**Sustainable Groundwater Management in Context of Climate Change in Northwest Bangladesh Climate Change in Northwest Bangladesh**

**Sustainable Groundwater Management in Context of** 

DOI: 10.5772/intechopen.73305

A.T.M. Sakiur Rahman, Takahiro Hosono, Quamrul H. Mazumder and Chowdhury S. Jahan Quamrul H. Mazumder and Chowdhury S. Jahan Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

A.T.M. Sakiur Rahman, Takahiro Hosono,

http://dx.doi.org/10.5772/intechopen.73305

#### **Abstract**

The objectives of the study are to understand the variability and changes in hydroclimatic variables in space and time dimensions, and to evaluate the performance of managed aquifer recharge (MAR) for sustainable water resources management in northwest Bangladesh. The study reveals that groundwater resource in the northwest Bangladesh is under stress. The stress has developed and it increases over the years, as a result, shallow groundwater resource has already become scarce. The people of the area are not getting even drinking water using their hand tube wells (HTWs) during the dry season and facing trouble with irrigation water. These problems are becoming acute as a result of uncontrolled and unplanned groundwater abstraction for irrigation. Moreover, rainfall in the study area decreases and dryness increases. Higher values of the seasonality index (¯ SI = 0.87) and precipitation concentration index (PCI = 19.8) are indicators of frequent dry spells. The area suffered from 12 moderate-extreme droughts during 1971–2011, and moderate to high drought risk (B) prevails in the area. The frequent drought, decreasing trend in rainfall, transboundary river flow, and thick clay surface lithology along with the uncontrolled irrigation are also responsible for rapid depletion of groundwater. As the annual surplus of water (average = 594 mm) is higher than groundwater recharge (330 mm), an experimental study on managed aquifer recharge (MAR) has been conducted to enhance the groundwater recharge. It shows good performance for restoring the groundwater without creating any sorts of hazards. Moreover, almost 5% of irrigated land can be irrigated from surface water sources by re-excavating the rivers, *Kharis* (small channels). It is necessary to prepare an integrated water resource management plan (IWRMP) considering the impacts of climate change, drought risk, driving factors of the groundwater resource depletion, and rainwater as a resource for achieving the sustainability.

**Keywords:** climate change, drought prone area, managed aquifer recharge, sustainable groundwater management

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

## **1. Introduction**

Water is a vital natural resource and is a key requisite for sustainable development. Groundwater depletion has been recognized as a global problem. The estimated global groundwater depletion during 1900–2008 is about 4500 km<sup>3</sup> , and rapid depletion of groundwater has occurred during 2000–2008 [1]. Groundwater withdrawal for irrigation has intensified around the world over the past few decades. This withdrawal has largely occurred without hydrological planning, as a result, a high groundwater depletion has occurred. Therefore, the sustainable management approach has attracted attention to the hydrological community and some concepts have developed. However, Unver [2] pointed out that sustainable development is a concept still in the making as most of the traditional concepts fail to ensure the use of water resources in a sustainable manner. The groundwater footprint concept focuses on groundwater recharge as an index of sustainability [3]. Groundwater recharge rates alone cannot serve to address the core policy question regarding the sustainable aquifer conditions [4]. Studies [4, 5] stated that groundwater management plans based on traditional concepts like safe yield, assured water supply, and groundwater footprints are not clear indicators of groundwater sustainability mainly due to ignoring the impact of climate change and drought. However, water resource is at the core of sustainable development recognized in the Rio World Summit in 1992. United Nation (UN) Sustainable Development Goals Report [6] has emphasized on sustainable management of water resources (Goal-6) and combating climate change impact (Goal-13). Hence, the present study has given the main attention to the sustainability of groundwater resource by integrating drought characteristics, and climate change effects and status of the groundwater resource. Our previous studies [7–9] investigated the groundwater level scenario, drought characteristics, and dynamics of drought in the northwest Bangladesh. However, the impact of climate change on rainfall pattern which is the main source of groundwater recharge and potentiality of surface water resource have not been investigated comprehensively yet. In the present study, rainfall climatology, reanalysis of long-term groundwater level data (1971– 2011), driving forces of groundwater depletion, groundwater recharge, and potentiality of surface water resource have been investigated comprehensively. Beside these, an experimental study on managed aquifer recharge (MAR) has been conducted and performance of MAR has been assessed. Therefore, it is expected that the study will contribute to the development of the concepts of sustainable water resources management and understand the phenomena groundwater sustainability in the context of climate change in drought prone areas.

### **2. Study area**

The study area includes Chapai Nawabganj, Naogaon, and Rajshahi districts and covers 25 Upazilas (sub-district) in the northwest Bangladesh (**Figure 1**). The area is popularly known as Barind area and the area covers approximately 7545.25 km2 . Geographically, the area extends from 24<sup>o</sup> 08′ to 25<sup>o</sup> 13′N latitudes and from 88<sup>o</sup> 01′ to 89<sup>o</sup> 10′E longitudes. The map of the study area, including the locations of rain gauge stations, meteorological stations, groundwater observation wells, vertical electrical sounding (VES) stations, and managed aquifer recharge (MAR) sites, is shown in **Figure 1**. Groundwater is the main source of irrigation in the agrobased northwest Bangladesh and Barind Multipurpose Development Authority (BMDA) is responsible for irrigation water management. Groundwater resource exploration is ongoing on the basis of one-third rainfall recharge hypothesis of BMDA that is beyond the sustainable yield [10]. About 75% of the land in the study area is used for agricultural practices. High yield variety (HYV) *Boro* rice, which cultivates during the dry season completely depends on

**Figure 1.** Study area with locations of meteorological, rain gauge, and VES stations, groundwater observation wells

Sustainable Groundwater Management in Context of Climate Change in Northwest Bangladesh

http://dx.doi.org/10.5772/intechopen.73305

103

The physiographic features of the area are mainly two types. These are (1) Floodplains which include Tista, Lower Purnabhaba, Mahananda and Ganges flood plains; and (2) Barind Tract

groundwater irrigation, shares almost 81.2% of the total cultivable area.

**2.1. Geology and hydrogeology**

(GOW) and MAR sites.

Sustainable Groundwater Management in Context of Climate Change in Northwest Bangladesh http://dx.doi.org/10.5772/intechopen.73305 103

**Figure 1.** Study area with locations of meteorological, rain gauge, and VES stations, groundwater observation wells (GOW) and MAR sites.

(MAR) sites, is shown in **Figure 1**. Groundwater is the main source of irrigation in the agrobased northwest Bangladesh and Barind Multipurpose Development Authority (BMDA) is responsible for irrigation water management. Groundwater resource exploration is ongoing on the basis of one-third rainfall recharge hypothesis of BMDA that is beyond the sustainable yield [10]. About 75% of the land in the study area is used for agricultural practices. High yield variety (HYV) *Boro* rice, which cultivates during the dry season completely depends on groundwater irrigation, shares almost 81.2% of the total cultivable area.

#### **2.1. Geology and hydrogeology**

**1. Introduction**

**2. Study area**

08′ to 25<sup>o</sup>

from 24<sup>o</sup>

tion during 1900–2008 is about 4500 km<sup>3</sup>

102 Achievements and Challenges of Integrated River Basin Management

Water is a vital natural resource and is a key requisite for sustainable development. Groundwater depletion has been recognized as a global problem. The estimated global groundwater deple-

during 2000–2008 [1]. Groundwater withdrawal for irrigation has intensified around the world over the past few decades. This withdrawal has largely occurred without hydrological planning, as a result, a high groundwater depletion has occurred. Therefore, the sustainable management approach has attracted attention to the hydrological community and some concepts have developed. However, Unver [2] pointed out that sustainable development is a concept still in the making as most of the traditional concepts fail to ensure the use of water resources in a sustainable manner. The groundwater footprint concept focuses on groundwater recharge as an index of sustainability [3]. Groundwater recharge rates alone cannot serve to address the core policy question regarding the sustainable aquifer conditions [4]. Studies [4, 5] stated that groundwater management plans based on traditional concepts like safe yield, assured water supply, and groundwater footprints are not clear indicators of groundwater sustainability mainly due to ignoring the impact of climate change and drought. However, water resource is at the core of sustainable development recognized in the Rio World Summit in 1992. United Nation (UN) Sustainable Development Goals Report [6] has emphasized on sustainable management of water resources (Goal-6) and combating climate change impact (Goal-13). Hence, the present study has given the main attention to the sustainability of groundwater resource by integrating drought characteristics, and climate change effects and status of the groundwater resource. Our previous studies [7–9] investigated the groundwater level scenario, drought characteristics, and dynamics of drought in the northwest Bangladesh. However, the impact of climate change on rainfall pattern which is the main source of groundwater recharge and potentiality of surface water resource have not been investigated comprehensively yet. In the present study, rainfall climatology, reanalysis of long-term groundwater level data (1971– 2011), driving forces of groundwater depletion, groundwater recharge, and potentiality of surface water resource have been investigated comprehensively. Beside these, an experimental study on managed aquifer recharge (MAR) has been conducted and performance of MAR has been assessed. Therefore, it is expected that the study will contribute to the development of the concepts of sustainable water resources management and understand the phenomena

groundwater sustainability in the context of climate change in drought prone areas.

Barind area and the area covers approximately 7545.25 km2

13′N latitudes and from 88<sup>o</sup>

The study area includes Chapai Nawabganj, Naogaon, and Rajshahi districts and covers 25 Upazilas (sub-district) in the northwest Bangladesh (**Figure 1**). The area is popularly known as

area, including the locations of rain gauge stations, meteorological stations, groundwater observation wells, vertical electrical sounding (VES) stations, and managed aquifer recharge

01′ to 89<sup>o</sup>

. Geographically, the area extends

10′E longitudes. The map of the study

, and rapid depletion of groundwater has occurred

The physiographic features of the area are mainly two types. These are (1) Floodplains which include Tista, Lower Purnabhaba, Mahananda and Ganges flood plains; and (2) Barind Tract (BT). There exists a significant lithological variation in the BT and the adjacent floodplain areas. BT is comprised of thick clay surface lithology which is underlined by thick coarser sediments of Early Pleistocene to Late Paleocene. The materials are dense and compact, and the hydraulic conductivity of the surface clay layer is low [11]. Two different aquifer units have been identified based on hydro-stratigraphic data in the area [11]. The upper-shallow aquifer exists just beneath thick surface silty clay layer. The thickness of this aquifer ranges from 10 to 35 m and it consists of very fine-to-fine sand with lenses of fine to medium sand and occasionally clay, silt, and trace mica lenses. Below the upper-shallow aquifer, there is a lower-shallow aquifer. The thickness of this unit ranges from 20 to 70 m, and it is composed of medium to coarse grain sand with occasional fine sediment lenses.

have been used [18] to find out the change point. The rate of change has been calculated by

Sustainable Groundwater Management in Context of Climate Change in Northwest Bangladesh

Our previous study characterized the drought in the study area [8] using the standardized precipitation index (SPI) [20]. Drought risk ranking is necessary to prepare the viable adaptation measures of an area. This study has ranked the risk of drought using the drought risk

+ *ETgw*

*gw* − *Qin*

The *Qbf* and *ETgw* are negligible for Bangladesh as river stage during the monsoon is higher than the groundwater level and land cover dominated by the shallow rooting depth crops

hydraulic gradients in water level in shallow aquifer during monsoon [24]. Shamsudduha

ima, and ∆*t* is time period (a year). Eq. (2) is similar to water table fluctuation (WTF) method and recharge is referred as "net" recharge [25]. In WTF method, ∆*h* is the difference between the peak water level and the theoretical lowest level [25]. However, Shamsudduha et al. [23] calculated ∆*h* as an annual range between the annual maxima and minima from weekly measured data. Groundwater recharge calculation using Eq. (2) did not provide good results for recent periods (1985–2007 and 2002–2007) for some particular areas (Dhaka City and BT) as the seasonality in groundwater fluctuation suppressed by the long-term trend associated with intensive abstraction [23]. For these areas in Bangladesh, net groundwater recharge was cal-

*gw*

irrigation during the rainy season as a huge amount of groundwater withdrawn during the dry season for *Boro* rice cultivation about 1 m per square meter in Bangladesh [24, 26]. Therefore,

adding the annual groundwater abstraction misleading the net recharge calculation.

is the annual groundwater abstraction. In the study, groundwater recharge has been

is the specific yield, ∆*h* is the water-level height between annual maxima and min-

*gw* = *Sy* \_\_\_ ∂*h* <sup>∂</sup>*<sup>t</sup>* <sup>=</sup> *Sy*

+ (*Qout gw* − *Qin*

*gw* = change in groundwater storage; *Qbf* = baseflow to river channel; *ETgw*

\_\_\_ ∆*h*

*gw*) (1)

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105

*gw* = net subsurface flow from the area.

<sup>∆</sup>*<sup>t</sup>* (2)

+ *Q<sup>P</sup>* (3)

is the groundwater abstraction for supplementary

*gw*) is also negligible due to the absence of substantial

Sen's slope estimator [19]. The details of the methods can be found in [7–9, 15–19].

ranking diagram [21] to know the risk condition of the area.

The groundwater budget of an area can be written as [22]:

= evapotranspiration from groundwater, and *Qout*

*gw* + *Qbf*

*gw* − *Qin*

et al. [23] simplified Eq. (1) and calculated groundwater recharge (R) as:

*3.2.3. Groundwater recharge and abstraction*

*R* = ∆*S*

[23]. Moreover, groundwater flow (*Qout*

*R* = ∆*S*

*R* = ∆*S*

calculated by Eq. (3) for the BT. However, *Q<sup>P</sup>*

Here, *R =* recharge; ∆*S*

where, *Sy*

culated [23] as:

where *Q<sup>P</sup>*

*3.2.2. Drought risk ranking*
