a)The shallow zone is characterized with a saturated thickness of 3- 20 m and water is found under confined to semi-confined conditions, b) Water levels were encountered at depths varying from 3-16m in the alluvial wadi deposits, and from 18-62 m in the sedimentary succession, c) Groundwater movement is towards the west and northwest, following the general surface drainage system, and d) Hydraulic gradient varies greatly from one point to another depending on the pumping rates and cross-sectional area of the aquifer in addition to its transmissivity.

In wadi An numan area, the groundwater salinity is rather low with EC ranged from 542 to 5400 µS/cm with an average of about 1539 µS/cm. The dominant water types are NaCl and CaCl2. The chemical analyses show that, the groundwater is enriched with nitrate (NO3) ions and most of the groundwater is very hard for use as a drinking water supply. In addition, a few trace elements showed an increase in their contents and exceed the maximum acceptable limits of the standards that restricted to its utilization for drinking water.

In Wadi Fatimah the groundwater salinity ranged between 969 to 26.500 µS/cm. Highly mineralized water zone almost found marked the lower part of the wadi e.g. Al Jumum–Bahrah area, where the groundwater salinity reached up to 26.500 µS/cm with an average of about 9500 µS/cm. Based on the irrigation indices (e.g. EC, SAR, RSC, B, MH and chloride hazard), it can be concluded that the groundwater within with exception of those located in the Al Jumum-Bahrah region in Wadi Fatimah basin, although its salinity ranged from medium to high, the groundwater can be safely used for irrigation.

#### **6. Acknowledgment**

132 Drainage Systems

Lead (average 0.001 mg/l) and it is relatively higher than the WHO (0.01). Lead on the other hand is used in automobile industries in form of tetramethyllead and tetraethyllead. Manganese (Mn) is present in wadi Fatimah by very low content (average 0.020 mg/l) and it is relatively lower than the WHO (0.01). Mercury (Hg) is important for the water quality. The average Hg in wadi Fatimah area is 0.018mg/l (Table 3) which is relatively higher than

Oxidation and dissolution rocks of gabbroic composition will contribute trace elements such as, Cu, Zn, Li, Cd, V and Mn. The source of these trace elements will be associated with the major cations such as Ca2+, Mg2+, Fe, Na+, Al and Si which are considered the major cations in the rocks of gabbroic composition. Whereas, in the weathering granitic rocks will contribute trace elements of Cu, Ba, Rb, Pb and As, These elements will be associated with

In Wadi Fatimah the groundwater salinity ranged between 969 to 26.500 µS/cm. All the subbasins are characterized by a relatively low to medium saline water. Highly mineralized water zone almost found marked the lower part of the wadi e.g. Al Jumum–Bahrah area, where the groundwater salinity reached up to 26.500 µS/cm with an average of about 9500

Based on the irrigation indices (e.g. EC, SAR, RSC, B, MH and chloride hazard), it can be concluded that the groundwater within with exception of those located in the Al Jumum-Bahrah region in Wadi Fatimah basin, although its salinity ranged from medium to high, the

For domestic purposes, the groundwater can be used safely in Fatimah basins. Within Wadi Fatimah, the analyses showed most of the groundwater to be too mineralized and very hard for use as a drinking water supply. In addition, a few trace elements showed increases in their contents and exceed the maximum acceptable limits which restricted to its utilization

The results of this study revealed that most of the water resources in Jeddah-Makkah area are present within the underground aquifers. These aquifers are of two main types: 1) shallow aquifers within the Quaternary alluvial deposits, and 2) The Oligo-Miocene siliciclastic succession of Ash Shumaysi and Haddat Ash Sham formations. In wadi Usfan, The results of theexploration tools revealed the following conclusions: a)The shallow zone is characterized with a saturated thickness of 3- 20 m and water is found under confined to semi-confined conditions, b) Water levels were encountered at depths varying from 3-16m in the alluvial wadi deposits, and from 18-62 m in the sedimentary succession, c) Groundwater movement is towards the west and northwest, following the general surface drainage system, and d) Hydraulic gradient varies greatly from one point to another depending on the pumping rates and cross-sectional area of the aquifer in addition to its

In wadi An numan area, the groundwater salinity is rather low with EC ranged from 542 to 5400 µS/cm with an average of about 1539 µS/cm. The dominant water types are NaCl

the WHO values.

µS/cm.

**5. Conclusions** 

transmissivity.

the major ions such as Na+, K+, Al and Si.

groundwater can be safely used for irrigation.

for drinking water, such as As, B and Mo.

The author would like to thank the staff members of the geophysical team of the project NO. AT, 16–20 funded by the King Abdulaziz City for Science and Technology (KACST). He also introduce deep thanks for the Deanship of Scientific Research and post graduate studies of King Abdulaziz University (KAU), Saudi Arabia.

#### **7. References**


A Study of Subsurface Drainage and Water Quality

New YorK p: 296.

Saudi Arabia.

Saudi Arabia.

in Jeddah-Makkah Aquifer Zone, West Central Arabian Shield, Saudi Arabia 135

Lloyd and Heathcote, 1985 Lloyd, J. A., and Heathcote, J.A. (1985) Natural inorganic

Mansour, M. A. (1984) Evaluation of groundwater resources of Wade Fatimah by Numerical

MAW (Ministry of Agriculture and Water) 1984. Water Atlas of Saudi Arabia. Department

Moore, T. A., and Al-Rehaili, M.H. (1989) Explantory notes to the geologic map of the

Sharaf, M. A. M. (2010a): Geophysical and Hydrochemical Studies on the Groundwater

Sharaf, M. A. M. (2010b): Hydrogeology of Haddat Ash Sham area: Geophysical and

Sharaf, M. A. M. (2011a): Hydrogeological and hydrochemistry of the aquifer system of

Sharaf, M. A. M. (2011b): Geological and Geophysical Exploration of the Groundwater

Sharaf, M. A. M. (2011c): Hydrochemistry of the Groundwater Aquifer in wadi Faydah-

Sharaf, M. A. M. (2011d): Hydrochemistry of the Groundwater Aquifer in As Suqah Area,

Sharaf, M.A.M and Subyani, A. M. (2011e): Assessing of Groundwater Contamination by

Sharaf, M. A., Farag, M. H., and Gazzaz, M. (1988) Groundwater chemistry of

Sharaf, M.A., Al-Bassam,A., Bayumi, T.H., and Qari,M. H. (2002) Hydrogeological and

Spincer, C. H.,and Vincent, P. L., 1984, Bentonite resource potential and geology of the

King Abdulaziz University (Earth Sciences) JKAU, V. 22, 2011).

& Engineering Research Volume 2, Issue 9, September-2011.

Resources, Open-File Report BRGM-O-F-02-34, 34 p.

Tethys Realm, South Valley University, January 2010, P.147-158.

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Environmental Hydrology, Paper 13, V. 18, 2010).

Water Science, (2011)-Am03027: 035 – 052

Journal of Geology, v. 55, 2011, p.1-13.

Final Report, Riyadh, Saudi Arabia.

Geosci (2011) 4:993–1004.

103-112.

hydrochemistry in relation to groundwater: An introduction. Oxford Uni. Press,

model. Unpub. M.Sc.Thesis, Faculty of Earth Sci., King Abdulaziz Uni., Jeddah,

of Water Resources Development, Ministry of Agriculture and Water, Riyadh,

Makkah quadrangle, sheet21D, Kingdom of Saudi Arabia: Saudi Arabian Dir.

Aquifer in Ash Shamiyah Area, Makkah District, Western Saudi Arabia. Journal of

hydrochemical Constrains. Fifth 5th International Conference on the Geology of the

Wadi An Numan, Makkah Al Mukarramah, Saudi Arabia. AquaMundi: Journal of

Aquifers of As Suqah Area, Makkah District, Western Arabian Shield. Arab J

Usfan Areas, Makkah District, Western Arabian Shield, Saudi Arabia. Egyptian

Makkah District, Western Arabian Shield, Saudi Arabia. (In Press in the Journal of

Toxic Elements through Multivariate Statistics and Spatial Interpolation, Wadi Fatimah, Western Arabian Shield, Saudi Arabia. International Journal of Scientific

WadiUoranah- Alabdiah area. Western Province, Saudi Arabia, JKAU: Earth Sci. 1,

hydrochemical investigation of the Cretaceous- Quaternary sedimentary sequence east of Jeddah city. King Abdulaziz City for Science and Technology (KACST),

Cenozoic sediments, Jeddah region: Saudi Arabian Deputy Ministry for Mineral


Alyamani, M.S.(1999). Physio-chemical processes on groundwater chemistry, under arid

Alyamani, M.S., Bazuhair, A. S., Bayumi, T. H., and Al-Sulaiman, K. (1996) Application of

Bolt, G. H. and Bruggenwert, M. G. M.: 1978, Soil Chemistry, Basic Elements, 2nd Edition, Elsevier Scientific Publishing Company Amsterdam. The Netherlands. Brady, N. C.: 1974, Nature and properties of soils, 8th EditionMacmillan Publishers Co.,

Brown, G.F., Jackson, R.O., Bogue, R.G., and MacLean, W.H. (1963) Geology of the Southern

Burden, D.J. 1982. Hydrogeological conditions in the Middle East. Quarterly Journal of

Edmunds. W. M., Kinniburgh, D. G. and Moss, P. D.: 1992, Trace Metals in Interstitial

Hem, 1989 Hem, J.D. (1989) The Study and Interpretation of the Chemical Characteristics of

Italconsult (1976) Detailed investigations of Wade Khulais basin. Unpub. Report. Ministry

Jamman, A. M. (1978) Hydrogeology of Wadi An Numan, Saudi Arabia. Unpub M.

Karpoff, R.,1958. Esquisse geologiques de I,Arabie Saoudite : Bulletin Societe Geologique de

Kfupm/Ri (King Fahd University of Petroleum and Minerals, Research Institute) 1988.

Liptrot, G. F.: 1989, Modern Inorganic Chemistry 4th Edit, Scoltprint Musselburgh.

Arabia. Proj. No. 005/413, King Abdulaziz Uni., Jeddah, Saudi Arabia. Basmci, Y., and Al Kabir, M.A. (1988). Recharge characteristics of aquifers of Jeddah-Makkah-Taif region. Mathematical and Physical Sci., Vol. 222, p: 367-375. Bazuhair, A.S., Hussein,M.T., Alyamani,M.S., and Ibrahim, K.(1992) Hydrogeophysical

Abdulaziz Uni., Jeddah, Saudi Arabia.

Abdulaziz Uni, Jeddah, Saudi Arabia.

Engineering Geology 15: 71–81.

Crystalline Rocks. (Unpublished).

Survey.

EditionMacmillan Publishers Co., INC, NewYork.

of Agriculture and Water, Riyadh, Saudi Arabia

Arabia, technical report SGS-Tr-2006-4.

France, 6 ser. VIIm, pp. 653 – 696.

Institute. 61 pp

Res.Misc. Geologic Invest. Map I - 210A, 1:500,000 scale.

climatic conditions,western province, Saudi Arabia. Proj. No. 203/418, King

environmental isotope on groundwater study in the western province, Saudi

studies of Khulais basin, western region, Saudi Arabia. Unpub. Report, King

INC, NewYork Brady, N. C.: 1974, Nature and properties of soils, 8th

Hijaz quadrangle, Kingdom of Saudi Arabia: Saudi Arabian Dir. Gen. Min.

Waters from Sandstones Acidic Inputs to Shallow Groundwater, Environmental Pollution, Elsevier Science Publishers Ltd, England. Edmunds, W. M. and Savage, D.: Geochemical Characteristics of Groundwater in Granites and Related

Natural Water. 3rd edn. USGS Water Supply Paper 2254, US Geological

Sc.Thesis, Faculty of Earth Sci., King Abdulaziz Uni., Jeddah, Saudi Arabia. M.Sc. Thesis, Institute of Applied Geology, King Abdulaziz Uni., Jeddah, Saudi Arabia. Johnson, P. R. (2006) Explanatory notes to the map of Proterozoic geology of western Saudi

Groundwater Resources Conditions in the Eastern Province of Saudi Arabia, Research report, King Fahd University of Petroleum and Minerals, Research


**Part 3** 

**Surface Drainage –** 

**Modern Trends and Research** 


## **Part 3**

**Surface Drainage – Modern Trends and Research** 

136 Drainage Systems

USSL 1954: Diagnosis and improvement of saline and alkali soils. USDA Agr. Handbook

Zaidi, S. (1983) Landform and geomorphic evolution of Wade Khulais area.Western Saudi

Zaidi, S.(1984) Geomorphology of Wadi Khulais area. FES, Res. Ser. No.18, 98p.

Geneva

Arabia. FES, Bull. 5, 153-156pp.

No. 60, Washington DC WHO (1993) Guidelines for Drinking Water Quality,

**7** 

Mashael Al Saud

*Kingdom of Saudi Arabia* 

**Use of Remote Sensing and GIS to Analyze** 

**Drainage System in Flood Occurrence,** 

*Space Research Institute, King Abdel Aziz City for Science and Technology,* 

Lately, natural hazards have been increased and occupied the attention at the regional and the global levels. Flood is one among the most severe aspects of these hazards, and more than one million people are killed each year in the low-income countries due to flooding as

The Kingdom of Saudi Arabia, the major territory of the Arabian Peninsula, is located along an active tectonic zone of the Red Sea Rift System, which makes it unstable region, with complicated geology and geomorphology. Therefore, its territory is known by several natural disasters that occurred in different regions of the country over the past history, but they almost concentrated in the western coast, between the Arabian Shield and Red Sea, where the area of study is situated. Several aspects of natural hazards have been witnessed in this area, mainly floods, earthquakes and dust storms. These hazards are usually considered by inhabitants since they have a direct impact on their lifestyle, while the other

However, it has been longtime, this region haven't witnessed any remarkable catastrophic event, until the late 2009 when torrential rainfall existed in the city of Jeddah and the surroundings, and followed by damaging floods. This city is located on the middle of the western Saudi Arabia coast, is considered as the economic and touristic capital of the country with an increasing population of about 3.4 million people. It is also the main

The statistical overview introduced by the International Disaster Database (EM-DAT: The OFDA/CRED, 2010), shows that the number of people killed in Saudi Arabia in different natural disasters was 299 over 25 years ago (between 1982 and 2005). This in turn reveals the magnitude of impact the occurred flood disaster in 2009. This shows the magnitude of impact of the last occurred flood disaster. One year later, in January 2011, another flood event has taken place and covered larger geographic region. It also resulted damages and

Studies in this regard were rare and some of them focused only on technical issues, thus it is still difficult to figure out a clear understanding for the reasons behind these events and the

estimated by International Disaster Database (EM-DAT: The OFDA/CRED, 2010).

aspects, such as soil and rock erosion, drought are not.

several people were killed, lost or injured.

crossing point for pilgrims from different countries around the world.

**1. Introduction** 

**Jeddah - Western Saudi Coast** 

## **Use of Remote Sensing and GIS to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast**

Mashael Al Saud

*Space Research Institute, King Abdel Aziz City for Science and Technology, Kingdom of Saudi Arabia* 

#### **1. Introduction**

Lately, natural hazards have been increased and occupied the attention at the regional and the global levels. Flood is one among the most severe aspects of these hazards, and more than one million people are killed each year in the low-income countries due to flooding as estimated by International Disaster Database (EM-DAT: The OFDA/CRED, 2010).

The Kingdom of Saudi Arabia, the major territory of the Arabian Peninsula, is located along an active tectonic zone of the Red Sea Rift System, which makes it unstable region, with complicated geology and geomorphology. Therefore, its territory is known by several natural disasters that occurred in different regions of the country over the past history, but they almost concentrated in the western coast, between the Arabian Shield and Red Sea, where the area of study is situated. Several aspects of natural hazards have been witnessed in this area, mainly floods, earthquakes and dust storms. These hazards are usually considered by inhabitants since they have a direct impact on their lifestyle, while the other aspects, such as soil and rock erosion, drought are not.

However, it has been longtime, this region haven't witnessed any remarkable catastrophic event, until the late 2009 when torrential rainfall existed in the city of Jeddah and the surroundings, and followed by damaging floods. This city is located on the middle of the western Saudi Arabia coast, is considered as the economic and touristic capital of the country with an increasing population of about 3.4 million people. It is also the main crossing point for pilgrims from different countries around the world.

The statistical overview introduced by the International Disaster Database (EM-DAT: The OFDA/CRED, 2010), shows that the number of people killed in Saudi Arabia in different natural disasters was 299 over 25 years ago (between 1982 and 2005). This in turn reveals the magnitude of impact the occurred flood disaster in 2009. This shows the magnitude of impact of the last occurred flood disaster. One year later, in January 2011, another flood event has taken place and covered larger geographic region. It also resulted damages and several people were killed, lost or injured.

Studies in this regard were rare and some of them focused only on technical issues, thus it is still difficult to figure out a clear understanding for the reasons behind these events and the

Use of Remote Sensing and GIS

**No. Basin Area** 

15 Ghlil 23.1 Minor

Table 1. Watersheds in the area of study and their types.

2 Om El-

in the study area.

the study area.

(289.4 km2).

(km2)

**Basin type**

Table 1).

**Basin** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 141

In this study, topographic maps, of scale 1:50000 and contour interval 20m, were utilized and they were supported by the application of DEM in order to extract the related parameters for drainage systems, and they were directly digitized in the GIS system using *Arc-GIS 9.3* software*.* Consequently, streams were illustrated for each watershed and the watershed boundaries were identified. The area of study is about 1947km2 (Figure 2 and

**Basin** 

Hableen 75.7 Major 17 Muwaieha 23.7 Minor

1 Ghouimer 319.7 Major 16 Selsli 13.7 Joining

3 Basin # 3 6.5 Joining 18 Basin # 18 17.6 Joining 4 Daghbj 56.9 Major 19 Basin # 19 14.8 Minor 5 El Hatiel 59.6 Major 20 Basin # 20 21.6 Joining 6 Basin # 6 10.3 Joining 21 Abou Je'Alah 21.2 Minor 7 Basin # 7 25.8 Minor 22 Al A'ayah 14.7 Minor 8 El Assla 289.4 Major 23 Ed-Dowikhlah 17.1 Minor 9 Basin # 9 10.4 Joining 24 El-Baghdadi 29.6 Minor 10 Mreikh 46.7 Minor 25 Ketanah 34.7 Major 11 Kawes 70.1 Major 26 Basin # 26 13.0 Joining 12 Osheer 17.7 Minor 27 Esh-Shoabaa 40.5 Major 13 Basin # 13 12.5 Joining 28 Basin # 28 24.4 Joining 14 Methweb 54.2 Major 29 Da'af 37.9 Major

Accordingly, the watersheds in the area of concern were divided into three types as follows: 1. Major basin: It encompasses principal hydrological characteristic, mainly funnel-like shape, where the difference between the numbers of branches is high in upstream and downstream areas, and it is characterized by uniform run-off. There are 10 major basins

2. Minor basin: It is characterized by smaller areas than the major ones (usually less than 50km2), and it has almost a uniform run-off regime. They are 10 minor basins existing in

3. Joining basin: It is a geographic land extension between the major and minor basins. It is characterized by non-uniform run-off. There are 9 joining basins in the study area. There are 29 watersheds in the area of study, 19 of them outlet towards Jeddah city at the coast, and totaling an area of about 1170 km2, while the rest outlet into Wadi Fatima to the southern side of Jeddah city. The largest watersheds are Ghouimer (319.7km2) and El Assla

**No Basin Area** 

(km2)

**Basin type**

mechanism of disaster action. Accordingly, implements for mitigation and risk reduction could not be properly applied in the lack of comprehensive studies, notably in analyzing the behavior and characteristics of the existing drainage system.

The study aims to analyze the topological elements of drainage systems and to induce their geomorphologic and hydrologic characteristics. It shows the geo-spatial data acquired from satellite images and the application of GIS. Digital Elevation Models (DEM) was also diagnosed to assess valuable elements for drainage analysis.

The area for study was selected through the correspondence between the limits of the existing water basins and the environs that are vulnerable to frequent floods according to floods of 2009 and 2011 (Figure 1). Thus, the resulting area totals about 1947km2 and it extends from the coastline to the adjacent mountain chains. It lies between the following geographical coordinates: 39°32′ and 39°06′ E & 21°56′ and 21°1′9N.

Fig. 1. Location maps of the Saudi Kingdom and Jeddah city.

#### **2. Natural and anthropogenic characteristics**

#### **2.1 Drainage systems**

Advanced techniques have been well demonstrated in illustrating streams and surface water basins. In this respect, DEM can be well utilized, and it can help inducing flow directions, and locating low-lands. However, erroneous results sometimes appear from DEM if the digital applications do not accurately obtain. Topographic maps are also used to delineate drainage systems. Therefore, streams are directly digitized in the GIS system, and thus catchment areas are extracted following geomorphologic and hydrological concepts.

mechanism of disaster action. Accordingly, implements for mitigation and risk reduction could not be properly applied in the lack of comprehensive studies, notably in analyzing the

The study aims to analyze the topological elements of drainage systems and to induce their geomorphologic and hydrologic characteristics. It shows the geo-spatial data acquired from satellite images and the application of GIS. Digital Elevation Models (DEM) was also

The area for study was selected through the correspondence between the limits of the existing water basins and the environs that are vulnerable to frequent floods according to floods of 2009 and 2011 (Figure 1). Thus, the resulting area totals about 1947km2 and it extends from the coastline to the adjacent mountain chains. It lies between the following

Advanced techniques have been well demonstrated in illustrating streams and surface water basins. In this respect, DEM can be well utilized, and it can help inducing flow directions, and locating low-lands. However, erroneous results sometimes appear from DEM if the digital applications do not accurately obtain. Topographic maps are also used to delineate drainage systems. Therefore, streams are directly digitized in the GIS system, and thus catchment areas are extracted following geomorphologic and hydrological concepts.

behavior and characteristics of the existing drainage system.

diagnosed to assess valuable elements for drainage analysis.

geographical coordinates: 39°32′ and 39°06′ E & 21°56′ and 21°1′9N.

Fig. 1. Location maps of the Saudi Kingdom and Jeddah city.

**2. Natural and anthropogenic characteristics** 

**2.1 Drainage systems** 

In this study, topographic maps, of scale 1:50000 and contour interval 20m, were utilized and they were supported by the application of DEM in order to extract the related parameters for drainage systems, and they were directly digitized in the GIS system using *Arc-GIS 9.3* software*.* Consequently, streams were illustrated for each watershed and the watershed boundaries were identified. The area of study is about 1947km2 (Figure 2 and Table 1).


Table 1. Watersheds in the area of study and their types.

Accordingly, the watersheds in the area of concern were divided into three types as follows:


There are 29 watersheds in the area of study, 19 of them outlet towards Jeddah city at the coast, and totaling an area of about 1170 km2, while the rest outlet into Wadi Fatima to the southern side of Jeddah city. The largest watersheds are Ghouimer (319.7km2) and El Assla (289.4 km2).

Use of Remote Sensing and GIS

from TRMM data (Figure 3).

distribution of rainfall.

**2.2 Rainfall distribution**

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 143

There is still undefined annual rainfall rate for Jeddah area. It was estimated at 350-400mm in the last few decades (Italconsult, 1967), while it has been recently estimated with less than 60mm, whereas, run-off is estimated between 5-6% according to Es-Saeed, et al. (2004). This decline in annual rainfall rate (i.e. about five times) is accompanied with a number of rainfall peaks, which is attributed mainly to the changing climatic conditions (IPCC, 2007). Due to the lack of continuous and comprehensive climatic data, the remotely sensed data, which can be retrieved from satellite images, was used. Therefore, Tropical Rainfall Mapping Mission (TRMM) data was utilized in this study, and thus the geographic distribution, through maps, of rainfall in November 2009 and January 2011 were illustrated

Fig. 3. Rainfall distribution in 2009 and 2011 according to TRMM data.

**2.3 Geomorphologic and geologic characteristics**

These maps could introduce essential tools to figure out the geographic distribution of rainfall in the two periods, which will be used consequently to compare it with the geographic distribution of damaged areas. Hence, it is clear that there is one dense cloudy domain in each event (2009 and 2011). These are A in 2009 and C in 2011, in addition to other less-dense ones. However, this was not very well realized previously. For the dense cloudy domain in 2009, it was estimated with a diameter of about 90km, whilst the other one of 2011, it was about 30km, and this reflects the degree of impact in the two periods. However the rainfall rate was estimated at about 95mm, and 120mm in 2009 and 2011; respectively; but this was attributed to a gauge point and not for the entire geographic

Geomorphologic and geologic characteristics are of great importance in studying floods, since they govern the flow regime and many other related surficial processes (e.g.

Fig. 2. Watersheds in the area of study.

#### **2.2 Rainfall distribution**

142 Drainage Systems

Fig. 2. Watersheds in the area of study.

There is still undefined annual rainfall rate for Jeddah area. It was estimated at 350-400mm in the last few decades (Italconsult, 1967), while it has been recently estimated with less than 60mm, whereas, run-off is estimated between 5-6% according to Es-Saeed, et al. (2004). This decline in annual rainfall rate (i.e. about five times) is accompanied with a number of rainfall peaks, which is attributed mainly to the changing climatic conditions (IPCC, 2007).

Due to the lack of continuous and comprehensive climatic data, the remotely sensed data, which can be retrieved from satellite images, was used. Therefore, Tropical Rainfall Mapping Mission (TRMM) data was utilized in this study, and thus the geographic distribution, through maps, of rainfall in November 2009 and January 2011 were illustrated from TRMM data (Figure 3).

Fig. 3. Rainfall distribution in 2009 and 2011 according to TRMM data.

These maps could introduce essential tools to figure out the geographic distribution of rainfall in the two periods, which will be used consequently to compare it with the geographic distribution of damaged areas. Hence, it is clear that there is one dense cloudy domain in each event (2009 and 2011). These are A in 2009 and C in 2011, in addition to other less-dense ones. However, this was not very well realized previously. For the dense cloudy domain in 2009, it was estimated with a diameter of about 90km, whilst the other one of 2011, it was about 30km, and this reflects the degree of impact in the two periods. However the rainfall rate was estimated at about 95mm, and 120mm in 2009 and 2011; respectively; but this was attributed to a gauge point and not for the entire geographic distribution of rainfall.

#### **2.3 Geomorphologic and geologic characteristics**

Geomorphologic and geologic characteristics are of great importance in studying floods, since they govern the flow regime and many other related surficial processes (e.g.

Use of Remote Sensing and GIS

**3.1.2 Maps** 

**3.1.3 Satellite images** 

**Satellite Spatial** 

**resolution** 

**Worldview-1** 0.5m 8 27/1/2011,

**Quick Bird** 0.5m 5 2/3/2011

Table 2. Used satellite images and their major specifications.


*ENVI-4.3* for satellite image processing, produced by *IBM*, Colorado, USA.

*Arc-GIS 9.3* for GIS applications, produced by *ESRI*, Redlands, USA.

*ERDAS Imagine 9.3* for satellite image processing, produced by *Leica*, Georgia, USA.

**Ikonos** 1m 5

**3.1.4 Digital Elevation Model (DEM)** 

and Technology.

**3.1.5 Software** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 145


Satellite images of different optical and spectral specifications were used in this study. They have different characteristics, such as re-visit time, swath width, etc. there was a great concern to have these images in dates close to the disasters dates of disasters (Table 2).

**bands Acquiring date Utility** 

Comparison before and after floods. Identification areas under flood damages (2009).

Identification areas under flood damages (2011).

High precision of comparative analysis for flooded areas.

features.

10/10/2009, 30/11/2009, 19/2/2010

1/3/2011

**Worldview-2** 0.5m 8 8/2/2011 Spatial data overlapping.

**Geo-eye 1** 0.5m 5 2010 Establishing DEM

**Aster** 15m 14 2009 Identification of geological

Digital Elevation Model (DEM) was analyzed in this study to induce empirical approaches for drainage analysis. This DEM data was supported by King Abdulaziz City for Science



**No. of** 


infiltration rate, flow direction, water accumulation, etc). The area of study can be divided into three major zones according to their altitude and the existing rock bodies. These are:


In addition, the study area includes large number of valleys, with diverse aspects. They are almost filled with sand and mixed sediments. These valleys are characterized by shallow depth (about 2-3m) and wide cross-section (500-700m), where the flood plains are often undefined or shallow enough to be identified.

According to the geology of the area, it is characterized by the interference of igneous and sedimentary rocks that interbedded in some instances with metamorphic rocks. Most of the exposed rocks are of the Precambrian age, whilst the coastal area is totally covered by sedimentary deposits, which are almost of looses. These rocks have tremendous deformation systems, including mainly fractures of different scale, joints and several folding aspects.

#### **2.4 Urban expansion**

The kingdom of Saudi Arabia occupies outstanding level in urban expansion, and this is well pronounced in Jeddah city where the population growth rate ranges between 20-28%, and thus the city is occupying now about 3.4 million people (3500 person/km2). This is merely attributed to the number of foreign people attend during different periods for pilgrims and related religious tasks.

Lately, the geographic distribution of urban settlements has been extended towards the mountainous areas to the east. However, this distribution extends along the existing valleys from the elevated regions, which results obstacles in many valleys passageways. Accordingly, the interpretation of satellite images in combination with the analysis of old topographic maps show that urban expansion has been three times increased over 21 years (1975-1996), and thus it is followed by another increase of about 2.7 time in the last fifteen years (1996-2011), and this increase concentrates mainly along the eastern part of Jeddah city.

#### **3. Materials and methods**

There are many methods to study and assess floods and their controlling geomorphologic factors. They usually follow different approaches of analysis, and thus different results exist. This relies on the used tools; however, the utilization of new space techniques is utmost important in this respect, since they became of essential role for topological and drainage analysis. However, the use of such tools is still dependant on its availability. In addition, many studies focus on specific concept relates to floods and torrents, such as the analysis of hydrologic systems (Subyani, 2009), Digital Elevation Models (KACST, 2011), or the morphometric analysis for valleys (Yehia and El-Ater, 1997).

#### **3.1 Used tools**

#### **3.1.1 Information and data**


#### **3.1.2 Maps**

144 Drainage Systems

infiltration rate, flow direction, water accumulation, etc). The area of study can be divided into three major zones according to their altitude and the existing rock bodies. These are:

In addition, the study area includes large number of valleys, with diverse aspects. They are almost filled with sand and mixed sediments. These valleys are characterized by shallow depth (about 2-3m) and wide cross-section (500-700m), where the flood plains are often

According to the geology of the area, it is characterized by the interference of igneous and sedimentary rocks that interbedded in some instances with metamorphic rocks. Most of the exposed rocks are of the Precambrian age, whilst the coastal area is totally covered by sedimentary deposits, which are almost of looses. These rocks have tremendous deformation systems, including mainly fractures of different scale, joints and several folding aspects.

The kingdom of Saudi Arabia occupies outstanding level in urban expansion, and this is well pronounced in Jeddah city where the population growth rate ranges between 20-28%, and thus the city is occupying now about 3.4 million people (3500 person/km2). This is merely attributed to the number of foreign people attend during different periods for

Lately, the geographic distribution of urban settlements has been extended towards the mountainous areas to the east. However, this distribution extends along the existing valleys from the elevated regions, which results obstacles in many valleys passageways. Accordingly, the interpretation of satellite images in combination with the analysis of old topographic maps show that urban expansion has been three times increased over 21 years (1975-1996), and thus it is followed by another increase of about 2.7 time in the last fifteen years (1996-2011), and this

There are many methods to study and assess floods and their controlling geomorphologic factors. They usually follow different approaches of analysis, and thus different results exist. This relies on the used tools; however, the utilization of new space techniques is utmost important in this respect, since they became of essential role for topological and drainage analysis. However, the use of such tools is still dependant on its availability. In addition, many studies focus on specific concept relates to floods and torrents, such as the analysis of hydrologic systems (Subyani, 2009), Digital Elevation Models (KACST, 2011), or the


increase concentrates mainly along the eastern part of Jeddah city.

morphometric analysis for valleys (Yehia and El-Ater, 1997).


1. Coastal area (10-20km width, 3m/km slope gradient). 2. Slopping lands (<5km width, 20m/km slope gradient). 3. Elevated areas (about 25km width, 6-7m/km slope gradient).

undefined or shallow enough to be identified.

**2.4 Urban expansion** 

pilgrims and related religious tasks.

**3. Materials and methods** 

**3.1 Used tools** 

**3.1.1 Information and data** 


#### **3.1.3 Satellite images**

Satellite images of different optical and spectral specifications were used in this study. They have different characteristics, such as re-visit time, swath width, etc. there was a great concern to have these images in dates close to the disasters dates of disasters (Table 2).


Table 2. Used satellite images and their major specifications.

#### **3.1.4 Digital Elevation Model (DEM)**

Digital Elevation Model (DEM) was analyzed in this study to induce empirical approaches for drainage analysis. This DEM data was supported by King Abdulaziz City for Science and Technology.


#### **3.1.5 Software**


Use of Remote Sensing and GIS

systems, low-lands, etc.

determine the overall shape of the surface.

Fig. 4. Example showing the steps obtained to create DME aspects*.* 

Currently, the use of Digital Elevation Models (DEM) has found widespread applications in several geomorphologic and hydrological purposes; especially that this technique allows the extraction of topographic features of the earth surface making possible the display of all

**4.2 Analyzing digital elevation mode** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 147

of any site needs data form three-dimensions (z, y, x), which is known as digital elevation model (DEM). Thus, the applications of DEM is well pronounced in several applications, and more certainly to induce many components, such as slope, sunlight exposure, drainage

The concept behind establishing DEMs implies the treatment of elevation points whether from digital contour lines or from stereoscopic satellite images (e.g. SPOT images). Hence, triangulated irregulated network *(TIN)* must be primarily constructed, which represents digital data structure used in *GIS* of surface attributes of the physical land surface or sea bottom, made up of irregularly distributed nodes and lines with three dimensional coordinates (*X, Y* and *Z*) that are arranged in a network of non-overlapping triangles (Figure 4). *TIN*s are made from mass points, break-lines, and polygons. Mass points are height points; they become nodes in the network, thus they primary input into a *TIN* in order to

#### **3.2 Methods of analysis**

#### **3.2.1 Images processing**

Satellite images have become important tools of Earth observation since they can be used in several terrain applications and the processes occur. The science of remote sensing, in a broad sense, is represented by digital satellite images acquired in defined technical procedures. All selected digital satellite image data were primarily subjected to two principal stages: these are the: pre-processing and images processing procedures.

Pre-processing procedures are essential and diverse set of image preparation programs that act to offset problems. These processes are applied into the specialized software (e.g. *ERDAS Imagine, ENVI, etc.*) to increase the accuracy and interpretability of the digital data during the image processing phase. These commonly include: image sub-setting, atmospheric correction, geometric correction, image registration, geo-referencing and mosaicing.

Consequently, digital image processing can be applied to facilitate recognition of objects appear on terrain surface, and thus applying different analyses and measures required. For example, in *ERDAS Imagine* software, the most useful steps are: directional filtering, contrasting and sharpness. In addition, band combination is also applied, where single band and multi-band enhancement were carried out by interrelating each three bands as one set. These applications provided helped detecting color differentiation, pattern and tone, which would discriminate distinguished geomorphologic features. Moreover, thermal interpretation from thermal bands was applied. While *ENVI* software is also useful and can be friendly used for digital satellite images processing. The following digital applications were performed: Enhancement, Interactive stretching, Density slicing and coloring.

#### **3.2.2 GIS applications**

The capability of using GIS technology for earth surface based scientific investigation makes it more usable; especially for geographic applications when satellite images are not available. Modern GIS technologies use digital information, for which various digitized data creation methods are used. The most common method of data creation is digitization, where a hard copy map or survey plan is transferred into a digital medium through the use of a computer-aided design and geo-referencing capabilities.

*Arc GIS* 9.3, which was used in this study, is a software program used to create, display and analyze geospatial data. It consists of three components: Arc Map, Arc Catalog and Arc Toolbox. Arc Map is used for visualizing spatial data, performing spatial analysis and creating maps to show the work results. While, Arc Catalog is used for browsing and exploring spatial data, as well as viewing a creating metadata and managing spatial data. Arc Toolbox is an interface for accessing the data conversion and analysis function the come from *Arc GIS*.

#### **4. Data analysis and results**

#### **4.1 Three-dimensional models (DEM) production**

Geographic information systems can be used also to build three-dimensional models for any geographical location on the surface of the Earth. The representation of terrain topography

Satellite images have become important tools of Earth observation since they can be used in several terrain applications and the processes occur. The science of remote sensing, in a broad sense, is represented by digital satellite images acquired in defined technical procedures. All selected digital satellite image data were primarily subjected to two

Pre-processing procedures are essential and diverse set of image preparation programs that act to offset problems. These processes are applied into the specialized software (e.g. *ERDAS Imagine, ENVI, etc.*) to increase the accuracy and interpretability of the digital data during the image processing phase. These commonly include: image sub-setting, atmospheric

Consequently, digital image processing can be applied to facilitate recognition of objects appear on terrain surface, and thus applying different analyses and measures required. For example, in *ERDAS Imagine* software, the most useful steps are: directional filtering, contrasting and sharpness. In addition, band combination is also applied, where single band and multi-band enhancement were carried out by interrelating each three bands as one set. These applications provided helped detecting color differentiation, pattern and tone, which would discriminate distinguished geomorphologic features. Moreover, thermal interpretation from thermal bands was applied. While *ENVI* software is also useful and can be friendly used for digital satellite images processing. The following digital applications

principal stages: these are the: pre-processing and images processing procedures.

correction, geometric correction, image registration, geo-referencing and mosaicing.

were performed: Enhancement, Interactive stretching, Density slicing and coloring.

computer-aided design and geo-referencing capabilities.

**4.1 Three-dimensional models (DEM) production** 

The capability of using GIS technology for earth surface based scientific investigation makes it more usable; especially for geographic applications when satellite images are not available. Modern GIS technologies use digital information, for which various digitized data creation methods are used. The most common method of data creation is digitization, where a hard copy map or survey plan is transferred into a digital medium through the use of a

*Arc GIS* 9.3, which was used in this study, is a software program used to create, display and analyze geospatial data. It consists of three components: Arc Map, Arc Catalog and Arc Toolbox. Arc Map is used for visualizing spatial data, performing spatial analysis and creating maps to show the work results. While, Arc Catalog is used for browsing and exploring spatial data, as well as viewing a creating metadata and managing spatial data. Arc Toolbox is an interface for accessing the data conversion and analysis function the come

Geographic information systems can be used also to build three-dimensional models for any geographical location on the surface of the Earth. The representation of terrain topography

**3.2 Methods of analysis 3.2.1 Images processing** 

**3.2.2 GIS applications** 

from *Arc GIS*.

**4. Data analysis and results** 

of any site needs data form three-dimensions (z, y, x), which is known as digital elevation model (DEM). Thus, the applications of DEM is well pronounced in several applications, and more certainly to induce many components, such as slope, sunlight exposure, drainage systems, low-lands, etc.

The concept behind establishing DEMs implies the treatment of elevation points whether from digital contour lines or from stereoscopic satellite images (e.g. SPOT images). Hence, triangulated irregulated network *(TIN)* must be primarily constructed, which represents digital data structure used in *GIS* of surface attributes of the physical land surface or sea bottom, made up of irregularly distributed nodes and lines with three dimensional coordinates (*X, Y* and *Z*) that are arranged in a network of non-overlapping triangles (Figure 4). *TIN*s are made from mass points, break-lines, and polygons. Mass points are height points; they become nodes in the network, thus they primary input into a *TIN* in order to determine the overall shape of the surface.

Fig. 4. Example showing the steps obtained to create DME aspects*.* 

#### **4.2 Analyzing digital elevation mode**

Currently, the use of Digital Elevation Models (DEM) has found widespread applications in several geomorphologic and hydrological purposes; especially that this technique allows the extraction of topographic features of the earth surface making possible the display of all

Use of Remote Sensing and GIS

with their angles will be calculated.

**Basin** 

on the number of surfaces (Ns) as follows:

**No. Basin name (Na) (A)** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 149

In order to evaluate the effectiveness of the total slope in the surface water flow energy, the area (basin) must be divided into a number of surfaces, where each surface is characterized by a defined slope angle (level of inclination) (Na). Therefore, the areas of these surfaces (A)

Thus, the exponential interaction of to surface inclination with its area (multiplication calculation), can induce the effectiveness (St) of water volume loaded towards valleys. It can be calculated to every surface then the sum can be calculated by dividing the resulted values

> 1 a1 2 a2 3 a3 s

N 

Km2

**Average slope effectiveness**  (º)

**Total effectiveness**  ( St)

(A x N ) A x N A x N St

In this study, the surface slope angles were classified into nine intervals ranging between 0º-10º for the very low slope effectiveness to 80º -90º for the very high slope effectiveness. Thus, slope effectiveness values were calculated for the 29 basins exist in the area of study (Table 3).

1 Ghouimer 23 12.5 °8 Medium 2 Om El-Hableen 16 0.84 10° Medium 3 Basin # 3 2 0.48 3° Low 4 Daghbj 20 1.02 15° High 5 El Hatiel 17 0.96 11° High 6 Basin # 6 3 0.65 4° Low 7 Basin # 7 5 2.74 12° High 8 El Assla 32 5.72 7° Medium 9 Basin # 9 3 1.43 4° Low 10 Mreikh 9 1.88 7° Medium 11 Kawes 18 2.12 9° Medium 12 Osheer 5 0.98 5° Low 13 Basin # 13 2 1.97 4° Low 14 Methweb 13 2.05 11° High 15 Ghlil 7 0.78 4° Low 16 Selsli 2 0.27 1° Low 17 Muwaieha 5 1.57 8° Medium 18 Basin # 18 4 1.18 6° Medium 19 Basin # 19 3 0.87 2° Low 20 Basin # 20 1 0.58 1° Low 21 Abou Je'Alah 5 1.08 9° Medium 22 Al A'ayah 4 1.49 7° Medium 23 Ed-Dowikhlah 8 0.97 5° Low 24 El-Baghdadi 17 1.07 12° High 25 Ketanah 19 1.24 14° High 26 Basin # 26 7 0.58 15° High 27 Esh-Shoabaa 19 1.22 17° High 28 Basin # 28 9 1.13 13° High 29 Da'af 14 1.76 15° High

Table 3. Slope effectiveness in water basins after calculating values from DEM.

natural features for the both vertical and horizontal resolutions. However, DEM extraction requires elevation data for topographic features with geographic coordinates of each elevation. Therefore, topographic maps with contour lines are electronically digitized in specialized GIS software. In case these maps weren't available at a digital format, satellite images with stereoscopic characteristics can be used. In this study, Geo-eye-1 satellite images, with 2m precision were used.

In this study, after establishing the DEM, the resulting data was analyzed to recognize slope gradient, cross-sections, channel slopes and depressions. Hence, the three first factors interact together to form water flow network from drainage system thresholds to the valleys outlet.

#### **4.2.1 Terrain slope**

Terrain slope is considered as an important factor in identifying the flood regime. In this study, terrain slopes are considered rather than the valley slopes. Naturally flood risk increases with terrain slope gradient (angle of inclination with the horizontal) due to the increasing energy of run-off resulted from the surrounded surfaces to the adjacent valleys. It is viewed from the capacity of valleys receiving water bulk and bed loads from these surfaces, which may result flooding.

In order to evaluate these geometric variables from DEM, every surface must be taken independently (i.e. terrain surface in certain exposure), and since these variables will be used in studying the overland flow, it was necessary to analyze the variation required for every water basin separately in the area of study. Since water basins consist of a set of surfaces expanding toward valleys; however, it can be dividing each basin into zones with a specified surfaces slopes and defined area for each surface. It makes it possible to evaluate the total slope effectiveness in every basin in the study area. This can be done by creating DEM in GIS; and more specifically in Arc-GIS software (example in Figure 5).

Fig. 5. Classifying terrain surfaces according their slopes for each surface.

Nevertheless, slope gradient of the surface is taken from a linear approach where it is described as the length slope (Ls) according to several studies (Khosrowpanah, et al., 2007), and the total surface of the area is not considered.

natural features for the both vertical and horizontal resolutions. However, DEM extraction requires elevation data for topographic features with geographic coordinates of each elevation. Therefore, topographic maps with contour lines are electronically digitized in specialized GIS software. In case these maps weren't available at a digital format, satellite images with stereoscopic characteristics can be used. In this study, Geo-eye-1 satellite

In this study, after establishing the DEM, the resulting data was analyzed to recognize slope gradient, cross-sections, channel slopes and depressions. Hence, the three first factors interact together to form water flow network from drainage system thresholds to the valleys

Terrain slope is considered as an important factor in identifying the flood regime. In this study, terrain slopes are considered rather than the valley slopes. Naturally flood risk increases with terrain slope gradient (angle of inclination with the horizontal) due to the increasing energy of run-off resulted from the surrounded surfaces to the adjacent valleys. It is viewed from the capacity of valleys receiving water bulk and bed loads from these

In order to evaluate these geometric variables from DEM, every surface must be taken independently (i.e. terrain surface in certain exposure), and since these variables will be used in studying the overland flow, it was necessary to analyze the variation required for every water basin separately in the area of study. Since water basins consist of a set of surfaces expanding toward valleys; however, it can be dividing each basin into zones with a specified surfaces slopes and defined area for each surface. It makes it possible to evaluate the total slope effectiveness in every basin in the study area. This can be done by creating

DEM in GIS; and more specifically in Arc-GIS software (example in Figure 5).

Fig. 5. Classifying terrain surfaces according their slopes for each surface.

and the total surface of the area is not considered.

Nevertheless, slope gradient of the surface is taken from a linear approach where it is described as the length slope (Ls) according to several studies (Khosrowpanah, et al., 2007),

images, with 2m precision were used.

surfaces, which may result flooding.

outlet.

**4.2.1 Terrain slope** 

In order to evaluate the effectiveness of the total slope in the surface water flow energy, the area (basin) must be divided into a number of surfaces, where each surface is characterized by a defined slope angle (level of inclination) (Na). Therefore, the areas of these surfaces (A) with their angles will be calculated.

Thus, the exponential interaction of to surface inclination with its area (multiplication calculation), can induce the effectiveness (St) of water volume loaded towards valleys. It can be calculated to every surface then the sum can be calculated by dividing the resulted values on the number of surfaces (Ns) as follows:

$$\text{St} = \frac{\text{(A}\_1 \times \text{N}\_{\text{a1}}) + \left(\text{A}\_2 \times \text{N}\_{\text{a2}}\right) + \left(\text{A}\_3 \times \text{N}\_{\text{a3}}\right) + \dots}{\text{N}\_{\text{s}}}$$

In this study, the surface slope angles were classified into nine intervals ranging between 0º-10º for the very low slope effectiveness to 80º -90º for the very high slope effectiveness. Thus, slope effectiveness values were calculated for the 29 basins exist in the area of study (Table 3).


Table 3. Slope effectiveness in water basins after calculating values from DEM.

Use of Remote Sensing and GIS

 L1 is the segment length, Nsg is the number of segments.

variables to each segment (Table 4).

**No. Basin name No. of** 

Table 4. Cross-section areas of primary valleys as calculated from DEM.

In addition to terrain surface slope that adjacent to valleys; yet the slope gradient (degree of inclination) of the valley channel itself is an important geometric element that must be

**Basin** 

**4.2.3 Channel slope** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 151

It is possible to calculate geometric variables using DEM if it is characterized with high resolution that fits with the width and depth of cross-sections. The analysis is done by dividing the sections into different segments. Thus, Arc-GIS software is used to calculate the

1 Ghouimer 4 0.126 Medium 2 Om El-Hableen 2 0.215 High 3 Basin # 3 1 0.095 Low 4 Daghbj 2 0.128 Medium 5 El Hatiel 2 0.075 Low 6 Basin # 6 1 0.102 Medium 7 Basin # 7 1 0.087 Low 8 El Assla 8 0.121 Medium 9 Basin # 9 1 0.230 High 10 Mreikh 1 0.183 High 11 Kawes 4 0.182 High 12 Osheer 1 0.105 Medium 13 Basin # 13 1 0.021 Low 14 Methweb 1 0.099 Low 15 Ghlil 1 0.258 High 16 Selsli 1 0.177 High 17 Muwaieha 1 0.183 Low 18 Basin # 18 1 0.172 High 19 Basin # 19 1 0.114 Medium 20 Basin # 20 1 0.247 High 21 Abou Je'Alah 1 0.084 Low 22 Al A'ayah 1 0.097 Low 23 Ed-Dowikhlah 1 0.073 Low 24 El-Baghdadi 1 0.035 Low 25 Ketanah 1 0.045 Low 26 Basin # 26 1 0.046 Low 27 Esh-Shoabaa 1 0.076 Low 28 Basin # 28 1 0.104 Medium 29 Da'af 1 0.062 Low

**Channels** (Xt) Km2 ( St)

#### **4.2.2 Cross sections**

Cross sections of valleys are commonly used in many geomorphologic and hydrologic studies that rely on evaluating tributaries and the mechanism of run-off of water and the bed load, whether for run-off rate or erosion and sedimentation. It is well known that the characteristics of cross-section of tributaries separately have no impact on the hydrological system for flood assessment, but it needs an interaction with other hydrological and geomorphologic characteristics.

Cross section variables to any water course comprise the width, depth and the length of the primary stream, but in the case of wide flood plain, with shallow depth (as in the study area); however, width and depth of these plains will be included too. In the case of wide and shallow flood plains, run-off water can easily overflow into these plains when water level increases in the primary watercourse even with a small amount because the difference in depth, of the primary watercourse and flood plains, is relatively negligible (Figure 6).

Fig. 6. Schematic cross-section showing major dimensions of a valley.

Normally, the width and depth *o*f water channel are not constant, and they vary with valley length. Therefore, in calculating the capacity of each channel, it must be divided into different channel segments each with specific depth, width and length. Where the length is determined according to channel diversions (i.e. a section is attributed to each stream segment with specific direction). When the three geometric variables (length, width and depth) are determined, with those variables of the flood plain, thus the total section area of each segment can be calculated and the sum of the resulted values will extend the total cross-section area of the valley (Xt). It can be calculated as follows:

$$\mathbf{X}\_{t} = \frac{\left(\begin{bmatrix} \mathbf{W}\_{\mathrm{m1}} \mathbf{x} \, \mathrm{D}\_{\mathrm{m1}} \end{bmatrix} + \begin{pmatrix} \mathbf{W}\_{\mathrm{f1}} \mathbf{x} \, \mathrm{D}\_{\mathrm{f1}} \end{pmatrix}\right) \mathbf{x} \, \mathrm{L}\_{1} \rangle + \left(\begin{bmatrix} \mathbf{W}\_{\mathrm{m2}} \mathbf{x} \, \mathrm{D}\_{\mathrm{m2}} \end{bmatrix} + \begin{pmatrix} \mathbf{W}\_{\mathrm{f2}} \mathbf{x} \, \mathrm{D}\_{\mathrm{f2}} \end{pmatrix}\right) \mathbf{x} \, \mathrm{L}\_{2} \rangle + \dots}{\mathrm{N}\_{\mathrm{sg}}}$$

Where:


L1 is the segment length,

150 Drainage Systems

Cross sections of valleys are commonly used in many geomorphologic and hydrologic studies that rely on evaluating tributaries and the mechanism of run-off of water and the bed load, whether for run-off rate or erosion and sedimentation. It is well known that the characteristics of cross-section of tributaries separately have no impact on the hydrological system for flood assessment, but it needs an interaction with other hydrological and

Cross section variables to any water course comprise the width, depth and the length of the primary stream, but in the case of wide flood plain, with shallow depth (as in the study area); however, width and depth of these plains will be included too. In the case of wide and shallow flood plains, run-off water can easily overflow into these plains when water level increases in the primary watercourse even with a small amount because the difference in depth, of the primary watercourse and flood plains, is relatively negligible (Figure 6).

Normally, the width and depth *o*f water channel are not constant, and they vary with valley length. Therefore, in calculating the capacity of each channel, it must be divided into different channel segments each with specific depth, width and length. Where the length is determined according to channel diversions (i.e. a section is attributed to each stream segment with specific direction). When the three geometric variables (length, width and depth) are determined, with those variables of the flood plain, thus the total section area of each segment can be calculated and the sum of the resulted values will extend the total

m1 m1 f1 f1 1 m2 m2 f2 f2 2

{ W x D W x D x L } { W x D W x D x L } <sup>X</sup> N

sg

Fig. 6. Schematic cross-section showing major dimensions of a valley.

cross-section area of the valley (Xt). It can be calculated as follows:

 Wm1 is the width of the main valley, No. 1. Dm1 is the depth of the main valley, No. 1, Wf1 is the width of flood plains No.1, Df1 is the depth of flood plain No.1,

**4.2.2 Cross sections** 

t

Where:

geomorphologic characteristics.

Nsg is the number of segments.

It is possible to calculate geometric variables using DEM if it is characterized with high resolution that fits with the width and depth of cross-sections. The analysis is done by dividing the sections into different segments. Thus, Arc-GIS software is used to calculate the variables to each segment (Table 4).


Table 4. Cross-section areas of primary valleys as calculated from DEM.

#### **4.2.3 Channel slope**

In addition to terrain surface slope that adjacent to valleys; yet the slope gradient (degree of inclination) of the valley channel itself is an important geometric element that must be

Use of Remote Sensing and GIS

**No. Basin name** 

**Basin** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 153

**Channels No.** 

**General slope** 

**Average ( St)** 

**Number of terrain surfaces** 

Table 5. Valleys' slope and their water-bearing capacity.

considered as a zone with depression.

elevations according to the terrain characteristics. Hence, any elevation below will be

Table 6 shows the total area of depression among each water basin. But it must be taken into account that these depressions are not only natural ones, since a large part of the study area is occupied by low-lands that collect water due to excavation and construction (planned zones, roadsides, etc.). In this respect, the integration of satellite images taken after the occurrence of torrential rainfall in the 25th of November 2009 and the 26th of January 2011,

with DEM can help in identifying natural depressions from man-made ones.

considered in assessing floods and torrents. Hence, flow rate increases with the degree of inclination of the valley channel. In this respect, flow rate plays a major role in accelerating the process of channel discharge, which is also accompanied with high rate erosion process. Whilst, slow flow rate decreases the discharge rate and consequently influences flood occurrence.

The channel slope can be calculated using the following simplified equation:

L Lenghth of the channel h Difference in elevation 

However it is obvious that stream channels are characterized by different elevations along each valley, and they are not similar. For this reason, sometime it is referred to the following equation introduced by Morisawa (1976).

```
= (E 0.85 L) – (E 0.10L)/ E 0.75L
```
Where:

E is the elevation, L is a lenght point along the channel,

As for example, (E 0.85 L) means the elevation at 85% distance from the upstream.

The availability of DEM easily enables calculating the channel slope with considerable precision, where the slope gradient is calculated on several defined parts along the valley with more accuracy then using the mathematical equation mentioned above.

Accordingly, in this study, this method was followed and the results are as shown in Table 5. Results show the channel slopes of primary valleys. Thus, having the three main variables (terrain slope, cross sections and their slopes) enables assessing the flow capacity of these valleys, which together influence flood occurrence. Therefore, it is obvious that there are basins more prone to floods and torrents (such as Om El-Hableen and Daghbj basins) than other basins in the area (such as basins no. 1 and 6).

#### **4.2.4 Depressions**

Depressions are considered as one the most important terrain features in floods and torrents occurrence. They play a double role in surface water flow and surface water storage, since depressions are naturally retarding water flow and store almost capture water within the terrain surface. As well as, depressions may accumulate water directly from rainfall. Therefore, they are considered as flooded areas, but with least damage.

Hence, identifying depressions directly from satellite images in dry seasons is not an easy task, unless they filled with water for better observations. However, DEM can help identifying depression in any condition, since it relies on elevation differentiation (e.g. 2 meters accuracy). Therefore, depressions characterize terrain surface and enable to cartography the water accumulation from torrential rainfall.

In this study, a new concept was followed in using DEM manipulation to localize depressions.. This concept relies on creating reference lines to the earth surface at defined

considered in assessing floods and torrents. Hence, flow rate increases with the degree of inclination of the valley channel. In this respect, flow rate plays a major role in accelerating the process of channel discharge, which is also accompanied with high rate erosion process. Whilst, slow flow rate decreases the discharge rate and consequently influences flood

> L Lenghth of the channel h Difference in elevation

However it is obvious that stream channels are characterized by different elevations along each valley, and they are not similar. For this reason, sometime it is referred to the following

= (E 0.85 L) – (E 0.10L)/ E 0.75L

The availability of DEM easily enables calculating the channel slope with considerable precision, where the slope gradient is calculated on several defined parts along the valley

Accordingly, in this study, this method was followed and the results are as shown in Table 5. Results show the channel slopes of primary valleys. Thus, having the three main variables (terrain slope, cross sections and their slopes) enables assessing the flow capacity of these valleys, which together influence flood occurrence. Therefore, it is obvious that there are basins more prone to floods and torrents (such as Om El-Hableen and Daghbj basins) than

Depressions are considered as one the most important terrain features in floods and torrents occurrence. They play a double role in surface water flow and surface water storage, since depressions are naturally retarding water flow and store almost capture water within the terrain surface. As well as, depressions may accumulate water directly from rainfall.

Hence, identifying depressions directly from satellite images in dry seasons is not an easy task, unless they filled with water for better observations. However, DEM can help identifying depression in any condition, since it relies on elevation differentiation (e.g. 2 meters accuracy). Therefore, depressions characterize terrain surface and enable to

In this study, a new concept was followed in using DEM manipulation to localize depressions.. This concept relies on creating reference lines to the earth surface at defined

As for example, (E 0.85 L) means the elevation at 85% distance from the upstream.

with more accuracy then using the mathematical equation mentioned above.

Therefore, they are considered as flooded areas, but with least damage.

cartography the water accumulation from torrential rainfall.

The channel slope can be calculated using the following simplified equation:

 

equation introduced by Morisawa (1976).

L is a lenght point along the channel,

other basins in the area (such as basins no. 1 and 6).

occurrence.

Where:

E is the elevation,

**4.2.4 Depressions** 


Table 5. Valleys' slope and their water-bearing capacity.

elevations according to the terrain characteristics. Hence, any elevation below will be considered as a zone with depression.

Table 6 shows the total area of depression among each water basin. But it must be taken into account that these depressions are not only natural ones, since a large part of the study area is occupied by low-lands that collect water due to excavation and construction (planned zones, roadsides, etc.). In this respect, the integration of satellite images taken after the occurrence of torrential rainfall in the 25th of November 2009 and the 26th of January 2011, with DEM can help in identifying natural depressions from man-made ones.

Use of Remote Sensing and GIS

**4.3.1.2 Shape factor (Sf)** 

used to elaborate this factor.

**4.3.1.3 Width/outlet width ration** 

Where L is the maximum length of water basin

Lca is the distance from the center of the basin circle to the outlet.

Fig. 7. Representation showing the shape factor in surface water flow regime.

impossible the regular drainage mechanism through the outlet.

Width/outlet width ration is the ration between the basin width to the outlet width. If the basin width from the upstream is bigger enough than the outlet width, flood occurrence is more probable (Al Saud, 2010a a, b), as shown in Figure 8. This can be attributed to the inadequate drainage capacity of water derived from upstream; and therefore made

The width/outlet width ration is almost consistent with the characteristics that can be extracted from the DEM, as mentioned previously. However, in this case we treat the basin

> W Basin width W Outlet width

outer limits and not with the terrain features inside. It can be simply represented as:

 

*b d*

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 155

L length of the basin Length / Width ratio W = Width of the basin

The controlling factor in shaping water basin is determined according to the central length (Lca), which is the length of the main channel (Figure 7). It largely represents the basin orientation, and has an integral role in the flow mechanism from different tributaries to the major outlet. It also contributes to infiltration rate and time duration of run-ff to be joined from different existing branches with different dimensions. Thus, the following equation is

*Sf* = (LLca) 0.3


Table 6. Areas of depressions in different watersheds.

#### **4.3 Geometric analysis of watersheds**

Geometric shaping of water basins is considered as a one of the key factors that control the mechanism of geographic distribution of water on the surface of the earth. In this study, geometric standards are considered for water basin perimeter without taking into account morphometric standards located within this basin. Thus, the shape of the water basin, as well as the elongation rate and rotation rate are the most important standards.

#### **4.3.1 Shape**

There are several patterns that characterize the outer shape of water basin, each of them play a role in run-off from the upstream to downstream. The basins shape control the branching process of tributaries and thus the flow regime (Black, 1991). For example, basinswith circular shape has regular water discharge from all available tributaries and consequently water can reach the outlet at the same time. But this is not the case in basin with oval-like shape basins where there are differences in the discharge process according to the timing and therefore is considered as less prone to floods. There are several characteristics for specifying the shape of water basins, and the most important are as follow:

#### **4.3.1.1 Length/Width ration**

The ratio between the basin length and width (LW) is an indicator of surface flow effectiveness, and consequently an increase in the ratio of the width compared to the length make longer the flow duration and vice versa. Where the average value of this ratio in regular basins is 0.5, which means that the basin length is equal to the twice of its width. This is defined by the following simplified equation:

$$\text{Length / Width ratio} = \frac{\text{L} = \text{length of the basin}}{\text{W} = \text{Width of the basin}}$$

#### **4.3.1.2 Shape factor (Sf)**

154 Drainage Systems

1 Ghouimer 6.52 16 Selsli 0.35 2 Om El-Hableen 2.13 17 Muwaieha 1.81 3 Basin # 3 0.35 18 Basin # 18 0.73 4 Daghbj 1.86 19 Basin # 19 0.53 5 El Hatiel 2.14 20 Basin # 20 1.04 6 Basin # 6 0.12 21 Abou Je'Alah 1.54 7 Basin # 7 1.05 22 Al A'ayah 0.88 8 El Assla 11.24 23 Ed-Dowikhlah 1.17 9 Basin # 9 0.83 24 El-Baghdadi 0.46 10 Mreikh 2.19 25 Ketanah 0.37 11 Kawes 2.88 26 Basin # 26 0.24 12 Osheer 1.22 27 Esh-Shoabaa 0.87 13 Basin # 13 0.24 28 Basin # 28 1.43 14 Methweb 3.05 29 Da'af 0.34

Geometric shaping of water basins is considered as a one of the key factors that control the mechanism of geographic distribution of water on the surface of the earth. In this study, geometric standards are considered for water basin perimeter without taking into account morphometric standards located within this basin. Thus, the shape of the water basin, as

There are several patterns that characterize the outer shape of water basin, each of them play a role in run-off from the upstream to downstream. The basins shape control the branching process of tributaries and thus the flow regime (Black, 1991). For example, basinswith circular shape has regular water discharge from all available tributaries and consequently water can reach the outlet at the same time. But this is not the case in basin with oval-like shape basins where there are differences in the discharge process according to the timing and therefore is considered as less prone to floods. There are several characteristics for

The ratio between the basin length and width (LW) is an indicator of surface flow effectiveness, and consequently an increase in the ratio of the width compared to the length make longer the flow duration and vice versa. Where the average value of this ratio in regular basins is 0.5, which means that the basin length is equal to the twice of its width.

well as the elongation rate and rotation rate are the most important standards.

specifying the shape of water basins, and the most important are as follow:

This is defined by the following simplified equation:

**Basin** 

**No. Basin name**

**Total depressions area** (km2)

**Total depressions area** (km2)

**Basin** 

**4.3.1 Shape** 

**4.3.1.1 Length/Width ration** 

**No. Basin name** 

15 Ghlil 1.34

**4.3 Geometric analysis of watersheds** 

Table 6. Areas of depressions in different watersheds.

The controlling factor in shaping water basin is determined according to the central length (Lca), which is the length of the main channel (Figure 7). It largely represents the basin orientation, and has an integral role in the flow mechanism from different tributaries to the major outlet. It also contributes to infiltration rate and time duration of run-ff to be joined from different existing branches with different dimensions. Thus, the following equation is used to elaborate this factor.

$$S\_{\!\!\!/} = (\text{LL}\_{\text{ca}})^{0.3}$$

Where L is the maximum length of water basin

Lca is the distance from the center of the basin circle to the outlet.

Fig. 7. Representation showing the shape factor in surface water flow regime.

#### **4.3.1.3 Width/outlet width ration**

Width/outlet width ration is the ration between the basin width to the outlet width. If the basin width from the upstream is bigger enough than the outlet width, flood occurrence is more probable (Al Saud, 2010a a, b), as shown in Figure 8. This can be attributed to the inadequate drainage capacity of water derived from upstream; and therefore made impossible the regular drainage mechanism through the outlet.

The width/outlet width ration is almost consistent with the characteristics that can be extracted from the DEM, as mentioned previously. However, in this case we treat the basin outer limits and not with the terrain features inside. It can be simply represented as:

> W Basin width W Outlet width *b d*

Use of Remote Sensing and GIS

this type of natural disasters.

**Basin name** 

2 Om El-

<sup>21</sup>Abou

23 Ed-

24 El-

27 Esh-

**Basin No.** 

basin comparing to its circular form (Miller, 1953).

Where A0 is the perimeter of the circle, A area of the basin

**Length/width ratio** (Lw)

**4.3.1.5 Circularity ration** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 157

Circularity ration (Rc) represents the uniformity between the external perimeter of the water

Rc= A/A0

The analysis of principal geometric characteristics was applied on the main water basins in the area of study with the exception to none completed basins (joining basins) as shown in Table 7. It is shown some basins are characterized by normal effectiveness with respect to

> **Shape factor** (Sf)

1 Ghouimer 1:0.87 5.83 1:2.5 0.82 3.30

4 Daghbj 1:3 4.42 1:2 0.51 1.03 5 El Hatiel 1:4.3 4.72 1:3 0.44 0.96 7 Basin # 7 1:3 3.22 1:2 0.53 0.60 8 El Assla 1:1.2 6.77 1:8.5 0.58 2.36 10 Mreikh 1:1.75 3.64 1:1.3 0.78 1.08 11 Kawes 1:3.8 5.99 1:2.57 0.38 0.85 12 Osheer 1:1.6 2.81 1:3 0.58 0.62 14 Methweb 1:2.2 5.26 1:5 0.43 0.82 15 Ghlil 1:2.15 3.45 1:2.3 0.47 0.57 17 Muwaieha 1:1.55 3.05 1:1.6 0.63 0.72

Hableen 1:2 3.88 1:1.8 0.68 1.39

Je'Alah 1:1.5 2.57 1:1.7 0.91 0.80

Dowikhlah 1:1.6 2.92 1:1.55 0.61 0.58

Baghdadi 1:2.2 3.34 1:1.4 0.59 0.91

Shoabaa 1:2.5 4.16 1:1.5 0.49 0.80

22 Al A'ayah 1:2 3.25 1:1 0.45 0.48

25 Ketanah 1:1.7 3.78 1:2.3 0.56 0.80

29 Da'af 1:1.75 3.58 1:1.45 0.62 0.93

Table 7. Shape characteristics in water basins as shown from DEM.

**Width/outlet width** (Wb/Wd**)** 

**Elongation ration** (Re)

**Circularity ration** (Rc)

Fig. 8. Representative figure showing the widths of upstream and out let.

#### **4.3.1.4 Elongation ration**

It also essential to characterize the basin elongation, or one-direction stretching, according to its area. It equals 1 for the intake circle, whilst, it is zero for the straight line. According to Schumm (1956), the elongation ration equals:

$$R\_e = 2/L\_m \text{ (A/
π)}^{
α5}$$

where Lm is the basin length parallel to the primary watercourse, and A is the basin area, as shown in Figure 9. Therefore elongation ration governs the flow regime at the outlet.

Fig. 9. Representation for two basins with different elongation ratio.

#### **4.3.1.5 Circularity ration**

156 Drainage Systems

Fig. 8. Representative figure showing the widths of upstream and out let.

Fig. 9. Representation for two basins with different elongation ratio.

It also essential to characterize the basin elongation, or one-direction stretching, according to its area. It equals 1 for the intake circle, whilst, it is zero for the straight line. According to

*Re* = 2/Lm (A/) 0.5 where Lm is the basin length parallel to the primary watercourse, and A is the basin area, as

shown in Figure 9. Therefore elongation ration governs the flow regime at the outlet.

**4.3.1.4 Elongation ration** 

Schumm (1956), the elongation ration equals:

Circularity ration (Rc) represents the uniformity between the external perimeter of the water basin comparing to its circular form (Miller, 1953).

$$\text{Rc} = \text{A/A0}$$

Where A0 is the perimeter of the circle, A area of the basin

The analysis of principal geometric characteristics was applied on the main water basins in the area of study with the exception to none completed basins (joining basins) as shown in Table 7. It is shown some basins are characterized by normal effectiveness with respect to this type of natural disasters.


Table 7. Shape characteristics in water basins as shown from DEM.

Use of Remote Sensing and GIS

for a higher order.

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 159

Br = Nr/Nr+1 Where "Nr "is the number of streams for the order "r", and "Nr+1" is the number of streams

In this study, the Arc-GIS 9.3 software was used to classify streams in their specific orders (Figure 10), followed by calculating the morphometric variables needed where all streams

and their tributaries are numbered, making the calculations easier (Table 9).

Fig. 10. Stream orders in the basins of the area of study.

#### **4.4 Morphometric analysis of drainage systems**

#### **4.4.1 Drainage density**

Water channels take several geometric patterns, and compose a collection of natural networks. However, the most important in drainage distributions is the density of tributaries among the basin. For example, we can find areas with high drainage density faced with areas with a lower density. This is primarily due factors related to the terrain characteristics. Also, drainage density can be calculated using the following equation:

$$\frac{\sum \text{L}}{\text{A}} = \frac{\text{Total length of tribitaries in a particular area}}{\text{Surface of the area}}$$


Table 8 shows the resulting values of drainage density in each basin.

Table 8. Drainage density in the water basins.

#### **4.4.2 Stream order**

Usually, the biggest fraction of the surface runoff occur in the channel and its different tributaries to form a water network starting from reaches from the highest elevations to reach at the end the outlet. From this point, the relation between different stream orders is seen. Small streams that starts from the top of the mountains and that are connected from one side are given the 1st order appellation. The 2nd stream order is created by the junction of two or more 1st –order streams, and so on.

Hence the process of identifying different stream orders is not the purpose of this study, but it is a kind of tools that help us in analyzing the relation between the number of these streams and more certainly the bifurcation ratio which is calculated from the following equation:

Water channels take several geometric patterns, and compose a collection of natural networks. However, the most important in drainage distributions is the density of tributaries among the basin. For example, we can find areas with high drainage density faced with areas with a lower density. This is primarily due factors related to the terrain characteristics. Also, drainage density can be calculated using the following equation:

L Total length of tributaries in a particular area

**Basin** 

1 Ghouimer 0.98 16 Selsli 0.53 2 Om El-Hableen 1.12 17 Muwaieha 1.02 3 Basin # 3 0.28 18 Basin # 18 1.13 4 Daghbj 0.96 19 Basin # 19 0.97 5 El Hatiel 1.36 20 Basin # 20 1.20 6 Basin # 6 041 21 Abou Je'Alah 1.53 7 Basin # 7 1.15 22 Al A'ayah 1.27 8 El Assla 1.77 23 Ed-Dowikhlah 1.24 9 Basin # 9 0.61 24 El-Baghdadi 1.14 10 Mreikh 1.76 25 Ketanah 1.25 11 Kawes 1.37 26 Basin # 26 1.23 12 Osheer 0.54 27 Esh-Shoabaa 2.20 13 Basin # 13 0.35 28 Basin # 28 1.15 14 Methweb 1.33 29 Da'af 0.95

Usually, the biggest fraction of the surface runoff occur in the channel and its different tributaries to form a water network starting from reaches from the highest elevations to reach at the end the outlet. From this point, the relation between different stream orders is seen. Small streams that starts from the top of the mountains and that are connected from one side are given the 1st order appellation. The 2nd stream order is created by the junction of

Hence the process of identifying different stream orders is not the purpose of this study, but it is a kind of tools that help us in analyzing the relation between the number of these streams and more certainly the bifurcation ratio which is calculated from the following

**No. Basin name Density** 

(Km/Km2)

A Surface of the area

(Km/Km2)

Table 8 shows the resulting values of drainage density in each basin.

**4.4 Morphometric analysis of drainage systems** 

**No. Basin name Density** 

15 Ghlil 0.85 Table 8. Drainage density in the water basins.

two or more 1st –order streams, and so on.

**4.4.1 Drainage density** 

**Basin** 

**4.4.2 Stream order** 

equation:

Where "Nr "is the number of streams for the order "r", and "Nr+1" is the number of streams for a higher order.

In this study, the Arc-GIS 9.3 software was used to classify streams in their specific orders (Figure 10), followed by calculating the morphometric variables needed where all streams and their tributaries are numbered, making the calculations easier (Table 9).

Fig. 10. Stream orders in the basins of the area of study.

Use of Remote Sensing and GIS

**Basin** 

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 161

(Mr)

1 Ghouimer 1.05 3.2 2 Om El-Hableen 1.35 6.3 3 Basin # 3 1.18 70 4 Daghbj 1.31 6.1 5 El Hatiel 1.02 5.5 6 Basin # 6 1.01 0.8 7 Basin # 7 1.04 1.2 8 El Assla 1.27 7.6 9 Basin # 9 1.10 2.4 10 Mreikh 1.23 2.6 11 Kawes 1.28 3.1 12 Osheer 1.19 0.53 13 Basin # 13 1.03 0.26 14 Methweb 1.17 3.4 15 Ghlil 1.14 1.9 16 Selsli 1.01 0.34 17 Muwaieha 1.12 2.4 18 Basin 18 1.12 1.61 19 Basin 19 1.05 1.15 20 Basin 20 1.12 1.04 21 Abou Je'Alah 1.19 4.6 22 Al A'ayah 1.17 2.04 23 Ed-Dowikhlah 1.20 1.92 24 El-Baghdadi 1.14 1.80 25 Ketanah 1.23 3.61 26 Basin # 26 1.12 2.03 27 Esh-Shoabaa 1.27 5.8 28 Basin # 28 1.17 1.17 29 Da'af 1.20 2.11

**Intersection Ratio (Ir)** Km2

**No. Basin name Meandering ratio** 

Table 10. Meandering and intersection ratio for the basins in the study area.


Table 9. Major variable for stream orders in the area basins.

#### **4.4.3 Meandering ration**

A stream channel takes many meandering aspects along the channel length, where several flow characteristics occur on each meander. This depends on many geomorphologic and hydrological characteristics such as slope gradient, rock types, geological formations and many others. And it is found that the meandering ratio play a role in water floods, since the increase in the meandering ratio decrease the flow energy and increase the stream load capacity due to erosion mechanism on the meandering sites. The meandering ratio is calculated according to the following equation, and the results are shown in Table 10.

> Primary stream length curved <sup>m</sup> Primary stream straight *<sup>s</sup> L L*

1 Ghouimer 107 68 15 8 - 342.7 2.64

4 Daghbj 37 24 14 - - 101.7 1.62 5 El Hatiel 73 24 16 8 - 117.5 2.18 6 Basin # 6 14 5 3 - - 16.2 2.23 7 Basin # 7 30 10 7 3 - 51.9 2.25 8 El Assla 351 135 54 38 14 589.4 2.30 9 Basin # 9 7 7 - - - 12.8 1.00 10 Mreikh 31 23 14 2 - 74.9 3.33 11 Kawes 52 24 12 7 - 117.3 1.96 12 Osheer 7 7 5 - - 20.2 1.20 14 Methweb 56 16 6 7 - 87.3 2.34 15 Ghlil 17 3 7 - - 37.8 2.41 17 Muwaieha 17 9 13 1 - 37.9 5.19 21 Abou Je'Alah 30 11 5 - - 45.8 2.46 22 Al A'ayah 13 6 - - - 25.6 2.16 23 Ed-Dowikhlah 18 10 - - - 29.6 1.80 24 El-Baghdadi 31 14 5 - - 41.4 2.50 25 Ketanah 48 26 8 2 - 74.7 3.03 27 Esh-Shoabaa 55 20 25 - - 88.1 1.77 29 Da'af 18 12 - - - 41.3 1.50

A stream channel takes many meandering aspects along the channel length, where several flow characteristics occur on each meander. This depends on many geomorphologic and hydrological characteristics such as slope gradient, rock types, geological formations and many others. And it is found that the meandering ratio play a role in water floods, since the increase in the meandering ratio decrease the flow energy and increase the stream load capacity due to erosion mechanism on the meandering sites. The meandering ratio is calculated according to the following equation, and the results are shown in Table 10.

> Primary stream length curved <sup>m</sup> Primary stream straight *<sup>s</sup>*

*L L* 

Table 9. Major variable for stream orders in the area basins.

**Number of stream orders Total length**

Hableen <sup>45</sup> 24 26 - - 148.9 1.39

(Br) **<sup>1</sup> 2 3 4 5** 

(km)

**Bifurcation ratio** 

**Basin** 

**No. Basin name** 

2 Om El-

**4.4.3 Meandering ration** 


Table 10. Meandering and intersection ratio for the basins in the study area.

Use of Remote Sensing and GIS

**6. References** 

2010.

253

to Analyze Drainage System in Flood Occurrence, Jeddah - Western Saudi Coast 163

In addition, the expansion of urban settlements within the valleys courses interrupts the majority of the analyzed parameters. Thus, several basins are being closed at their outlets due to the existing human settlements. As well as these settlements, with the tremendous excavation processes and engineering particles motivated the release of sediments, which

Al-Saud, M. (2009). Morphometric Analysis of Wadi Aurnah Drainage System, Western

Al Saud, M. (2010a). Applying Geoinformation Techniques in Studying Flood and torrents in Jeddah Region, 2009 *(In Arabic). Arab Journal for Geoinformation*. 3, 1, 2010. Al-Saud, M. (2010b). Assessment of Flood Hazard of Jeddah Area 2009, Saudi Arabia. *Journal of Water Resource and Protection (JWARP),Vol.* 2, No. 9, pp. 839-847 Black, P. (1991). Watershed Hydrology. *Prentice Hall Advanced Reference Series, NJ*, pp. 324 EM-DAT: The OFDA/CRED. (2010). International Disaster Data base. *Université catholique* 

Es-Saeed, M., Sen, Z., Basamad, A., Dahlawi, & A. Al-Bardi, W. 2004. Strategic groundwater

IPCC Report. (March 2007). *The Fourth Assessment Report (AR4), March 14th 2008*, Available

Italconsult. (1967). Water supply survey for Yeddah-Makkah-Taif area. *Special Report.* 

KACT (King Abdulaziz City for Science and Technology). (2011). Production of digital

Khosrowpanah, Sh., Heitz, L., Wen, Y., Park., M. (2007). Developing a GIS-based soil erosion

*Research Institute (WERI) of the western Pacific*. University of Guam, pp. 1-103 Miller, V. 1953. A Quantitive Geomorphic Study for Drainage Basin Characteristics in the

Morisawa, M. (1976). Geomorphology Laboratory Manual, *John Wiley & Sons Inc. N.Y*., pp.1-

Schumm, S. 1956. The elevation of drainage systems and slopes in badlands at Perth Amboy,

Subyani, A., Qari, M., Matsah, M., Al-Modayan, A. & Al-Ahmadi, F. (2009). Utilizing remote

*Geological investigation- Ministry of Agriculture and Water,* No.3.

*de Louvain, Brussels, Bel.* Data version: v11.08. Available from www.emdat.be/,

storage in Wadi Naáman, Makka region, Saudi Arabia. *Technical Report (in Arabic),* 

elevation model (DEM/DTM) with high resolution using stereoscopic satellite imagery and the deduction of drainage network and its direction and the water

potential model of the Ugum Watershed, *Technical Report, Water and Environmental* 

Clinch Mountain Area, Virginia and Tennessee, *Technical Report No.3*, I-30, N6

sensing and GIS technologies to produce hydrological and environmental hazards in some Wadis, western Saudi Arabia (Jeddah-Yanbu). Dept of Hydrology. King Abdulaziz City for Science and Technology. General Directorate of Research Grants

in turn move easily with water and thus increase the bed load of the flooded water.

Arabian Peninsula, *The Open Hydrology Journal*, Vol.3, pp. 1-10

*Saudi Geological Survey-TR-2004-1*, pp. 32p.

bains for Jeddah regions. *Technical report*, pp. 1-62

ONR 271-30, Geology Depart., Colombia University, n.d.

New Jersey. *Geol. Soc. Amer. Bull*., Vol. 67, pp. 597-646

Program. Kingdom of Saudi Arabia.

from : http://www.ipcc.ch/

#### **4.4.4 Intersection ration**

Usually in studying morphometric characteristics of drainage systems, many formulas and concepts interfere from analysis. However, some characteristics are found with a great importance but less concern. Among these characteristics, is the intersection ratio that can be obtained through identifying the intersection nodes (i.e. confluences and diversions) of different channels and branches (Al Saud, 2009).

The number of intersection nodes reflects higher drainage density and thus uniform flow. They are usually measured as the number of nodes within a specified area. Results of insertion ratio are plotted in Table 10.

### **5. Conclusion and discussion**

Flood, as a hydrologic process with catastrophic impact, is mainly governed by the geomorphologic characteristics of the terrain where it exists. Therefore, it is a common criterion to assess the terrain behavior and its respond to receive rainfall water and how it drains water. In this concern, all required geomorphologic elements must be primarily considered, taking into account the entire drainage system, including the catchment area and the existing streams characteristics among the catchment. However, in the lack of adequate data and information on the drainage system for any area, often alternative tools for analysis are used, and more certainly the remotely sensed (i, e. many satellite images) and GIS tools have become of great role in this respect. In this study, these advance tools were utilized using specified software types for data manipulation and analysis, plus a series of satellite images and thematic maps that can fulfill the subject matter.

Accordingly, three major parameters were analyzed and then they were correlated to their response to water flow regime and thus floods. This was applied to Jeddah city, which has witnessed to severe flood events, and the hydrologic and geomorphologic measures are still unclear. These parameters include: the geometric analysis for digital elevation models (DEM), geometry of basins and drainage morphometry of streams. This will enable assessment the vulnerability of the basins in the study area to floods, as well as these parameter can be well utilized in applying flood control management approaches.

Based on the analyzed geometric measures; however, there are a number of basins exist with relatively large values, such as Ghouimer with respect to the shape factor, elongation and circularity ratio. Also Al-Assla basin has an obvious respond to flood due to its width/length ration, which reaches 8.5:1. However, there are a number of basins with less responding to floods such as Abou Je'Alah basin.

The morphometry of streams among these basins is also of utmost importance in controlling the flooding process. This is well pronounced on the sites where streams are connected, notably those streams with thick sediment sequences, as those exist in several valleys in the study area. Moreover, the area of concern was found to be characterized by dense drainage systems unlike the rest coastal zones in the western Saudi Arabia, which in turn reflects a unique surface water flow among channels due to the large number of connected streams.

In addition, the expansion of urban settlements within the valleys courses interrupts the majority of the analyzed parameters. Thus, several basins are being closed at their outlets due to the existing human settlements. As well as these settlements, with the tremendous excavation processes and engineering particles motivated the release of sediments, which in turn move easily with water and thus increase the bed load of the flooded water.

#### **6. References**

162 Drainage Systems

Usually in studying morphometric characteristics of drainage systems, many formulas and concepts interfere from analysis. However, some characteristics are found with a great importance but less concern. Among these characteristics, is the intersection ratio that can be obtained through identifying the intersection nodes (i.e. confluences and diversions) of

The number of intersection nodes reflects higher drainage density and thus uniform flow. They are usually measured as the number of nodes within a specified area. Results of

Flood, as a hydrologic process with catastrophic impact, is mainly governed by the geomorphologic characteristics of the terrain where it exists. Therefore, it is a common criterion to assess the terrain behavior and its respond to receive rainfall water and how it drains water. In this concern, all required geomorphologic elements must be primarily considered, taking into account the entire drainage system, including the catchment area and the existing streams characteristics among the catchment. However, in the lack of adequate data and information on the drainage system for any area, often alternative tools for analysis are used, and more certainly the remotely sensed (i, e. many satellite images) and GIS tools have become of great role in this respect. In this study, these advance tools were utilized using specified software types for data manipulation and analysis, plus a

Accordingly, three major parameters were analyzed and then they were correlated to their response to water flow regime and thus floods. This was applied to Jeddah city, which has witnessed to severe flood events, and the hydrologic and geomorphologic measures are still unclear. These parameters include: the geometric analysis for digital elevation models (DEM), geometry of basins and drainage morphometry of streams. This will enable assessment the vulnerability of the basins in the study area to floods, as well as these

Based on the analyzed geometric measures; however, there are a number of basins exist with relatively large values, such as Ghouimer with respect to the shape factor, elongation and circularity ratio. Also Al-Assla basin has an obvious respond to flood due to its width/length ration, which reaches 8.5:1. However, there are a number of basins with less

The morphometry of streams among these basins is also of utmost importance in controlling the flooding process. This is well pronounced on the sites where streams are connected, notably those streams with thick sediment sequences, as those exist in several valleys in the study area. Moreover, the area of concern was found to be characterized by dense drainage systems unlike the rest coastal zones in the western Saudi Arabia, which in turn reflects a unique surface water flow among channels due to the large number of

series of satellite images and thematic maps that can fulfill the subject matter.

parameter can be well utilized in applying flood control management approaches.

**4.4.4 Intersection ration** 

different channels and branches (Al Saud, 2009).

responding to floods such as Abou Je'Alah basin.

connected streams.

insertion ratio are plotted in Table 10.

**5. Conclusion and discussion** 


**8** 

*México* 

**Comparison of Two Nonlinear Radiation Models** 

One of the basic functions of subsurface agricultural drainage systems is to avoid the establishment of a moisture regime adverse to crop development by means of the depletion of shallow groundwater and the timely evacuation of water excess stemming from overirrigation, rainfall, losses due to infiltration in channels and contributions from underground streams. In order to make an efficient water evacuation, it is crucial to know the way in which it moves in the soil so as to determine the water flow that can be removed from the porous medium by means of drainage with the corresponding variation of the

The determination of the variables of an agricultural drainage system requires the analysis of the mass and energy transfers occurring in the soil. The study of these transfers, despite it being highly complex - since it is about analysing processes that are basically nonlinear and occurring in a medium in which properties vary over time and space - may be executed by

*Microscopic scale*: In this analysis scale, and corresponding to each soil pore, the mean velocity or microscopic water flow is estimated with the Poiseuille law, which comes from the Navier-Stokes equations, and the pressure in each pore is estimated with a Laplace equation. This analysis scale is recommended for a fine understanding of the fundamental

*Macroscopic scale*: The complexity outlined by the specific definition of the geometric shape of the pore space means that the microscopic description cannot be implemented without a change of the scale, whose essential stage consists in the introduction of the concept of the representative volume element (RVE) which allows for the establishment of an equivalence between the real porous medium (dispersed) and a fictitious porous medium (continuous). In this analysis scale, which concurs with a set of pores of a size's range, the mean velocity in the pores filled with water or macroscopic flow is estimated with the Darcy-Buckingham law (1907), and the water pressure associated to the set is estimated with their own Laplace law applied to a larger pore size. The corresponding transfer equation is known as Richards

**1. Introduction** 

aquifer level.

equation (1931).

considering some of the following analysis scales:

mechanisms of water transfer processes in the soil.

Manuel Zavala1, Heber Saucedo2, Carlos Bautista1 and Carlos Fuentes3

**for Agricultural Subsurface Drainage** 

*1Universidad Autónoma de Zacatecas;* 

*3Universidad Autónoma de Querétaro,* 

*2Instituto Mexicano de Tecnología del Agua, Morelos;* 


### **Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage**

Manuel Zavala1, Heber Saucedo2, Carlos Bautista1 and Carlos Fuentes3 *1Universidad Autónoma de Zacatecas; 2Instituto Mexicano de Tecnología del Agua, Morelos; 3Universidad Autónoma de Querétaro, México* 

#### **1. Introduction**

164 Drainage Systems

Tribe, A. (1991). Automated Recognition of Valley Heads from Digital Elevation Models,

Yehia, M. & El-Ater, J. 1997. Flood and mechanism of confronting tisk on the Egypt red sea

coast. National Authority for Remote Sensing and Space Sciences. *Scientifc report* 

*Earth Surface Processes Landforms*, Vol. 16, pp. 33-49.

*submitted to the Red sea Governorate*, pp. 1-294

One of the basic functions of subsurface agricultural drainage systems is to avoid the establishment of a moisture regime adverse to crop development by means of the depletion of shallow groundwater and the timely evacuation of water excess stemming from overirrigation, rainfall, losses due to infiltration in channels and contributions from underground streams. In order to make an efficient water evacuation, it is crucial to know the way in which it moves in the soil so as to determine the water flow that can be removed from the porous medium by means of drainage with the corresponding variation of the aquifer level.

The determination of the variables of an agricultural drainage system requires the analysis of the mass and energy transfers occurring in the soil. The study of these transfers, despite it being highly complex - since it is about analysing processes that are basically nonlinear and occurring in a medium in which properties vary over time and space - may be executed by considering some of the following analysis scales:

*Microscopic scale*: In this analysis scale, and corresponding to each soil pore, the mean velocity or microscopic water flow is estimated with the Poiseuille law, which comes from the Navier-Stokes equations, and the pressure in each pore is estimated with a Laplace equation. This analysis scale is recommended for a fine understanding of the fundamental mechanisms of water transfer processes in the soil.

*Macroscopic scale*: The complexity outlined by the specific definition of the geometric shape of the pore space means that the microscopic description cannot be implemented without a change of the scale, whose essential stage consists in the introduction of the concept of the representative volume element (RVE) which allows for the establishment of an equivalence between the real porous medium (dispersed) and a fictitious porous medium (continuous). In this analysis scale, which concurs with a set of pores of a size's range, the mean velocity in the pores filled with water or macroscopic flow is estimated with the Darcy-Buckingham law (1907), and the water pressure associated to the set is estimated with their own Laplace law applied to a larger pore size. The corresponding transfer equation is known as Richards equation (1931).

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 167

 <sup>1</sup> <sup>z</sup> <sup>K</sup> zx

where is the pressure head L ; Cdd is the specific water capacity <sup>1</sup> <sup>L</sup> ;

is the volumetric water content 3 3 L L ; K is the hydraulic conductivity

<sup>1</sup> LT ; x and z are, respectively, the horizontal and vertical coordinates L ; and t is time

If a drainage system with equidistant parallel pipes installed at the same depth is considered, it is possible to define a domain for equation (1) as with the one shown in Fig. 1.

**Soil surface**

L/2

The description of agricultural subsurface drainage by equation (1) requires the definition of the initial status of the pressure head in the porous media as well as its boundary conditions. The initial condition of the water pressure in the soil is specified as a known

By the flow symmetry, it is known that the Darcy flow in a perpendicular direction to segments AF, DE and BC is null (Neumann boundary condition), and a similar situation

occurs in the boundary segment CD due to the impervious layer.

K 0 <sup>x</sup>

<sup>z</sup> K 0 <sup>z</sup>

K 0 <sup>x</sup>

**Impervious layer**

 

 

K

T .

**A**

x

**Drain**

Fig. 1. Domain for the Richards equation.

**F E**

z

**D**

space function:

xt

 

**B**

**C**

PE

 

ix,z (2)

x 0; z AF y z DE; t0 (3)

x L 2; z BC; t0 (4)

x CD ; E z P; t0 (5)

C (1)

*Megascopic Scale:* In this analysis scale, which corresponds to a set of soils, the mean velocity - or megascopic flow - is estimated with the Darcy law and averaged through consideration of the Dupuit–Forcheimer hypothesis, relevant to a hydrostatic pressure distribution; moreover, water pressure is provided by the piezometers. The relevant transfer equation is known as the Boussinesq equation of agriculture drainage.

As a practical matter, the analysis of agricultural drainage is made either with the Richards equation (Zaradny & Feddes, 1979; Fipps & Skaags, 1986; Saucedo *et al.* 2002) or else with the Boussinesq equation of agriculture drainage (Dumm, 1954; Pandey, *et al.,* 1992; Gupta *et al.*, 1994; Samani *et al.*, 2007). The Richards equation allows the executing of descriptions of the transfer processes occurring in the saturated and unsaturated zones of the soil; however, its application to the scale of an irrigation district and even that of the a farm field, is limited due to the difficulty and cost of the experimental work required to depict the soil's hydrodynamic characteristics (the moisture retention curve and the hydraulic conductivity curve) as well as the necessary effort of calculating a three-dimensional water movement in the soil. These limitations have led to the analysis of agricultural drainage being mainly performed with the Boussinesq equation, an approach that considers in a simplified manner the transfers occurring in the soil's unsaturated zone, but with a smaller amount of data requirements than the Richards equation, adequately describes water dynamics in the saturated layer of the soil.

Recently, two mechanistic models have been developed for agricultural drainage that improve the traditional hypotheses of the models reported in the literature. On the one hand, Zavala *et al.* (2005) have developed a model for agricultural subsurface drainage based on the two-dimensional Richards equation. This differential equation is subjected in the drains boundary to a nonlinear radiation condition, and in this form the mass and energy transfers in a drainage system are better represented. On the other hand, Zavala *et al*. (2004) and Fuentes *et al.* (2009) have studied agricultural drainage with the Boussinesq equation and have deduced, respectively, the boundary condition to be used in agricultural drains by this equation and the relation between the moisture retention curve and the storage coefficient in shallow unconfined aquifers.

The aim of this chapter is to present the two models just described to develop their numerical solutions and compare the mass and energy transfers obtained with the Richards equation and the Boussinesq equation, both of which are subject to nonlinear radiation conditions in the drains.

#### **2. Materials and methods**

#### **2.1 Macroscopic scale**

Soil water movement in a subsurface drainage system is a three-dimensional phenomenon, for which reason its description should be made using the Richards equation in three dimensions; nonetheless, due to the effort of calculation that the resolution of this form of Richards equation entails, it is convenient to accept the hypothesis that the phenomenon is basically two-dimensional (that is to say, it is made according to planes perpendicular to the direction of the drain). If, in addition, it is assumed that the water uptake by plant roots is negligible, the two-dimensional form of the Richards equation may be written as follows:

$$\mathbf{C}(\boldsymbol{\Psi})\frac{\partial \boldsymbol{\Psi}}{\partial \mathbf{t}} = \frac{\partial}{\partial \mathbf{x}} \left[ \mathbf{K}(\boldsymbol{\Psi})\frac{\partial \boldsymbol{\Psi}}{\partial \mathbf{x}} \right] + \frac{\partial}{\partial \mathbf{z}} \left[ \mathbf{K}(\boldsymbol{\Psi}) \left( \frac{\partial \boldsymbol{\Psi}}{\partial \mathbf{z}} - \mathbf{1} \right) \right] \tag{1}$$

where is the pressure head L ; Cdd is the specific water capacity <sup>1</sup> <sup>L</sup> ; is the volumetric water content 3 3 L L ; K is the hydraulic conductivity <sup>1</sup> LT ; x and z are, respectively, the horizontal and vertical coordinates L ; and t is time T .

If a drainage system with equidistant parallel pipes installed at the same depth is considered, it is possible to define a domain for equation (1) as with the one shown in Fig. 1.

Fig. 1. Domain for the Richards equation.

166 Drainage Systems

*Megascopic Scale:* In this analysis scale, which corresponds to a set of soils, the mean velocity - or megascopic flow - is estimated with the Darcy law and averaged through consideration of the Dupuit–Forcheimer hypothesis, relevant to a hydrostatic pressure distribution; moreover, water pressure is provided by the piezometers. The relevant transfer equation is

As a practical matter, the analysis of agricultural drainage is made either with the Richards equation (Zaradny & Feddes, 1979; Fipps & Skaags, 1986; Saucedo *et al.* 2002) or else with the Boussinesq equation of agriculture drainage (Dumm, 1954; Pandey, *et al.,* 1992; Gupta *et al.*, 1994; Samani *et al.*, 2007). The Richards equation allows the executing of descriptions of the transfer processes occurring in the saturated and unsaturated zones of the soil; however, its application to the scale of an irrigation district and even that of the a farm field, is limited due to the difficulty and cost of the experimental work required to depict the soil's hydrodynamic characteristics (the moisture retention curve and the hydraulic conductivity curve) as well as the necessary effort of calculating a three-dimensional water movement in the soil. These limitations have led to the analysis of agricultural drainage being mainly performed with the Boussinesq equation, an approach that considers in a simplified manner the transfers occurring in the soil's unsaturated zone, but with a smaller amount of data requirements than the Richards equation, adequately describes water dynamics in the

Recently, two mechanistic models have been developed for agricultural drainage that improve the traditional hypotheses of the models reported in the literature. On the one hand, Zavala *et al.* (2005) have developed a model for agricultural subsurface drainage based on the two-dimensional Richards equation. This differential equation is subjected in the drains boundary to a nonlinear radiation condition, and in this form the mass and energy transfers in a drainage system are better represented. On the other hand, Zavala *et al*. (2004) and Fuentes *et al.* (2009) have studied agricultural drainage with the Boussinesq equation and have deduced, respectively, the boundary condition to be used in agricultural drains by this equation and the relation between the moisture retention curve and the

The aim of this chapter is to present the two models just described to develop their numerical solutions and compare the mass and energy transfers obtained with the Richards equation and the Boussinesq equation, both of which are subject to nonlinear radiation

Soil water movement in a subsurface drainage system is a three-dimensional phenomenon, for which reason its description should be made using the Richards equation in three dimensions; nonetheless, due to the effort of calculation that the resolution of this form of Richards equation entails, it is convenient to accept the hypothesis that the phenomenon is basically two-dimensional (that is to say, it is made according to planes perpendicular to the direction of the drain). If, in addition, it is assumed that the water uptake by plant roots is negligible, the two-dimensional form of the Richards equation may be written as follows:

known as the Boussinesq equation of agriculture drainage.

saturated layer of the soil.

conditions in the drains.

**2.1 Macroscopic scale** 

**2. Materials and methods** 

storage coefficient in shallow unconfined aquifers.

The description of agricultural subsurface drainage by equation (1) requires the definition of the initial status of the pressure head in the porous media as well as its boundary conditions. The initial condition of the water pressure in the soil is specified as a known space function:

$$
\Psi = \Psi\_{\mathbf{i}} \left( \mathbf{x}\_{\prime} \mathbf{z} \right) \tag{2}
$$

By the flow symmetry, it is known that the Darcy flow in a perpendicular direction to segments AF, DE and BC is null (Neumann boundary condition), and a similar situation occurs in the boundary segment CD due to the impervious layer.

$$-\mathbf{K}(\boldsymbol{\psi})\frac{\partial \boldsymbol{\psi}}{\partial \mathbf{x}} = 0 \quad \mathbf{x} = 0; \quad \mathbf{z} \in \overline{\mathbf{AF}} \text{ y } \mathbf{z} \in \overline{\mathbf{DE}}; \quad \mathbf{t} > 0 \tag{3}$$

$$-\mathbf{K}\left(\boldsymbol{\psi}\right)\frac{\partial\boldsymbol{\psi}}{\partial\mathbf{x}}=\mathbf{0} \quad \mathbf{x}=\mathbf{L}/2; \quad \mathbf{z}\in\overline{\mathbf{BC}}; \quad \mathbf{t}>\mathbf{0} \tag{4}$$

$$-\mathbf{K}(\boldsymbol{\psi})\frac{\partial(\boldsymbol{\psi}-\mathbf{z})}{\partial\mathbf{z}}=\mathbf{0} \quad \mathbf{x}\in\overline{\mathbf{CD}}\;\;\mathbf{y} \quad \mathbf{z}=\mathbf{P}\_{\mathcal{E}};\quad \mathbf{t}>\mathbf{0} \tag{5}$$

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 169

where V is the water's mean velocity in the drain <sup>1</sup> LT ; d is a dimensionless parameter that varies between 12 d 1 in terms of the type of flow (turbulent or laminar); is a dimensionless coefficient; g is the gravitational acceleration <sup>2</sup> L T ; is the water kinematic viscosity 2 1 L T ; RH is the hydraulic radius L ; and J is the friction slope

The combination of relation (8) and the continuity equation for steady flow - which indicates that the flow Q is the product of the hydraulic area and the mean velocity ( Q VA ) - allows the obtaining of the relation between the mean depth of the water in the drain and the water

displays a limitation: there are two unknown variables (flow and water depth) and only one equation. This problem is resolved by outlining a second equation that is obtained when the

> <sup>t</sup> <sup>o</sup> <sup>h</sup> Q2q1 <sup>d</sup>

In order to model agricultural drainage with the system of equations (1-9), it is crucial to have the analytical representations of the soil hydrodynamic characteristics and K . In field and in laboratory applications, Fuentes *et al.* (1992) recommend using the van Genuchten model for the moisture retention curve (van Genuchten, 1980), subject to the

<sup>m</sup> <sup>n</sup>

where s is the saturated volumetric water content; r is the residual volumetric water

As for the hydraulic conductivity curve, they suggest using the Brooks & Corey model

<sup>r</sup> <sup>s</sup>

where Ks is the saturated hydraulic conductivity <sup>1</sup> LT ; and is a positive

Rough descriptions of the mass and energy transfers of subsurface agricultural drainage systems can be obtained with the Boussinesq equation for unconfined aquifers. As per the hypothesis that variations in the direction of the drain are negligible and that the null

s r

content; d 0 is a pressure scale parameter; m and n are the shape parameters.

K K

where is the perimeter of the drain semi-circumference and is its length.

P P

<sup>2</sup> m 1

. However, the application of this relation

(9)

<sup>n</sup> with n 2 (10)

(11)

<sup>1</sup> LL .

(1964):

flow that leads to d 3d 1 d 2d 1 Q g AR J <sup>H</sup>

Burdine restriction (Burdine, 1953):

dimensionless shape parameter.

**2.2 Megascopic scale** 

nonlinear radiation condition is integrated with (7):

 <sup>1</sup> 

r sr d

where PE is the depth of the impervious layer, measured as from the soil surface; and L is the space between drains.

In the soil surface (segment AB) when the rain or evaporation intensity (i) is known, a Neumann type boundary condition can be implemented:

$$-\mathbf{K}(\boldsymbol{\psi})\frac{\partial(\boldsymbol{\psi}-\mathbf{z})}{\partial\mathbf{z}}=\mathbf{i} \quad \mathbf{x}\in\overline{\mathbf{AB}}\,, \quad \mathbf{z}=\mathbf{0}\;\text{;}\tag{6} \qquad \text{(6)}$$

Consistent with Zavala *et al.* (2005), the soil water transfer to the drain shall be described with the following nonlinear radiation condition:

$$-\mathbf{K}(\boldsymbol{\Psi})\frac{\partial \left(\boldsymbol{\Psi} - \mathbf{z}\right)}{\partial \mathbf{n}} = \mathbf{q}\_o \left(\mathbf{1} - \frac{\boldsymbol{\Psi}}{\mathbf{P}}\right)^{\alpha} \left(\frac{\boldsymbol{\Psi} - \mathbf{h}\_t}{\mathbf{P}}\right)^{\beta} \quad \forall \mathbf{x}, \mathbf{z} \in \overline{\mathbf{EF}}; \quad \mathbf{t} > \mathbf{0} \tag{7}$$

where n is the normal derivative; qo is a particular value of the water flow in the soil <sup>1</sup> LT ; and are dimensionless shape parameters; P is the depth of the drain L ; and ht is the pressure inside the drain L , equal to the atmospheric pressure h 0 <sup>t</sup> in the segment of the drain's internal perimeter in contact with the air and equal to the water depth had at every point of the drain's internal perimeter in contact with water (Fig. 2).

Fig. 2. Scheme of the water flow in a drain.

The application of relation (7) requires knowledge of the evolution of mean depth of the water in the drain. If the variations in the longitudinal direction are negligible, the depth of the water in the drain may be supposed to be uniform in space but variable in time. In this situation, the evolution in time of the depth of water may be calculated as from an equation that relates the flow velocity with the energy loss in the movement direction. Because of its generality, the fractal resistance law proposed by Fuentes *et al.* (2004) is used in this work:

$$\mathbf{V} = \kappa \frac{\mathbf{g}^{\mathrm{d}}}{\mathbf{v}^{\mathrm{2d}-1}} \mathbf{R}\_{\mathrm{H}}^{\mathrm{3d}-1} \mathbf{J}^{\mathrm{d}} \tag{8}$$

where V is the water's mean velocity in the drain <sup>1</sup> LT ; d is a dimensionless parameter that varies between 12 d 1 in terms of the type of flow (turbulent or laminar); is a dimensionless coefficient; g is the gravitational acceleration <sup>2</sup> L T ; is the water kinematic viscosity 2 1 L T ; RH is the hydraulic radius L ; and J is the friction slope <sup>1</sup> LL .

The combination of relation (8) and the continuity equation for steady flow - which indicates that the flow Q is the product of the hydraulic area and the mean velocity ( Q VA ) - allows the obtaining of the relation between the mean depth of the water in the drain and the water flow that leads to d 3d 1 d 2d 1 Q g AR J <sup>H</sup> . However, the application of this relation displays a limitation: there are two unknown variables (flow and water depth) and only one equation. This problem is resolved by outlining a second equation that is obtained when the nonlinear radiation condition is integrated with (7):

$$\mathbf{Q} = 2\ell \int\_{\Omega} \mathbf{q}\_o \left( 1 - \frac{\boldsymbol{\Psi}}{\mathbf{P}} \right)^{\alpha} \left( \frac{\boldsymbol{\Psi} - \mathbf{h}\_t}{\mathbf{P}} \right)^{\beta} d\Omega \tag{9}$$

where is the perimeter of the drain semi-circumference and is its length.

In order to model agricultural drainage with the system of equations (1-9), it is crucial to have the analytical representations of the soil hydrodynamic characteristics and K . In field and in laboratory applications, Fuentes *et al.* (1992) recommend using the van Genuchten model for the moisture retention curve (van Genuchten, 1980), subject to the Burdine restriction (Burdine, 1953):

$$\frac{\Theta(\boldsymbol{\Psi}) - \Theta\_{\mathbf{r}}}{\Theta\_{\mathbf{s}} - \Theta\_{\mathbf{r}}} = \left[ 1 + \left( \frac{\boldsymbol{\Psi}}{\boldsymbol{\Psi}\_{\mathbf{d}}} \right)^{n} \right]^{-m} \quad \mathbf{m} = 1 - \frac{2}{\mathbf{n}} \quad \text{with} \quad \mathbf{n} > 2 \tag{10}$$

where s is the saturated volumetric water content; r is the residual volumetric water content; d 0 is a pressure scale parameter; m and n are the shape parameters.

As for the hydraulic conductivity curve, they suggest using the Brooks & Corey model (1964):

$$\mathbf{K}(\boldsymbol{\Theta}) = \mathbf{K}\_s \left( \frac{\boldsymbol{\Theta} - \boldsymbol{\Theta}\_\mathbf{r}}{\boldsymbol{\Theta}\_s - \boldsymbol{\Theta}\_\mathbf{r}} \right)^\eta \tag{11}$$

where Ks is the saturated hydraulic conductivity <sup>1</sup> LT ; and is a positive dimensionless shape parameter.

#### **2.2 Megascopic scale**

168 Drainage Systems

where PE is the depth of the impervious layer, measured as from the soil surface; and L is

In the soil surface (segment AB) when the rain or evaporation intensity (i) is known, a

Consistent with Zavala *et al.* (2005), the soil water transfer to the drain shall be described

where n is the normal derivative; qo is a particular value of the water flow in the soil

 ; and are dimensionless shape parameters; P is the depth of the drain L ; and ht is the pressure inside the drain L , equal to the atmospheric pressure h 0 <sup>t</sup> in the segment of the drain's internal perimeter in contact with the air and equal to the water depth had at every point of the drain's internal perimeter in contact with water (Fig. 2).

yw <sup>z</sup> <sup>z</sup> k+1

 

The application of relation (7) requires knowledge of the evolution of mean depth of the water in the drain. If the variations in the longitudinal direction are negligible, the depth of the water in the drain may be supposed to be uniform in space but variable in time. In this situation, the evolution in time of the depth of water may be calculated as from an equation that relates the flow velocity with the energy loss in the movement direction. Because of its generality, the fractal resistance law proposed by Fuentes *et al.* (2004) is used in this work:

d

2d 1 H <sup>g</sup> V RJ 

3d 1 d

(8)

yPzDP

d w

<sup>h</sup> yw= water depth

<sup>w</sup>

<sup>t</sup> yPz

k

x AB , z 0 ; t 0 (6)

x ,z EF; t0 (7)

**drain**

the space between drains.

<sup>1</sup> LT

*z*

*x y*

Neumann type boundary condition can be implemented:

with the following nonlinear radiation condition:

Dd

 

Fig. 2. Scheme of the water flow in a drain.

w i

zy 0

z =P-Dd

z =P

<sup>z</sup> K i <sup>z</sup>

 <sup>t</sup> <sup>o</sup> <sup>z</sup> <sup>h</sup> <sup>K</sup> q 1 n PP

> Rough descriptions of the mass and energy transfers of subsurface agricultural drainage systems can be obtained with the Boussinesq equation for unconfined aquifers. As per the hypothesis that variations in the direction of the drain are negligible and that the null

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 171

In general terms, the pressure's initial condition shall be specified as the elevation of the free

Zavala *et al.* (2004) have shown that the relation that will subject the Boussinesq equation in

h hh KK 0 x PL

where is a dimensionless conductance coefficient; s is the quotient of the soil fractal dimension Df and the dimensional Euclidean space ( <sup>f</sup> sD3 ); Ks is the hydraulic conductivity of the soil-drain interface. The positive sign in equation (16) is taken for the drain located in coordinate x 0 and the negative sign for x L . As per Zavala *et al.* (2007),

> s s h h Kq 0 x P

The quotient dimension s is implicitly defined in terms of the total volumetric porosity ( )

If a represents the total areal porosity, and considering that 2s <sup>a</sup> , the equation that

<sup>1</sup> <sup>1</sup> <sup>s</sup> 2s

The comparison of the mass and energy transfers provided by the systems of equations (1- 11) and (12-18) is executed considering the drainage experimental information of Zavala *et al.* (2004). The experiment was carried out in a drainage module made with acrylic sheets in which two PVC drains were installed (Fig. 4). The drain length and diameter are 0.30 m and D 0.05 m <sup>d</sup> ; the total number of circular openings in the drain-wall is No = 233 and the opening diameter 1.58 mm; and the drains' slope is J 0.001 . Other features of the drainage module are: L 1.0 m , P 1.20 m and D 0.25m <sup>o</sup> . The module was filled with an altered sample of sandy soil of the Mexican region of Tezoyuca, Morelos, passed through a 2 mm sieve; the soil was disposed at 0.20 m thick layers, seeking to maintain a constant bulk density. The soil was saturated by applying a constant water head on its surface until the entrapped air was virtually removed. Once the drains were closed, the water head was

2s 1

2s

the boundary of the drains is the following fractal radiation condition:

s s

h x,0 h x (15)

(16)

(16.1)

<sup>s</sup> 2s 1 1 (17)

a a 1 1 (18)

surface throughout the horizontal coordinate x:

it is convenient to express equation (16) as follows:

defines the relationship between s and a is:

where s q KPL <sup>s</sup> .

**3. Application** 

as:

recharge - the dynamic of the water in the saturated thickness of the soil - can be described with the Boussinesq equation of agricultural drainage:

$$
\mu\text{(H)}\frac{\partial\text{H}}{\partial\text{t}} = \frac{\partial}{\partial\text{x}}\bigg[\text{K}\_{\text{s}}(\text{H}-\text{H}\_{\text{i}})\frac{\partial\text{H}}{\partial\text{x}}\bigg] \tag{12}
$$

where H and Hi are, respectively, elevations of the free surface or hydraulic head and of the impervious layer, measured from the same reference level L , when the impervious layer is approximately horizontal it may be supposed as the marker level and take H 0 <sup>i</sup> ; H is the storage coefficient 3 3 L L , which, in a shallow unconfined aquifer is a function of the hydraulic head (Hilberts *et al.*, 2005; Fuentes *et al.*, 2009).

Taking into account the van Genuchten model for the moisture retention curve, subject to the Burdine restriction and the hydrostatic pressure distribution hypothesis, this allows the obtaining of the following analytical representation for the storage coefficient (Fuentes *et al.*, 2009):

$$\mu\left(\mathbf{H}\right) = \left(\boldsymbol{\theta}\_{\mathrm{s}} - \boldsymbol{\theta}\_{\mathrm{r}}\right) \left(\mathbf{1} - \left\{\mathbf{1} + \left[\left(\mathbf{H} - \mathbf{H}\_{\mathrm{s}}\right) \Big/ \boldsymbol{\psi}\_{\mathrm{d}}\right]^{\mathrm{n}}\right\}^{-\mathrm{m}}\right) \quad \text{with} \quad \mathrm{m} = \mathrm{1} - \mathrm{2}/\mathrm{n} \tag{13}$$

where Hs is the soil surface elevation.

To resolve equation (12) on the domain shown in Fig. 3, it is necessary to define the initial conditions and the boundary conditions. The specification of these limit conditions is more convenient if the free surface position is counted as from the impervious layer:

Fig. 3. Domain to the Boussinesq equation.

$$\mathbf{H}(\mathbf{x}, \mathbf{t}) = \mathbf{D}\_o + \mathbf{h}(\mathbf{x}, \mathbf{t}) \tag{14}$$

where h x,t is the hydraulic head counted as from the position of the drains; and Do is the depth of the impervious layer measured as from the drain's position (see Fig. 3).

In general terms, the pressure's initial condition shall be specified as the elevation of the free surface throughout the horizontal coordinate x:

$$\mathbf{h}\left(\mathbf{x},0\right) = \mathbf{h}\left(\mathbf{x}\right) \tag{15}$$

Zavala *et al.* (2004) have shown that the relation that will subject the Boussinesq equation in the boundary of the drains is the following fractal radiation condition:

$$-\mathbf{K}\_s \frac{\partial \mathbf{h}}{\partial \mathbf{x}} \pm \gamma \overline{\mathbf{K}}\_s \left(\frac{\mathbf{h}}{\mathbf{P}}\right)^{2s-1} \left(\frac{\mathbf{h}}{\mathbf{L}}\right) = \mathbf{0} \tag{16}$$

where is a dimensionless conductance coefficient; s is the quotient of the soil fractal dimension Df and the dimensional Euclidean space ( <sup>f</sup> sD3 ); Ks is the hydraulic conductivity of the soil-drain interface. The positive sign in equation (16) is taken for the drain located in coordinate x 0 and the negative sign for x L . As per Zavala *et al.* (2007), it is convenient to express equation (16) as follows:

$$-\mathbf{K}\_s \frac{\partial \mathbf{h}}{\partial \mathbf{x}} \pm \mathbf{q}\_s \left(\frac{\mathbf{h}}{\mathbf{P}}\right)^{2s} = 0\tag{16.1}$$

where s q KPL <sup>s</sup> .

170 Drainage Systems

recharge - the dynamic of the water in the saturated thickness of the soil - can be described

 s i H H H KHH tx x 

where H and Hi are, respectively, elevations of the free surface or hydraulic head and of the impervious layer, measured from the same reference level L , when the impervious layer is approximately horizontal it may be supposed as the marker level and take H 0 <sup>i</sup> ; H is the storage coefficient 3 3 L L , which, in a shallow unconfined aquifer is a

Taking into account the van Genuchten model for the moisture retention curve, subject to the Burdine restriction and the hydrostatic pressure distribution hypothesis, this allows the obtaining of the following analytical representation for the storage coefficient (Fuentes *et al.*,

To resolve equation (12) on the domain shown in Fig. 3, it is necessary to define the initial conditions and the boundary conditions. The specification of these limit conditions is more

function of the hydraulic head (Hilberts *et al.*, 2005; Fuentes *et al.*, 2009).

 <sup>m</sup> <sup>n</sup> H 1 1 HH s r s d 

convenient if the free surface position is counted as from the impervious layer:

L

the depth of the impervious layer measured as from the drain's position (see Fig. 3).

x = 0 x = L

x = L/2

where h x,t is the hydraulic head counted as from the position of the drains; and Do is

impervious layer

Do

hc

H h

free surface (water table)

soil surface

dren dren

(12)

with m 1 2n (13)

x

Pd

P

0

H x,t D h x,t <sup>o</sup> (14)

hs

with the Boussinesq equation of agricultural drainage:

2009):

where Hs is the soil surface elevation.

z

Hi

Fig. 3. Domain to the Boussinesq equation.

Hd

Hs

The quotient dimension s is implicitly defined in terms of the total volumetric porosity ( ) as:

$$\left(\mathbf{1} - \boldsymbol{\phi}\right)^{s} + \boldsymbol{\phi}^{2s} = \mathbf{1} \tag{17}$$

If a represents the total areal porosity, and considering that 2s <sup>a</sup> , the equation that defines the relationship between s and a is:

$$(1 - \mu\_{\mathbf{a}})^{\mathbb{X}\_\*} + \mu\_{\mathbf{a}}{}^{\mathbb{X}\_\*} = 1 \tag{18}$$

#### **3. Application**

The comparison of the mass and energy transfers provided by the systems of equations (1- 11) and (12-18) is executed considering the drainage experimental information of Zavala *et al.* (2004). The experiment was carried out in a drainage module made with acrylic sheets in which two PVC drains were installed (Fig. 4). The drain length and diameter are 0.30 m and D 0.05 m <sup>d</sup> ; the total number of circular openings in the drain-wall is No = 233 and the opening diameter 1.58 mm; and the drains' slope is J 0.001 . Other features of the drainage module are: L 1.0 m , P 1.20 m and D 0.25m <sup>o</sup> . The module was filled with an altered sample of sandy soil of the Mexican region of Tezoyuca, Morelos, passed through a 2 mm sieve; the soil was disposed at 0.20 m thick layers, seeking to maintain a constant bulk density. The soil was saturated by applying a constant water head on its surface until the entrapped air was virtually removed. Once the drains were closed, the water head was

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 173

To compare the transfers described, with two flow models, it is necessary to resolve the systems (1-11) and (12-18). Both systems of equations are numerically solved following the process employed by Zavala *et al.* (2004) & (2005). The spatial discretisation is carried out by using the Galerkin finite-element method; temporal discretisation is performed with a finitedifference implicit method. The resulting system becomes lineal using the Picard iterative method; the algebraic equation system is solved using a preconditioned conjugated gradient method. These methods are well documented, for example in Zienkiewicz *et al*. (2005).

The solution domain discretisation of the two-dimensional Richards equation is carried out by applying the Argus-One program, with which a finite element mesh of 10,795 nodes was generated and distributed in 21,082 elements (Fig. 5) - this being the minimum spaces min min x z 0.2 cm and the maximum ones min min x z 2.0 cm -. The solution domain of the one-dimension Boussinesq equation was discretised generating a mesh of 201

By applying the numerical solutions of the systems (1-11) and (12-18), the drainage experiment is simulated to determine and to compare the evolution in time of the water depth evacuated by the drain and the corresponding variation of the free surface to half of the space between the drains. The results obtained for the mass transfer are presented in Fig. 6a and 6b and, for the energy transfer, the results are presented in Fig. 7a and 7b; in each case, as the drainage time increases, the calculated evolutions trend to a limit value because

A good agreement between the evolution of the drained depth described with the Richards equation and the evolution obtained with the Boussinesq equation ( <sup>2</sup> R 0.9847 ) can be appreciated in Fig. 6a and 6b; this is a logical result because both evolutions are the direct

nodes and 200 finite elements of a uniform size ( x 0.5 cm ).

Fig. 5. Finite element mesh (Richards equation domain).

the recharge is null.

removed from the soil surface; the surface of the module was then covered with a plastic in order to avoid evaporation. Finally, the drains were opened to measure the drained water volume (ten days); it is worth noticing that the initial condition corresponded to a hydrostatic pressure distribution and the recharge was null (R = 0) during the drainage phase.

The hydrodynamic characterisation of the soil, executed independently of the transient drainage test, allowed the determination of the parameters of the van Genuchten model and the Brooks & Corey model (Zavala *et al.*, 2004): 3 3 <sup>s</sup> 0.539 cm cm , 3 3 <sup>r</sup> 0 cm cm , m 0.373 , 3.767 , K 0.183 m h <sup>s</sup> and d 0.418 m . To estimate the dimensionless coefficient of the fractal resistance law (equation 8), Zavala *et al.* (2005) compare this law with the Hazen-Williams relation, considering d 0.54 and determining 9.83 (smooth PVC drains).

Fig. 4. Scheme of the drainage module.

The experimental conditions allow the identification of all the domain boundary segments, except the one associated with the drain, as impermeable (Neumann boundary condition). When the porosity 3 3 0.539 cm cm is introduced in equation (17) and this function is resolved, the exponent of the fractal radiation condition (equation 16.1) for the Boussinesq equation is obtained ( s 0.636 ). Eventually, the parameters , and qo intervening in the nonlinear radiation condition (equation 7), as well as scale parameter qs (equation 16.1), are determined as from the evolution in time of the experimental drained depth. To save the problem of estimating three parameters from one test only, Zavala *et al.* (2005) assume and obtain 1.88 and q 300K o s ; in the case of the Boussinesq equation, Zavala *et al.* (2004) report q 0.913K s s .

removed from the soil surface; the surface of the module was then covered with a plastic in order to avoid evaporation. Finally, the drains were opened to measure the drained water volume (ten days); it is worth noticing that the initial condition corresponded to a hydrostatic pressure distribution and the recharge was null (R = 0) during the drainage

The hydrodynamic characterisation of the soil, executed independently of the transient drainage test, allowed the determination of the parameters of the van Genuchten model and

m 0.373 , 3.767 , K 0.183 m h <sup>s</sup> and d 0.418 m . To estimate the dimensionless coefficient of the fractal resistance law (equation 8), Zavala *et al.* (2005) compare this law with the Hazen-Williams relation, considering d 0.54 and determining 9.83 (smooth

*x=L*

<sup>s</sup> 0.539 cm cm , 3 3

<sup>r</sup> 0 cm cm ,

0.225 m 0.050 m

1.175 m

1.45 m

the Brooks & Corey model (Zavala *et al.*, 2004): 3 3

2L

The experimental conditions allow the identification of all the domain boundary segments, except the one associated with the drain, as impermeable (Neumann boundary condition). When the porosity 3 3 0.539 cm cm is introduced in equation (17) and this function is resolved, the exponent of the fractal radiation condition (equation 16.1) for the Boussinesq equation is obtained ( s 0.636 ). Eventually, the parameters , and qo intervening in the nonlinear radiation condition (equation 7), as well as scale parameter qs (equation 16.1), are determined as from the evolution in time of the experimental drained depth. To save the problem of estimating three parameters from one test only, Zavala *et al.* (2005) assume and obtain 1.88 and q 300K o s ; in the case of the Boussinesq equation, Zavala *et al.*

Dd (L-Dd)/2 (L-Dd) Dd (L-Dd)/2

drains

sandy soil

soil surface

*x=0*

phase.

PVC drains).

*z*

*x*

Fig. 4. Scheme of the drainage module.

(2004) report q 0.913K s s .

*y*

To compare the transfers described, with two flow models, it is necessary to resolve the systems (1-11) and (12-18). Both systems of equations are numerically solved following the process employed by Zavala *et al.* (2004) & (2005). The spatial discretisation is carried out by using the Galerkin finite-element method; temporal discretisation is performed with a finitedifference implicit method. The resulting system becomes lineal using the Picard iterative method; the algebraic equation system is solved using a preconditioned conjugated gradient method. These methods are well documented, for example in Zienkiewicz *et al*. (2005).

The solution domain discretisation of the two-dimensional Richards equation is carried out by applying the Argus-One program, with which a finite element mesh of 10,795 nodes was generated and distributed in 21,082 elements (Fig. 5) - this being the minimum spaces min min x z 0.2 cm and the maximum ones min min x z 2.0 cm -. The solution domain of the one-dimension Boussinesq equation was discretised generating a mesh of 201 nodes and 200 finite elements of a uniform size ( x 0.5 cm ).

Fig. 5. Finite element mesh (Richards equation domain).

By applying the numerical solutions of the systems (1-11) and (12-18), the drainage experiment is simulated to determine and to compare the evolution in time of the water depth evacuated by the drain and the corresponding variation of the free surface to half of the space between the drains. The results obtained for the mass transfer are presented in Fig. 6a and 6b and, for the energy transfer, the results are presented in Fig. 7a and 7b; in each case, as the drainage time increases, the calculated evolutions trend to a limit value because the recharge is null.

A good agreement between the evolution of the drained depth described with the Richards equation and the evolution obtained with the Boussinesq equation ( <sup>2</sup> R 0.9847 ) can be appreciated in Fig. 6a and 6b; this is a logical result because both evolutions are the direct

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 175

Fig. 7a. Comparison of the evolutions of the free surface to half of the space between the drains calculated with the Richards model (1-11) and the Boussinesq model (12-18). Twelve

> 0 2 4 6 810 Time (day)

Fig. 7b. Comparison of the evolutions of the free surface to half of the space between drains calculated with the Richards model (1-11) and the Boussinesq model (12-18). Ten days of the

0 2 4 6 8 10 12 Time (h)

> Boussinesq model Richards model

Boussinesq model Richards model

0.0

0.2

0.4

0.6

Vertical coordinate z (m)

0.8

1.0

1.2

Depth of the drains

1.4

0.0

0.2

0.4

0.6

Vertical coordinate z (m)

0.8

1.0

1.2

Depth of the drains

1.4

drainage experiment.

hours of the drainage experiment.

Fig. 6a. Comparison of the drained depth evolutions calculated with the Richards model (1- 11) and the Boussinesq model (12-18). Twelve hours of the drainage experiment.

Fig. 6b. Comparison of the drained depth evolutions calculated with the Richards model (1- 11) and the Boussinesq model (12-18). Ten days of the drainage experiment.

0 2 4 6 8 10 12 Time (h)

0 2 4 6 810 Time (day)

Fig. 6b. Comparison of the drained depth evolutions calculated with the Richards model (1-

11) and the Boussinesq model (12-18). Ten days of the drainage experiment.

Fig. 6a. Comparison of the drained depth evolutions calculated with the Richards model (1-

11) and the Boussinesq model (12-18). Twelve hours of the drainage experiment.

Total drained depth Boussinesq model Richards model

Richards model Boussinesq model Total drained depth

0.00

0.00

0.05

0.10

0.15

Cumulative drained depth (m)

0.20

0.25

0.05

0.10

0.15

Cumulative drained depth (m)

0.20

0.25

Fig. 7a. Comparison of the evolutions of the free surface to half of the space between the drains calculated with the Richards model (1-11) and the Boussinesq model (12-18). Twelve hours of the drainage experiment.

Fig. 7b. Comparison of the evolutions of the free surface to half of the space between drains calculated with the Richards model (1-11) and the Boussinesq model (12-18). Ten days of the drainage experiment.

Fig. 8b.

0.0

model with K 0.500 m h <sup>s</sup> (best fit).

0.00

model with K 0.500 m h <sup>s</sup> .

0.05

0.10

0.15

Drained depth (m)

0.20

0.25

0.2

0.4

0.6

Free surface to half of space between

drains (Richards model)

0.8

1.0

1.2

Simulated

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 177

value is 2.78 times higher than the value determined in the laboratory by Zavala *et al.* (2004). With this, it is shown that the hypotheses considered in the derivation of the Boussinesq equation noticeably affect their Ks estimation capacity. The overestimation of the Ks value necessarily results in an overestimation of the evolution of the drained depth, as shown in

> 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Free surface to half of space between drains (Boussinesq model)

Fig. 8a. Comparison of the free surface evolution obtained by the application the Richards model with K 0.183 m h <sup>s</sup> , and the evolution obtained by application the Boussinesq

> 0.0001 0.001 0.01 0.1 1 10 Time (day)

Fig. 8b. Comparison of the drained depth evolution obtained by the application the Richards model with K 0.183 m h <sup>s</sup> , and the evolution obtained by the application the Boussinesq

y = x R2 = 0.9761

> Boussinesq model Richards model

product of the estimation of the radiation conditions' parameters (7) and (16.1), as from the experimental data of the drained depth. However, the evolution of the water table was not considered to optimise parameters, for which reason this variable is a good comparison element. When observing the results shown in Fig. 7a and 7b, an important discrepancy can be appreciated between the evolution described by the model based on the Richards equation as to the evolution obtained with the Boussinesq model; during all the drainage time, the water table drawdown calculated with the Boussinesq model is slower than the one obtained with the Richards model.

Taking into account that the Boussinesq equation may be obtained by integrating the Richards equation in the vertical with the hypothesis of a hydrostatic pressure distribution (Bear, 1972) - circumstances that are not met in the regions closer to the drain - we have the most accurate description of the hydraulic variables in a subsurface drainage system corresponding to the one provided by the Richards equation. Considering, in addition, the simulation results, it can be seen that the model based on the Boussinesq equation (equations 12-18) cannot simultaneously reproduce the evolutions of the mass and energy transfers that are described by the model based on the Richards equation; that is to say, if it reproduces the evolution of the mass, it is not feasible that it reproduces the energy evolution or, if it reproduces the energy evolution, it cannot reproduce the mass evolution.

The limitations of an accurate simultaneous description of mass and energy transfers with the Boussinesq equation should be had in mind when it is used to estimate soil's hydraulic properties or when it is applied to the design of drainage systems. On one hand, it is traditional to consider this equation in estimating the saturated hydraulic conductivity as with the lowering or recovery measurements of the groundwater; if this were the case, the determined value would be higher than the real value of the hydraulic conductivity of the porous medium, because - as per the results of this work - the Boussinesq equation describes a minor lowering of the free surface than the one occurring in the drainage system. On the other hand, if the saturated hydraulic conductivity has been estimated according to field or laboratory tests that consider relations that are more accurate than the Boussinesq equation, and this value is used together with the Boussinesq equation to calculate the space between drains, it is possible to obtain separations shorter than that which is really needed to satisfy the water-table drawdown.

To illustrate both situations, the drainage results obtained with the Richards model are regarded as benchmarks, and numerical simulations with the Boussinesq model are carried out. The first case involves determining the saturated hydraulic conductivity value which allows for approaching with the Boussinesq model, with the water-table drawdown to half of space between drains as described with the Richards equation. In the second case, the saturated hydraulic conductivity value determined in the laboratory by Zavala *et al*. (2004) is taken up again, and the space between drains required by the Boussinesq model is calculated in order to approximate the water-table drawdown obtained with the Richards model.

The results obtained for the first case are shown in Fig. 8a and 8b. The first Figure shows the better approach of the Boussinesq equation compared to the Richards model, as to the evolution of the free surface to half of the space between drains ( <sup>2</sup> R 0.9761 ), obtained with a saturated hydraulic conductivity value for the Boussinesq model of K 0.500 m h <sup>s</sup> ; this

product of the estimation of the radiation conditions' parameters (7) and (16.1), as from the experimental data of the drained depth. However, the evolution of the water table was not considered to optimise parameters, for which reason this variable is a good comparison element. When observing the results shown in Fig. 7a and 7b, an important discrepancy can be appreciated between the evolution described by the model based on the Richards equation as to the evolution obtained with the Boussinesq model; during all the drainage time, the water table drawdown calculated with the Boussinesq model is slower than the

Taking into account that the Boussinesq equation may be obtained by integrating the Richards equation in the vertical with the hypothesis of a hydrostatic pressure distribution (Bear, 1972) - circumstances that are not met in the regions closer to the drain - we have the most accurate description of the hydraulic variables in a subsurface drainage system corresponding to the one provided by the Richards equation. Considering, in addition, the simulation results, it can be seen that the model based on the Boussinesq equation (equations 12-18) cannot simultaneously reproduce the evolutions of the mass and energy transfers that are described by the model based on the Richards equation; that is to say, if it reproduces the evolution of the mass, it is not feasible that it reproduces the energy evolution or, if it reproduces the energy evolution, it cannot reproduce the mass evolution. The limitations of an accurate simultaneous description of mass and energy transfers with the Boussinesq equation should be had in mind when it is used to estimate soil's hydraulic properties or when it is applied to the design of drainage systems. On one hand, it is traditional to consider this equation in estimating the saturated hydraulic conductivity as with the lowering or recovery measurements of the groundwater; if this were the case, the determined value would be higher than the real value of the hydraulic conductivity of the porous medium, because - as per the results of this work - the Boussinesq equation describes a minor lowering of the free surface than the one occurring in the drainage system. On the other hand, if the saturated hydraulic conductivity has been estimated according to field or laboratory tests that consider relations that are more accurate than the Boussinesq equation, and this value is used together with the Boussinesq equation to calculate the space between drains, it is possible to obtain separations shorter than that which is really needed to satisfy

To illustrate both situations, the drainage results obtained with the Richards model are regarded as benchmarks, and numerical simulations with the Boussinesq model are carried out. The first case involves determining the saturated hydraulic conductivity value which allows for approaching with the Boussinesq model, with the water-table drawdown to half of space between drains as described with the Richards equation. In the second case, the saturated hydraulic conductivity value determined in the laboratory by Zavala *et al*. (2004) is taken up again, and the space between drains required by the Boussinesq model is calculated in order to approximate the water-table drawdown obtained with the Richards

The results obtained for the first case are shown in Fig. 8a and 8b. The first Figure shows the better approach of the Boussinesq equation compared to the Richards model, as to the evolution of the free surface to half of the space between drains ( <sup>2</sup> R 0.9761 ), obtained with a saturated hydraulic conductivity value for the Boussinesq model of K 0.500 m h <sup>s</sup> ; this

one obtained with the Richards model.

the water-table drawdown.

model.

value is 2.78 times higher than the value determined in the laboratory by Zavala *et al.* (2004). With this, it is shown that the hypotheses considered in the derivation of the Boussinesq equation noticeably affect their Ks estimation capacity. The overestimation of the Ks value necessarily results in an overestimation of the evolution of the drained depth, as shown in Fig. 8b.

Fig. 8a. Comparison of the free surface evolution obtained by the application the Richards model with K 0.183 m h <sup>s</sup> , and the evolution obtained by application the Boussinesq model with K 0.500 m h <sup>s</sup> (best fit).

Fig. 8b. Comparison of the drained depth evolution obtained by the application the Richards model with K 0.183 m h <sup>s</sup> , and the evolution obtained by the application the Boussinesq model with K 0.500 m h <sup>s</sup> .

Comparison of Two Nonlinear Radiation Models for Agricultural Subsurface Drainage 179

installed in the field (a real farm environment), the only requirement being to carry out an adequate hydrodynamic characterisation of the soil, using either direct methods or indirect methods (inverse problems). If the hydrodynamic characteristics of the soil (moisture retention curve and hydraulic conductivity curve) are well-identified in the field and the application of both models is performed as described in this study, the results will be similar

If the soil hydrodynamic characterisation is carried out by an inverse method, it is recommended that the procedure developed by Fuentes is applied (see Saucedo *et al*., 2002; Zavala *et al*., 2003), based on the volumetric porosity of the soil, the granulometric curve and the drainage test (local or global). This methodology takes into account the Laplace law, Stoke's law and concepts of fractal geometry. The methodology is very precise for the

The two numerical models presented in this study considers the classical hypothesis of a deterministic model, accordingly a good description of real farm conditions can be to carry out with an adequately represented of the spatial variability of the hydrodynamic properties

This work was supported by SEP (Secretaría de Educación Pública) through of the projects: PROMEP/103.5/09/4144, PROMEP/103.5/10/8830 (UAZ/PTC/090) and PIFI 2010 (P/PIFI

Bear, J. (1972). *Dynamics of Fluids in Porous Media*. Dover Publications, Inc., New York, 764 Brooks, R.H., & Corey, A.T. (1964). *Hydraulic properties of porous media*. Hydrol. Pap.3. Fourth

Buckingham, E. (1907). *Studies on the movement of soil moisture*. Bureau of Soils Bulletin No.

Burdine, N. T. (1953). *Relative permeability calculation from size distribution data.* Pet. Trans.

Fipps, G. & Skaggs, R.W. (1986). *Drains as a Boundary Condition in Finite Elements.* Water

Fuentes, C., Haverkamp, R. & Parlange, J.-Y. (1992). *Parameter constraints on closed-form soil-*

Fuentes, C., De León, B., Saucedo, H., Parlange, J.-Y., & Antonino, A.C.D. (2004). *El sistema* 

Gupta, R. K., Bhattacharya, A.K., & Chandra, P. (1994). *Unsteady drainage with variable* 

*resistencia hidráulica.* Ingeniería Hidráulica en México, XIX (2), 65-75. Fuentes, C., Zavala, M. & Saucedo, H. (2009). *Relationship between the Storage Coefficient and* 

*de ecuaciones de Saint-Venant y Richards del riego por gravedad: 1. La ley potencial de* 

*the Soil-Water Retention Curve in Subsurface Agricultural Drainage Systems: Water Table* 

*drainage porosity.* Journal of Irrigation and Drainage Engineering , Vol. 120 (4), 703-

to those presented in this paper.

of the soil.

**5. Acknowledgments** 

2010-32MSU0017H-09).

715.

38, USDA, 1–61.

AIME, 198, 71-78.

**6. References** 

representation of laboratory conditions and field conditions.

Collins, Colorado State University.

Resources Res., 22, (11), 1613-1621.

Dumm, L. D. (1954). *Drain spacing formula*. Agric. Eng. 35, 726–730.

*water relationships.* Journal of Hydrology, 134, 117-142.

*Drawdown.* J. Irrig. Drain. Eng., ASCE, 135 (3), 279-285.

For case of the space between drains, it was calculated that the best approach when considering the water-table drawdown between Boussinesq model (equations 12-18) and the Richards model (equations 1-11) is obtained when the space between drains for the first model is 0.41 m ( <sup>2</sup> R 0.9899 ). The difference between the real separation of the experimental drainage system considered by the Richards model and the theoretical separation required by the Boussinesq model to reproduce the lowering settled is 143%.

### **4. Conclusions**

Two mechanistic models to simulate the mass and energy transfers in agricultural subsurface drainage systems have been analysed: the first model resolves the Richards equation on a two-dimensional domain by using a nonlinear radiation boundary condition in the drain's perimeter; the second model considers the Boussinesq equation with a variable storage coefficient on a one-dimensional domain using a fractal radiation condition in the drain's.

Drawing upon experimental drainage information in an unconfined aquifer with null vertical recharge, the description capacity of both simulation models has been evaluated, obtaining that the Boussinesq equation cannot simultaneously reproduce the mass and energy transfers that the Richards equation provides. On one hand, if the Boussinesq equation is used to reproduce the mass evolution described with the Richards equation, the Boussinesq necessarily describes an energy evolution slower than the one provided by Richards. On the other hand, if the energy evolution that is described by the Richards equation is reproduced with the Boussinesq equation, it over-predicts the mass evolution associated with the Richards equation.

It has been shown that the description limits of the Boussinesq equation give rise to the overestimation of the saturated hydraulic conductivity when this equation is considered in the hydrodynamic characterisation of the soils, or else the overestimation of the space between drains if the saturated hydraulic conductivity is a value estimated as by the Richards equation.

The problem in the simultaneous description the mass and energy transfers with the Boussinesq equation is attributable to the hypothesis of a hydrostatic pressure distribution considered in its derivation; this hypothesis is not satisfied in the vicinity of the drains since, in this zone, the stream lines show an important curvature.

Once the usefulness and advantages the use of the Boussinesq equation in the study of the agricultural drainage has been informed and its description limits have become known, it is recommended that the determination of the parameters of a drainage system and the estimation of the hydraulic properties of the porous media with the Boussinesq equation be executed simultaneously (considering the optimisation procedure, the drained depth evolution as well as the water table variations) in order to proportionally distribute in the adjustment parameters the effect of the hypothesis considered in its derivation and so obtain a more appropriate description of the transferences of mass and energy in a subsurface drainage system.

The numerical models have been applied by considering one laboratory drainage test. However, both models can be applied equally to the description of drainage systems installed in the field (a real farm environment), the only requirement being to carry out an adequate hydrodynamic characterisation of the soil, using either direct methods or indirect methods (inverse problems). If the hydrodynamic characteristics of the soil (moisture retention curve and hydraulic conductivity curve) are well-identified in the field and the application of both models is performed as described in this study, the results will be similar to those presented in this paper.

If the soil hydrodynamic characterisation is carried out by an inverse method, it is recommended that the procedure developed by Fuentes is applied (see Saucedo *et al*., 2002; Zavala *et al*., 2003), based on the volumetric porosity of the soil, the granulometric curve and the drainage test (local or global). This methodology takes into account the Laplace law, Stoke's law and concepts of fractal geometry. The methodology is very precise for the representation of laboratory conditions and field conditions.

The two numerical models presented in this study considers the classical hypothesis of a deterministic model, accordingly a good description of real farm conditions can be to carry out with an adequately represented of the spatial variability of the hydrodynamic properties of the soil.

### **5. Acknowledgments**

This work was supported by SEP (Secretaría de Educación Pública) through of the projects: PROMEP/103.5/09/4144, PROMEP/103.5/10/8830 (UAZ/PTC/090) and PIFI 2010 (P/PIFI 2010-32MSU0017H-09).

#### **6. References**

178 Drainage Systems

For case of the space between drains, it was calculated that the best approach when considering the water-table drawdown between Boussinesq model (equations 12-18) and the Richards model (equations 1-11) is obtained when the space between drains for the first model is 0.41 m ( <sup>2</sup> R 0.9899 ). The difference between the real separation of the experimental drainage system considered by the Richards model and the theoretical separation required by the Boussinesq model to reproduce the lowering settled is 143%.

Two mechanistic models to simulate the mass and energy transfers in agricultural subsurface drainage systems have been analysed: the first model resolves the Richards equation on a two-dimensional domain by using a nonlinear radiation boundary condition in the drain's perimeter; the second model considers the Boussinesq equation with a variable storage coefficient on a one-dimensional domain using a fractal radiation condition

Drawing upon experimental drainage information in an unconfined aquifer with null vertical recharge, the description capacity of both simulation models has been evaluated, obtaining that the Boussinesq equation cannot simultaneously reproduce the mass and energy transfers that the Richards equation provides. On one hand, if the Boussinesq equation is used to reproduce the mass evolution described with the Richards equation, the Boussinesq necessarily describes an energy evolution slower than the one provided by Richards. On the other hand, if the energy evolution that is described by the Richards equation is reproduced with the Boussinesq equation, it over-predicts the mass evolution

It has been shown that the description limits of the Boussinesq equation give rise to the overestimation of the saturated hydraulic conductivity when this equation is considered in the hydrodynamic characterisation of the soils, or else the overestimation of the space between drains if the saturated hydraulic conductivity is a value estimated as by the

The problem in the simultaneous description the mass and energy transfers with the Boussinesq equation is attributable to the hypothesis of a hydrostatic pressure distribution considered in its derivation; this hypothesis is not satisfied in the vicinity of the drains since,

Once the usefulness and advantages the use of the Boussinesq equation in the study of the agricultural drainage has been informed and its description limits have become known, it is recommended that the determination of the parameters of a drainage system and the estimation of the hydraulic properties of the porous media with the Boussinesq equation be executed simultaneously (considering the optimisation procedure, the drained depth evolution as well as the water table variations) in order to proportionally distribute in the adjustment parameters the effect of the hypothesis considered in its derivation and so obtain a more appropriate description of the transferences of mass and energy in a subsurface

The numerical models have been applied by considering one laboratory drainage test. However, both models can be applied equally to the description of drainage systems

**4. Conclusions** 

in the drain's.

Richards equation.

drainage system.

associated with the Richards equation.

in this zone, the stream lines show an important curvature.

Bear, J. (1972). *Dynamics of Fluids in Porous Media*. Dover Publications, Inc., New York, 764


**9** 

*Lithuania* 

**An Assessment of Lime Filter Drainage Systems** 

Fine-textured clayey soils are of high fertility but often have a low hydraulic conductivity (Forsburg, 2003; Tuli et al., 2005). The infiltration of water into these soils is too slow therefore frequent surface ponding occurs. It follows that clay soils are usually poorly drained and difficult to manage when wet. Agricultural activities and mechanisation are extremely restricted without adequate drainage (Ritzema, 1994). Besides, clay soils often have a seasonal variation in hydraulic conductivity because of swelling and shrinking (Tuller & Or, 2003). Due to the swelling of clay, rainfall is unable to percolate deeper into drains. It either accumulates in depressions or discharges as surface runoff. Therefore the effectiveness of subsurface drainage of clay soils much depends on the permeability of trench backfill. Based on the assumption that 2.5% of the soil volume in a newly tile-drained clay soil is made up of backfill (0.5 m wide pipe trench and 20 m drain spacing), it is obvious that the backfilling method has a great impact on drainage efficiency of such soil (Ulén, 2007). Traditional subsurface drainage in such soils does not always ensure excess water removal within the normative period; therefore, adding of the amendments to the trench backfill increasing water infiltration rate is practiced frequently. The permeability of these soils can be greatly improved by filling the trenches with coarse material. In Western Europe gravel was used for drainage trench backfill (Ritzema, 1994; Smedema et al., 2004). However, in some countries this is too expensive because of the limit of natural resources of

Many researchers reported that lime additives contribute substantially to the change in the physical properties of clay soils (Puustinen, 2001; Rajasekaran & Narasimha, 2002; Halme et al., 2003; Mubeen, 2005; Cox et al., 2005). They referred that due to a certain rate of added lime the soil bulk density may be reduced by 25%, porosity increased by 30%, filtration coefficient increased 100-300 times, the amount of aggregates (0.25-10 mm) increased 3 times and the swelling practically disappear. As a result, soil mixed with lime is less susceptible to compaction, because calcium and magnesium carbonates may form hydro-silicates inducing soil resistance to the pressure. In addition, lime modifies the characteristics of clay particles so that they flocculate resulting in easier movement of all major ingredients in plant development i. e. higher amount of mobile phosphorus, potassium, nitrogen, sulphur, calcium and magnesium, and lower amount of mobile aluminium. Therefore, liming leads

Calcium carbonate (CaCO3), gypsum (CaSO4·2H2O), dolomitic limestone (CaMg(CO3)2), quicklime (CaO) or other calcium-containing materials may be used as liming material.

not only to an improved water regime but also to the changes in water quality.

**1. Introduction** 

gravel.

Nijole Bastiene, Valentinas Šaulys and Vidmantas Gurklys

*Aleksandras Stulginskis University* 


### **An Assessment of Lime Filter Drainage Systems**

Nijole Bastiene, Valentinas Šaulys and Vidmantas Gurklys

*Aleksandras Stulginskis University Lithuania* 

#### **1. Introduction**

180 Drainage Systems

Hilberts, A.G.J., Troch, P.A. & Paniconi, C. (2005). *Storage-dependent drainable porosity for* 

Pandey, R., Bhattacharya, A., Singh, O., & Gupta, S. (1992). *Drawdown solution with variable drainable porosity.* Journal of Irrigation and Drainage Engineering 118 (3), 382–396. Richards, L. A. (1931). *Capillary conduction of liquids through porous mediums.* Physics 1, 318-

Samani, J. M. V., Fathi, P., & Homaee, M. (2007). *Simultaneous prediction of saturated hydraulic* 

Saucedo, H., Fuentes, C., Zavala, M. & Vauclin, M. (2002). *Una solución de elemento finito para* 

Van Genuchten, M. Th. (1980). *A closed-form equation for predicting the hydraulic conductivity of* 

Zaradny, H. & Feddes, R.A. (1979). *Calculation of Non-Steady Flow Towards a Drain in* 

Zavala, M., Fuentes, C. y Saucedo, H. (2003). Sobre la condición de radiación en el drenaje

Zavala, M., Fuentes, C. & Saucedo, H. (2004). Radiación fractal en la ecuación de Boussinesq del drenaje agrícola. Ingeniería hidráulica en México, XIX(3), 103-111. Zavala, M., Fuentes, C. & Saucedo, H. (2005). *Radiación no lineal en la ecuación de Richards* 

Zavala, M., Fuentes, C., & Saucedo, H. (2007). *Nonlinear radiation in the Boussinesq equation of* 

Zienkiewicz O.C., Taylor, R.L. & Zhu, J.Z. (2005). *The finite element method. Its basis &* 

333.

53.

18(2), 121-131.

XX(4), 111-119.

Eng., 133(2), 10–115.

Hidráulica en México, XVII(1), 93-105.

*the unsaturated soils.* Soil Sci. Soc. Amer. J., 44, 892-898.

*agricultural drainage.* J. Hydrol., 332(3–4), 374–380.

*fundamental.* Elsevier, sixth edition, 733.

*complex hillslopes.* Water Resour. Res., 41, W06001, doi:10.1029/2004WR003725, 1-13.

*conductivity and drainable porosity using the inverse problem technique.* J. Irrig. Drain.

*la transferencia de agua en un sistema de drenaje agrícola subterráneo.* Ingeniería

*Saturated-Unsaturated Soil by Finite Elements*. Agricultural Water Management, 2, 37-

de una columna de suelo inicialmente saturado. Ingeniería Hidráulica en México,

*bidimensional aplicada al drenaje agrícola subterráneo.* Ingeniería hidráulica en México,

Fine-textured clayey soils are of high fertility but often have a low hydraulic conductivity (Forsburg, 2003; Tuli et al., 2005). The infiltration of water into these soils is too slow therefore frequent surface ponding occurs. It follows that clay soils are usually poorly drained and difficult to manage when wet. Agricultural activities and mechanisation are extremely restricted without adequate drainage (Ritzema, 1994). Besides, clay soils often have a seasonal variation in hydraulic conductivity because of swelling and shrinking (Tuller & Or, 2003). Due to the swelling of clay, rainfall is unable to percolate deeper into drains. It either accumulates in depressions or discharges as surface runoff. Therefore the effectiveness of subsurface drainage of clay soils much depends on the permeability of trench backfill. Based on the assumption that 2.5% of the soil volume in a newly tile-drained clay soil is made up of backfill (0.5 m wide pipe trench and 20 m drain spacing), it is obvious that the backfilling method has a great impact on drainage efficiency of such soil (Ulén, 2007). Traditional subsurface drainage in such soils does not always ensure excess water removal within the normative period; therefore, adding of the amendments to the trench backfill increasing water infiltration rate is practiced frequently. The permeability of these soils can be greatly improved by filling the trenches with coarse material. In Western Europe gravel was used for drainage trench backfill (Ritzema, 1994; Smedema et al., 2004). However, in some countries this is too expensive because of the limit of natural resources of gravel.

Many researchers reported that lime additives contribute substantially to the change in the physical properties of clay soils (Puustinen, 2001; Rajasekaran & Narasimha, 2002; Halme et al., 2003; Mubeen, 2005; Cox et al., 2005). They referred that due to a certain rate of added lime the soil bulk density may be reduced by 25%, porosity increased by 30%, filtration coefficient increased 100-300 times, the amount of aggregates (0.25-10 mm) increased 3 times and the swelling practically disappear. As a result, soil mixed with lime is less susceptible to compaction, because calcium and magnesium carbonates may form hydro-silicates inducing soil resistance to the pressure. In addition, lime modifies the characteristics of clay particles so that they flocculate resulting in easier movement of all major ingredients in plant development i. e. higher amount of mobile phosphorus, potassium, nitrogen, sulphur, calcium and magnesium, and lower amount of mobile aluminium. Therefore, liming leads not only to an improved water regime but also to the changes in water quality.

Calcium carbonate (CaCO3), gypsum (CaSO4·2H2O), dolomitic limestone (CaMg(CO3)2), quicklime (CaO) or other calcium-containing materials may be used as liming material.

An Assessment of Lime Filter Drainage Systems 183

tightly and are generally resistant to leaching (Bergström et al., 2007). Phosphate binding capacity increases from sand to clay because of the adsorption of phosphorus to soil

In 1995-1999, lime filter drainage (LFD) was installed on almost 1000 hectares of land in Finland as means to combat drainage-induced adverse environmental impacts of acid sulphate soils (Bärlund et al., 2005; Aström et al., 2007). The average lifetime for the LFD has been shown to exceed 10 years without any loss in treatment effect. In Sweden, the method has only been tested at one experimental site (Ulén, 2003) and the long-term effects have not

The territory of Lithuania lies in the zone of excessive humidity; therefore, 88% of farmlands are artificially drained. The problem of agricultural non-point pollution is typical for Lithuania because the surplus of nutrients is leached from the soil profile to the drainage water. According to the data of the Agency of the Environment Protection, in 2005 concentrations of biogenic compounds exceeded the maximum admissible concentrations (MAC) in 64% of the investigated rivers. It was estimated that agriculture contributes from 42.2 to 71.1% of the total phosphorus load depending on the percentage of arable land (Šileika, 2010). However, there are large regional differences and great variations in the amounts of P lost from agricultural land as a result of differences in soils, soil hydrology and land use patterns (Valsami-Jones, 2004; Withers & Haygarth, 2007). Curtailment of pollution extension is a very urgent question in the clayey soils with low water permeability that makes up 45.3% of soil cover in Lithuania. Therefore, the field studies, the aim of which was to investigate the efficiency of lime filter drainage under the different climate conditions and to evaluate the impact of lime admixture in trench backfill on drainage water quality in clay

The greater part of fine-textured clay soils are located in the Middle Lithuanian Plain. Two sites at different districts were arranged for field experiments in order to assess the

*Pasvalys site*. The site was arranged in 1986. It has been in operation for a ten-year period. The *Endocalcari-Epihypogleyic Cambisols* with soil texture of silty clay loam (according to FAO classification) are prevailing here. Soil acidity in the topsoil layer (0.0-0.2 m) ranges from pH 5.9 to pH 6.6. Deeper soil horizons were near neutrality (6.6 < pH < 7.2). The experimental set-up consisted of 200 x 40 m levelled plots surrounded by a 0.4-m high dike and resembled to an artificial land surface depression (Fig. 1). The site was drained with single tile drains, spacing at 4 m, trench width of 0.5 m, 33 cm long tile drains with an inner diameter of 75

Steady-state infiltration method using a ring infiltrometer was applied to determine saturated hydraulic conductivity (K-values) of the soil. The ring (H = 0.25 m, d = 0.4 m) driven into the soil at the depth of 0.1 m was supplied with a constant head of water at 0.1 m from a mariotte bottle. K-values of the topsoil layer vary within a wide range (0.65–2.75 m/d). The statistical mean value at *p*<0.05 equalled to 1.70±1.05 m/d whereas the mean

value of the subsoil layer (at the depth of 0.30 m) was only 0.04±0.03 m/d.

particles (Djodjic et al., 2004).

been monitored.

soils were conducted.

**2. Study objects and investigation methods** 

efficiency of lime filter drainage in such soils.

mm were laid at the depth of 1.0 m.

Lime is usually applied by spreading it on the soil surface. However, lime will not react well unless it is incorporated into the soil (Doss et al., 1979). Stable structure of clay soils may ensure properly prepared soil-lime mixture. Therefore it is crucial to mix thoroughly the soil with liming material before the arrangement of lime filters and the filling of the drainage trenches. To obtain excellent soil structure, the optimal proportion of lime should be determined. Unfortunately, there is insufficient research about the methods for calculation lime rates required to improve infiltration features of clay soils.

Nowadays usage of the drained land must be substantiated not only economically, but have also corresponded to the ecological requirements. Drainage impact on water quality is evaluated contradictorily. It stimulates the natural process of organic matter mineralization and expedites the transport of chemical substances from the soil zone to surface waters (Zucker & Brown, 1998; Busman & Sands, 2002). Therefore the new tasks and functions of land reclamation activities should be focused on the reduction of their negative action on the environment, which consists of the intensive emission of biogenic substances by drainage water (Skaggs et al., 1994; Heiskanen et al., 2004).

As in the clay soil the largest part of runoff discharges through more permeable drainage trenches, backfilled trench above drain tiles can be considered as a pathway for preferential transport of biogenic substances (Dekker et al., 2001; Cho et al., 2005). Preferential flow has always been conceived to have a detrimental impact on water quality because it moves solutes beyond the soil zone where both biotic and abiotic chemical reactions are usually at their highest potentials (Ryan 1998; Ekholm et al., 1999; Van den Eertwegh, 2006). In finetextured soils preferential flow is generally considered more significant in contrast to coarsetextured soils, therefore for these soils additional measures should be considered to reduce leaching of pollutants (Van der Salm et al., 2007).

Various technologies are currently being developed to reduce concentrations of biogenic substances in tile effluent (Foy & Dils, 1998). Ionic composition of water changes with the introduction of calcium-containing materials to the soil. Increased soil pH influences the concentration of many dissolved ions in the soil solution. Literature sources affirmed that soil treated with lime amendments noticeably prevent the migration of phosphorus (Rhoton & Bigham, 2005), however, limited data is available on the alternation of the concentrations of other basic ions.

A method developed for clayey soils in Finland involves incorporating burnt lime (CaO) with the backfill material in drains (Weppling & Palko, 1994). Soils treated with lime contain high amount of soluble and exchangeable Ca2+ ions, and frequently also calcium carbonate CaCO3. Phosphate is reported to react with both ionic and the carbonate form of Ca to form insoluble compounds (Tan, 2010). The reactions can be illustrated as follows:

$$\text{3 Ca}^{2+} + 2\text{PO}\_4^{3-} \rightarrow \text{Ca(PO}\_4)\_2\downarrow$$

$$\text{\color{red}{3}CaCO\_3 + 2PO\_4^{3-} \rightarrow Ca\_3(PO\_4)\_2\downarrow} + \text{\color{red}{3}CO\_2\uparrow}$$

Therefore the lime filter drainage acts as a mini chemical treatment plant and may be treated as one of water pollution control methods in agriculture (Rhoton & Bigham, 2005). The result is a stable and porous backfill that efficiently binds the phosphorus in percolating water (Curtin & Syers, 2001; Murphy & Stevens, 2010). The adsorbed phosphates are held

Lime is usually applied by spreading it on the soil surface. However, lime will not react well unless it is incorporated into the soil (Doss et al., 1979). Stable structure of clay soils may ensure properly prepared soil-lime mixture. Therefore it is crucial to mix thoroughly the soil with liming material before the arrangement of lime filters and the filling of the drainage trenches. To obtain excellent soil structure, the optimal proportion of lime should be determined. Unfortunately, there is insufficient research about the methods for calculation

Nowadays usage of the drained land must be substantiated not only economically, but have also corresponded to the ecological requirements. Drainage impact on water quality is evaluated contradictorily. It stimulates the natural process of organic matter mineralization and expedites the transport of chemical substances from the soil zone to surface waters (Zucker & Brown, 1998; Busman & Sands, 2002). Therefore the new tasks and functions of land reclamation activities should be focused on the reduction of their negative action on the environment, which consists of the intensive emission of biogenic substances by drainage

As in the clay soil the largest part of runoff discharges through more permeable drainage trenches, backfilled trench above drain tiles can be considered as a pathway for preferential transport of biogenic substances (Dekker et al., 2001; Cho et al., 2005). Preferential flow has always been conceived to have a detrimental impact on water quality because it moves solutes beyond the soil zone where both biotic and abiotic chemical reactions are usually at their highest potentials (Ryan 1998; Ekholm et al., 1999; Van den Eertwegh, 2006). In finetextured soils preferential flow is generally considered more significant in contrast to coarsetextured soils, therefore for these soils additional measures should be considered to reduce

Various technologies are currently being developed to reduce concentrations of biogenic substances in tile effluent (Foy & Dils, 1998). Ionic composition of water changes with the introduction of calcium-containing materials to the soil. Increased soil pH influences the concentration of many dissolved ions in the soil solution. Literature sources affirmed that soil treated with lime amendments noticeably prevent the migration of phosphorus (Rhoton & Bigham, 2005), however, limited data is available on the alternation of the concentrations

A method developed for clayey soils in Finland involves incorporating burnt lime (CaO) with the backfill material in drains (Weppling & Palko, 1994). Soils treated with lime contain high amount of soluble and exchangeable Ca2+ ions, and frequently also calcium carbonate CaCO3. Phosphate is reported to react with both ionic and the carbonate form of Ca to form

3 Ca2+ + 2PO43- Ca3(PO4)2

3CaCO3 + 2PO43- Ca3(PO4)2 + 3CO2 Therefore the lime filter drainage acts as a mini chemical treatment plant and may be treated as one of water pollution control methods in agriculture (Rhoton & Bigham, 2005). The result is a stable and porous backfill that efficiently binds the phosphorus in percolating water (Curtin & Syers, 2001; Murphy & Stevens, 2010). The adsorbed phosphates are held

insoluble compounds (Tan, 2010). The reactions can be illustrated as follows:

lime rates required to improve infiltration features of clay soils.

water (Skaggs et al., 1994; Heiskanen et al., 2004).

leaching of pollutants (Van der Salm et al., 2007).

of other basic ions.

tightly and are generally resistant to leaching (Bergström et al., 2007). Phosphate binding capacity increases from sand to clay because of the adsorption of phosphorus to soil particles (Djodjic et al., 2004).

In 1995-1999, lime filter drainage (LFD) was installed on almost 1000 hectares of land in Finland as means to combat drainage-induced adverse environmental impacts of acid sulphate soils (Bärlund et al., 2005; Aström et al., 2007). The average lifetime for the LFD has been shown to exceed 10 years without any loss in treatment effect. In Sweden, the method has only been tested at one experimental site (Ulén, 2003) and the long-term effects have not been monitored.

The territory of Lithuania lies in the zone of excessive humidity; therefore, 88% of farmlands are artificially drained. The problem of agricultural non-point pollution is typical for Lithuania because the surplus of nutrients is leached from the soil profile to the drainage water. According to the data of the Agency of the Environment Protection, in 2005 concentrations of biogenic compounds exceeded the maximum admissible concentrations (MAC) in 64% of the investigated rivers. It was estimated that agriculture contributes from 42.2 to 71.1% of the total phosphorus load depending on the percentage of arable land (Šileika, 2010). However, there are large regional differences and great variations in the amounts of P lost from agricultural land as a result of differences in soils, soil hydrology and land use patterns (Valsami-Jones, 2004; Withers & Haygarth, 2007). Curtailment of pollution extension is a very urgent question in the clayey soils with low water permeability that makes up 45.3% of soil cover in Lithuania. Therefore, the field studies, the aim of which was to investigate the efficiency of lime filter drainage under the different climate conditions and to evaluate the impact of lime admixture in trench backfill on drainage water quality in clay soils were conducted.

#### **2. Study objects and investigation methods**

The greater part of fine-textured clay soils are located in the Middle Lithuanian Plain. Two sites at different districts were arranged for field experiments in order to assess the efficiency of lime filter drainage in such soils.

*Pasvalys site*. The site was arranged in 1986. It has been in operation for a ten-year period. The *Endocalcari-Epihypogleyic Cambisols* with soil texture of silty clay loam (according to FAO classification) are prevailing here. Soil acidity in the topsoil layer (0.0-0.2 m) ranges from pH 5.9 to pH 6.6. Deeper soil horizons were near neutrality (6.6 < pH < 7.2). The experimental set-up consisted of 200 x 40 m levelled plots surrounded by a 0.4-m high dike and resembled to an artificial land surface depression (Fig. 1). The site was drained with single tile drains, spacing at 4 m, trench width of 0.5 m, 33 cm long tile drains with an inner diameter of 75 mm were laid at the depth of 1.0 m.

Steady-state infiltration method using a ring infiltrometer was applied to determine saturated hydraulic conductivity (K-values) of the soil. The ring (H = 0.25 m, d = 0.4 m) driven into the soil at the depth of 0.1 m was supplied with a constant head of water at 0.1 m from a mariotte bottle. K-values of the topsoil layer vary within a wide range (0.65–2.75 m/d). The statistical mean value at *p*<0.05 equalled to 1.70±1.05 m/d whereas the mean value of the subsoil layer (at the depth of 0.30 m) was only 0.04±0.03 m/d.

An Assessment of Lime Filter Drainage Systems 185

During the investigations water from an adjacent stream was pumped into the experimental site. The site was flooded 16 times during the season from April to November considering

Three sets of soil samples with 30 replications at the mid-point between the drains were taken at a depth of 0.25-0.30 m every time before the site was flooded. Soil moisture content was determined in the laboratory by the gravimetric method (the moisture content to be expressed as a percentage of the sample's dry weight). Drain discharges were measured

The lime filter drainage effectiveness when trench backfill was mixed with different amounts of lime was assessed by comparing drainage coefficients as calculated from the

where q – drainage coefficient, m/d, Q *–* pipe discharge, m3/d, L – drain spacing, m, B –

*Kalnujai site*. Another experimental site with a total area of 14.6 ha was arranged in the Jūra

<sup>Q</sup> , L B *<sup>q</sup>* (1)

three times a day, keeping the water level at 0.2 m above the soil surface.

soil water content.

length of line, m.

following equation (Ritzema, 1994):

river catchment of the South-Western Lithuania (Fig. 2).

Fig. 2. Geographical location and experimental layout of Kalnujai site.

Drainage water from the main collectors discharges into the modified (deepened and straightened) reach of the Šilupė stream. This stream (length – 4.4 km, basin area – 4.0 km2)

Fig. 1. Plan (A) and cross section (B) of the Pasvalys model site: 1 – dykes (*h* = 0.4 m), 2 – drainage outlet, 3 – non-perforated plastic pipe (*l* = 10 m; *d* = 100 mm), 4 – tile drains (*d* = 75 mm), 5 – trenches with different backfill, 6 – topsoil layer, 7 – open main drain, 8 – open water inlet to the pipe collector.

For the investigation of the efficiency of the surface water drainage in heavy soils, drains with the higher permeability of trench backfill (when using both mineral and organic materials) were arranged. Alongside the lime filter, backfills with sand/gravel mixture (Kf=11.2 m/d), breakstone (Ø10-30 mm), turf (decomposition rate 10%), chopped straw (5 kg/m), wood chips (0.036 m3/m) were arranged in the site.

Shale ashes containing 16.8% CaO from Estonia were used as liming material. It is the rest product the burning of shale (in power stations) and contains a mixture of calcium, magnesium, potassium and other trace elements. Neutralising value of shale ashes ranges from 65 to 90% CaCO3. Four different amounts of shale ashes (0.15, 0.30, 0.40 and 0.80% of active CaO for soil mass) were mixed with the clay soil using the transporter of a multiscoop excavator and backfilled to the drainage trenches. Control treatment was backfilled with the disturbed native soil from the trench. All treatments were installed in three replications.

Fig. 1. Plan (A) and cross section (B) of the Pasvalys model site: 1 – dykes (*h* = 0.4 m), 2 – drainage outlet, 3 – non-perforated plastic pipe (*l* = 10 m; *d* = 100 mm), 4 – tile drains (*d* = 75 mm), 5 – trenches with different backfill, 6 – topsoil layer, 7 – open main drain, 8 – open

For the investigation of the efficiency of the surface water drainage in heavy soils, drains with the higher permeability of trench backfill (when using both mineral and organic materials) were arranged. Alongside the lime filter, backfills with sand/gravel mixture (Kf=11.2 m/d), breakstone (Ø10-30 mm), turf (decomposition rate 10%), chopped straw (5

Shale ashes containing 16.8% CaO from Estonia were used as liming material. It is the rest product the burning of shale (in power stations) and contains a mixture of calcium, magnesium, potassium and other trace elements. Neutralising value of shale ashes ranges from 65 to 90% CaCO3. Four different amounts of shale ashes (0.15, 0.30, 0.40 and 0.80% of active CaO for soil mass) were mixed with the clay soil using the transporter of a multiscoop excavator and backfilled to the drainage trenches. Control treatment was backfilled with the disturbed native soil from the trench. All treatments were installed in three

water inlet to the pipe collector.

replications.

kg/m), wood chips (0.036 m3/m) were arranged in the site.

During the investigations water from an adjacent stream was pumped into the experimental site. The site was flooded 16 times during the season from April to November considering soil water content.

Three sets of soil samples with 30 replications at the mid-point between the drains were taken at a depth of 0.25-0.30 m every time before the site was flooded. Soil moisture content was determined in the laboratory by the gravimetric method (the moisture content to be expressed as a percentage of the sample's dry weight). Drain discharges were measured three times a day, keeping the water level at 0.2 m above the soil surface.

The lime filter drainage effectiveness when trench backfill was mixed with different amounts of lime was assessed by comparing drainage coefficients as calculated from the following equation (Ritzema, 1994):

$$q = \frac{\mathbf{Q}}{\mathbf{L} \cdot \mathbf{B}'} \tag{1}$$

where q – drainage coefficient, m/d, Q *–* pipe discharge, m3/d, L – drain spacing, m, B – length of line, m.

*Kalnujai site*. Another experimental site with a total area of 14.6 ha was arranged in the Jūra river catchment of the South-Western Lithuania (Fig. 2).

Fig. 2. Geographical location and experimental layout of Kalnujai site.

Drainage water from the main collectors discharges into the modified (deepened and straightened) reach of the Šilupė stream. This stream (length – 4.4 km, basin area – 4.0 km2)

An Assessment of Lime Filter Drainage Systems 187

where A – amount of lime for one linear meter of the trench, kg; γ – soil bulk density, g/cm3; b – width of drainage trench, m; h – depth of drainage trench, m; n – neutralizing value of lime according to the total amount of CaO and MgO, %; a – optimal amount of lime

Silty clay soil samples (sum of <0.01 mm physical clay particles made up 73.8%) were mixed with lime additives (0.6% of active lime for soil mass). After 28 days a microphoto was taken and then enlarged 400 times (Fig. 4). The photo clearly shows 15-20% higher soil porosity (black color) than that of the soil where no lime was added. Based on the laboratory results the amount of lime for one linear meter of the trench backfill was calculated out of the soil characteristic and drainage parameters in Kalnujai site (γ = 1.58 g/cm3, b = 0.5 m, h *=* 1.1 m,

Fig. 4. Microphoto of clay soils (enlarged 400 times): 1 – silty clay; 2 – the same clay mixed

*Soil and climate data.* The Jūra catchment drains middle part of Žemaičiai Upland, the surface of which is covered with humus rich but poor in labile phosphorus clay loams (80% of the basin area). Almost half (47%) of average annual precipitation amount turns to runoff. Such conditions stimulate soil outwash and inflow of adsorbed phosphorus. High concentrations of suspended matter in the Jūra and its tributaries show the phosphorus loads to be formed there by soil erosion. It must be noted, that Lithuanian soils have low phosphorus retention

*Orthi-Haplic Luvisols* (*LVh-or*) and *Hapli-Epihypogleyic Luvisols* (*LVg-p-w-ha*) with soaking features prevail in the site. The soils of sandy clay loam/clay loam are maintained at about pH 6.9-7.5. The layer below 40 cm consisted from over 60 to 34% of clay. At the beginning of the investigations the average bulk density determined in the soil profile to the depth of 1.0 m was 1.65±0.02 g/cm3, particle density – 2.67±0.01 g/cm3, porosity – 38.05±0.43%, phosphorus content in the plough-layer (0–23 cm) ranges from very low to medium (27-144

Perennial grasses for hay were grown in the period of four years (1999-2002). In autumn of 2002, the plot was tilled and since 2003 it has been used under crop cultivation. Principal

potential (the definition is based on global soil climate map and global soil map).

mg/kg), potassium content varied from 84 to 124 mg/kg.

N = 43.0%, n = 21.5%). Estimated amount of shale ashes was 24 kg/m.

required to improve soil permeability, %.

with 0.6% CaO

crops are cereals.

A = b h a n-1, (3)

according to the Lithuanian river classification, is attributed to small rivers that constitute 75.5% of the total length of all rivers (Gailiušis et al., 2001). Small and medium rivers that usually are drainage water recipients are very important from the ecological point of view because concentrations of biogenic substances there are often higher than in the large rivers.

Experimental drainage systems with lime backfill were installed in 1989 (Fig. 3). The site was drained by composite subsurface drainage systems. Tile drainpipes (length of 33 cm, laterals Ø50 mm, collectors Ø75 mm) have been installed at the depth of 1.1 m, width of drainage trench – 0.5 m. Three drainage treatments have been installed with four replications of each:


Fig. 3. Installation of lime filter drainage in Kalnujai site

*Calculations of the optimal lime rate*. Laboratory experiments with different clay soil samples were carried out before the lime filter drainage installation in order to determine the optimal rates of lime additives to be mixed with clay soil of a trench backfill. Equation (2) was obtained from the results of laboratory analyses (Blažys et al., 1993):

$$\mathbf{a} = 0.13 + 0.011 \text{ N},\tag{2}$$

where a – optimal lime rate considering active CaO and MgO, %; N – amount of physical clay particles contained in soil, %.

This equation should be applied when the soil contains from 20 to 80% of physical clay particles (<0.01 mm). This particular composition was named as physical clay according to soil textural classification by Kačinskij, which was used in the former Soviet Union.

Laboratory findings showed, that water permeability of clay soils is increasing when lime rate is increased to a certain limit that depends on the amount of physical clay particles obtained in the soil. Lime activity should not be less than 70-85% for dry mass as this is the best material to improve the texture of clay soils. The optimal amount of lime that needs to be mixed with clay soil in order to enhance its best hydraulic conductivity may be calculated from the following equation:

according to the Lithuanian river classification, is attributed to small rivers that constitute 75.5% of the total length of all rivers (Gailiušis et al., 2001). Small and medium rivers that usually are drainage water recipients are very important from the ecological point of view because concentrations of biogenic substances there are often higher than in the large rivers. Experimental drainage systems with lime backfill were installed in 1989 (Fig. 3). The site was drained by composite subsurface drainage systems. Tile drainpipes (length of 33 cm, laterals Ø50 mm, collectors Ø75 mm) have been installed at the depth of 1.1 m, width of drainage trench – 0.5 m. Three drainage treatments have been installed with four

1. drainage trench backfill mixed with lime (0.6% CaO), drain spacing L = 16 m;

*Calculations of the optimal lime rate*. Laboratory experiments with different clay soil samples were carried out before the lime filter drainage installation in order to determine the optimal rates of lime additives to be mixed with clay soil of a trench backfill. Equation (2) was

where a – optimal lime rate considering active CaO and MgO, %; N – amount of physical

This equation should be applied when the soil contains from 20 to 80% of physical clay particles (<0.01 mm). This particular composition was named as physical clay according to

Laboratory findings showed, that water permeability of clay soils is increasing when lime rate is increased to a certain limit that depends on the amount of physical clay particles obtained in the soil. Lime activity should not be less than 70-85% for dry mass as this is the best material to improve the texture of clay soils. The optimal amount of lime that needs to be mixed with clay soil in order to enhance its best hydraulic conductivity may be calculated

soil textural classification by Kačinskij, which was used in the former Soviet Union.

a = 0.13 + 0.011 N, (2)

3. (control) – drainage trench backfilled with native clay loam soil, L = 16 m.

Fig. 3. Installation of lime filter drainage in Kalnujai site

clay particles contained in soil, %.

from the following equation:

obtained from the results of laboratory analyses (Blažys et al., 1993):

replications of each:

2. the same, L = 24 m;

$$\mathbf{A} = \mathbf{y} \text{ b } \mathbf{h} \text{ a } \mathbf{n}^{\text{-1}},\tag{3}$$

where A – amount of lime for one linear meter of the trench, kg; γ – soil bulk density, g/cm3; b – width of drainage trench, m; h – depth of drainage trench, m; n – neutralizing value of lime according to the total amount of CaO and MgO, %; a – optimal amount of lime required to improve soil permeability, %.

Silty clay soil samples (sum of <0.01 mm physical clay particles made up 73.8%) were mixed with lime additives (0.6% of active lime for soil mass). After 28 days a microphoto was taken and then enlarged 400 times (Fig. 4). The photo clearly shows 15-20% higher soil porosity (black color) than that of the soil where no lime was added. Based on the laboratory results the amount of lime for one linear meter of the trench backfill was calculated out of the soil characteristic and drainage parameters in Kalnujai site (γ = 1.58 g/cm3, b = 0.5 m, h *=* 1.1 m, N = 43.0%, n = 21.5%). Estimated amount of shale ashes was 24 kg/m.

Fig. 4. Microphoto of clay soils (enlarged 400 times): 1 – silty clay; 2 – the same clay mixed with 0.6% CaO

*Soil and climate data.* The Jūra catchment drains middle part of Žemaičiai Upland, the surface of which is covered with humus rich but poor in labile phosphorus clay loams (80% of the basin area). Almost half (47%) of average annual precipitation amount turns to runoff. Such conditions stimulate soil outwash and inflow of adsorbed phosphorus. High concentrations of suspended matter in the Jūra and its tributaries show the phosphorus loads to be formed there by soil erosion. It must be noted, that Lithuanian soils have low phosphorus retention potential (the definition is based on global soil climate map and global soil map).

*Orthi-Haplic Luvisols* (*LVh-or*) and *Hapli-Epihypogleyic Luvisols* (*LVg-p-w-ha*) with soaking features prevail in the site. The soils of sandy clay loam/clay loam are maintained at about pH 6.9-7.5. The layer below 40 cm consisted from over 60 to 34% of clay. At the beginning of the investigations the average bulk density determined in the soil profile to the depth of 1.0 m was 1.65±0.02 g/cm3, particle density – 2.67±0.01 g/cm3, porosity – 38.05±0.43%, phosphorus content in the plough-layer (0–23 cm) ranges from very low to medium (27-144 mg/kg), potassium content varied from 84 to 124 mg/kg.

Perennial grasses for hay were grown in the period of four years (1999-2002). In autumn of 2002, the plot was tilled and since 2003 it has been used under crop cultivation. Principal crops are cereals.

An Assessment of Lime Filter Drainage Systems 189

The comparison of ion concentration means during the investigation period was made, i.e. a hypothesis was checked if mixing lime into drainage trench backfill had impact on the basic ions concentrations in drainage water. In parallel, water quality differences of the control

The reliability of the results was determined by processing them with mathematical statistical methods, using MS Excel 2000 Data Analysis Tool Pack. Differences of drainage treatments were tested at the significance level *p* < 0.05 and *p* < 0.01. The temporal changes in concentrations of basic ions were evaluated choosing the most reliable trendlines for the data sets. Correlation between phosphorus concentrations in the drainage treatments and meteorological indices (precipitation and temperature) was established. The annual load of phosphorus and nitrogen was calculated on the basis of the linear interpolation method

**3.1 The effect of lime admixture to trench backfill on the functioning of tile drainage in** 

The drainage treatments efficiency was assessed by comparing drainage coefficients in the Pasvalys site. The data obtained shows that the drainage coefficient (q) from the control trench backfill reduces by 13 times on the average when the soil moisture content increases from 23.0 to 27.0% (Fig. 6). When the drainage trench is mixed with shale ashes, lime reduces clay swelling and ensures stabilized clay soil structure. This results in more stable drainage coefficients. When trench backfill is mixed with 0.15 and 0.30% CaO, q decrease by 4.2 and 3.3 times respectively; when 0.40 and 0.80% CaO is applied, – only 2.6

In case when the soil moisture content is less (23.0%), the average drainage coefficients from trench backfill mixed with 0.40% CaO are 0.58 m/d, i. e. 11 times higher than in the control treatment (0.05 m/d). With higher soil moisture content (27.0%) q is even 55 times higher in treatment with 0.40% CaO (0.22 m/d) than in the control treatment (0.004 m/d). This is a

drainage treatment and stream water were compared.

**3. Results** 

**clay soils** 

times.

recommended by the Helsinki Commission (Guidelines…, 1994).

rather favourable index for drainage functioning at critical moments.

Parameter Method References pH Electrometry ISO 10523-1:1994 Calcium EDTA Titrimetry LAND 68:2002 Magnesium EDTA Titrimetry LAND 73:2005 Potassium Flame Photometry LST ISO 9964-3:1998 Sodium Flame Photometry LST ISO 9964-3:1998 Chloride Mohr's method LAND 63-2004 Sulphate Gravimetric ISO 9280 Bicarbonate Potentiometric LST EN ISO 9963-2:1999 Phosphate Spectrophotometry LAND 58:2003 Nitrate Spectrophotometry LST EN ISO 13395:2000 Ammonia Spectrophotometry LAND 38:2000 Table 1. Analytical methods for determining chemical composition of drainage water.

The data of Meteorological Station located 5 km from the experimental site was used to characterize meteorological conditions. The mean air temperature of the study period was 7.1°C and exceeded the seasonal norm (5.9°C) by about +1.2°C. In the warmest years – 2000, 2002 and 2008 – it was by about +2°C higher than the norm (higher temperatures were more frequent in winter–spring months – December–April and July) (Fig. 5).

Fig. 5. The means of monthly precipitation and air temperature, 1999–2009 (error bars show data range)

The territory experienced 71% of annual precipitation during the warm season (April – October). Comparison with seasonal norm of annual precipitation the years of 2001 and 2007 attributes to humid ones (precipitation likelihood 14 and 2%). In the dry year (2005) precipitation likelihood was 93%. The remaining period may be considered as moderate: annual precipitation was close to long-term average for this region (665 mm). Significantly uneven rainfall distribution was observed in April and May (variation coefficient V = 68– 73%). In some years precipitation in January, May and October made 2.5–3 of monthly norm, while the average of April made only 60%. Drainage occurred during the entire year of 2001 and 2007, in 2005 dormant period of the drainage lasted even for ten months.

*Data collection and analysis.* To evaluate the efficiency of lime filter drainage, drain discharge and watertable depth were measured once a day in the main drainage season (from January to May). Drain discharges were measured by volumetric way in the tile outlets, while the depth of the watertable was measured in observation wells installed at the mid-point between the parallel laterals in each treatment. Hydraulic conductivity of drainage trench backfill, topsoil layer and soil between the drains were measured by the same ring infiltration method as in the Pasvalys site.

Monitoring on water quality in the site has been ongoing since 1999. Water samples were analysed for pH, calcium (Ca2+), magnesium (Mg2+), potassium (K+), sodium (Na+), chloride (Cl–), sulphate (SO42–), bicarbonate (HCO3–) phosphate (PO4 3–), nitrate (NO3 –) and ammonia (NH4 +) ions also for total phosphorus (TP) and total nitrogen (TN). Periodicity of sampling was once a month. Water samples from the Šilupė stream were taken simultaneously. The methods used to determine chemical parameters are summarized in Table 1.

The data of Meteorological Station located 5 km from the experimental site was used to characterize meteorological conditions. The mean air temperature of the study period was 7.1°C and exceeded the seasonal norm (5.9°C) by about +1.2°C. In the warmest years – 2000, 2002 and 2008 – it was by about +2°C higher than the norm (higher temperatures were more

Fig. 5. The means of monthly precipitation and air temperature, 1999–2009 (error bars show

The territory experienced 71% of annual precipitation during the warm season (April – October). Comparison with seasonal norm of annual precipitation the years of 2001 and 2007 attributes to humid ones (precipitation likelihood 14 and 2%). In the dry year (2005) precipitation likelihood was 93%. The remaining period may be considered as moderate: annual precipitation was close to long-term average for this region (665 mm). Significantly uneven rainfall distribution was observed in April and May (variation coefficient V = 68– 73%). In some years precipitation in January, May and October made 2.5–3 of monthly norm, while the average of April made only 60%. Drainage occurred during the entire year

of 2001 and 2007, in 2005 dormant period of the drainage lasted even for ten months.

*Data collection and analysis.* To evaluate the efficiency of lime filter drainage, drain discharge and watertable depth were measured once a day in the main drainage season (from January to May). Drain discharges were measured by volumetric way in the tile outlets, while the depth of the watertable was measured in observation wells installed at the mid-point between the parallel laterals in each treatment. Hydraulic conductivity of drainage trench backfill, topsoil layer and soil between the drains were measured by the same ring

Monitoring on water quality in the site has been ongoing since 1999. Water samples were analysed for pH, calcium (Ca2+), magnesium (Mg2+), potassium (K+), sodium (Na+), chloride (Cl–), sulphate (SO42–), bicarbonate (HCO3–) phosphate (PO43–), nitrate (NO3–) and ammonia (NH4+) ions also for total phosphorus (TP) and total nitrogen (TN). Periodicity of sampling was once a month. Water samples from the Šilupė stream were taken simultaneously. The

methods used to determine chemical parameters are summarized in Table 1.

frequent in winter–spring months – December–April and July) (Fig. 5).

data range)

infiltration method as in the Pasvalys site.


Table 1. Analytical methods for determining chemical composition of drainage water.

The comparison of ion concentration means during the investigation period was made, i.e. a hypothesis was checked if mixing lime into drainage trench backfill had impact on the basic ions concentrations in drainage water. In parallel, water quality differences of the control drainage treatment and stream water were compared.

The reliability of the results was determined by processing them with mathematical statistical methods, using MS Excel 2000 Data Analysis Tool Pack. Differences of drainage treatments were tested at the significance level *p* < 0.05 and *p* < 0.01. The temporal changes in concentrations of basic ions were evaluated choosing the most reliable trendlines for the data sets. Correlation between phosphorus concentrations in the drainage treatments and meteorological indices (precipitation and temperature) was established. The annual load of phosphorus and nitrogen was calculated on the basis of the linear interpolation method recommended by the Helsinki Commission (Guidelines…, 1994).

#### **3. Results**

#### **3.1 The effect of lime admixture to trench backfill on the functioning of tile drainage in clay soils**

The drainage treatments efficiency was assessed by comparing drainage coefficients in the Pasvalys site. The data obtained shows that the drainage coefficient (q) from the control trench backfill reduces by 13 times on the average when the soil moisture content increases from 23.0 to 27.0% (Fig. 6). When the drainage trench is mixed with shale ashes, lime reduces clay swelling and ensures stabilized clay soil structure. This results in more stable drainage coefficients. When trench backfill is mixed with 0.15 and 0.30% CaO, q decrease by 4.2 and 3.3 times respectively; when 0.40 and 0.80% CaO is applied, – only 2.6 times.

In case when the soil moisture content is less (23.0%), the average drainage coefficients from trench backfill mixed with 0.40% CaO are 0.58 m/d, i. e. 11 times higher than in the control treatment (0.05 m/d). With higher soil moisture content (27.0%) q is even 55 times higher in treatment with 0.40% CaO (0.22 m/d) than in the control treatment (0.004 m/d). This is a rather favourable index for drainage functioning at critical moments.

An Assessment of Lime Filter Drainage Systems 191

1 Control backfill 1.02 0.31 0.05 0.005 0.96 2 0.15% CaO 1.62 0.48 0.10 0.012 0.77 3 0.30% CaO 2.22 0.66 0.17 0.019 0.67 4 0.40% CaO 7.53 2.22 0.69 0.252 0.82 5 0.80% CaO 7.18 2.12 0.59 0.171 0.81

Drainage coefficient, m/d

Correlation coefficient

regression equation

Table 2. Coefficients of regression equation (4), and comparable values of drainage

Fig. 7. Comparison of different backfills efficiency in the reference of drainage water discharges per unit length (soil moisture content W=27%): 1 – control (native clay soil) , 2 – wood chips , 3 – chopped straw , 4 – sand/gravel mixture; 5 – turf; 6 – breakstone; 7 – the

The obvious advantage of lime filter drainage over other backfills shows the unquestionable efficiency of this measure when draining the surface water excess in heavy clay soils. Since this conclusion was based on the experiments carried out in the model site it was important to investigate efficiency of lime filter drainage under natural field conditions. Further

backfill mixed with lime (0.40 % of active CaO).

investigations were carried out in the Kalnujai site.

Analysing the permeability of other drainage backfills it was defined that the permeability of all of them was higher than of the control one. It was substantiated on the calculated discharges per unit length. The data show that with the higher moisture content (27%) in clay soils, discharges from the drains with wood chips backfill are 5 times higher than from the drains with control backfill, with chopped straw backfill – 10, with sand and gravel mixture – 14, with turf backfill – 18, with breakstone backfill – 24 times higher (Fig. 7). The drainage works even more effectively when backfill was mixed with lime (0.40% of active CaO) – 45 times better than drains with control backfill (drainage discharge 0.045 l/sm).

**A B** max min

No Type of backfill Coefficients of

coefficient (*p* < 0.01).

Fig. 6. Trendlines of drainage coefficients in the Pasvalys site.

In case when soil moisture content is higher (27.0%) drainage coefficients from trench backfill mixed with 0.80% CaO are 0.20 m/d, i.e. 50 times higher than in the treatment without lime (0.004 m/d). When trench backfill contained half as much lime (0.40% CaO), q is by 55 times higher. This shows that a certain limit was achieved above which the increased amount of lime additives does not result in the increased permeability of the trench backfill. It could be explained by the large amount of ballast elements contained in shale ashes that frequently make up 85% of the whole material. The ballast elements fill in a certain part of soil pores, and so decrease water permeability of the trench backfill.

The following logarithmic relationship between soil moisture content and drainage coefficients of different drainage trench backfill was determined when analyzing the data over a ten-year period (1987-1997):

$$\mathbf{q} = \mathbf{A} \text{-B } \ln \mathbf{w}\_2 \tag{4}$$

where q – drainage coefficient, m/d; A and B – coefficients of regression equation (Table 2), w – soil moisture content at a 25-30 cm deep soil layer, %.

The equation (4) is valid when the soil moisture content is changing within the range of 23 to 27%. Observations have shown that the changing moisture content of clay soils enhances the changes in water permeability of the trench backfill: with the increase in soil moisture content the drainage coefficients decrease (*r* = 0.67 - 0.96). A strong reverse relationship was determined between the soil moisture content and drainage coefficients from the control drains and in treatments with 0.40 and 0.80% CaO; a moderate relationship was determined when the drains were backfilled with fewer amounts of lime (0.15 and 0.30% CaO) (Šaulys, 1999).

In case when soil moisture content is higher (27.0%) drainage coefficients from trench backfill mixed with 0.80% CaO are 0.20 m/d, i.e. 50 times higher than in the treatment without lime (0.004 m/d). When trench backfill contained half as much lime (0.40% CaO), q is by 55 times higher. This shows that a certain limit was achieved above which the increased amount of lime additives does not result in the increased permeability of the trench backfill. It could be explained by the large amount of ballast elements contained in shale ashes that frequently make up 85% of the whole material. The ballast elements fill in a

The following logarithmic relationship between soil moisture content and drainage coefficients of different drainage trench backfill was determined when analyzing the data

where q – drainage coefficient, m/d; A and B – coefficients of regression equation (Table 2),

The equation (4) is valid when the soil moisture content is changing within the range of 23 to 27%. Observations have shown that the changing moisture content of clay soils enhances the changes in water permeability of the trench backfill: with the increase in soil moisture content the drainage coefficients decrease (*r* = 0.67 - 0.96). A strong reverse relationship was determined between the soil moisture content and drainage coefficients from the control drains and in treatments with 0.40 and 0.80% CaO; a moderate relationship was determined when the drains were backfilled with fewer amounts of lime (0.15 and 0.30% CaO) (Šaulys,

q = A-B ln w, (4)

certain part of soil pores, and so decrease water permeability of the trench backfill.

Fig. 6. Trendlines of drainage coefficients in the Pasvalys site.

w – soil moisture content at a 25-30 cm deep soil layer, %.

over a ten-year period (1987-1997):

1999).


Table 2. Coefficients of regression equation (4), and comparable values of drainage coefficient (*p* < 0.01).

Analysing the permeability of other drainage backfills it was defined that the permeability of all of them was higher than of the control one. It was substantiated on the calculated discharges per unit length. The data show that with the higher moisture content (27%) in clay soils, discharges from the drains with wood chips backfill are 5 times higher than from the drains with control backfill, with chopped straw backfill – 10, with sand and gravel mixture – 14, with turf backfill – 18, with breakstone backfill – 24 times higher (Fig. 7). The drainage works even more effectively when backfill was mixed with lime (0.40% of active CaO) – 45 times better than drains with control backfill (drainage discharge 0.045 l/sm).

Fig. 7. Comparison of different backfills efficiency in the reference of drainage water discharges per unit length (soil moisture content W=27%): 1 – control (native clay soil) , 2 – wood chips , 3 – chopped straw , 4 – sand/gravel mixture; 5 – turf; 6 – breakstone; 7 – the backfill mixed with lime (0.40 % of active CaO).

The obvious advantage of lime filter drainage over other backfills shows the unquestionable efficiency of this measure when draining the surface water excess in heavy clay soils. Since this conclusion was based on the experiments carried out in the model site it was important to investigate efficiency of lime filter drainage under natural field conditions. Further investigations were carried out in the Kalnujai site.

An Assessment of Lime Filter Drainage Systems 193

I (0.6% CaO, L=16 m) 0.55 0.54 0.42 0.93 0.61 II (0.6% CaO, L=24 m) 0.57 0.52 0.41 0.93 0.61 III (control, L=16 m) 0.49 0.33 0.22 0.77 0.45

The relationship between drainage coefficients and watertable depth in between the drains

where q – drainage coefficient, m/d; m and n – coefficients of regression equation; h – depth

Fig. 9. Relationship between drainage discharge and watertable depth in between the drains

The statistical analysis shows there are significant differences between the mean values of watertable depths in the control drainage system and those of the treatments with lime

In the period 2000-2002 the watertable depth in LFD I was on average 0.25±0.04 m deeper than in the control drainage system while in LFD II it was 0.21±0.03 m deeper. It was also observed that during the wet period (in 2002) the differences between watertable depth in LFD and the control drainage were more distinct (0.33±0.05 m and 0.24±0.04 m respectively)

than during the dry period (in 2000) (0.20±0.02 and 0.18±0.02 m respectively).

q = m e-nh, (5)

Table 3. Average watertable depth between the drains (m) in 2000.

of the watertable in between the drains, m.

(Šaulys & Bastienė, 2003)

mixed into the trench backfill (Table 4).

(Fig. 9) may be expressed by the exponential regression (*r* = 0.85 - 0.91):

Treatments Months Average I II III IV (I-IV)

Under the meteorological conditions of Lithuania, drainage outflow commonly lasts till the beginning of May. In autumn it starts again in November. During the months from January to April there are usually several peaks of drainage outflow, the time and duration of which depend on the fluctuations of air temperature and precipitation.

Three peaks of drainage discharge were observed in Kalnujai site. The first peak was observed in the first ten-day period of January when the soil surface was frozen. Average drainage discharges were 3.0 mm/d (control), treatments with lime - 3.2–3.3 mm/d. The differences between the control drainage and LFD were 6.6–10%. The highest drainage discharge measured in the system of control drainage during the snow melt period at the outset of February reached 6.7 mm/d and was 1.3 times higher than the design drainage coefficient (5.2 mm/d). At the same time drainage discharge in LFD was lower, reaching 6.2 mm/d in treatment I, and 5.0 mm/d in treatment II. The third slightly lower discharge peak occurred on the middle of March. During this peak drainage discharge in the control system and in LFD I with the same spacing (L=16 m) were equal (4.2 mm/d). In LFD II with spacing L=24 m, drainage discharge was 3.8 mm/d, i.e. decreased by 11%. As the data shows, it is difficult to evaluate the advantage of drainage variants because of great impact of meteorological conditions on drainage work.

The differences between the control and lime filter drainage are more noticeable according to watertable depth between the drains (Fig. 8).

Fig. 8. Dynamic of groundwater level in different drainage treatments (Kalnujai site, 2000) (Šaulys & Bastienė, 2003).

During the main drainage season (from January to April) average depth of the watertable in the control drainage system was 0.16 m (35%) higher than in LFD. Increased drain spacing from 16 to 24 m has no negative impact as the depth of the watertable in LFD varied from 0.003 to 0.025 m and was statistically insignificant (Table 3).

Under the meteorological conditions of Lithuania, drainage outflow commonly lasts till the beginning of May. In autumn it starts again in November. During the months from January to April there are usually several peaks of drainage outflow, the time and duration of which

Three peaks of drainage discharge were observed in Kalnujai site. The first peak was observed in the first ten-day period of January when the soil surface was frozen. Average drainage discharges were 3.0 mm/d (control), treatments with lime - 3.2–3.3 mm/d. The differences between the control drainage and LFD were 6.6–10%. The highest drainage discharge measured in the system of control drainage during the snow melt period at the outset of February reached 6.7 mm/d and was 1.3 times higher than the design drainage coefficient (5.2 mm/d). At the same time drainage discharge in LFD was lower, reaching 6.2 mm/d in treatment I, and 5.0 mm/d in treatment II. The third slightly lower discharge peak occurred on the middle of March. During this peak drainage discharge in the control system and in LFD I with the same spacing (L=16 m) were equal (4.2 mm/d). In LFD II with spacing L=24 m, drainage discharge was 3.8 mm/d, i.e. decreased by 11%. As the data shows, it is difficult to evaluate the advantage of drainage variants because of great impact of

The differences between the control and lime filter drainage are more noticeable according

Fig. 8. Dynamic of groundwater level in different drainage treatments (Kalnujai site, 2000)

During the main drainage season (from January to April) average depth of the watertable in the control drainage system was 0.16 m (35%) higher than in LFD. Increased drain spacing from 16 to 24 m has no negative impact as the depth of the watertable in LFD varied from

0.003 to 0.025 m and was statistically insignificant (Table 3).

depend on the fluctuations of air temperature and precipitation.

meteorological conditions on drainage work.

to watertable depth between the drains (Fig. 8).

(Šaulys & Bastienė, 2003).


Table 3. Average watertable depth between the drains (m) in 2000.

The relationship between drainage coefficients and watertable depth in between the drains (Fig. 9) may be expressed by the exponential regression (*r* = 0.85 - 0.91):

$$\mathbf{q} \equiv \mathbf{m} \ e^{\mathbf{m} \mathbf{h}} \tag{5}$$

where q – drainage coefficient, m/d; m and n – coefficients of regression equation; h – depth of the watertable in between the drains, m.

Fig. 9. Relationship between drainage discharge and watertable depth in between the drains (Šaulys & Bastienė, 2003)

The statistical analysis shows there are significant differences between the mean values of watertable depths in the control drainage system and those of the treatments with lime mixed into the trench backfill (Table 4).

In the period 2000-2002 the watertable depth in LFD I was on average 0.25±0.04 m deeper than in the control drainage system while in LFD II it was 0.21±0.03 m deeper. It was also observed that during the wet period (in 2002) the differences between watertable depth in LFD and the control drainage were more distinct (0.33±0.05 m and 0.24±0.04 m respectively) than during the dry period (in 2000) (0.20±0.02 and 0.18±0.02 m respectively).

An Assessment of Lime Filter Drainage Systems 195

In order to ensure satisfactory functioning of drainage in clay soils, the inflow through drainage trench backfill should be more than the inflow through the topsoil layer. Between the permeability of topsoil layer and trench backfill the following dependency should be:

 ktbt 1,48 kaha. (8) The width of drainage trenches dug by multi-scoop excavator – bt = 50 cm, thickness of the

 kt 0,450,60 ka. (9) The tests of infiltration allowed to compare the hydraulic conductivity of the control and lime filter drainage backfill with hydraulic conductivity of undisturbed clay soil at the same

Fig. 10. Variation of water infiltration rate in the Kalnujai site: ()–trench backfill mixed with

The mean value of water infiltration rate in the trench backfill with lime at p< 0.05 after the steady flow was established amounted to 3.2±0.25 m/d and was 1.5 times higher than in control backfill – 2.2±0.14 m/d. The water infiltration rate between the drains reached only 0.83±0.09 m/d, i.e. 2.6 times lower than in the control backfill and 3.8 times lower than in the backfill with lime. The power trendlines show the changes of infiltration rate (*r* = 0.65-0.82). Lime admixture into the trench backfill in clay soils ensures lower watertables and improved water regime of the body of soil between the trenches because heavy clay soils often have relatively high permeable top layer, which is determined by the agriculture activity. In cases of perched watertable surplus of water interflows the pervious top layer, which has connection with trench backfill more permeable than the original soil. This flow

mechanism will only work if the backfill is of high hydraulic conductivity.

**3.2 The effect of lime filter drainage on chemical composition of drainage water** 

Chemical analysis showed that lime admixture determined changes of ions composition of drainage water (Table 5). Lime admixture has hardly any influence on drainage water pH

topsoil layer in clay soils ha = 15-20 cm. Based on the equation (8) we receive that:

depth between the drains (Fig. 10).

lime, ()–control backfill, ()–soil between the drains.


*Note*: Mean value ± confidence interval

Table 4. Statistical estimation of differences in the reference of watertable depth in lime filter drainage and control drainage (*p*<0.05)

The data obtained at the Kalnujai site were similar to the study results gained by Gurklys (1998), who has determined that watertable between the drains was 20-30% lower when lime was added into the drainage trench backfill (this difference is most obvious when watertable are at their highest level).

According to measurements watertable depth at 0.10 m below the soil surface in the control drainage system lasted for 11 days; at the depths of 0.20 and 0.30 m it remained for 20.5 and 24 days. In drainage treatments with lime it rose only to 0.30 m from the soil surface and remained here for 5.5 and 6 days respectively. The increased drain spacing did not result in less drainage functioning.

Clay soils often have relatively high permeable top layer, which is determined by the agriculture activity. Under extreme conditions topsoil layer saturates by surface water and depression curve does not form. In this case, inflow to the drains can be roughly estimated according to the Donat-Slichter formula (Bereslavskii, 2008):

$$\mathbf{q} = \mathbf{1}/48 \text{ k}\_a \text{ h}\_\nu \tag{6}$$

where q – water inflow from the 1 m width strip formed between the drains, m3/s; ka – hydraulic conductivity of top layer, m/s; ha *–* thickness of the top layer, m.

In cases of perched watertable (when clay soils are swollen) surplus of water interflows the pervious top layer, which has connection with trench backfill more permeable than the original soil. This flow mode will only be evident if the backfill is of high hydraulic conductivity:

$$\mathbf{q} = \mathbf{k}\_{\ell} \cdot \mathbf{b}\_{\nu} \tag{7}$$

where kt – hydraulic conductivity of the drainage backfill, m/s; bt – width of the trench, m.

2000 (precipitation 112% of seasonal norm) I (L=16 m) 60 0.31 0.08 0.20±0.02 0.06 28.6 II (L=24 m) 60 0.29 0.06 0.18±0.02 0.05 30.7 2001 (precipitation 116% of seasonal norm) I (L=16 m) 41 0.40 0.07 0.23±0.04 0.08 38.1 II (L=24 m) 41 0.36 0.02 0.23±0.04 0.09 39.4 2002 (precipitation 143% of seasonal norm) I (L=16 m) 56 0.62 0.10 0.33±0.05 0.14 43.9 II (L=24 m) 56 0.44 0.08 0.24±0.04 0.11 44.4 2000-2002 I (L=16 m) 157 0.62 0.07 0.25±0.04 0.10 38.7 II (L=24 m) 157 0.44 0.02 0.21±0.03 0.07 32.5

Table 4. Statistical estimation of differences in the reference of watertable depth in lime filter

The data obtained at the Kalnujai site were similar to the study results gained by Gurklys (1998), who has determined that watertable between the drains was 20-30% lower when lime was added into the drainage trench backfill (this difference is most obvious when

According to measurements watertable depth at 0.10 m below the soil surface in the control drainage system lasted for 11 days; at the depths of 0.20 and 0.30 m it remained for 20.5 and 24 days. In drainage treatments with lime it rose only to 0.30 m from the soil surface and remained here for 5.5 and 6 days respectively. The increased drain spacing did not result in

Clay soils often have relatively high permeable top layer, which is determined by the agriculture activity. Under extreme conditions topsoil layer saturates by surface water and depression curve does not form. In this case, inflow to the drains can be roughly estimated

where q – water inflow from the 1 m width strip formed between the drains, m3/s; ka –

In cases of perched watertable (when clay soils are swollen) surplus of water interflows the pervious top layer, which has connection with trench backfill more permeable than the original soil. This flow mode will only be evident if the backfill is of high hydraulic

q=ktbt, (7)

where kt – hydraulic conductivity of the drainage backfill, m/s; bt – width of the trench, m.

hydraulic conductivity of top layer, m/s; ha *–* thickness of the top layer, m.

q=1,48 ka ha, (6)

Groundwater level differences, m Standard

*n* Max Min Mean SD, m V, %

deviation

Variation coefficient

Drainage treatments

Number of measureme nts

*Note*: Mean value ± confidence interval

drainage and control drainage (*p*<0.05)

watertable are at their highest level).

according to the Donat-Slichter formula (Bereslavskii, 2008):

less drainage functioning.

conductivity:

In order to ensure satisfactory functioning of drainage in clay soils, the inflow through drainage trench backfill should be more than the inflow through the topsoil layer. Between the permeability of topsoil layer and trench backfill the following dependency should be:

$$\mathbf{k}\_l \cdot \mathbf{b}\_l \ge \mathbf{1}\_l \mathbf{48} \,\mathrm{k}\_a \mathbf{h}\_a \tag{8}$$

The width of drainage trenches dug by multi-scoop excavator – bt = 50 cm, thickness of the topsoil layer in clay soils ha = 15-20 cm. Based on the equation (8) we receive that:

$$\mathbf{k} \ge \mathbf{0}.45 \div \mathbf{0}.60 \text{ k}\_{\text{u}}.\tag{9}$$

The tests of infiltration allowed to compare the hydraulic conductivity of the control and lime filter drainage backfill with hydraulic conductivity of undisturbed clay soil at the same depth between the drains (Fig. 10).

Fig. 10. Variation of water infiltration rate in the Kalnujai site: ()–trench backfill mixed with lime, ()–control backfill, ()–soil between the drains.

The mean value of water infiltration rate in the trench backfill with lime at p< 0.05 after the steady flow was established amounted to 3.2±0.25 m/d and was 1.5 times higher than in control backfill – 2.2±0.14 m/d. The water infiltration rate between the drains reached only 0.83±0.09 m/d, i.e. 2.6 times lower than in the control backfill and 3.8 times lower than in the backfill with lime. The power trendlines show the changes of infiltration rate (*r* = 0.65-0.82).

Lime admixture into the trench backfill in clay soils ensures lower watertables and improved water regime of the body of soil between the trenches because heavy clay soils often have relatively high permeable top layer, which is determined by the agriculture activity. In cases of perched watertable surplus of water interflows the pervious top layer, which has connection with trench backfill more permeable than the original soil. This flow mechanism will only work if the backfill is of high hydraulic conductivity.

#### **3.2 The effect of lime filter drainage on chemical composition of drainage water**

Chemical analysis showed that lime admixture determined changes of ions composition of drainage water (Table 5). Lime admixture has hardly any influence on drainage water pH


Table 5. Statistical estimation of basic ions concentrations (mg/l) in the Kalnujai site in 1999- 2007.

An Assessment of Lime Filter Drainage Systems 197

because the mean values of the pH for the different treatments are almost the same (pH 7.40.06). They have relatively small standard deviations and variation coefficients (3.4-

Calcium and magnesium cations prevail in drainage water. They make 64 and 25% of the total cation amount respectively. In treatments with lime (I and II), the mean Ca2+ concentrations were 97.64.0 and 96.44.2 mg/l, in the control treatment they were 2–3% higher (99.94.3 mg/l). Statistically the differences of these concentrations were insignificant (Table 6). The mean Ca2+ concentration in the stream water was only 5–8% lower compared with the drainage water outflow. However, the estimation of mean differences by t-test showed that it was significant (*p*<0.01). During the entire period of observations Ca2+ concentrations did not exceed maximum admissible concentrations (MAC) in surface water

I-III - - - ++ - ++ ++ - ++ - - III-str ++ ++ ++ ++ ++ + ++ ++ ++ ++ - *Notes*: - difference statistically insignificant at *p <* 0.05; + difference statistically significant at *p <* 0.05; ++

Table 6. Testing of **s**tatistical differences between the means of basic ions concentrations in

Average concentrations of Mg2+ in drainage water were 2.5 times lower than the average concentrations of Ca2+. They vary between 16 and 52 mg/l (the mean of I-III treatments – 38.6±2.2 mg/l). At certain moments due to biochemical processes taking place in the soil (especially in summer) the maximum values of Mg2+ concentrations were 30% higher than the MAC (40 mg/l) in surface water. In the stream water average Mg2+ concentration was

Migration of K+ depends on the hydrogeological environment of soil (especially on pH). As the pH increases, increased soil cation exchange capacity (CEC) occurs, as well as reduced leaching of basic cations, particularly K+. The research made in the Kalnujai site showed that K+ ions were more stable in the neutral environment. Therefore, it was observed that lime filter drainage water had the average potassium concentrations 1.7 times lower compared with the control treatments and 6.8 times lower compared with the Šilupė stream water (0.95±0.08, 1.62±0.13 and 6.42±0.66 mg/l respectively). The test on the differences between the mean values of the potassium ions concentrations in the different treatments would lead

Analysis show that lime did not have any effect on Na+ concentrations in drainage water: treatments I-II – 16.7±1.3 mg/l, III – 17.0±0.9 mg/l. Sodium ions concentrations were nearly two times lower in the stream water compared with drainage water (mean value 9.7±0.7

There were significant differences between the mean values of the concentrations of Cl-

SO42- anions in drainage water of LFD and in control treatment where they were thereabout

to the conclusion that they are indeed statistically significant at *p* < 0.01.

SO42- \*HCO3- PO4

3- NO3- NH4

+

and

3.7%), pH values of stream water range from 7.4 to 8.4.

(180 mg/l).

21.4±1.1 mg/l.

mg/l).

Treat- Chemical parameters

difference statistically significant at *p <* 0.01.

drainage treatments and the Šilupė stream

ments pH Ca2+ \*Mg2+ K+ \*Na+ Cl-

Table 5. Statistical estimation of basic ions concentrations (mg/l) in the Kalnujai site in 1999-

2007.

because the mean values of the pH for the different treatments are almost the same (pH 7.40.06). They have relatively small standard deviations and variation coefficients (3.4- 3.7%), pH values of stream water range from 7.4 to 8.4.

Calcium and magnesium cations prevail in drainage water. They make 64 and 25% of the total cation amount respectively. In treatments with lime (I and II), the mean Ca2+ concentrations were 97.64.0 and 96.44.2 mg/l, in the control treatment they were 2–3% higher (99.94.3 mg/l). Statistically the differences of these concentrations were insignificant (Table 6). The mean Ca2+ concentration in the stream water was only 5–8% lower compared with the drainage water outflow. However, the estimation of mean differences by t-test showed that it was significant (*p*<0.01). During the entire period of observations Ca2+ concentrations did not exceed maximum admissible concentrations (MAC) in surface water (180 mg/l).


*Notes*: - difference statistically insignificant at *p <* 0.05; + difference statistically significant at *p <* 0.05; ++ difference statistically significant at *p <* 0.01.

Table 6. Testing of **s**tatistical differences between the means of basic ions concentrations in drainage treatments and the Šilupė stream

Average concentrations of Mg2+ in drainage water were 2.5 times lower than the average concentrations of Ca2+. They vary between 16 and 52 mg/l (the mean of I-III treatments – 38.6±2.2 mg/l). At certain moments due to biochemical processes taking place in the soil (especially in summer) the maximum values of Mg2+ concentrations were 30% higher than the MAC (40 mg/l) in surface water. In the stream water average Mg2+ concentration was 21.4±1.1 mg/l.

Migration of K+ depends on the hydrogeological environment of soil (especially on pH). As the pH increases, increased soil cation exchange capacity (CEC) occurs, as well as reduced leaching of basic cations, particularly K+. The research made in the Kalnujai site showed that K+ ions were more stable in the neutral environment. Therefore, it was observed that lime filter drainage water had the average potassium concentrations 1.7 times lower compared with the control treatments and 6.8 times lower compared with the Šilupė stream water (0.95±0.08, 1.62±0.13 and 6.42±0.66 mg/l respectively). The test on the differences between the mean values of the potassium ions concentrations in the different treatments would lead to the conclusion that they are indeed statistically significant at *p* < 0.01.

Analysis show that lime did not have any effect on Na+ concentrations in drainage water: treatments I-II – 16.7±1.3 mg/l, III – 17.0±0.9 mg/l. Sodium ions concentrations were nearly two times lower in the stream water compared with drainage water (mean value 9.7±0.7 mg/l).

There were significant differences between the mean values of the concentrations of Cl- and SO4 2- anions in drainage water of LFD and in control treatment where they were thereabout

An Assessment of Lime Filter Drainage Systems 199

Fig. 11. Variation of calcium cations concentration in drainage treatments and stream water.

Fig. 12. Variation of potassium cations concentration in the Kalnujai site.

They were near the natural background levels for most Lithuanian rivers.

(Fig. 13). Accordingly, the mean values of sodium concentrations decreased by 25% (LFD) and by 21% (III) while bicarbonates concentrations – by 20% on the average. At the same time there was no decreasing/increasing trend in these concentrations in the stream water.

23% higher. Sulphate concentration in the stream water varied from 21 to 120 mg/l (mean value 62±3.9 mg/l). It is noteworthy, that during warm season sulphate concentration in the stream water was higher than it is allowed in open water bodies (MAC=100 mg/l), however, it was not influenced by drainage water but by biochemical processes in the nature.

HCO3 - anions prevail in the Kalnujai site water. Their concentrations vary from 209 to 595 mg/l in drainage water and from 205 to 398 mg/l in the stream water. Concentration differences between the drainage treatments are insignificant; values are closely grouped around the mean (CV = 15–18%).

The highest average concentrations of PO43- were determined in the drainage outflow of the control treatment (0.114 mg/l). Summing-up all study period the mean value of phosphate ions was 1.9 times higher than the average concentrations in the Šilupė stream water (0.06 mg/l). In the outflow of lime filter drainage PO4 3- concentrations were 66% lower than in the control drainage water. The statistical analysis determined those differences to be significant at *p*<0.01. So, it can be concluded that LFD may reduce phosphate ions concentrations considerably. PO43- in Šilupė stream ranged between 0.003 and 0.150 mg/l and do not exceed Lithuanian surface water quality standards.

Water containing nitrate concentrations above 10 mg/l is considered to be of relatively poor quality, whereas 55–60% higher NO3 concentrations were determined in LFD treatments I-II (15.5±3.8 – 15.9±4.1 mg/l). The average concentrations of NO3- in control drainage water were 15% higher compared to the treatments with lime. Nitrate levels in the Šilupė stream were about 2.5 times higher and exceeded the guideline concentration for nitrate in surface water.

In the water of small rivers ammonium made up about 5–10% of the total amount of nitrogen, therefore, the concentrations of this ion were much less: in the Šilupė stream – 0.11±0.04 mg/l, in drainage treatments – 0.08±0.03 – 0.09±0.04 mg/l. They did not exceed MAC approved in Lithuania (1 mg/l).

The following regularities were established by analysing the variation tendencies of the basic ions concentrations in the experimental drainage water and the Šilupė stream water during the studies. The fluctuations of Ca2+ ions concentrations were expressed by an Order 2 polynomial trendlines with one valley in the autumn of 2002 (*r*=0.69–0.76) (Fig. 11). The same type regression was detected when analysing the fluctuations of Mg2+ and Cl- concentrations; however, the trendlines reliability is of less significance (*r*Mg=0.55–0.60, *r*Cl=0.62–0.73).

As the soil solution in the site was near neutrality (pH=6.8) K+ concentrations in LFD water were stably lower compared with the control drainage during the entire observation period. Despite the seasonal variation (CV=33–51%), trends of concentrations of K+ ions generally remained steady throughout the ten-year period both in water of drainage treatments and the Šilupė stream (Fig. 12).

The similar slightly decreasing linear trends of Na+, SO4 2- and HCO3 ions concentrations (*r*Na=0.31–0.42, *r*SO4=0.59–0.65, *r*HCO3=0.32–0.40) in drainage water were detected. At the end of monitoring the mean values of sulphate concentrations decreased by 50% in LFD and by 53% in control treatment in comparison with those observed at the onset of investigations

23% higher. Sulphate concentration in the stream water varied from 21 to 120 mg/l (mean value 62±3.9 mg/l). It is noteworthy, that during warm season sulphate concentration in the stream water was higher than it is allowed in open water bodies (MAC=100 mg/l), however, it was not influenced by drainage water but by biochemical processes in the

HCO3- anions prevail in the Kalnujai site water. Their concentrations vary from 209 to 595 mg/l in drainage water and from 205 to 398 mg/l in the stream water. Concentration differences between the drainage treatments are insignificant; values are closely grouped

The highest average concentrations of PO43- were determined in the drainage outflow of the control treatment (0.114 mg/l). Summing-up all study period the mean value of phosphate ions was 1.9 times higher than the average concentrations in the Šilupė stream water (0.06 mg/l). In the outflow of lime filter drainage PO43- concentrations were 66% lower than in the control drainage water. The statistical analysis determined those differences to be significant at *p*<0.01. So, it can be concluded that LFD may reduce phosphate ions concentrations

Water containing nitrate concentrations above 10 mg/l is considered to be of relatively poor

(15.5±3.8 – 15.9±4.1 mg/l). The average concentrations of NO3- in control drainage water were 15% higher compared to the treatments with lime. Nitrate levels in the Šilupė stream were about 2.5 times higher and exceeded the guideline concentration for nitrate in surface

In the water of small rivers ammonium made up about 5–10% of the total amount of nitrogen, therefore, the concentrations of this ion were much less: in the Šilupė stream – 0.11±0.04 mg/l, in drainage treatments – 0.08±0.03 – 0.09±0.04 mg/l. They did not exceed

The following regularities were established by analysing the variation tendencies of the basic ions concentrations in the experimental drainage water and the Šilupė stream water during the studies. The fluctuations of Ca2+ ions concentrations were expressed by an Order 2 polynomial trendlines with one valley in the autumn of 2002 (*r*=0.69–0.76) (Fig. 11). The same type regression was detected when analysing the fluctuations of Mg2+ and Cl- concentrations; however, the trendlines reliability is of less significance (*r*Mg=0.55–0.60,

As the soil solution in the site was near neutrality (pH=6.8) K+ concentrations in LFD water were stably lower compared with the control drainage during the entire observation period. Despite the seasonal variation (CV=33–51%), trends of concentrations of K+ ions generally remained steady throughout the ten-year period both in water of drainage treatments and

(*r*Na=0.31–0.42, *r*SO4=0.59–0.65, *r*HCO3=0.32–0.40) in drainage water were detected. At the end of monitoring the mean values of sulphate concentrations decreased by 50% in LFD and by 53% in control treatment in comparison with those observed at the onset of investigations

3- in Šilupė stream ranged between 0.003 and 0.150 mg/l and do not

concentrations were determined in LFD treatments I-II

2- and HCO3-

ions concentrations

nature.

around the mean (CV = 15–18%).

quality, whereas 55–60% higher NO3-

MAC approved in Lithuania (1 mg/l).

exceed Lithuanian surface water quality standards.

considerably. PO4

water.

*r*Cl=0.62–0.73).

the Šilupė stream (Fig. 12).

The similar slightly decreasing linear trends of Na+, SO4

Fig. 11. Variation of calcium cations concentration in drainage treatments and stream water.

Fig. 12. Variation of potassium cations concentration in the Kalnujai site.

(Fig. 13). Accordingly, the mean values of sodium concentrations decreased by 25% (LFD) and by 21% (III) while bicarbonates concentrations – by 20% on the average. At the same time there was no decreasing/increasing trend in these concentrations in the stream water. They were near the natural background levels for most Lithuanian rivers.

An Assessment of Lime Filter Drainage Systems 201

I-III were 0.77, 0.64 and 1.02 mg/l respectively. Conspicuous moderate downward trend (r=0.66–0.74) in all treatments was determined in the time series. The situation changed after the grassland had been tilled in the autumn of 2002. The concentrations of NO3- began progressively increase every year. Trends of nitrates of the second streak can be expressed by strong linear regression (*r*=0.83–0.88). It must be noted that NO3- concentrations in Šilupė stream water started rising thereabout the year later than in drainage water (from the

NH4+ level both in the Šilupė stream and drainage water changed widely from the beginning of the investigations until the middle of 2001. Later, fluctuations of ammonium

**3.3 Fluctuation of biogenic substances concentration and loads with drainage outflow**  The highest average concentrations of TP and PO4–P were determined in the drainage outflow of the control treatment (Table 7). They reached 0.044±0.006 and 0.032±0.004 mg/l, respectively. Summing-up of all study period the mean value of PO4–P was 1.8 times higher than its average concentrations in the Šilupė stream water (0.018±0.003 mg/l) and 3.2 times higher than its average concentrations in the outflow of LFD treatments (0.010±0.001 mg/l). Extreme annual values of PO4–P (0.049 mg/l) were quantified in the dry year of 2003, when

Indices I II III Stream I II III Stream

Mean 0.021 0.021 0.044 0.039 0.010 0.010 0.032 0.018 Max 0.035 0.034 0.060 0.062 0.013 0.015 0.046 0.027 Min 0.012 0.012 0.028 0.026 0.008 0.007 0.022 0.012 SD 0.007 0.007 0.009 0.012 0.001 0.002 0.006 0.005 V % 33 33 20 31 13 22 19 26 Conf 95 0.004 0.004 0.006 0.007 0.001 0.001 0.004 0.003

TP PO4-P

SD – standard deviation, V % - variation coefficient, Conf95 – 95% confidence interval for a mean Table 7. The mean concentrations of phosphorus (mg/l) in drain discharge and stream

TP concentration in the Šilupė steam varied between 0.026 and 0.062 mg/l (the mean value 0.039±0.007 mg/l). PO4–P concentration in receiving stream increased from the lowest values in spring (0.012 mg/l) to 0.027 mg/l in August (the mean value 0.018±0.003 mg/l). According to the rates approved in Lithuania, surface water quality is considered to be good than TP < 0.1 mg/l and PO4–P < 0.065 mg/l. Consequently, the water of the Šilupė stream can be considered as uncontaminated with phosphorus because the concentrations do not exceed Lithuanian surface water quality standards. However, critical levels of phosphorus in water, above which eutrophication is likely to be triggered, are approximately 0.03 mg/l of dissolved phosphorus and 0.1 mg/l of total phosphorus. According to the UN ECE classification, surface water is considered fairly eutrophic at 0.025 mg P/l consequently the risk of eutrophication in the Šilupė stream still exists. Whereas phosphorus concentrations in the Šilupė stream besides the Kalnujai site were 1.5 times higher than those found in the

in drainage treatments

cultivation (2003–2007). During the first streak mean values of NO3-

autumn of 2003).

water in 1999–2009.

concentrations assumed a moderate character.

the lowest annual drainage runoff was observed (33 mm).

The distribution of PO43- concentrations in the stream water and lime filter drainage water showed slightly downward trends (*r*str=0.32, *r*(I)=0.27). Considerable fluctuations in phosphate concentrations in the control drainage water were detected, therefore, the reliability of chosen linear trendline is very low (*r*(III)=0.05) (Fig. 14).

Fig. 13. Dynamics of sulphate anions concentration and temporal trends.

Fig. 14. Temporal changes in phosphate ions concentrations for the period 1999-2008.

The distribution of annual average phosphorus concentration in Šilupė stream water within the period of 1999–2008 shows a slightly decreasing trend of TP (*r* = 0.49) and PO4–P (*r* = 0.84). These results confirm the tendencies established earlier and correspond to general character of downward trends found in the Lithuanian rivers within agricultural areas (Povilaitis, 2004; 2006).

Two periods can be discerned when analysing the dynamics of NO3 - concentration in subject to land management. First period lasted from the beginning of the investigations until the end of 2002 when the site was used for grassland. The second period spanned since crop

The distribution of PO43- concentrations in the stream water and lime filter drainage water showed slightly downward trends (*r*str=0.32, *r*(I)=0.27). Considerable fluctuations in phosphate concentrations in the control drainage water were detected, therefore, the

reliability of chosen linear trendline is very low (*r*(III)=0.05) (Fig. 14).

Fig. 13. Dynamics of sulphate anions concentration and temporal trends.

Fig. 14. Temporal changes in phosphate ions concentrations for the period 1999-2008.

(Povilaitis, 2004; 2006).

The distribution of annual average phosphorus concentration in Šilupė stream water within the period of 1999–2008 shows a slightly decreasing trend of TP (*r* = 0.49) and PO4–P (*r* = 0.84). These results confirm the tendencies established earlier and correspond to general character of downward trends found in the Lithuanian rivers within agricultural areas

Two periods can be discerned when analysing the dynamics of NO3- concentration in subject to land management. First period lasted from the beginning of the investigations until the end of 2002 when the site was used for grassland. The second period spanned since crop cultivation (2003–2007). During the first streak mean values of NO3 in drainage treatments I-III were 0.77, 0.64 and 1.02 mg/l respectively. Conspicuous moderate downward trend (r=0.66–0.74) in all treatments was determined in the time series. The situation changed after the grassland had been tilled in the autumn of 2002. The concentrations of NO3 - began progressively increase every year. Trends of nitrates of the second streak can be expressed by strong linear regression (*r*=0.83–0.88). It must be noted that NO3- concentrations in Šilupė stream water started rising thereabout the year later than in drainage water (from the autumn of 2003).

NH4+ level both in the Šilupė stream and drainage water changed widely from the beginning of the investigations until the middle of 2001. Later, fluctuations of ammonium concentrations assumed a moderate character.

#### **3.3 Fluctuation of biogenic substances concentration and loads with drainage outflow**

The highest average concentrations of TP and PO4–P were determined in the drainage outflow of the control treatment (Table 7). They reached 0.044±0.006 and 0.032±0.004 mg/l, respectively. Summing-up of all study period the mean value of PO4–P was 1.8 times higher than its average concentrations in the Šilupė stream water (0.018±0.003 mg/l) and 3.2 times higher than its average concentrations in the outflow of LFD treatments (0.010±0.001 mg/l). Extreme annual values of PO4–P (0.049 mg/l) were quantified in the dry year of 2003, when the lowest annual drainage runoff was observed (33 mm).


SD – standard deviation, V % - variation coefficient, Conf95 – 95% confidence interval for a mean

Table 7. The mean concentrations of phosphorus (mg/l) in drain discharge and stream water in 1999–2009.

TP concentration in the Šilupė steam varied between 0.026 and 0.062 mg/l (the mean value 0.039±0.007 mg/l). PO4–P concentration in receiving stream increased from the lowest values in spring (0.012 mg/l) to 0.027 mg/l in August (the mean value 0.018±0.003 mg/l). According to the rates approved in Lithuania, surface water quality is considered to be good than TP < 0.1 mg/l and PO4–P < 0.065 mg/l. Consequently, the water of the Šilupė stream can be considered as uncontaminated with phosphorus because the concentrations do not exceed Lithuanian surface water quality standards. However, critical levels of phosphorus in water, above which eutrophication is likely to be triggered, are approximately 0.03 mg/l of dissolved phosphorus and 0.1 mg/l of total phosphorus. According to the UN ECE classification, surface water is considered fairly eutrophic at 0.025 mg P/l consequently the risk of eutrophication in the Šilupė stream still exists. Whereas phosphorus concentrations in the Šilupė stream besides the Kalnujai site were 1.5 times higher than those found in the

An Assessment of Lime Filter Drainage Systems 203

 I II III I II III I II III 1999 0.016 0.014 0.042 0.030 0.029 0.062 1.784 1.585 1.951 2000 0.018 0.018 0.058 0.042 0.040 0.085 2.058 1.449 1.856 2001 0.021 0.026 0.048 0.042 0.047 0.074 5.660 3.690 7.510 2002 0.021 0.017 0.062 0.037 0.033 0.078 0.696 0.491 0.791 2003 0.008 0.008 0.016 0.015 0.012 0.022 13.490 12.320 10.900 2004 0.011 0.018 0.050 0.023 0.034 0.062 8.804 11.590 9.513 2005 0.011 0.012 0.036 0.017 0.021 0.038 9.133 6.652 9.822 Total 0.104 0.114 0.313 0.205 0.216 0.420 41.624 37.777 42.343

Year PO4–P TP NO3–N

0.029 ±0.008

Table 8. Annual load of biogenic substances (kg/ha) by drainage outflow in the Kalnujai site

The negative charge on the clay particles retains ammonium ions (NH4+) and protects them from leaching. Nitrate ions (NO3-) are negatively charged and are not retained by the clay particles; therefore, subsurface drainage increased the amount of nitrates that can potentially leach from the soil to the drainage water. The calculations showed that in the control drainage treatment NO3–N load amounted to 6.049±3.2 kg/ha per year on the average. In LFD when drain spacing L=16 m the load of nitrate nitrogen amounted to 5.946±3.5 kg/ha per year, when drain spacing L=24 m, NO3–N load was 9% less (5.397±3.6 kg/ha) on the average. During the seven-year investigations the nitrate nitrogen load was 1.7% and 10.8% less from the lime filter drainage systems than that from the control drainage, but these differences could not be treated as statistically significant. Furthermore, it must be noted that nitrates load in particular years differed much more (variation of data 72-91%) than phosphorus, the load variation of which was only 35-38%. At the same treatment the ratio between marginal values of nitrate load varied from 13.8 to 25.1 during the investigation period. The largest nitrate nitrogen input to the stream water observed in 2003 is likely to be related to intensified agricultural activities (tillage of grassland and crop cultivation, application of mineral fertilizers). Other references also proved that the magnitude of nitrogen loss depended on the soil management (Zucker & Brown, 1998; Povilaitis, 2006). However, the results obtained in the Kalnujai site revealed that the drainage trench backfill permeability improved with lime additives did not increase nitrate

**3.4 Seasonal variability of phosphorus concentrations in lime filter drainage outflow**  Research shows that the differences in between conventional drainage and LFD have a seasonal variation in respect of phosphorus concentrations in drain discharge (Fig. 16). The lowest concentration of TP was determined in September, whereas the highest one – in January. The values of TP concentrations from the plot with LFD shows more variability depending on seasonal peculiarities (V = 33%) versus phosphate phosphorus (V = 13–22%). Dils & Heathwaite (1999) appeal to field experiments in mixed agricultural catchment in the UK and state that phosphorus concentrations in drain discharge are low (<100 μg TP/1) and stable during base-flow periods (<0.5 1/min), and generally lower than the ones in the

0.031 ±0.009

0.060 ±0.017 5.946 ±3.5

5.397 ±3.6

6.049 ±3.2

Annual mean\*

0.015 ±0.004

in 1999-2005 (*p<*0.05).

leaching to drainage water.

0.016 ±0.004

0.045 ±0.011

effluent of LFD, it must be concluded that this drainage practice may reduce surface water pollution with phosphorus compounds.

In Fig. 15 the dynamics of nitrogen concentrations in the Kalnujai site is represented. Despite the seasonal changes, the average concentrations of NO3–N in the Šilupė stream (5.43±0.72 mg/l) generally remained steady during 1999-2003. NO3–N concentrations in the stream water started rising from the autumn of 2003 (approximately the year later than in drainage water). The average NO3–N concentrations of 9.83±1.92 mg/l were determined in 2004-2005.

Fig. 15. Dynamics of nitrogen concentrations in the Kalnujai site (dash and line show linear trends of NO3-N in stream water: *r* = 0.003 and *r* = 0.76, solid line – in drainage water: *r* = 0.66 and *r* = 0.88).

In Lithuanian rivers with natural background level pollution the average concentrations of 0.29 mg/l NO3–N and 0.13 mg/l NH4–N were established (Povilaitis, 2006). The concentrations of NO3–N below 0.3 mg/l are considered to be natural or background levels for most European rivers (Nixon, 2004). It is obvious that in comparison with rivers of natural background level pollution nitrate nitrogen levels in the Šilupė stream are about 20- 30 times higher and exceed the guideline concentration for NO3–N (2.3 mg/l) given for the surface water. The concentrations of NO3–N above 7.5 mg/l are considered to be related with relatively poor quality, though twice-higher concentrations (15.20 mg/l) were determined in 2005.

The annual loads of biogenic substances with drainage outflow in the Kalnujai site are given in Table 8. The greatest annual mean of TP losses (0.06±0.017 kg/ha) was calculated in the control treatment. In LFD the mean leached amounts of TP (0.029-0.031 kg/ha) are 1.9-2.0 times less than in the control treatment; while PO4–P amounts (0.015-0.016 kg/ha) are even 2.7-3.0 times less (0.045±0.011 kg/ha) (the differences are statistically significant at *p* < 0.05). The same differences in terms of total phosphorus loads are statistically significant too. The comparison of phosphorus loads in the drainage treatments with drain spacing L=16 m and L=24 m revealed no significant difference. Hence the lime as amendment of the finetextured soils positively affects the quality of drainage water and reduces the transport of phosphorus into open water bodies.

effluent of LFD, it must be concluded that this drainage practice may reduce surface water

In Fig. 15 the dynamics of nitrogen concentrations in the Kalnujai site is represented. Despite the seasonal changes, the average concentrations of NO3–N in the Šilupė stream (5.43±0.72 mg/l) generally remained steady during 1999-2003. NO3–N concentrations in the stream water started rising from the autumn of 2003 (approximately the year later than in drainage water). The average NO3–N concentrations of 9.83±1.92 mg/l were

Fig. 15. Dynamics of nitrogen concentrations in the Kalnujai site (dash and line show linear trends of NO3-N in stream water: *r* = 0.003 and *r* = 0.76, solid line – in drainage water: *r* =

In Lithuanian rivers with natural background level pollution the average concentrations of 0.29 mg/l NO3–N and 0.13 mg/l NH4–N were established (Povilaitis, 2006). The concentrations of NO3–N below 0.3 mg/l are considered to be natural or background levels for most European rivers (Nixon, 2004). It is obvious that in comparison with rivers of natural background level pollution nitrate nitrogen levels in the Šilupė stream are about 20- 30 times higher and exceed the guideline concentration for NO3–N (2.3 mg/l) given for the surface water. The concentrations of NO3–N above 7.5 mg/l are considered to be related with relatively poor quality, though twice-higher concentrations (15.20 mg/l) were

The annual loads of biogenic substances with drainage outflow in the Kalnujai site are given in Table 8. The greatest annual mean of TP losses (0.06±0.017 kg/ha) was calculated in the control treatment. In LFD the mean leached amounts of TP (0.029-0.031 kg/ha) are 1.9-2.0 times less than in the control treatment; while PO4–P amounts (0.015-0.016 kg/ha) are even 2.7-3.0 times less (0.045±0.011 kg/ha) (the differences are statistically significant at *p* < 0.05). The same differences in terms of total phosphorus loads are statistically significant too. The comparison of phosphorus loads in the drainage treatments with drain spacing L=16 m and L=24 m revealed no significant difference. Hence the lime as amendment of the finetextured soils positively affects the quality of drainage water and reduces the transport of

pollution with phosphorus compounds.

determined in 2004-2005.

0.66 and *r* = 0.88).

determined in 2005.

phosphorus into open water bodies.


Table 8. Annual load of biogenic substances (kg/ha) by drainage outflow in the Kalnujai site in 1999-2005 (*p<*0.05).

The negative charge on the clay particles retains ammonium ions (NH4+) and protects them from leaching. Nitrate ions (NO3-) are negatively charged and are not retained by the clay particles; therefore, subsurface drainage increased the amount of nitrates that can potentially leach from the soil to the drainage water. The calculations showed that in the control drainage treatment NO3–N load amounted to 6.049±3.2 kg/ha per year on the average. In LFD when drain spacing L=16 m the load of nitrate nitrogen amounted to 5.946±3.5 kg/ha per year, when drain spacing L=24 m, NO3–N load was 9% less (5.397±3.6 kg/ha) on the average. During the seven-year investigations the nitrate nitrogen load was 1.7% and 10.8% less from the lime filter drainage systems than that from the control drainage, but these differences could not be treated as statistically significant. Furthermore, it must be noted that nitrates load in particular years differed much more (variation of data 72-91%) than phosphorus, the load variation of which was only 35-38%. At the same treatment the ratio between marginal values of nitrate load varied from 13.8 to 25.1 during the investigation period. The largest nitrate nitrogen input to the stream water observed in 2003 is likely to be related to intensified agricultural activities (tillage of grassland and crop cultivation, application of mineral fertilizers). Other references also proved that the magnitude of nitrogen loss depended on the soil management (Zucker & Brown, 1998; Povilaitis, 2006). However, the results obtained in the Kalnujai site revealed that the drainage trench backfill permeability improved with lime additives did not increase nitrate leaching to drainage water.

#### **3.4 Seasonal variability of phosphorus concentrations in lime filter drainage outflow**

Research shows that the differences in between conventional drainage and LFD have a seasonal variation in respect of phosphorus concentrations in drain discharge (Fig. 16). The lowest concentration of TP was determined in September, whereas the highest one – in January. The values of TP concentrations from the plot with LFD shows more variability depending on seasonal peculiarities (V = 33%) versus phosphate phosphorus (V = 13–22%). Dils & Heathwaite (1999) appeal to field experiments in mixed agricultural catchment in the UK and state that phosphorus concentrations in drain discharge are low (<100 μg TP/1) and stable during base-flow periods (<0.5 1/min), and generally lower than the ones in the

An Assessment of Lime Filter Drainage Systems 205

ments 1 2 3 4 5 6 7 8 9 10 11 12 TP I-II – – – – – – – – – – – – I-III ++ + + + + – – – – – ++ ++ II-III ++ + + + + – – – – – + ++ I-st + – – – – – ++ + + ++ + ++ II-st – – – – – – ++ ++ ++ + + ++ III-st + – – – – – – – – – – – PO4-P I-II – – – – – – – – – – – – I-III ++ + ++ ++ ++ – – – – – ++ ++ II-III + + ++ ++ ++ – – – – – ++ ++ I-st – – – – – – – – – – ++ – II-st – – – – – – + – + – ++ + III-st + + – + + – – – – – – – Table 9. Statistical estimation of phosphorus concentrations in drainage outflow and in the Šilupė stream in the period of 1999–2009 (+ significant difference at *p<*0.05; ++ significant

Hence, the effectiveness of LFD depends on the meteorological conditions of the season. It has been established that in cold season (November–January) TP concentrations decrease by 56–63% in the outflow of LFD (significant differences at *p<*0.01), differences are less significant in February – May period (*p<*0.05), and no significant differences have been established for the June – October period due to high variation of data. Similar variability detected for PO4–P concentrations. According to the data of wet year, phosphate phosphorus content in LFD treatments is significantly lower than that in conventional drainage (*p<*0.01) in all months, with exception of June – October period, when drainage

Comparison of TP concentrations in LFD outflow and in the stream shows that significant differences become distinct in the beginning of July, after the discharge has decreased, and persist until January – in this period TP concentration in the stream increases 2.0–3.6 times. Significant differences between PO4–P concentrations in the stream and in drainage outflow are estimated in November (*p<*0.01), and those at the significance level *p<*0.05 – in July, September and December. In the comparison of LFD no significant differences between

Differences between phosphorus concentrations in stream water and control drainage outflow are observed in some months only. In January – February TP concentration in drainage outflow is 1.8 times higher than that in the stream, but statistically significant differences are estimated only in January. PO4–P concentration in drainage outflow significantly increases (2.3–2.9 times) in January – May, with exception of March. In any other time of year the PO4–P content in drainage outflow was 1.2–1.5 times higher, than that

Treat- Months

difference at *p<*0.01; – no differences)

phosphorus concentrations have been established.

in the stream water, but statistically differences are insignificant.

outflow usually stops.

receiving stream. In contrast, temporary (hours) elevated P peaks are measured in drainflow during high discharge periods (>10 1/min). Large sediment-associated particulate P losses are measured during the first major drain-flow event of the autumn.

Fig. 16. Seasonal variability of mean phosphorus concentrations in drain discharge and stream water during 1999–2009 (I-II – lime filter drainage, III- control drainage)

Results of studies carried out in the Kalnujai site indicate otherwise. The highest PO4–P concentrations in control drainage outflow are fixed during the entire year with extreme values in January. In the Šilupė stream increased PO4–P concentrations are observed in summer, decreased ones – in spring. However, in all months the PO4–P content in receiving stream is lower than that in the control drainage outflow but exceeds that in the outflow from LFD. This confirms that in cultivated areas drainage has a significant impact on PO4–P content in surface water and such means as LFD in clay soils can reduce this negative impact.

The salient inflow of TP in receiving stream was observed in warm season from April to July later concentrations gradually decrease. The highest phosphorus concentrations (0.052-0.062 mg/l) are observed in summer time (June–August) when runoff is low and intensive release of dissolved phosphorus from the sediments takes place. From July to October is the period when TP content in the stream is higher than that in the drainage outflow. A. Povilaitis (2004) states that trends in the change of phosphorus concentrations in Lithuanian rivers are strongly affected by fluctuations of runoff and phosphorus content in streambed sediment. Taking into account the fact that high quantities of phosphorus can be transported with suspended sediments, the significantly increased loads of suspended matter during the heavy rains in summer can result in the increased particulate phosphorus content.

The changes in predominating phosphorus forms in the Šilupė stream depend on the season of the year. The portions of phosphate phosphorus amounts make from 33% to 63% of total phosphorus amount there. The largest ones were detected in winter months. Thus, the water outflowing from the conventional drainage systems can influence water quality in the recipient stream in cold season only but this influence may vary.

Comparison of lime filter drainage (I and II) and control drainage (III) outflow gives ambiguous results, which show that significant differences develop only in certain months (Table 9).

receiving stream. In contrast, temporary (hours) elevated P peaks are measured in drainflow during high discharge periods (>10 1/min). Large sediment-associated particulate P

Fig. 16. Seasonal variability of mean phosphorus concentrations in drain discharge and

Results of studies carried out in the Kalnujai site indicate otherwise. The highest PO4–P concentrations in control drainage outflow are fixed during the entire year with extreme values in January. In the Šilupė stream increased PO4–P concentrations are observed in summer, decreased ones – in spring. However, in all months the PO4–P content in receiving stream is lower than that in the control drainage outflow but exceeds that in the outflow from LFD. This confirms that in cultivated areas drainage has a significant impact on PO4–P content in surface water and such means as LFD in clay soils can reduce this negative

The salient inflow of TP in receiving stream was observed in warm season from April to July later concentrations gradually decrease. The highest phosphorus concentrations (0.052-0.062 mg/l) are observed in summer time (June–August) when runoff is low and intensive release of dissolved phosphorus from the sediments takes place. From July to October is the period when TP content in the stream is higher than that in the drainage outflow. A. Povilaitis (2004) states that trends in the change of phosphorus concentrations in Lithuanian rivers are strongly affected by fluctuations of runoff and phosphorus content in streambed sediment. Taking into account the fact that high quantities of phosphorus can be transported with suspended sediments, the significantly increased loads of suspended matter during the

The changes in predominating phosphorus forms in the Šilupė stream depend on the season of the year. The portions of phosphate phosphorus amounts make from 33% to 63% of total phosphorus amount there. The largest ones were detected in winter months. Thus, the water outflowing from the conventional drainage systems can influence water quality in the

Comparison of lime filter drainage (I and II) and control drainage (III) outflow gives ambiguous results, which show that significant differences develop only in certain months

heavy rains in summer can result in the increased particulate phosphorus content.

recipient stream in cold season only but this influence may vary.

stream water during 1999–2009 (I-II – lime filter drainage, III- control drainage)

impact.

(Table 9).

losses are measured during the first major drain-flow event of the autumn.


Table 9. Statistical estimation of phosphorus concentrations in drainage outflow and in the Šilupė stream in the period of 1999–2009 (+ significant difference at *p<*0.05; ++ significant difference at *p<*0.01; – no differences)

Hence, the effectiveness of LFD depends on the meteorological conditions of the season. It has been established that in cold season (November–January) TP concentrations decrease by 56–63% in the outflow of LFD (significant differences at *p<*0.01), differences are less significant in February – May period (*p<*0.05), and no significant differences have been established for the June – October period due to high variation of data. Similar variability detected for PO4–P concentrations. According to the data of wet year, phosphate phosphorus content in LFD treatments is significantly lower than that in conventional drainage (*p<*0.01) in all months, with exception of June – October period, when drainage outflow usually stops.

Comparison of TP concentrations in LFD outflow and in the stream shows that significant differences become distinct in the beginning of July, after the discharge has decreased, and persist until January – in this period TP concentration in the stream increases 2.0–3.6 times. Significant differences between PO4–P concentrations in the stream and in drainage outflow are estimated in November (*p<*0.01), and those at the significance level *p<*0.05 – in July, September and December. In the comparison of LFD no significant differences between phosphorus concentrations have been established.

Differences between phosphorus concentrations in stream water and control drainage outflow are observed in some months only. In January – February TP concentration in drainage outflow is 1.8 times higher than that in the stream, but statistically significant differences are estimated only in January. PO4–P concentration in drainage outflow significantly increases (2.3–2.9 times) in January – May, with exception of March. In any other time of year the PO4–P content in drainage outflow was 1.2–1.5 times higher, than that in the stream water, but statistically differences are insignificant.

An Assessment of Lime Filter Drainage Systems 207

mm

Temperature °C

I II III Stream Precipitation

0.058 0.049 0.190 **0.817** 1

°C -0.113 -0.328 -0.236 0.486 0.503 1


°C 0.071 -0.106 -0.099 0.805 0.503 1

Table 10. Pirson's correlation coefficients between phosphorus concentration and climate

Subsurface lime filter drainage systems installed in clay soils differ from conventional drainage due to their more efficient hydrological functioning. Lime added to the trench backfill ensures significantly higher surface water infiltration rate, lower watertable depth in

Lime filter drainage positively affects the quality of drainage water. This mean may reduce potassium, chloride, sulphate and phosphate concentrations in drainage water considerably. In the outflow of lime filter drainage the total phosphorus concentrations were 50% lower while phosphate phosphorus concentrations were 64.4% lower than those in the control drainage water. Therefore with certainty must be concluded that lime admixture in trench

However, seasonal variability is characteristic of the efficiency of lime filter drainage under the climatic conditions of Lithuania. It has been estimated that in cold season (November– January) TP concentrations are 2.3–2.7 times lower in outflow of lime filter drainage (significant differences at *p*=0.01), in February – May the differences are less significant (1.5– 2.0 times, *p*=0.05), and no significant differences have been estimated for the June – October period. PO4–P concentration in lime filter drainage treatments is significantly lower than that in conventional drainage (*p*=0.01), with exception of June – October period, when

between the drains and more stable drainage coefficients at critical moments.

backfill may reduce phosphorus transport into open water bodies.

TP

mm

PO4-P

mm

indices.

I 1

I 1

Precipitation

Temperature

Precipitation

Temperature

**4. Conclusions** 

drainage outflow usually stops.

II **0.827** 1

II 0.935 1

III 0.480 0.571 1

III 0.655 0.759 1

Stream 0.364 0.130 0.211 1

Stream 0.301 0.134 0.257 1

In the period of observations phosphorus concentrations in LFD outflow do not pertain neither to precipitation amount nor to fluctuations of air temperature (Fig. 17, Fig. 18). This brings to the statement that the effectiveness of lime does not depend on meteorological conditions.

Fig. 17. Correlation between monthly precipitation (x) and mean PO4-P concentration in drain discharge and stream water (y)

Fig. 18. Correlation between average monthly temperature (x) and mean PO4-P concentration in drain discharge and stream water (y)

Correlation between phosphorus concentrations in the control drainage outflow and the amount of precipitation and temperature are very weak. At the same time strong correlation between TP concentration in surface water and monthly precipitation (*r* = 0.82), and medium correlation (*r* = 0.49) between the PO4–P concentration and the temperature was estimated (Table 10).

In the period of observations phosphorus concentrations in LFD outflow do not pertain neither to precipitation amount nor to fluctuations of air temperature (Fig. 17, Fig. 18). This brings to the statement that the effectiveness of lime does not depend on meteorological

Fig. 17. Correlation between monthly precipitation (x) and mean PO4-P concentration in

Fig. 18. Correlation between average monthly temperature (x) and mean PO4-P

Correlation between phosphorus concentrations in the control drainage outflow and the amount of precipitation and temperature are very weak. At the same time strong correlation between TP concentration in surface water and monthly precipitation (*r* = 0.82), and medium correlation (*r* = 0.49) between the PO4–P concentration and the temperature was

concentration in drain discharge and stream water (y)

estimated (Table 10).

conditions.

drain discharge and stream water (y)


Table 10. Pirson's correlation coefficients between phosphorus concentration and climate indices.

#### **4. Conclusions**

Subsurface lime filter drainage systems installed in clay soils differ from conventional drainage due to their more efficient hydrological functioning. Lime added to the trench backfill ensures significantly higher surface water infiltration rate, lower watertable depth in between the drains and more stable drainage coefficients at critical moments.

Lime filter drainage positively affects the quality of drainage water. This mean may reduce potassium, chloride, sulphate and phosphate concentrations in drainage water considerably.

In the outflow of lime filter drainage the total phosphorus concentrations were 50% lower while phosphate phosphorus concentrations were 64.4% lower than those in the control drainage water. Therefore with certainty must be concluded that lime admixture in trench backfill may reduce phosphorus transport into open water bodies.

However, seasonal variability is characteristic of the efficiency of lime filter drainage under the climatic conditions of Lithuania. It has been estimated that in cold season (November– January) TP concentrations are 2.3–2.7 times lower in outflow of lime filter drainage (significant differences at *p*=0.01), in February – May the differences are less significant (1.5– 2.0 times, *p*=0.05), and no significant differences have been estimated for the June – October period. PO4–P concentration in lime filter drainage treatments is significantly lower than that in conventional drainage (*p*=0.01), with exception of June – October period, when drainage outflow usually stops.

An Assessment of Lime Filter Drainage Systems 209

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Heiskanen, A. S.; Van de Bund, W.; Cardoso, A. C. & Nõges, P. (2004). Towards good

Murphy, P. N. C. & Stevens, R. J. (2010). Lime and Gypsum as Source Measures to Decrease

Povilaitis, A. (2004). Phosphorus trends in Lithuanian rivers affected by agricultural non-

Povilaitis, A. (2006). Impact of agriculture decline on nitrogen and phosphorus loads in

Puustinen, M. (2001). *Management of runoff water from arable land*. Finnish Environment

Rajasekaran, G. & Narasimha, R. S. (2002). Permeability characteristics of lime treated

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The results obtained in experimental sites in Lithuania show that lime filter drainage is long lasting improvement of clay soils because persistent significant differences were observed in drainage treatments that are in operation since the year of 1989. Therefore this drainage practice can be treated as an effective measure preventing non-point pollution of surface waters in agricultural areas where clay soils prevailing.

#### **5. References**


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**10** 

*Romania* 

**Tile Drainage on Agricultural Lands from North-**

Romania is situated in geographical center of Europe (south-east of Central Europe) at north of Balkan Peninsula at the half of distance between Atlantic Coast and The Urals, inside and outside the Carpathians Arch, on the Danube lower course and has exit to the Black Sea. Otherwise, parallel 45°N with the meridian 25°E intersects near the geometrical center of the country, 100 km N-V of the country capital, Bucharest. Romania is the twelfth country of

Romania's relief consists of three major levels: the highest one in the Carpathians, the middle one which corresponds to the Sub-Carpathians, to the hills and to the plateaus and

Romania's climate is temperate-continental of transition, with oceanic influences from the West, Mediterranean ones from South-West and continental-excessive ones from the East. Multiannual average temperature is latitudinally different, 8°C in the North and over 11°C in the South, and altitudinally, with values of -2.5°C in the mountain floor and 11.6°C in the

Yearly precipitations decrease in intensity from west to east, from over 600 mm to less 500 mm in the East Romanian Plain, under 450 mm in Dobrogea and about 350 mm by seaside,

Romanian running waters are radially displayed, most of them having the springs in the Carpathians. Their main collector is the Danube river, which crosses the country in the south on 1075 km length and flows into the Black Sea (Romanian Statistical Yearbook, 2010). Maps of Excess of moisture show the geographic occurrence, at national and district level, and intensity of the three kinds of excess of moisture: from groundwater, rainfall and by floods. The classes are defined according to intensity and the subclasses according to the

Drainage systems reduces the volume of drainage water leaving a field by 20-30% on average; however, outflow varies widely depending on soil type, rainfall, type of drainage

**1. Introduction** 

plain.

Europe, having an area of 238,391 km2.

the lowest one in plains, meadows and Danube Delta.

in the mountainous areas they reach 1000-1500 mm.

nature (source) of the excess moisture (Munteanu et al., 2004).

system and management intensity (Ramoska et al., 2011).

**East Romania - Experimental Variants** 

*University of Agricultural Sciences and Veterinary Medicine in Iasi* 

**and Technical Efficiency** 

Daniel Bucur and Valeriu Moca


## **Tile Drainage on Agricultural Lands from North-East Romania - Experimental Variants and Technical Efficiency**

Daniel Bucur and Valeriu Moca *University of Agricultural Sciences and Veterinary Medicine in Iasi Romania* 

#### **1. Introduction**

210 Drainage Systems

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Romania is situated in geographical center of Europe (south-east of Central Europe) at north of Balkan Peninsula at the half of distance between Atlantic Coast and The Urals, inside and outside the Carpathians Arch, on the Danube lower course and has exit to the Black Sea. Otherwise, parallel 45°N with the meridian 25°E intersects near the geometrical center of the country, 100 km N-V of the country capital, Bucharest. Romania is the twelfth country of Europe, having an area of 238,391 km2.

Romania's relief consists of three major levels: the highest one in the Carpathians, the middle one which corresponds to the Sub-Carpathians, to the hills and to the plateaus and the lowest one in plains, meadows and Danube Delta.

Romania's climate is temperate-continental of transition, with oceanic influences from the West, Mediterranean ones from South-West and continental-excessive ones from the East. Multiannual average temperature is latitudinally different, 8°C in the North and over 11°C in the South, and altitudinally, with values of -2.5°C in the mountain floor and 11.6°C in the plain.

Yearly precipitations decrease in intensity from west to east, from over 600 mm to less 500 mm in the East Romanian Plain, under 450 mm in Dobrogea and about 350 mm by seaside, in the mountainous areas they reach 1000-1500 mm.

Romanian running waters are radially displayed, most of them having the springs in the Carpathians. Their main collector is the Danube river, which crosses the country in the south on 1075 km length and flows into the Black Sea (Romanian Statistical Yearbook, 2010).

Maps of Excess of moisture show the geographic occurrence, at national and district level, and intensity of the three kinds of excess of moisture: from groundwater, rainfall and by floods. The classes are defined according to intensity and the subclasses according to the nature (source) of the excess moisture (Munteanu et al., 2004).

Drainage systems reduces the volume of drainage water leaving a field by 20-30% on average; however, outflow varies widely depending on soil type, rainfall, type of drainage system and management intensity (Ramoska et al., 2011).

Tile Drainage on Agricultural Lands

from North-East Romania - Experimental Variants and Technical Efficiency 213

surface. By land use, Suceava County has 349,544 hectares agricultural land, representing 41 % of the total surface, and 505,806 ha, i.e. 59 %, non-agricultural land (Jitareanu et al., 2009). The resources of agricultural land of Suceava County are limited both by the size of the contained area, and by production capacity. With the aim of normal use of soil resources, a series of hydro-ameliorative works have been done over time. The goal of performing these works was to combat the following soil agricultural capacity limiting factors: excess

Among the first works to eliminate the water excess, which were applied on the agricultural land with excess moisture in Bucovina can be mentioned: surface water drainage channels between the parcels of different owners; land forming in the bedding system with ridges and furrows; canals for water evacuation and others. Documents from that time show that the first ameliorative works associated with drainage works were performed in the late nineteenth century and early twentieth century in Radauti Depression, by the Agricultural Society of Vienna, who executed both, subsurface drainage and small regularization of rivers. Starting with 1895 and then between 1903 and 1910, was done a series of important

The drainage and subsurface drainage works included several development stages, which took place, particularly between 1950 and 1990. In the first stages, from 1950 to 1975, were designed drainage systems and river regularization with dikes. In the second period that ranges between 1976 and 1990, some older systems were improved and resized. Also, in some hydrographic basins were executed new works, which included the hydro-

In the social and economical context of Romania after 1990, which led to a substantial decline of investments, land improvements were, also diminished. At this stage, was done only maintenance work and completion of existing improvements. Among the specific works carried out during 1990-2010 can be mentioned: the maintenance of drainage ditch

In Suceava County, surface drainage systems were set up on 55,100 ha, tile drainage networks on 26,300 ha and systems of embanking and protection against floods on 7,400 ha

The structure of land use types from Suceava County, which includes a share of agricultural land of 41 % and 53 % for forests and forest plantations, is relatively balanced for a territory

Highest soil resources belong to the *class of Luvosols*, which has a share of 25.3 % from the effectively charted area and among the soil types, can be, and noted the *faeoziom* with 18 %. The distribution of soil resources on the five quality categories indicates that most of them are included in the *III-rd class* (35 %) of soils with average fertility, and in the *IV-th class* (30

The main limiting factors for soil quality are as follows: excess moisture affecting 185,316 ha,

water erosion and land sliding, compaction, acidity and nutrients deficiency.

moisture, flooding risk, soil erosion, unstable slopes and others.

ameliorative systems with canal drainage and subsurface drainage.

networks, pipe and tile drains and flood prevention works.

between 1960 - 1990 to remove this excess moisture.

%) of soils with low fertility.

belonging to the *Carpathian orogeny* and the plateaus unit.

tile drainage works in Radauti Depression.

The impact of drainage on yields is variable. Long-term computer simulations indicate that the average annual yield increase is less than 5%, but it could be substantial in some years depending on annual precipitation variability and regional climatic characteristics as well (Cooke et al., 2002, Troeh et al, 2005).

Drainage systems must cost-effectively manage flooding, control streambank erosion, and protect water quality (Lukianas et al., 2006). To do this, designers must integrate conventional flood control strategies for large, infrequent storms with three basic stormwater quality control strategies for small, frequent storms: infiltrate runoff into the soil, retain/detain runoff for later release, and convey runoff slowly through vegetation (Ritzema et al., 1996, Singh et al., 2006).

Integrated flood control/stormwater quality control designs must meet a variety of engineering, horticultural, aesthetic, functional, economic, and safety standards (Townend et al., 2001, Walker et al., 1989).

The preservation and sustainable use of soil resources include also the differentiate application of hydro-ameliorative works depending of the limiting factors of soil fertility.

Monitoring within Romania has revealed that there are approximately 4.0 million ha of farmland that have suitable soil resources, 3.7 million ha of which are arable lands, capable of sustaining competitive agriculture (Dumitru et al., 2004).

According to the *Romanian Statistical Yearbook* from 2008, the area of agricultural land categories affected by various limiting factors of productive capacity included: frequent droughts - 7,100 thousand ha; periodic excess moisture in the soil - 3,800 thousand ha; soil erosion and landslide - 7,000 thousand ha; soil compaction - 6,500 thousand ha; high and moderate acidity - 3,400 thousand ha; small and very small reserves of humus in soil - 7,500 thousand ha; low and very low concentration of mobile phosphorus - 6,300 thousand ha.

According to the data highlighted by Man et al., 2002, based on specialized studies carried out in the counties of Timis, Arad, Bihor and Maramures, there was estimated an agricultural area of 958,000 ha affected by excessive moisture. On these agricultural lands having excess moisture, there were carried out drainages for 854,925 ha, of which an area of 18,159 ha was drained with tile and plastic drains.

The spatial distribution of the ecosystemic territorial units in north-east of Romania, respectively, in Suceava County, showed a percent of soil with excess moisture ranging between 30% and 40% of the considered area, with an extension from south to north and from east to west. According to data estimated by Moca et al., 1988, 2001, the permanent and / or temporary excess moisture has been present over time on a area of more than 100,000 ha. Among the hydro-ameliorative improvements performed on agricultural lands with excess moisture in the extra-Carpathian region of Suceava County, there can be mentioned the drainage systems with open canals, and in some areas includes also subsurface drainage provided with ceramic and/or plastic pipes. The management of soil resources having excess moisture and a high risk of suitability for agricultural use requires the use of photogrammetric products as images and digital data files.

Suceava County is situated in the north part of Romania and is included, together with other five counties, in the North-Eastern Development Region. Having a total area of 855,350 ha, Suceava County is the second largest county of Romania, representing 3.6% of the country

The impact of drainage on yields is variable. Long-term computer simulations indicate that the average annual yield increase is less than 5%, but it could be substantial in some years depending on annual precipitation variability and regional climatic characteristics as well

Drainage systems must cost-effectively manage flooding, control streambank erosion, and protect water quality (Lukianas et al., 2006). To do this, designers must integrate conventional flood control strategies for large, infrequent storms with three basic stormwater quality control strategies for small, frequent storms: infiltrate runoff into the soil, retain/detain runoff for later release, and convey runoff slowly through vegetation

Integrated flood control/stormwater quality control designs must meet a variety of engineering, horticultural, aesthetic, functional, economic, and safety standards (Townend

The preservation and sustainable use of soil resources include also the differentiate application of hydro-ameliorative works depending of the limiting factors of soil fertility.

Monitoring within Romania has revealed that there are approximately 4.0 million ha of farmland that have suitable soil resources, 3.7 million ha of which are arable lands, capable

According to the *Romanian Statistical Yearbook* from 2008, the area of agricultural land categories affected by various limiting factors of productive capacity included: frequent droughts - 7,100 thousand ha; periodic excess moisture in the soil - 3,800 thousand ha; soil erosion and landslide - 7,000 thousand ha; soil compaction - 6,500 thousand ha; high and moderate acidity - 3,400 thousand ha; small and very small reserves of humus in soil - 7,500 thousand ha; low and very low concentration of mobile phosphorus - 6,300 thousand ha.

According to the data highlighted by Man et al., 2002, based on specialized studies carried out in the counties of Timis, Arad, Bihor and Maramures, there was estimated an agricultural area of 958,000 ha affected by excessive moisture. On these agricultural lands having excess moisture, there were carried out drainages for 854,925 ha, of which an area of

The spatial distribution of the ecosystemic territorial units in north-east of Romania, respectively, in Suceava County, showed a percent of soil with excess moisture ranging between 30% and 40% of the considered area, with an extension from south to north and from east to west. According to data estimated by Moca et al., 1988, 2001, the permanent and / or temporary excess moisture has been present over time on a area of more than 100,000 ha. Among the hydro-ameliorative improvements performed on agricultural lands with excess moisture in the extra-Carpathian region of Suceava County, there can be mentioned the drainage systems with open canals, and in some areas includes also subsurface drainage provided with ceramic and/or plastic pipes. The management of soil resources having excess moisture and a high risk of suitability for agricultural use requires the use of

Suceava County is situated in the north part of Romania and is included, together with other five counties, in the North-Eastern Development Region. Having a total area of 855,350 ha, Suceava County is the second largest county of Romania, representing 3.6% of the country

(Cooke et al., 2002, Troeh et al, 2005).

(Ritzema et al., 1996, Singh et al., 2006).

of sustaining competitive agriculture (Dumitru et al., 2004).

18,159 ha was drained with tile and plastic drains.

photogrammetric products as images and digital data files.

et al., 2001, Walker et al., 1989).

surface. By land use, Suceava County has 349,544 hectares agricultural land, representing 41 % of the total surface, and 505,806 ha, i.e. 59 %, non-agricultural land (Jitareanu et al., 2009).

The resources of agricultural land of Suceava County are limited both by the size of the contained area, and by production capacity. With the aim of normal use of soil resources, a series of hydro-ameliorative works have been done over time. The goal of performing these works was to combat the following soil agricultural capacity limiting factors: excess moisture, flooding risk, soil erosion, unstable slopes and others.

Among the first works to eliminate the water excess, which were applied on the agricultural land with excess moisture in Bucovina can be mentioned: surface water drainage channels between the parcels of different owners; land forming in the bedding system with ridges and furrows; canals for water evacuation and others. Documents from that time show that the first ameliorative works associated with drainage works were performed in the late nineteenth century and early twentieth century in Radauti Depression, by the Agricultural Society of Vienna, who executed both, subsurface drainage and small regularization of rivers. Starting with 1895 and then between 1903 and 1910, was done a series of important tile drainage works in Radauti Depression.

The drainage and subsurface drainage works included several development stages, which took place, particularly between 1950 and 1990. In the first stages, from 1950 to 1975, were designed drainage systems and river regularization with dikes. In the second period that ranges between 1976 and 1990, some older systems were improved and resized. Also, in some hydrographic basins were executed new works, which included the hydroameliorative systems with canal drainage and subsurface drainage.

In the social and economical context of Romania after 1990, which led to a substantial decline of investments, land improvements were, also diminished. At this stage, was done only maintenance work and completion of existing improvements. Among the specific works carried out during 1990-2010 can be mentioned: the maintenance of drainage ditch networks, pipe and tile drains and flood prevention works.

In Suceava County, surface drainage systems were set up on 55,100 ha, tile drainage networks on 26,300 ha and systems of embanking and protection against floods on 7,400 ha between 1960 - 1990 to remove this excess moisture.

The structure of land use types from Suceava County, which includes a share of agricultural land of 41 % and 53 % for forests and forest plantations, is relatively balanced for a territory belonging to the *Carpathian orogeny* and the plateaus unit.

Highest soil resources belong to the *class of Luvosols*, which has a share of 25.3 % from the effectively charted area and among the soil types, can be, and noted the *faeoziom* with 18 %.

The distribution of soil resources on the five quality categories indicates that most of them are included in the *III-rd class* (35 %) of soils with average fertility, and in the *IV-th class* (30 %) of soils with low fertility.

The main limiting factors for soil quality are as follows: excess moisture affecting 185,316 ha, water erosion and land sliding, compaction, acidity and nutrients deficiency.

Tile Drainage on Agricultural Lands

conditions in Romania are the following:

**2.1 The causes of excess moisture on agricultural land** 

unevenness respectively, with clay soils, poorly permeable.

sources increases almost to the ground surface.

result of association between water sources said.

**2.2 Soil water balance** 

specific flow discharged through drains network.

from North-East Romania - Experimental Variants and Technical Efficiency 215

The main water sources and factors that determine the formation of excess soil moisture






Agricultural land drainage fitting sizes, in general, for non-permanent or permanent regime, depending on soil water balance, respectively, of the elements considered for calculation of

swampiness of the land, especially in humid and subhumid climates.

### **2. Surface and pipe drainage systems**

**Natural drainage of the soil** is represented by all conditions of terrain, soil and hydrogeology of an area which causes gravity circulation of water located at a point in excess of the land surface or on soil profile (Mirsal et al., 2004).

In terms of hydroameliorative works, the drainage is all that apply to land surface or underground, from which excess water is eliminated.

**Surface drainage** works is the ensemble of hydro-ameliorative works which removes excess water from rainfall, land surface or accumulated stagnant at the top of the soil profile, above the hard permeable horizons.

From surface drainage category of works are highlighted the following:


**Pipe drainage systems** with pipes is represented by all hydro-ameliorative works used for lowering groundwater levels at the depth required by the grown plants, respectively, of climate and soil conditions (Mejia et al., 1998). In this category of work is a contained tubular drain of different sizes, network channels and exhaust collection related construction, filled sometimes with surface drainage.

#### **2.1 The causes of excess moisture on agricultural land**

214 Drainage Systems

**Natural drainage of the soil** is represented by all conditions of terrain, soil and hydrogeology of an area which causes gravity circulation of water located at a point in

In terms of hydroameliorative works, the drainage is all that apply to land surface or

**Surface drainage** works is the ensemble of hydro-ameliorative works which removes excess water from rainfall, land surface or accumulated stagnant at the top of the soil profile, above








**Pipe drainage systems** with pipes is represented by all hydro-ameliorative works used for lowering groundwater levels at the depth required by the grown plants, respectively, of climate and soil conditions (Mejia et al., 1998). In this category of work is a contained tubular drain of different sizes, network channels and exhaust collection related

collection network channels, outlet channels and all related construction.

its drained water volume either by gravity or by pumping.

construction, filled sometimes with surface drainage.

**2. Surface and pipe drainage systems** 

the hard permeable horizons.

from precipitation.

excess of the land surface.

from 200 to 500 m.

excess of the land surface or on soil profile (Mirsal et al., 2004).

From surface drainage category of works are highlighted the following:

underground, from which excess water is eliminated.

surface of local depressions without drainage.

slopes, easily traversed by agricultural machinery.

The main water sources and factors that determine the formation of excess soil moisture conditions in Romania are the following:


#### **2.2 Soil water balance**

Agricultural land drainage fitting sizes, in general, for non-permanent or permanent regime, depending on soil water balance, respectively, of the elements considered for calculation of specific flow discharged through drains network.

Tile Drainage on Agricultural Lands

where:

the soil.

and field cultivation.

capillary rise.

**3.1 Soil genetic conditions** 

P - average annual rainfall;

ET - average annual evapotranspiration; S - surface water drainage of land;

of excess moisture is obtained by the relation:

Af - water intake from the phreatic layer under pressure;

mountainous and mountainous areas of the Carpathian chain.

**3. Experimental drainage site - Baia depression** 

I - the amount of water infiltrated in the soil profile, below the plant roots;

Wmax - the maximum amount of water that soil can accumulate in the plants root zone.

Crisana and Maramures, in internal river meadows and some areas in the Danube.

The agricultural land with this type of moisture excess is common on low land in the Banat,

After the estimated forecast by *National Meteorological Administration* in the coming years is likely to increase the size of the droughts that will occur in alternation with periods of intense rainfall. During relatively short periods of heavy rainfall, flooding will occur quickly in river meadows with different intensities inside and manifestation of excess moisture in

The effect of increasing average temperatures predicted for the coming years is considered to be more pronounced in areas of the Romanian Plain and less significant in sub-

Water excess in soil is a complex process that is determined by some factors like water uptake, circulation and removal in the system soil-subjacent rock. For removing water excess from soil profile, drainage systems were planned for improving soil aeration regime

For knowing the long-term effect of hydro-ameliorative and soil-ameliorative works, applied under conditions of soil from drainage fields arranged in Baia, was determined the

The Baia Depression is located in the Sub-Carpathian Basin of the Moldova River, which is located in Suceava County, Romania. The total area of the Baia Depression is approximately 15,000 ha, 5,000 ha of which have excess soil moisture owing to rainfall or groundwater

evolution of main eco-soil indicators of unimproved and improved soils.

from North-East Romania - Experimental Variants and Technical Efficiency 217

Agricultural land with excess moisture from the category of soil water balance are commonly encountered in the irrigated or unirrigated territories from the Romanian Plain, more specific soils with good permeability (K> 0.5 m/day). These soils are formed on loess and sandy deposits where the water table is located at medium depths, less than 2-4 m.


P + Af - Et > S + I + Wmax

Depending on the causes of formation of excess moisture in the soil which were previously presented, the most representative and most common cases encountered in practice of drainage work are.


$$\text{P-ET} \gtrless \text{S} + \text{I} + \text{W}\_{\text{max}}$$

where:

P - average annual rainfall;

ET - average annual evapotranspiration;

S - surface water drainage of land;

I - the amount of water infiltrated in the soil profile, below the plant roots;

Wmax - the maximum amount of water that can accumulate in the soil in the plants root zone.

In practical terms, this formula in a simplified form of soil water balance equation is complete in terms of knowledge of natural factors causing excess moisture in the soil and established necessary drainage work.

In this case, **the excess water volume** (**Ve**) can be expressed by the relationship:

$$\text{Ve} = \text{P} \cdot \text{Et} \cdot \text{S} \cdot \text{I} \cdot \text{W}\_{\text{max}}$$

Specific agricultural land of humid and sub-humid climates are located on terraces, high and piedmont plains, highlands and hills: Banat, Crisana, Maramures, Transylvania and the northern Oltenia and Muntenia. However, large areas have been reported in the sub-Carpathian hills of Moldova and in the hard permeable soils of Romanian.


Water balance during periods of excess moisture relation is expressed as:

$$\text{P} + \text{Inf} + \text{Ir} \cdot \text{Et} \ge \text{S} + \text{I} + \text{W}\_{\text{max}}$$

where:

P - average annual rainfall;

Inf - infiltration from rivers, lakes and other sources;

Ir - loss of water from irrigation systems;

ET - average annual evapotranspiration;

S - surface water drainage of land;

I - the amount of water infiltrated in the soil profile, below the plant roots;

Wmax - the maximum amount of water that a soil can accumulate in the plants root zone.

In this case, **the excess water volume** (**Ve**) is the appropriate minimum amount of porosity of aeration required for normal respiration of plant roots, respectively, of aerobic microorganisms.

Agricultural land with excess moisture from the category of soil water balance are commonly encountered in the irrigated or unirrigated territories from the Romanian Plain, more specific soils with good permeability (K> 0.5 m/day). These soils are formed on loess and sandy deposits where the water table is located at medium depths, less than 2-4 m.


$$\text{P} + \text{Af} \cdot \text{Et} \ge \text{S} + \text{I} + \text{W}\_{\text{max}}$$

where:

216 Drainage Systems

Depending on the causes of formation of excess moisture in the soil which were previously presented, the most representative and most common cases encountered in practice of


P - ET > S + I + Wmax

Wmax - the maximum amount of water that can accumulate in the soil in the plants root zone. In practical terms, this formula in a simplified form of soil water balance equation is complete in terms of knowledge of natural factors causing excess moisture in the soil and

Ve = P - Et - S - I - Wmax Specific agricultural land of humid and sub-humid climates are located on terraces, high and piedmont plains, highlands and hills: Banat, Crisana, Maramures, Transylvania and the northern Oltenia and Muntenia. However, large areas have been reported in the sub-


P + Inf + Ir - Et > S + I + Wmax

I - the amount of water infiltrated in the soil profile, below the plant roots;

In this case, **the excess water volume** (**Ve**) can be expressed by the relationship:

Carpathian hills of Moldova and in the hard permeable soils of Romanian.

Water balance during periods of excess moisture relation is expressed as:

I - the amount of water infiltrated in the soil profile, below the plant roots;

Wmax - the maximum amount of water that a soil can accumulate in the plants root zone.

In this case, **the excess water volume** (**Ve**) is the appropriate minimum amount of porosity of aeration required for normal respiration of plant roots, respectively, of aerobic

drainage work are.

where:

the following form:

P - average annual rainfall;

irrigation water.

P - average annual rainfall;

microorganisms.

Inf - infiltration from rivers, lakes and other sources;

Ir - loss of water from irrigation systems; ET - average annual evapotranspiration; S - surface water drainage of land;

where:

ET - average annual evapotranspiration; S - surface water drainage of land;

established necessary drainage work.

P - average annual rainfall; Af - water intake from the phreatic layer under pressure; ET - average annual evapotranspiration; S - surface water drainage of land; I - the amount of water infiltrated in the soil profile, below the plant roots; Wmax - the maximum amount of water that soil can accumulate in the plants root zone.

The agricultural land with this type of moisture excess is common on low land in the Banat, Crisana and Maramures, in internal river meadows and some areas in the Danube.

After the estimated forecast by *National Meteorological Administration* in the coming years is likely to increase the size of the droughts that will occur in alternation with periods of intense rainfall. During relatively short periods of heavy rainfall, flooding will occur quickly in river meadows with different intensities inside and manifestation of excess moisture in the soil.

The effect of increasing average temperatures predicted for the coming years is considered to be more pronounced in areas of the Romanian Plain and less significant in submountainous and mountainous areas of the Carpathian chain.

#### **3. Experimental drainage site - Baia depression**

Water excess in soil is a complex process that is determined by some factors like water uptake, circulation and removal in the system soil-subjacent rock. For removing water excess from soil profile, drainage systems were planned for improving soil aeration regime and field cultivation.

For knowing the long-term effect of hydro-ameliorative and soil-ameliorative works, applied under conditions of soil from drainage fields arranged in Baia, was determined the evolution of main eco-soil indicators of unimproved and improved soils.

#### **3.1 Soil genetic conditions**

The Baia Depression is located in the Sub-Carpathian Basin of the Moldova River, which is located in Suceava County, Romania. The total area of the Baia Depression is approximately 15,000 ha, 5,000 ha of which have excess soil moisture owing to rainfall or groundwater capillary rise.

Tile Drainage on Agricultural Lands

slope of the drain lines was 0.2%.

Spacing between drain lines /depth drain (m)

A 20/1,0

B 15/1,0

C 12/1,0

D 20/0,8

E 15/0,8

F 12/0,8

Drain line number

> 1 2 3

> 4 5 6

> 7 8 9

10 11 12

13 14 15

16 17 18

Table 1. Materials used for construction of the Baia drainage experimental site.

12 m in variant F.

(Table 1).

Tile drainage variant

from North-East Romania - Experimental Variants and Technical Efficiency 219

Moreover, in variant A, the tile drainage was combined with the land forming in the bedding system with ridges and furrows. In this variant, furrows were constructed upon tile drains with spacing at 20 m. The bedding turning furrows to the middle of a cut to form a

Each drainage variant includes three drain lines. The length of each drain was 100 m and the

In variants A, B and C the depth of the tile drains is 1.0 m. The spacing between drains is 20 m in variant A, 15 m in B variant and 12 m in C variant. In variants D, E and F, the depth of the tile drains is 0.8 m. The spacing of the drains is 20 m in variant D, 15 m in variant E and

Hydrotechnical scheme of the Baia drainage experimental site (Figure 1) was sized to optimize the basic design elements, used routinely in the design of tiles drainage systems

> Pipe type and diameter (mm)

> > Tile Ø 70 Tile Ø 125 Tile Ø 70

Tile Ø 70 Tile Ø 70 Tile Ø 70

Corrugated plastic Ø 65 Smooth plastic Ø 63 Tile Ø 70

Corrugated plastic Ø 65 Smooth plastic Ø 110 Tile Ø 70

> Tile Ø 70 Tile Ø 70 Tile Ø 70

Corrugated plastic Ø 65 Smooth plastic Ø 63 Tile Ø 70

 *Spacing between drain lines:* 20 m (variants A and D), 15 m (variants B and E) and 12 m (variants C and F) were determined assuming a non-permanent flow regime.

In terms of functional efficiency, the spacing between drain lines, should allow lowering the groundwater level from the maximum height to optimum height, within

Type and thickness of complex drain + filter (cm)

Ballast (20) + Flax stems (50) Ballast (70) + Green sods Ballast (20) + Green sods

Flax strains (30) Ballast (12) + Flax stems (20) Ballast (15) + Green sods

Ballast (12) + Green sods Ballast (12) + Green sods Ballast (15) + Green sods

Ballast (20) + Flax stems (40) Ballast (60) + Green sods Ballast (20) + Green sods

Flax strains (30) Ballast (12) + Flax stems (20) Ballast (15) + Green sods

Ballast (12) + Green sods Ballast (12) + Green sods Ballast (15) + Green sods

ridge that gradually slopes toward deep furrows to ensure good drainage.

The Baia Drain Field has an area of 3 ha and is located on a terrace platform of the Moldova River. The area bends slightly to the southeast and has a longitudinal slope of 2 - 5% and a height of 393 m. The parental material is silty clay with a thickness of 10 - 15 m. As a result, the natural drainage of the soil is weak to very weak. In addition, the groundwater is situated at a mean depth of 9 - 10 m, and the perched water table is located at a mean depth of 0.2 - 0.5 m.

The climate of the study area is continental temperate, with great thermal amplitude and rainfall that occurs primarily in the vegetative season. The rainfall in the study area is generally spread non-uniformly and usually torrential. The mean multiannual temperature from 1978 - 2008 was 7.9 ºC, the average rainfall was 806 mm and the average evapotranspiration was 599 mm, with an average water excess of 207 mm.

The vegetation in the study area was composed of a hygrophilous environment that contained an association of *Agrostis tenuis* and a sub-association of *Deschampsia caespitosa*, *Juncus effuzus*, and *Carex sp*.

Evaluation of the study location revealed that the area was characterized by albic stagnic glossic Luvosol under the *Romanian System of Soil Taxonomy* (Florea et al., 2003) or albeluvisol under the *World Reference Base for Soil Resources* (WRB, 2006).

#### **3.2 Tile drainage experimental variants**

To optimize the air and water regime of soil in the area, an experimental field containing a tile drainage system designed to remove excess water was constructed in 1978.

During the study period (1978 - 2010), six different tiles drainage systems (A, B, C, D, E, F) were installed and the effect of the removal of excess moisture from the soil by these systems was evaluated (Figure 1).


Fig. 1. Hydrotechnical scheme of the Baia drainage experimental site.

The Baia Drain Field has an area of 3 ha and is located on a terrace platform of the Moldova River. The area bends slightly to the southeast and has a longitudinal slope of 2 - 5% and a height of 393 m. The parental material is silty clay with a thickness of 10 - 15 m. As a result, the natural drainage of the soil is weak to very weak. In addition, the groundwater is situated at a mean depth of 9 - 10 m, and the perched water table is located at a mean depth

The climate of the study area is continental temperate, with great thermal amplitude and rainfall that occurs primarily in the vegetative season. The rainfall in the study area is generally spread non-uniformly and usually torrential. The mean multiannual temperature from 1978 - 2008 was 7.9 ºC, the average rainfall was 806 mm and the average

The vegetation in the study area was composed of a hygrophilous environment that contained an association of *Agrostis tenuis* and a sub-association of *Deschampsia caespitosa*,

Evaluation of the study location revealed that the area was characterized by albic stagnic glossic Luvosol under the *Romanian System of Soil Taxonomy* (Florea et al., 2003) or

To optimize the air and water regime of soil in the area, an experimental field containing a

During the study period (1978 - 2010), six different tiles drainage systems (A, B, C, D, E, F) were installed and the effect of the removal of excess moisture from the soil by these

evapotranspiration was 599 mm, with an average water excess of 207 mm.

albeluvisol under the *World Reference Base for Soil Resources* (WRB, 2006).

Fig. 1. Hydrotechnical scheme of the Baia drainage experimental site.

tile drainage system designed to remove excess water was constructed in 1978.

of 0.2 - 0.5 m.

*Juncus effuzus*, and *Carex sp*.

**3.2 Tile drainage experimental variants** 

systems was evaluated (Figure 1).

Moreover, in variant A, the tile drainage was combined with the land forming in the bedding system with ridges and furrows. In this variant, furrows were constructed upon tile drains with spacing at 20 m. The bedding turning furrows to the middle of a cut to form a ridge that gradually slopes toward deep furrows to ensure good drainage.

Each drainage variant includes three drain lines. The length of each drain was 100 m and the slope of the drain lines was 0.2%.

In variants A, B and C the depth of the tile drains is 1.0 m. The spacing between drains is 20 m in variant A, 15 m in B variant and 12 m in C variant. In variants D, E and F, the depth of the tile drains is 0.8 m. The spacing of the drains is 20 m in variant D, 15 m in variant E and 12 m in variant F.

Hydrotechnical scheme of the Baia drainage experimental site (Figure 1) was sized to optimize the basic design elements, used routinely in the design of tiles drainage systems (Table 1).


Table 1. Materials used for construction of the Baia drainage experimental site.

 *Spacing between drain lines:* 20 m (variants A and D), 15 m (variants B and E) and 12 m (variants C and F) were determined assuming a non-permanent flow regime. In terms of functional efficiency, the spacing between drain lines, should allow lowering the groundwater level from the maximum height to optimum height, within

Tile Drainage on Agricultural Lands

furrow cross-section (Figure 3);

analysed:

(Figure 3);

(V2).

from North-East Romania - Experimental Variants and Technical Efficiency 221

*Cycle 1*, crop rotation I: maize-two-row barley-potato-flax fibers (1979 - 1982); crop

 *Cycle 2,* mixture of seeded perennial grasses (70%) and legumes (30%) (1987 - 1990); mixture of perennial grasses (70%) and overseeded legumes (30%) (1990 - 1997);

To quantify the changes in the major physical and chemical characteristics of the improved soil in response to the following variations of the drainage treatments described above (Figure 1), at the end of each cycle soil samples from the following treatments were

V1 - tile drainage combined with land forming in the bedding system variant: top of ridges

V2 - tile drainage combined with land forming in the bedding system variant: drain line -

Fig. 3. Tile drainage combined with the bedding system variant - top of ridges (V1) / furrow

Crop rotations and plants were cultivated in the following three experimental cycles:

rotation II: (wheat + rye), (maize + potato), maize - potato (1983 - 1986);

*Cycle 3*, overseeded natural meadow (1997 - 2010).

V0 - control variant, natural unimproved meadow (Figure 2);

V3 - tile drainage variant: middle of the drain lines (Figure 4); V4 - tile drainage variant: drain line cross-section (Figure 4).

Fig. 2. Soil sampling in the control variant (V0).

3-5 days. This lowering of groundwater level in time guaranteed certain plant root zone aeration.


Under Romania natural conditions the ballast from the river inland meadows is considered al widely used material as a filter in tube drainage works. Filter layer of Ballast has very good drainage effect because of the maintenance of its permeability over the period of operation of the drainage system. Ballast placed around and above the drainage pipes does not compact under soil conditions; it is not degraded by microorganisms in the soil or groundwater chemical action.

Implementation of drainage tubes was performed using E.T.T. 202-A equipment, a mechanic system that performed: digging trenches with a width of 50 cm, variable depth of 0.8 – 1.5 m and laying Tile drainage pipes and / or plastic.

After estimating the cost value of the lei / ha, on the time of implementation of drainage experimental variations has resulted some differentiate constructive solutions. For drain lines: 11/variant D, 2/variant A was the highest assessed values of the cost. Lower cost price values were obtained for the drains: 13/variant E and 12/variant D, depending on dimensional elements and building materials used.

#### **3.3 Improvement procedures**

After installation of the tile drainage system, the study area was used for farming.

The drained soil was then improved by applying the three following experimental cycles:


Crop rotations and plants were cultivated in the following three experimental cycles:


220 Drainage Systems

 *The depth of the tile drains:* **1.0 m** (A, B and C variants), **0.8 m** (variants D, E and F) was sized taking into account the horizontal position of the hard permeable soil profile. If the soil is albic stagnic - glossic Luvosol, the Bt1W textural horizon is located at a depth

 *Pipe type and diameter* that was used for the construction of all 18 drain lines included the following materials: *tile drain* (pipe are from ceramic) with inner diameter of 70 mm and 125 mm, tube length of 33 cm with circular inner section and outer section of hexagonal form*, smooth plastic drain* with external diameter of 63 and 110 mm; *corrugated* 

 *Filter material* that was put on top and around the drainage tube consisted of the following: river ballast, and, for some certain drain lines Ballast with flax strains and

Under Romania natural conditions the ballast from the river inland meadows is considered al widely used material as a filter in tube drainage works. Filter layer of Ballast has very good drainage effect because of the maintenance of its permeability over the period of operation of the drainage system. Ballast placed around and above the drainage pipes does not compact under soil conditions; it is not degraded by microorganisms in the soil or

Implementation of drainage tubes was performed using E.T.T. 202-A equipment, a mechanic system that performed: digging trenches with a width of 50 cm, variable depth of 0.8 – 1.5 m

After estimating the cost value of the lei / ha, on the time of implementation of drainage experimental variations has resulted some differentiate constructive solutions. For drain lines: 11/variant D, 2/variant A was the highest assessed values of the cost. Lower cost price values were obtained for the drains: 13/variant E and 12/variant D, depending on

After installation of the tile drainage system, the study area was used for farming.

of the soil with 7 - 8 t·ha-1 limestone, organic refertilization with 40 t·ha-1

*Cycle 3* (1998 - 2010): no application of soil improvement and/or cropping works.

The drained soil was then improved by applying the three following experimental cycles: *Cycle 1* (1978-1986): superficial land forming, cultivation of virgin hygrophilous meadow, deep loosening to a depth of 0 - 70 cm, amendment by the application of 10 - 12 t·ha-1 limestone with a content of 95 - 100% CaCO3, organic fertilizing with 40 t·ha-1 manure (in variants A, B, C, D, E and F), land forming in the bedding system with a ridge and furrow (only in variant A) once a cycle and annual mineral fertilization (in all

*Cycle 2* (1987 - 1997): deep re-loosening at the useful depth of 0 - 70 cm, re-amendment

manure once a

*plastic drains* with linear waves and external diameter of 65 mm.

vegetal soil on the form of green sods.

and laying Tile drainage pipes and / or plastic.

dimensional elements and building materials used.

cycle and annual mineral fertilization;

aeration.

of 0.9 to 1.0 m.

groundwater chemical action.

**3.3 Improvement procedures** 

variants);

3-5 days. This lowering of groundwater level in time guaranteed certain plant root zone

To quantify the changes in the major physical and chemical characteristics of the improved soil in response to the following variations of the drainage treatments described above (Figure 1), at the end of each cycle soil samples from the following treatments were analysed:

V0 - control variant, natural unimproved meadow (Figure 2);

V1 - tile drainage combined with land forming in the bedding system variant: top of ridges (Figure 3);

V2 - tile drainage combined with land forming in the bedding system variant: drain line furrow cross-section (Figure 3);

V3 - tile drainage variant: middle of the drain lines (Figure 4);

V4 - tile drainage variant: drain line cross-section (Figure 4).

Fig. 2. Soil sampling in the control variant (V0).

Fig. 3. Tile drainage combined with the bedding system variant - top of ridges (V1) / furrow (V2).

Tile Drainage on Agricultural Lands

horizon succession (Figure 2 and Figure 3): **A0** + **A0 (W)** + **EaW** - (0-30 cm): silt loam;

plastic; adherent.

**EaW** - 30-40 cm: silt loam; **Ea+BW** - 40 - 55 cm: clayey loam; **Bt1W** - 55 - 97cm: loamy clay.

**(A0 + Ea)p** - 0 - 30 cm: silt loam; **Ea+BW -** 30 - 46 cm: clayey loam; **Bt1W -** 46-97 cm: loam clay.

to the *Romanian System of Soil Taxonomy* - 2003.

**3.4 Hydrometeorological balance of field drainage pipes** 

experiment, the annual hydrometeorological balance **(± ΔP = P - ET**).

1982, with annual rainfall of 742 mm insurance and 80% (Table 2).

from North-East Romania - Experimental Variants and Technical Efficiency 223

**Bt1W** 46 - 97 cm - loamy clay, greenish gray 5GY 6/1 with frequent large yellowish brown mottles 10 YR 5/6 (wet) and light gray 7.5 Y 7/1 with light yellowish brown 10 YR 6/4 and brown-yellowish 10 YR 6/6 mottles (dry); large prismatic structure, moderately developed; coarse clay films on the faces of the structural aggregates; medium ferromanganese spots and concretions; hard in wet state and very compacted when dry;

Following placement of the tile drainage system, land was forming in the bedding system and then the soil was cultivated for the first time. In consequence, a mixture between the upper genetic horizons of the soil profile was observed. After the first experimental cycle (1978-1986), the soil from the surface formed in the bedding system presented the following

In the new conditions of the improved soil, the active physiological depth was greater than that in the unimproved soil. The succession of the horizon morphology revealed that the Bt1W textural horizon is situated at a higher depth when compared to the unimproved soil. The experimental parcels from the space between the drain lines also showed a mixture of the soil profile upper horizons. The changes inferred were signalled in the depth of the ploughed horizon (0 - 30 cm), and occurred due to the agricultural cultivation works and the deep loosening from the first two experimental cycles (1978 - 1986 and 1987 - 1996). The space between the tile drain lines resulted in the following horizon succession (Figure 4):

The analysed physical and chemical characteristics of soil sampled in 2010 were determined according to the norms of the *Methodology of soil studies elaboration* - *National Institute of Research and Development in Soil Science, Agrochemistry and Environment Bucharest* - 1987 and

Depending on **annual precipitation (P)** and **annual water consumption by evapotranspiration (ET)** was expressed, on the basis of made observations during the

 *Annual rainfall regime* (P) was the main source of excess water from the ground, being based on alternation between periods of intense rainfall and, respectively, dry periods in May. Database of observations made on annual rainfall were extracted for the case

For wet weather conditions area of north-eastern Romania, was considered as rainy year, 1981, with an annual rainfall of 968 mm fallen (statistical insurance 5%) and the dry year,

study examples, from a rainy year (1981), respectively, a dry year (1982).

The evolution of some physical and chemical features under the influence of the improvements was also analyzed in the three experimental cycles. To accomplish this, soil samples were collected from the ploughed stratum (0 - 20 cm) and the horizon below this layer (20 - 40 cm). Soil samples were collected using an agrochemical drill at the end of each experimental cycle in 1986, 1997 and 2010 from the entire surface of the experimental variants (V0, V1 and V3).

Fig. 4. Tile drainage variant - middle of the drain spacing (V3) and drain cross-section (V4).

In the natural conditions of this wetland, the albic stagnic - glossic Luvosol*,* which is used as a natural pasture, presented the following morphological features in the horizon succession (Figure 2):

**A0** 0 - 5 cm - strongly unreclaimed stratum; silt loam; very dark brown grey 10 YR 4/2 (wet) and light grey 10 YR 7/2 (dry); small polyhedral angular structure, moderately developed; very friable in wet state, quite hard in dry state; weakly plastic; weakly adherent; very frequent roots.

**A0 (W)** 5 - 18 cm - silt loam; dark greyish brown 10YR 4/2 (wet) and light greyish brown 10YR 6/2 (dry); small polyhedral angular structure, moderately developed, friable in wet state and easily compacted when dry; weakly plastic; weakly adherent; frequent coarse and medium pores; thin and very thin frequent roots; clear contact with the horizon below.

**EaW** 18 - 30 cm - silt loam; light olive colour 7.5Y 6/2 with small yellowish brown spots 10 YR 6/6 (wet) and white 7.5 Y 8/2 with yellowish brown mottles 10 YR 6/8 (dry); small polyhedral angular up to lamellar structure, weakly developed, friable in wet state and easily compacted when dry; weakly plastic; weakly adherent; frequent medium pores; rare very thin roots; diffuse irregular contact with the horizon below.

**E+BW** 30 - 46 cm - clayey loam; greenish gray 5GY 6/1 with small and medium frequent mottles, light yellowish brown 10 YR 6/4 (dry) and white 7.5 Y 8/1 with brown yellowish spots 10 YR 6/6 (dry); medium polyhedral angular structure, moderately developed; clay films on the faces of structural aggregates; small and medium ferromanganese spots and concretions; tough when wet and compacted in dry state; plastic; adherent; frequent pores; diffuse irregular contact with the horizon below.

**Bt1W** 46 - 97 cm - loamy clay, greenish gray 5GY 6/1 with frequent large yellowish brown mottles 10 YR 5/6 (wet) and light gray 7.5 Y 7/1 with light yellowish brown 10 YR 6/4 and brown-yellowish 10 YR 6/6 mottles (dry); large prismatic structure, moderately developed; coarse clay films on the faces of the structural aggregates; medium ferromanganese spots and concretions; hard in wet state and very compacted when dry; plastic; adherent.

Following placement of the tile drainage system, land was forming in the bedding system and then the soil was cultivated for the first time. In consequence, a mixture between the upper genetic horizons of the soil profile was observed. After the first experimental cycle (1978-1986), the soil from the surface formed in the bedding system presented the following horizon succession (Figure 2 and Figure 3):

**A0** + **A0 (W)** + **EaW** - (0-30 cm): silt loam; **EaW** - 30-40 cm: silt loam; **Ea+BW** - 40 - 55 cm: clayey loam; **Bt1W** - 55 - 97cm: loamy clay.

222 Drainage Systems

The evolution of some physical and chemical features under the influence of the improvements was also analyzed in the three experimental cycles. To accomplish this, soil samples were collected from the ploughed stratum (0 - 20 cm) and the horizon below this layer (20 - 40 cm). Soil samples were collected using an agrochemical drill at the end of each experimental cycle in 1986, 1997 and 2010 from the entire surface of the experimental

Fig. 4. Tile drainage variant - middle of the drain spacing (V3) and drain cross-section (V4).

In the natural conditions of this wetland, the albic stagnic - glossic Luvosol*,* which is used as a natural pasture, presented the following morphological features in the horizon succession

**A0** 0 - 5 cm - strongly unreclaimed stratum; silt loam; very dark brown grey 10 YR 4/2 (wet) and light grey 10 YR 7/2 (dry); small polyhedral angular structure, moderately developed; very friable in wet state, quite hard in dry state; weakly plastic; weakly adherent;

**A0 (W)** 5 - 18 cm - silt loam; dark greyish brown 10YR 4/2 (wet) and light greyish brown 10YR 6/2 (dry); small polyhedral angular structure, moderately developed, friable in wet state and easily compacted when dry; weakly plastic; weakly adherent; frequent coarse and medium pores; thin and very thin frequent roots; clear contact with the horizon below.

**EaW** 18 - 30 cm - silt loam; light olive colour 7.5Y 6/2 with small yellowish brown spots 10 YR 6/6 (wet) and white 7.5 Y 8/2 with yellowish brown mottles 10 YR 6/8 (dry); small polyhedral angular up to lamellar structure, weakly developed, friable in wet state and easily compacted when dry; weakly plastic; weakly adherent; frequent medium pores; rare

**E+BW** 30 - 46 cm - clayey loam; greenish gray 5GY 6/1 with small and medium frequent mottles, light yellowish brown 10 YR 6/4 (dry) and white 7.5 Y 8/1 with brown yellowish spots 10 YR 6/6 (dry); medium polyhedral angular structure, moderately developed; clay films on the faces of structural aggregates; small and medium ferromanganese spots and concretions; tough when wet and compacted in dry state; plastic; adherent; frequent pores;

very thin roots; diffuse irregular contact with the horizon below.

diffuse irregular contact with the horizon below.

variants (V0, V1 and V3).

(Figure 2):

very frequent roots.

In the new conditions of the improved soil, the active physiological depth was greater than that in the unimproved soil. The succession of the horizon morphology revealed that the Bt1W textural horizon is situated at a higher depth when compared to the unimproved soil.

The experimental parcels from the space between the drain lines also showed a mixture of the soil profile upper horizons. The changes inferred were signalled in the depth of the ploughed horizon (0 - 30 cm), and occurred due to the agricultural cultivation works and the deep loosening from the first two experimental cycles (1978 - 1986 and 1987 - 1996). The space between the tile drain lines resulted in the following horizon succession (Figure 4):

**(A0 + Ea)p** - 0 - 30 cm: silt loam; **Ea+BW -** 30 - 46 cm: clayey loam; **Bt1W -** 46-97 cm: loam clay.

The analysed physical and chemical characteristics of soil sampled in 2010 were determined according to the norms of the *Methodology of soil studies elaboration* - *National Institute of Research and Development in Soil Science, Agrochemistry and Environment Bucharest* - 1987 and to the *Romanian System of Soil Taxonomy* - 2003.

#### **3.4 Hydrometeorological balance of field drainage pipes**

Depending on **annual precipitation (P)** and **annual water consumption by evapotranspiration (ET)** was expressed, on the basis of made observations during the experiment, the annual hydrometeorological balance **(± ΔP = P - ET**).

 *Annual rainfall regime* (P) was the main source of excess water from the ground, being based on alternation between periods of intense rainfall and, respectively, dry periods in May. Database of observations made on annual rainfall were extracted for the case study examples, from a rainy year (1981), respectively, a dry year (1982).

For wet weather conditions area of north-eastern Romania, was considered as rainy year, 1981, with an annual rainfall of 968 mm fallen (statistical insurance 5%) and the dry year, 1982, with annual rainfall of 742 mm insurance and 80% (Table 2).

Tile Drainage on Agricultural Lands

Year Annual evapotranspiration

(Et mm)

559 580

months of winter.

mm in 1981 (Table 5) .

P (mm)

> 968 742

Year

1981 1982

hydrometeorological water balance.

Annual hydrometeorological balance

> ± ΔP (mm) <sup>P</sup>

> > - -

409 162

Et (mm)

> 559 580

1981 1982

from North-East Romania - Experimental Variants and Technical Efficiency 225

 *Annual evapotranspiration regime* (*ET*)*,* ranged between the limits of normal distribution of the wet weather conditions. For the two characteristic years of the climate conditions (1981 and 1982), annual evapotranspiration was 559 mm (1981) and 580 mm (1982), with an average of 569 mm. Distribution of mean annual evapotranspiration for the two growing seasons of the year difference between the value of 517 mm (91%) in the warm

> Warm season month (V-X)

 *Average annual evapotranspiration regime* throughout the period examined in the years 1978-2010 recorded an average of 599 mm per year which varied in size according to the





(mm)

592 489

Table 5. Annual hydro-meteorological balance and seasonal distribution in 1981-1982.

Warm season months (V-X)

> ± ΔP (mm) <sup>P</sup>

+ - + - + -


87 -

(mm)

376 253

Et (mm)

> 505 529

Average 855 569 286 - 541 517 44 20 314 52 262 -

505 529

Seasonal distribution of evapotranspiration (mm)

54 51

Cold season month (XI-IV)

> Cold season months (XI-IV)

> > ± ΔP (mm)

> > > - -

322 202

Et (mm)

> 54 51

season, respectively, 52 mm (9%) in cold season of the year (Table 4).

Average 569 517 52 Table 4. Annual and seasonal evapotranspiration in years 1981 - 1982.

general trend of climatic factors and the use of agricultural land.

annual average, water consumption of 118 mm, which is 20%.

The average volume distribution of 855 mm from the years 1981-1982 was 541 mm (63 %) in summer and 314 mm (27 %) in winter.


Table 2. Annual rainfall and seasonal distribution in 1981-1982.

 *Average multi-annual rainfall* throughout the period examined in the years 1978-2010 recorded an annual average value of 806 mm (50% assurance).

In terms of annual rainfall distribution and intensity of growing seasons, months and calendar time intervals from one day up to 5 consecutive days of the years 1978-2010 have been reported following characteristics:



Table 3. Multiannual precipitation (1978-2010), average and maximum, monthly and on intervals of 1-5 consecutive days.

The average volume distribution of 855 mm from the years 1981-1982 was 541 mm (63 %) in

Warm season months (V-X)

> 592 489

Average 855 541 314

*Average multi-annual rainfall* throughout the period examined in the years 1978-2010

In terms of annual rainfall distribution and intensity of growing seasons, months and calendar time intervals from one day up to 5 consecutive days of the years 1978-2010 have




average max. average max. average max. average max. average max.

31.3 23.2 25.1 53.6 95.1 96.5 100.7 81.8 59.8 73.4 59.4 39.9

largest amounts of water in June and July and lowest in January-March.

25.7 18.9 25.1 41.3 95.1 72.0 89.1 43.6 37.5 39.5 38.5 25.6

Annual 806 - 280 - 361 - 401 - 458 - Table 3. Multiannual precipitation (1978-2010), average and maximum, monthly and on

Season rainfall distribution (mm)

Rainfall in consecutive intervals of 1-5 days (mm) 1 day 2 days 3 days 5 days

36.5 30.0 25.1 65.5 97.5 140.8 109.6 118.5 59.8 75.8 61.4 41.0

49.2 33.5 28.3 79.9 97.5 153.8 137.0 158.7 66.5 98.2 62.2 43.7

Cold season months (XI-IV)

> 376 253

summer and 314 mm (27 %) in winter.

1981 1982

been reported following characteristics:

Monthly precipitation (mm)

> 69.3 80.2 63.0 12.3 199.1 193.2 236.5 186.2 125.8 127.5 105.1 103.8

intervals of 1-5 consecutive days.

Month of the year

> I II III IV V VI VII VIII IX X XI XII

and in winter (XI-IV), 257 mm (32%).

Year Annual rainfall

(P mm)

968 742

recorded an annual average value of 806 mm (50% assurance).

on the overall progress of the climatic conditions (Table 3).

Table 2. Annual rainfall and seasonal distribution in 1981-1982.

 *Annual evapotranspiration regime* (*ET*)*,* ranged between the limits of normal distribution of the wet weather conditions. For the two characteristic years of the climate conditions (1981 and 1982), annual evapotranspiration was 559 mm (1981) and 580 mm (1982), with an average of 569 mm. Distribution of mean annual evapotranspiration for the two growing seasons of the year difference between the value of 517 mm (91%) in the warm season, respectively, 52 mm (9%) in cold season of the year (Table 4).


Table 4. Annual and seasonal evapotranspiration in years 1981 - 1982.



Table 5. Annual hydro-meteorological balance and seasonal distribution in 1981-1982.

Tile Drainage on Agricultural Lands

3-17 II 9-29 III 27-30 IV 6-18 V 21-24 V 10-19 VII 21-25 VII 27-31 VII 1-4 VIII 16-19 IX 21-30 XI 7-15 XII 16-31 XII

12-31 III 1-5 IV 19-24 IV 28-30 IV 1-5 V 15-22 VI 25-29 VI 1-3 VII 11-22 VII 23-25 VII 26-31 VII 1-10 VIII

1981

1982

from North-East Romania - Experimental Variants and Technical Efficiency 227

Year Drainage period Number of days Hydrometeorological balance

Annual 108 770 145 625

Annual 77 581 180 401

the previous paragraph, specific drainage flows (q) expressed in l/s and ha for each drain

Specific flow drainage dynamics was analyzed depending on the size of the excess rainwater and drainage lines efficiency, respectively, on the average assessed for the six experimental drainage variants (A, B, C, D, E and F). Also, tube drainage operation was highlighted both in terms of association with land shaping in the bedding system with ridges and furrows (variant A) and, respectively, aeration soil to a depth of 50-60 cm on average (variants B, C, D, E and F). In the early hours of operating periods of pipes drains were measured, typically, maximum flow, which measure on the evolution of precipitation

Specific flow regime of pipe drains drainage tubes was characterized on the base of volumetric flows measured 2-3 times daily, on the discharge place of each drain, in drainage

increases and/or continuity of the excess volume of water till minimum values.

Table 6. Operating periods of drainage tubes in the years 1981 - 1982.

line were characterized, generally, depending on specific factors.

operation during the years 1981 and 1982 (Table 7).

P (mm) Et (mm) +ΔP (mm)

Distribution of surplus and/or water deficit equation from annual hydrometeorological balance individualized only by excess water in 1981, respectively by excess and water deficit in 1982. The distribution of the two seasons average surplus of 286 mm to 262 mm difference between the value (92%) in winter and 24 mm (8%) in summer.


#### **3.5 Technical efficiency of the experimental drainage variants**

#### **3.5.1 Periods of drainage system operation**

In periods of drainage operation with non-permanent flow regime, rainfalls volume (P) exceeded the water consumption by evapotranspiration (Et), deep infiltration (I) and drain the land surface (S). In periods of excess water removal (ΔP), drained soil is working functionally as a reservoir, which records under the effect of heavy rains filling, respectively, depletion under the effect of drainage.

To characterize evolution of climatic factors that determine the hydro-meteorological balance and proper functioning of pipe drainage are presented the observations from the operation of drainage tubes in the years 1981-1982 (Table 6).


#### **3.5.2 Specific drainage flows**

To characterize the dynamics of drainage specific flows, first were analyzed the observations from climatic conditions in 1981 and 1982. In periods of operation of drainage mentioned in

Distribution of surplus and/or water deficit equation from annual hydrometeorological balance individualized only by excess water in 1981, respectively by excess and water deficit in 1982. The distribution of the two seasons average surplus of 286 mm to 262 mm difference

 *Hydrometeorological annual average regime balance* of the period under review (1978-2010) recorded a surplus of 207 mm water, characterized by the following features on the




In periods of drainage operation with non-permanent flow regime, rainfalls volume (P) exceeded the water consumption by evapotranspiration (Et), deep infiltration (I) and drain the land surface (S). In periods of excess water removal (ΔP), drained soil is working functionally as a reservoir, which records under the effect of heavy rains filling, respectively,

To characterize evolution of climatic factors that determine the hydro-meteorological balance and proper functioning of pipe drainage are presented the observations from the

 Hydrometeorological balance, that helped triggering the operation of the drainage system with pipes, had on given weather conditions between 1981-1982, the following




To characterize the dynamics of drainage specific flows, first were analyzed the observations from climatic conditions in 1981 and 1982. In periods of operation of drainage mentioned in

space of soil, which led to its discharge in the drainage tubes system.

in the hot season of the year annual average and 68 mm (33%) in winter.

between the value (92%) in winter and 24 mm (8%) in summer.

seasons, months and characteristic times of the year.

the other months of the year, except August.

**3.5.1 Periods of drainage system operation** 

depletion under the effect of drainage.

significant issues:

102-113 mm.

**3.5.2 Specific drainage flows** 

rainfalls.

**3.5 Technical efficiency of the experimental drainage variants** 

operation of drainage tubes in the years 1981-1982 (Table 6).


Table 6. Operating periods of drainage tubes in the years 1981 - 1982.

the previous paragraph, specific drainage flows (q) expressed in l/s and ha for each drain line were characterized, generally, depending on specific factors.

Specific flow drainage dynamics was analyzed depending on the size of the excess rainwater and drainage lines efficiency, respectively, on the average assessed for the six experimental drainage variants (A, B, C, D, E and F). Also, tube drainage operation was highlighted both in terms of association with land shaping in the bedding system with ridges and furrows (variant A) and, respectively, aeration soil to a depth of 50-60 cm on average (variants B, C, D, E and F). In the early hours of operating periods of pipes drains were measured, typically, maximum flow, which measure on the evolution of precipitation increases and/or continuity of the excess volume of water till minimum values.

Specific flow regime of pipe drains drainage tubes was characterized on the base of volumetric flows measured 2-3 times daily, on the discharge place of each drain, in drainage operation during the years 1981 and 1982 (Table 7).

Tile Drainage on Agricultural Lands

s-1ha (drain 17/variant F).

and average depth of 0.8 m.

**3.5.3 Drained water volumes** 

arranged on the six variants, as follows:

achieved a 368 mm drained rate (3680 m3ha-1).

consumption of water by evapotranspiration.

and F).

and 20 m.

from North-East Romania - Experimental Variants and Technical Efficiency 229

Mean annual specific drainage flows were correlated with the size of maximum flow and maximum annual extreme, both for individual conditions of drains, and also for the estimated average experimental version of drainage lines consisted of three drains lines. Thus, in 1981 the annual average flows ranged from 0.31 s-1ha (drain 10/variant D) and 0.63 s-1ha (drain 1/variant A) and in 1982, from 0.27 s-1ha (drain 12/variant D) and 0.46

*Technical efficiency of drainage variants*, depending on the size of the specific flows




Depending on the size of specific drainage daily flow of the area served by the drainage lines (1-18) and experimental drainage variants (A-F) volumes of drained water were calculated, expressed in mm or m3ha-1. To calculate the volume of drained water areas were used areas of 0.60 ha (variants A and D), 0.45 ha (variants B and E), and 0.36 ha (variants C

 *Average annual volumes of drained water* (Table 8)*,* in the excess water conditions during 1981 and 1982 showed a differentiated technical efficiency, first drain lines respectively


*Technical efficiency of drainage variants*, depending on the size of the drained water


associated with land shaping in the bedding system with ridges and furrows. - Operational efficiency of the experimental variants, depending on the size of individual volumes of component drains was noted by a reduced capacity for variant D (20/0.8 m) with a drain rate of 245 mm (2450 m3ha-1) and better under variant F (12/0.8 m), which

volumes was materialized through the following significant features:

highlighted the following issues relevant to the experimental cycle:

shaping in the bedding system with ridges and furrows (variant A).


Table 7. The specific drainage flows in 1981-1982.


Mean annual specific drainage flows were correlated with the size of maximum flow and maximum annual extreme, both for individual conditions of drains, and also for the estimated average experimental version of drainage lines consisted of three drains lines. Thus, in 1981 the annual average flows ranged from 0.31 s-1ha (drain 10/variant D) and 0.63 s-1ha (drain 1/variant A) and in 1982, from 0.27 s-1ha (drain 12/variant D) and 0.46 s-1ha (drain 17/variant F).


#### **3.5.3 Drained water volumes**

228 Drainage Systems

1.89 1.55 1.46

0.95 0.99 1.02

1.30 1.39 1.38

0.87 0.95 0.96

1.23 1.22 1.32

1.48 1.61 1.31

 *The maximum extreme flows*, measured in the first functioning hours of drainage under the conditions of the 18 drains lines showed obvious differences. In terms of the year 1981, measured flows were hierarchized between 2.50 l s-1 and ha (drain 10/variant D) and 5.77 l s-1 and ha (drain 2/variant A), and in 1982 from 3.20 l s-1 and ha (drain

 *Annual maximum average flows* were individualized on the 18 line pipe drains between the minimum value of 0.87 l s-1ha (drain 10/variant D) and a maximum of 1.89 l s-<sup>1</sup>ha (drain 1/variant A), during operation of drainage in 1981. There is a similar dynamic in terms of 1982, with a variation of this flow from 1.01 l s-1ha (drain

 *Annual average flows,* that were expressed on the basis of all measurements from the 108 days in 1981 and 77 days in 1982 showed also, functional technical efficiency of

Average 5.31 4.96 5.14 1.63 1.28 1.46 0.53 0.31 0.42

Average 2.91 4.21 3.56 0.99 1.27 1.13 0.36 0.32 0.34

Average 4.00 6.26 5.13 1.36 1.73 1.55 0.48 0.43 0.46

Average 2.86 3.62 3.24 0.93 1.13 1.03 0.32 0.28 0.30

Average 3.78 5.42 4.60 1.26 1.60 1.43 0.44 0.39 0.42

Average 4.42 6.31 5.37 1.47 1.82 1.64 0.56 0.43 0.50

Maximum extreme flows

> 4.87 5.17 4.84

> 4.44 3.92 4.26

> 6.25 5.95 6.58

> 4.17 3.49 3.20

> 5.41 5.71 5.13

> 6.10 6.76 6.07

12/variant D) and 6.76 l s-1 and ha (drain 17/variant F).

12/variant D) and up to 1.93 l s-1ha (drain 17/variant F).

solutions designed in the 18 lines of drainage.

5.02 5.47 4.92

3.71 3.41 3.56

5.05 4.96 5.38

3.34 3.31 3.07

4.71 4.52 4.57

5.33 5.66 5.12

Specific drainage flow *q* (ls-1ha-1)

Annual maximum average flows

1981 1982 Average 1981 1982 Average 1981 1982 Average

1.57 1.46 1.34

1.11 1.12 1.16

1.55 1.57 1.52

1.06 1.05 0.99

1.46 1.37 1.46

1.64 1.77 1.52 0.63 0.49 0.48

0.36 0.36 0.36

0.48 0.48 0.48

0.31 0.33 0.33

0.44 0.42 0.45

0.54 0.60 0.53

1.25 1.37 1.21

1.27 1.25 1.30

1.80 1.74 1.66

1.24 1.15 1.01

1.69 1.51 1.59

1.80 1.93 1.73 Annual average flows

> 0.31 0.32 0.30

> 0.33 0.32 0.32

> 0.41 0.42 0.46

> 0.29 0.28 0.27

> 0.41 0.40 0.37

> 0.43 0.46 0.40

0.47 0.41 0.39

0.35 0.34 0.34

0.45 0.45 0.47

0.30 0.31 0.30

0.43 0.41 0.41

0.49 0.53 0.47

Variant and spacing between drain lines /depth drain (m)

> A 20/1.0

> B 15/1.0

> C 12/1.0

> D 20/0.8

> E 15/0.8

> F 12/0.8

Drain line number

> 1 2 3

> 4 5 6

> 7 8 9

10 11 12

13 14 15

16 17 18 5.17 5.77 5.00

2.98 2.90 2.86

3.85 3.97 4.17

2.50 3.13 2.94

4.00 3.33 4.00

4.55 4.55 4.17

Table 7. The specific drainage flows in 1981-1982.

Depending on the size of specific drainage daily flow of the area served by the drainage lines (1-18) and experimental drainage variants (A-F) volumes of drained water were calculated, expressed in mm or m3ha-1. To calculate the volume of drained water areas were used areas of 0.60 ha (variants A and D), 0.45 ha (variants B and E), and 0.36 ha (variants C and F).


Tile Drainage on Agricultural Lands

arrangement conditions:


into the drain pipes.

categories.

energy losses:

0.1 l/minute.

**3.5.4 The capture capacity of drain pipes** 

from North-East Romania - Experimental Variants and Technical Efficiency 231

The excess stagnant water from the surface of the field and/or as pedophreatic water in the upper part of the soil structure must be evacuated in a relatively optimal period of time.

Before the descendent water current from the soil structure gets into the drain pipe it encounters a series of resistances that in general depend of the following natural factors and


According to *van Someren (1964),* the total energy losses in pipes (Δh) that are due to the resistances that appear when the water enters the drain pipe and that is measured at the middle of the distance between the drains, can be divided into the following three



For the water current to enter into the drain pipe, the total energy losses *(Δh)* from the middle of the spacing between the drain lines must be higher than the sum of the partial

Δh > Δh0 + Δhr + Δhi The studies made on the *total energy losses (Δh)***,** under the conditions of a non-permanent regime were analyzed in the hypothesis of knowing the period of time (t days) in which the water level must be lowered from the maximum height (h0) to the minimum height (ht).

The effect of the total energy losses (Δh = h0 - ht) was followed in the piezometric pipe situated at the middle of the spacing between the drain pipes, with the distance between them of 12 m and the medium depth of 0.8 m. At different periods of time (t), the total energy loss was represented, in general, by the decrease of the excess water level at the maximum height of the depression curve of 60 - 70 cm, the best height of 15 - 20 cm. At the same periods of time (t) the drained flows decreased from 9 - 10 l/minute to

J

levels in the piezometer from the middle of the spacing between the drain lines, at the beginning and the end of the draining's functioning periods, with the help of the

*a* ) was determined in the base of the measured



the immediate area of the drain pipe.


following relation:

water current when entering into the drain pipe.


Table 8. Drained water volumes regime in 1981-1982.


#### **3.5.4 The capture capacity of drain pipes**

230 Drainage Systems

 

 

 

 

 

 





drains (B, C, D, E, F variants) than the unaerated surface soil of the third drain. - Average volumes of drained water from the corresponding size of the excess moisture from rainfall from 1981 and 1982, on the 6 variant were distributed among the 48%

Average 482 206 344 184 98 141 298 108 203

Average 357 201 279 143 107 125 214 94 154

Average 447 265 356 172 133 152 275 132 204

Average 320 170 245 129 90 109 191 80 136

Average 434 246 340 172 126 149 262 120 191

Average 456 280 368 183 146 165 273 134 203

Seasonal distribution of drained water volumes (mm) Warm season (V-X) Cold season (XI-IV)

> 

> 

> 

> 

> 

> 

 

> 

 

> 

 

   

 

 

 

 

 

1981 1982 Average 1981 1982 Average 1981 1982 Average

 

 

 

 

 

 

 

 

 

 

 

 

The annual volume of drained water (mm)

> 

> 

> 

> 

> 

> 

and 22 % for distance of 15 m (variant E to variant B).

efficiency (variant D) and up to 72% (variant F).

and lower in the warm season of the year (V -X).

12 m and average depth of 0.8 m or 1.0 m.

 

 

 

 

 

 

Spacing between drain lines /depth drain (m)

> A 20/1,0

> B 15/1,0

> C 12/1,0

> D 20/0,8

> E 15/0,8

> F 12/0,8

Drain line number

> 

> 

> 

 

 

   

 

 

 

 

 

Table 8. Drained water volumes regime in 1981-1982.

The excess stagnant water from the surface of the field and/or as pedophreatic water in the upper part of the soil structure must be evacuated in a relatively optimal period of time.

Before the descendent water current from the soil structure gets into the drain pipe it encounters a series of resistances that in general depend of the following natural factors and arrangement conditions:


According to *van Someren (1964),* the total energy losses in pipes (Δh) that are due to the resistances that appear when the water enters the drain pipe and that is measured at the middle of the distance between the drains, can be divided into the following three categories.


For the water current to enter into the drain pipe, the total energy losses *(Δh)* from the middle of the spacing between the drain lines must be higher than the sum of the partial energy losses:

$$
\Delta \mathbf{h} \rhd \Delta \mathbf{h}\_0 + \Delta \mathbf{h}\_\mathbf{\tilde{r}} + \Delta \mathbf{h}\_\mathbf{\tilde{i}}
$$

The studies made on the *total energy losses (Δh)***,** under the conditions of a non-permanent regime were analyzed in the hypothesis of knowing the period of time (t days) in which the water level must be lowered from the maximum height (h0) to the minimum height (ht).

The effect of the total energy losses (Δh = h0 - ht) was followed in the piezometric pipe situated at the middle of the spacing between the drain pipes, with the distance between them of 12 m and the medium depth of 0.8 m. At different periods of time (t), the total energy loss was represented, in general, by the decrease of the excess water level at the maximum height of the depression curve of 60 - 70 cm, the best height of 15 - 20 cm. At the same periods of time (t) the drained flows decreased from 9 - 10 l/minute to 0.1 l/minute.


levels in the piezometer from the middle of the spacing between the drain lines, at the beginning and the end of the draining's functioning periods, with the help of the following relation:

Tile Drainage on Agricultural Lands

drainage system (Canarache, 1991).

following factors:

follows:

assurance.

(Table 10).



**3.5.5 The behaviour during the use of draining pipes** 

excess that must be evacuated through a drainage system.

from North-East Romania - Experimental Variants and Technical Efficiency 233

variation of these three components characterizes the soil compaction condition according to the determining factors. For organic and organo-mineral soils, favourable conditions exist when the drained porosity is greater than 20%; however, this requires installation of a

In the case of the soils with excessive rain water, the functioning system of the drain pipes is determined by the size and the aleatory distribution of the rain water quantity. In a series of successive periods of time water excess appears in the soil and/or on the surface of the soil,

The evaluation of the water survey in the conditions of the existent *18 draining lines* (1, 2, 3, …., 18) and respectively, of the *six experimental drainage variants* (A, B, C, D, E and F) was analyzed taking into consideration the long time observations that were realized on the

The annual dynamic of the climatic factors from the period 1978 - 2010 that was also presented in the previous paragraphs respected the characteristics of the areas from the wet

The synthesis of the results obtained during the entire period of time when pipes drain experiments were made, can be characterized according to the annual and the seasonal dynamic of the climatic factors and the functional efficiency of the drainage system, as





situated between the limits of the normal distribution from the wet areas.

a medium multiannual value of 325 mm or 3250 m3ha-1 (Table 10).

climate area of Romania, area that includes the Baia Depression as well.

$$a = \frac{1}{\mathcal{J}} = \frac{2.3 \left(\log h\_o - \log h\_t\right)}{t}$$

where:

*a* - factor of the draining intensity (days-1)

*ho* - maximum height of the pedophreatic water level

*ht* - minimum height of the pedophreatic water level

t- period of time (days).

Depending of the amount of rain that fell, that in periods of 3 - 5 consecutive days, registered values of up to 60 - 140 mm, there were differentiated as well the values of the intensity draining factors. So, depending of the *total energy losses* (Δh), after the previously mentioned rains, the values of the draining intensity were of 4 - 6 days, during the hot season, and of 6 - 14 days, during the cold season (Table 9).


Table 9. The draining intensity factor depending of the total energy loss.


Pores larger than 10-30 μ form the drainage porosity, usually occupied by air, but through which is drained by way of infiltration the water excess. The 30 μ diameter is found in sandy soils and the 10 μ in the medium and coarse textured soils. Utile porosity includes mediumsized pores with a diameter between 0.2 and 10 to 30 μ, which are able to retain either air or mobile water accessible to plants. Inactive porosity includes smaller pores, with diameters under 0.2 μ, which retain the water inaccessible to plants (Canarache, 1990). Drained porosity, utile porosity and inactive porosity are the basic components of total porosity. The variation of these three components characterizes the soil compaction condition according to the determining factors. For organic and organo-mineral soils, favourable conditions exist when the drained porosity is greater than 20%; however, this requires installation of a drainage system (Canarache, 1991).

#### **3.5.5 The behaviour during the use of draining pipes**

In the case of the soils with excessive rain water, the functioning system of the drain pipes is determined by the size and the aleatory distribution of the rain water quantity. In a series of successive periods of time water excess appears in the soil and/or on the surface of the soil, excess that must be evacuated through a drainage system.

The evaluation of the water survey in the conditions of the existent *18 draining lines* (1, 2, 3, …., 18) and respectively, of the *six experimental drainage variants* (A, B, C, D, E and F) was analyzed taking into consideration the long time observations that were realized on the following factors:


232 Drainage Systems

*h h o t <sup>a</sup>*

Depending of the amount of rain that fell, that in periods of 3 - 5 consecutive days, registered values of up to 60 - 140 mm, there were differentiated as well the values of the intensity draining factors. So, depending of the *total energy losses* (Δh), after the previously mentioned rains, the values of the draining intensity were of 4 - 6 days, during the hot

days h0 (mm) ht (mm) Δh (mm) days -1 -



Pores larger than 10-30 μ form the drainage porosity, usually occupied by air, but through which is drained by way of infiltration the water excess. The 30 μ diameter is found in sandy soils and the 10 μ in the medium and coarse textured soils. Utile porosity includes mediumsized pores with a diameter between 0.2 and 10 to 30 μ, which are able to retain either air or mobile water accessible to plants. Inactive porosity includes smaller pores, with diameters under 0.2 μ, which retain the water inaccessible to plants (Canarache, 1990). Drained porosity, utile porosity and inactive porosity are the basic components of total porosity. The

Table 9. The draining intensity factor depending of the total energy loss.

J

where:

Time (t)

cm.

*a* - factor of the draining intensity (days-1)

until the necessary depth of 70 - 80 cm.

t- period of time (days).

*ho* - maximum height of the pedophreatic water level *ht* - minimum height of the pedophreatic water level

season, and of 6 - 14 days, during the cold season (Table 9).

The height of the depression curve at the middle of the spacing between the drain pipes

1 2.3 log log

*t*

Total energy losses

Factor

0.167 0.171 0.152 0.208 0.236 0.070 0.209 0.117

J <sup>1</sup> *<sup>a</sup>* Coefficient

6.0 5.8 6.6 4.8 4.2 14.3 4.8 8.5

a 1 *J*


The annual dynamic of the climatic factors from the period 1978 - 2010 that was also presented in the previous paragraphs respected the characteristics of the areas from the wet climate area of Romania, area that includes the Baia Depression as well.

The synthesis of the results obtained during the entire period of time when pipes drain experiments were made, can be characterized according to the annual and the seasonal dynamic of the climatic factors and the functional efficiency of the drainage system, as follows:


Tile Drainage on Agricultural Lands

average of 16%.

(variant F).

and of the drainage plot.

content.

cm.

surface, at different periods of the year.

from North-East Romania - Experimental Variants and Technical Efficiency 235





Soil-field mapping units, considered ecologically homogeneous, were established between the limits of the *six experimental* (Figure 1) plots arranged for subsurface drainage, having

The calculation of classification notes for crops was done according to the 17 eco-soil indicators of natural conditions for unimproved soil and, respectively, of the conditions for drained, improved and cultivated soil. According to the classification marks, established for each plot of the two plots, we gave the average mark per uses and crops of the control plot

In the case of quality classes, the classification marks were grouped from 20 to 20 marks: I

Under soil genetic conditions of the microclimate from the Baia Depression, with a *lower mean annual temperature* (7.9C), early frost and late thawing, at which higher *mean annual rainfall* are added (806 mm), frequently stagnant water excess takes place on the field

Among the important limitative factors of the production that were found in the natural conditions of albic stagnic-glossic Luvosol, used as "*hygrophilous natural meadow*", we noticed the following: stagnant moisture excess, soil acidity, soil compaction, low humus

*Soil texture* is dusty-loam at the depth 0-20 cm, and then it becomes average loam-clayey, in

*Total porosity* was generally correlated to the clay content (< 0.002 mm), being characterized by equal values of 52-65 % at the depth 0-20 cm and respectively, 44-47 % at the depth 20-40

*Base saturation degree* (VAh) is found within the oligomesobasic limits of 40-70 %.

(81-100 points); II (61-80 points); III (41-60 points); IV (21-40 points); V (0-20 points).

system with ridges and furrows, with an average of 23 % (variant A).

the following useful areas: 0.60 ha (A and D); 0.45 ha (B and E); 0.36 ha (C and F).

efficiency of the drainage system, with an average of 11 %.

**3.6 Classification and qualitative evaluation of soil** 

*Classification and qualitative evaluation of unimproved soil* 

the subjacent layer 20-40 cm and clayey-loam deep in the soil.

*Soil response* is moderately acid at depth 0-40 cm.



Table 10. The regime of the volumes of drained water in the period 1978 - 2010.

From the analysis of the functional efficiency of the experimented draining variants that were analyzed during the entire period of exploitation, results the following:


> Surface of the pipes joints / perforation s (cm2m-1)

> > 10-15 13-20 10-15

> > 10-15 10-15 10-15

> > 15-30 15-30 10-15

> > 15-30 30-40 10-15

> > 10-15 10-15 10-15

> > 15-30 15-30 10-15

Average - - 1610 50 2.7

Average - - 1423 44 2.4

Average - - 1830 57 3.0

Average - - 1243 38 2.1

Average - - 1810 56 3.0

Average - - 1907 59 3.2

Mean water excess (m3ha-1)

3250

3250

3250

3250

3250

3250

Drained soil water balance

Mean daily water flow

> 3.0 2.7 2.3

> 2.3 2.4 2.4

> 3.1 3.1 2.9

> 2.1 2.3 1.8

> 3.0 3.1 3.0

> 3.2 3.5 2.9

(mmday-1) m3ha-1 %

56 50 43

42 45 44

58 57 55

39 42 34

55 57 55

58 64 54

Mean drained water

1830 1610 1390

1370 1460 1440

1870 1850 1770

1260 1360 1110

1800 1840 1790

1900 2070 1750

of the drainage system (Table 10).

Pipe type and diameter (mm)

> Tile Ø 70 Tile Ø 125 Tile Ø 70

Tile Ø 70 Tile Ø 70 Tile Ø 70

Corrugated plastic Ø 65 Smooth plastic Ø 63 Tile Ø 70

Corrugated plastic Ø 65 Smooth plastic Ø 110 Tile Ø 70

> Tile Ø 70 Tile Ø 70 Tile Ø 70

Corrugated plastic Ø 65 Smooth plastic Ø 63 Tile Ø 70

Table 10. The regime of the volumes of drained water in the period 1978 - 2010.

were analyzed during the entire period of exploitation, results the following:

From the analysis of the functional efficiency of the experimented draining variants that

Drain line number

> 1 2 3

> 4 5 6

> 7 8 9

10 11 12

13 14 15

16 17 18

Variant and spacing between drain lines /depth drain (m)

> A 20/1,0

> B 15/1,0

> C 12/1,0

> D 20/0,8

> E 15/0,8

> F 12/0,8


#### **3.6 Classification and qualitative evaluation of soil**

Soil-field mapping units, considered ecologically homogeneous, were established between the limits of the *six experimental* (Figure 1) plots arranged for subsurface drainage, having the following useful areas: 0.60 ha (A and D); 0.45 ha (B and E); 0.36 ha (C and F).

The calculation of classification notes for crops was done according to the 17 eco-soil indicators of natural conditions for unimproved soil and, respectively, of the conditions for drained, improved and cultivated soil. According to the classification marks, established for each plot of the two plots, we gave the average mark per uses and crops of the control plot and of the drainage plot.

In the case of quality classes, the classification marks were grouped from 20 to 20 marks: I (81-100 points); II (61-80 points); III (41-60 points); IV (21-40 points); V (0-20 points).

*Classification and qualitative evaluation of unimproved soil* 

Under soil genetic conditions of the microclimate from the Baia Depression, with a *lower mean annual temperature* (7.9C), early frost and late thawing, at which higher *mean annual rainfall* are added (806 mm), frequently stagnant water excess takes place on the field surface, at different periods of the year.

Among the important limitative factors of the production that were found in the natural conditions of albic stagnic-glossic Luvosol, used as "*hygrophilous natural meadow*", we noticed the following: stagnant moisture excess, soil acidity, soil compaction, low humus content.

*Soil texture* is dusty-loam at the depth 0-20 cm, and then it becomes average loam-clayey, in the subjacent layer 20-40 cm and clayey-loam deep in the soil.

*Total porosity* was generally correlated to the clay content (< 0.002 mm), being characterized by equal values of 52-65 % at the depth 0-20 cm and respectively, 44-47 % at the depth 20-40 cm.

*Soil response* is moderately acid at depth 0-40 cm.

*Base saturation degree* (VAh) is found within the oligomesobasic limits of 40-70 %.

Tile Drainage on Agricultural Lands

of natural conditions was done.

Soil unit (SU) SU area

fertility (table 12).

Improved albic

Depression.

**4. Conclusion** 

of exploitation for land fund.

stagnic-glossic Luvosol 2.82

effect of intense mineralization of humic substances.

from North-East Romania - Experimental Variants and Technical Efficiency 237

*Humus content* that was determined after the 32-year exploitation periods, pointed out the

By the application of controlling moisture excess works, the "*increase*" of classification marks

Thus, we mention the diminution of defaults determined by classification coefficients for

Agro-soil ameliorative works have also contributed to the "*increase*" of classification marks for the favourable correction of soil response, total porosity and organic matter content from soil. For the increased conditions of using soil for "*pastures and hayfields*" there were good average classification marks of 79-88 points, with an average of the drainage plot of 84 points that framed the improved farm field in the first quality class, with a very good

(ha) Agricultural use and crops Classification

Average field meadows 84 I

Average arable land 64 II

Pastures Hayfield

> Wheat Barley Maize Potato Flax Alfalfa

Table 12. Field classification for the increased conditions of the drainage field-Baia

as "arable field" in the second quality class with a good fertility.

water, acidity, flood hazard, soil compaction and low permeability soils.

ha, which represents 21.7% of the total area of Suceava County.

The use of the improved soil as "arable field" framed the drained field between the average classification marks of 50 points for barley and until 81 points for alfalfa. The average of the classification marks of the drainage group for the first six crops of 64 points framed the use

Sustainable development of the agricultural area of Romania requires a balance between economic growth and environmental protection, depending on soil quality and the strategy

Comprehensive soil studies in Suceava County, on an area of 398,771 ha has allowed for classification of soil in ten classes and nineteen types of soil. Among the limiting factors of agricultural growth in the natural sol-units, one can mention: excess moisture, erosion by

Excess moisture of pluvial nature and/or from groundwater, plus the overflowing of hydrographic networks, showed up in various forms and intensities on a surface of 185,316

note

88 79

Quality class

> I II

III III III II II I

average annual rainfall, stagnant moisture excess and soil stagnogleyzation.

*The humus content* has recorded relatively high values until 194-199 t·ha-1 in the layers 0-5 and 5-18 cm. In the next two horizons EaW (18-30 cm) and EBW (36-40 cm), the humus reserve decreases once with depth until very low values.

The classification of farm field for the above-mentioned soil genetic conditions and actual use of "*hygrophilous natural meadow"* led to average classification marks of 39 points (Table 11).


Table 11. Field classification for the natural conditions of the control plot- Baia Depression.

In the case of using albic stagnic-glossic Luvosol as arable land, we have evaluated the suitability of the first six crops in the wet climatic area. The average classification marks comprised between 9 points (barley and maize) and 26 points (alfalfa) led to an average of the control plot of 13 points.

The natural soil classification has shown the following defaults: water stagnation at field surface, soil stagnogleyzation, soil-ground water depth and soil acidity and compaction.

*Classification and qualitative evaluation of improved soil* 

By planning the subsurface drainage and applying agro-soil ameliorative works, we noticed a significant improvement of the general physical and chemical condition of the drained soil.

*Soil texture* was dusty-loam at the depth of 0-20 cm, while at the depth of 20-40 cm it was dusty clayey-loam, because of the mixture between genetic horizons, after soil loosening and cultivation works.

*Total porosity* with values between 50 and 55 %, at depths 0-40 cm, has shown a weak soil loosening after the three exploitation cycles.

*Soil acidity* was maintained within the limits corresponding to moderately acid to weakly acid soils, because of the long-term effect of limestone applied in 1978 and 1988.

*Base saturation degree* (VAh) was maintained in the first two cycles (1978 - 1986 and 1986 - 1997) between the limits of 71-90 %, moderately mesobasic. In 2010, the base saturation degree of 48-53 %, corresponding to the extremely oligomesobasic field, required limestone amendment.

*Humus content* that was determined after the 32-year exploitation periods, pointed out the effect of intense mineralization of humic substances.

By the application of controlling moisture excess works, the "*increase*" of classification marks of natural conditions was done.

Thus, we mention the diminution of defaults determined by classification coefficients for average annual rainfall, stagnant moisture excess and soil stagnogleyzation.

Agro-soil ameliorative works have also contributed to the "*increase*" of classification marks for the favourable correction of soil response, total porosity and organic matter content from soil. For the increased conditions of using soil for "*pastures and hayfields*" there were good average classification marks of 79-88 points, with an average of the drainage plot of 84 points that framed the improved farm field in the first quality class, with a very good fertility (table 12).


Table 12. Field classification for the increased conditions of the drainage field-Baia Depression.

The use of the improved soil as "arable field" framed the drained field between the average classification marks of 50 points for barley and until 81 points for alfalfa. The average of the classification marks of the drainage group for the first six crops of 64 points framed the use as "arable field" in the second quality class with a good fertility.

#### **4. Conclusion**

236 Drainage Systems

*The humus content* has recorded relatively high values until 194-199 t·ha-1 in the layers 0-5 and 5-18 cm. In the next two horizons EaW (18-30 cm) and EBW (36-40 cm), the humus

The classification of farm field for the above-mentioned soil genetic conditions and actual use of "*hygrophilous natural meadow"* led to average classification marks of 39 points (Table

area (ha) Agricultural use and crops Classification

Pastures Hayfield

> Wheat Barley Maize Potato Flax Alfalfa

Table 11. Field classification for the natural conditions of the control plot- Baia Depression.

In the case of using albic stagnic-glossic Luvosol as arable land, we have evaluated the suitability of the first six crops in the wet climatic area. The average classification marks comprised between 9 points (barley and maize) and 26 points (alfalfa) led to an average of

The natural soil classification has shown the following defaults: water stagnation at field surface, soil stagnogleyzation, soil-ground water depth and soil acidity and compaction.

By planning the subsurface drainage and applying agro-soil ameliorative works, we noticed a significant improvement of the general physical and chemical condition of the drained

*Soil texture* was dusty-loam at the depth of 0-20 cm, while at the depth of 20-40 cm it was dusty clayey-loam, because of the mixture between genetic horizons, after soil loosening

*Total porosity* with values between 50 and 55 %, at depths 0-40 cm, has shown a weak soil

*Soil acidity* was maintained within the limits corresponding to moderately acid to weakly

*Base saturation degree* (VAh) was maintained in the first two cycles (1978 - 1986 and 1986 - 1997) between the limits of 71-90 %, moderately mesobasic. In 2010, the base saturation degree of 48-53 %, corresponding to the extremely oligomesobasic field, required limestone

acid soils, because of the long-term effect of limestone applied in 1978 and 1988.

note

42 35

Average field meadows 39 IV

Average arable land 13 V

Quality class

> III IV

> V V V V V IV

reserve decreases once with depth until very low values.

11).

soil.

Unimproved albic stagnicglosic Luvosol

Soil unit Soil unit

the control plot of 13 points.

and cultivation works.

amendment.

3.0

*Classification and qualitative evaluation of improved soil* 

loosening after the three exploitation cycles.

Sustainable development of the agricultural area of Romania requires a balance between economic growth and environmental protection, depending on soil quality and the strategy of exploitation for land fund.

Comprehensive soil studies in Suceava County, on an area of 398,771 ha has allowed for classification of soil in ten classes and nineteen types of soil. Among the limiting factors of agricultural growth in the natural sol-units, one can mention: excess moisture, erosion by water, acidity, flood hazard, soil compaction and low permeability soils.

Excess moisture of pluvial nature and/or from groundwater, plus the overflowing of hydrographic networks, showed up in various forms and intensities on a surface of 185,316 ha, which represents 21.7% of the total area of Suceava County.

Tile Drainage on Agricultural Lands

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Jitareanu, G., Rusu, C., Moca, V. (2009). Evaluation and use of soil resources, environmental

Lukianas, A., Vaikasas, S., Malisauskas, A. (2006). Water management tasks in the summer

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Mejia, M.N., Madramootoo, C.A. (1998). Improvement water quality through water table

Moca, V., Bofu, C., Filipov, F., Radu, O. (2001). Influenta de lunga durata a drenajului

Munteanu, I., Dumitru, M., Florea, N., Canarache, A., Lacatusu, R., Vlad, V., Simota, C.,

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protection and rural development in the north-eastern part of Romania, Ion

polders of the Nemunas Lowland. *Irrigation and drainage*. 55 (2): 145-156. DOI:

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*environmental analysis: Physical methods* (2nd ed.), Smith K. A., Mullins C. E. (eds.).

The diversity of natural conditions and the intrinsic characteristics of soil resources have determined a condition of middle to poor quality and suitability of the soil-units for agricultural use. In accordance with the specific requirements for soil crust improvements, in time were laid out a succession of hydro-ameliorative works.

Among these types of works, there can be emphasized the systems with ditches on a surface of about 55,000 ha and the pipes drainage on approximately 27,000 hectares, comprised in 20 large and local systems.

In order to increase the quality of the countryside and to promote sustainable farming systems, one has to protect the soil through both, the rehabilitation and / or extension of the existing barren hydro-ameliorative works, as well as by resizing the plots of the agricultural exploitations.

The pipe drainage system with spacing between drain lines of 12 - 15 m and of maximum 20 m resulted to be an efficient solution for the proper evacuation of excess water.

The process of removal of the excess water from the surface of the soil and/or within the soil, water that resulted from the rainfalls of 40 - 160 mm, which fell in periods of 1 - 5 consecutive days, was made in the conditions that were studied with the specific water flow of 1.5 - 2.5 ls-1ha-1.

The growth of the spacing between the drain lines with up to 20 - 30 m must be associated to the agro- and soil improvement: periodically deep loosening works, mole drainage and land shaping in the bedding system with ridges and furrows.

Classification and evaluation of soil quality for usages and crops is the database of qualitative farm cadastre at the level of soil-field mapping units of soil.

For the natural conditions of albic stagnic-glossic Luvosol from the Baia Depression, we have estimated an average classification mark of 39 points for grasslands and hayfields and of 13 points for the arable land, with extremely severe limitations caused by water excess.

By the arrangement of the farm field for water excess removal and the corresponding application of agro-soil ameliorative works, we have achieved the "increase" of some classification indicators, obtaining an average mark of 84 points for "improved pastures" and 64 points for "arable land".

#### **5. Acknowledgment**

This work was supported by CNCSIS - UEFISCSU, project number PNII - IDEI 1132 / 2008.

#### **6. References**

Canarache A. (1990). Fizica solurilor agricole. Ceres. Bucharest.


The diversity of natural conditions and the intrinsic characteristics of soil resources have determined a condition of middle to poor quality and suitability of the soil-units for agricultural use. In accordance with the specific requirements for soil crust improvements,

Among these types of works, there can be emphasized the systems with ditches on a surface of about 55,000 ha and the pipes drainage on approximately 27,000 hectares, comprised in 20

In order to increase the quality of the countryside and to promote sustainable farming systems, one has to protect the soil through both, the rehabilitation and / or extension of the existing barren hydro-ameliorative works, as well as by resizing the plots of the agricultural

The pipe drainage system with spacing between drain lines of 12 - 15 m and of maximum 20

The process of removal of the excess water from the surface of the soil and/or within the soil, water that resulted from the rainfalls of 40 - 160 mm, which fell in periods of 1 - 5 consecutive days, was made in the conditions that were studied with the specific water flow

The growth of the spacing between the drain lines with up to 20 - 30 m must be associated to the agro- and soil improvement: periodically deep loosening works, mole drainage and land

Classification and evaluation of soil quality for usages and crops is the database of

For the natural conditions of albic stagnic-glossic Luvosol from the Baia Depression, we have estimated an average classification mark of 39 points for grasslands and hayfields and of 13 points for the arable land, with extremely severe limitations caused by water excess. By the arrangement of the farm field for water excess removal and the corresponding application of agro-soil ameliorative works, we have achieved the "increase" of some classification indicators, obtaining an average mark of 84 points for "improved pastures"

This work was supported by CNCSIS - UEFISCSU, project number PNII - IDEI 1132 / 2008.

Canarache, A. (1991). Factors and indices regarding excessive compactness of agricultural

Cooke, R.A., Sands, G.R., Brown, L.C. (2002). Drainage water management: a practice for

soils. Soil & Tillage Research. Elsevier Science B.V. Publishers, 19: 145-164.

reducing nitrate loads from subsurface drainage systems. *ASAE Publication*, Paper

m resulted to be an efficient solution for the proper evacuation of excess water.

in time were laid out a succession of hydro-ameliorative works.

shaping in the bedding system with ridges and furrows.

qualitative farm cadastre at the level of soil-field mapping units of soil.

Canarache A. (1990). Fizica solurilor agricole. Ceres. Bucharest.

large and local systems.

exploitations.

of 1.5 - 2.5 ls-1ha-1.

and 64 points for "arable land".

Amsterdam.

No 05. St. Joseph, Mich; 8 pp.

**5. Acknowledgment** 

**6. References** 


Walker, W.R. (1989). Guidelines for designing and evaluating surface irrigation systems,

\*\*\*. (1987). Methodology of soil studies elaboration. National Institute of Research and

\*\*\*. (2006). World reference base for soil resources 2006*. World Soil Resources Reports*. 103.

\*\*\*. (2008). Romanian Statistical Yearbook. National Institute of Statistics. Bucharest. \*\*\*. (2010). Romanian Statistical Yearbook. National Institute of Statistics. Bucharest.

Development in Soil Science, Agrochemistry and Environment. Bucharest, vol. I, p.

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135-154,

FAO. Rome.

### *Edited by Muhammad Salik Javaid*

The subject of 'drainage: draining the water off' is as important as 'irrigation: application of water', if not more. 'Drainage' has a deep impact on food security, agricultural activity, hygiene and sanitation, municipal usage, land reclamation and usage, flood and debris flow control, hydrological disaster management, ecological and environmental balance, and water resource management. 'Drainage Systems' provides the reader with a tri-dimensional expose of drainage in terms of sustainable systems, surface drainage and subsurface drainage. Ten eminent authors and their colleagues with varied technical backgrounds and experiences from around the world have dealt with extensive range of issues concerning the drainage phenomenon. Field engineers, hydrologists, academics and graduate students will find this book equally benefitting.

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Drainage Systems

Drainage Systems

*Edited by Muhammad Salik Javaid*