**1. Introduction**

106 Current Issues of Water Management

Van Koppen, B. (2009). Widening gaps in water reform. PLAAS Umhlaba Wethu 9,

Van Koppen, B., Sally, H., Aliber, M., Cousins, B. and Tapela, B. (2009). Water resources

Vink, N. and Van Rooyen, J. (2009). The Economic Performance of Agriculture in South

Walker, C. (2005). The limits to land reform: Rethinking 'the land question'. *Journal of* 

Water Research Commission (1996). Policy proposal for irrigated agriculture in South

Woodhouse, P. (2008). Water Rights in South Africa: Insights from Legislative Reform. BWPI

Department of Agriculture, Forestry and Fisheries (DAFF). 2011a. Personal communication

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with government official. 22 February 2011, Pretoria, South Africa.

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*Southern African Studies*, Vol. 31, No. 4, (December 2005), pp. (805-824), ISSN 0305-

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Irrigation is the largest water user in the world, using up to 85% of the available water in the developing countries [1]. A lot of irrigation water is used in the production of rice as the staple food of more than half the world population. However, despite the constraints of water scarcity, rice production must be raised to feed the growing population. Producing more rice with less water is therefore a formidable challenge for food, economic, social and water security.

Asia is relatively well endowed with water resources, but water resources per inhabitant are only slightly above half of the world's average. Countries like India and China are approaching the limit of water scarcity. About 84% of water withdrawal is for agriculture, with major emphasis on flooded rice irrigation. There has been a rapid increase in irrigation development. Most countries have achieved self-sufficiency in rice. Schemes are designed primarily to secure rice cultivation in the main cropping season. Some countries design new irrigation schemes for year-round irrigation. Rice represents about 45% of irrigated areas and 59% of the rice land is irrigated. Average cropping intensity is 127%. The 28 million hectares under intense irrigation producing two to three crops per year suffer from declining productivity.

Growth in irrigated areas has declined in recent years. Groundwater draw-down has reached alarming levels in many areas. Declining prices of rice, higher marginal development costs, environmental concerns, and poor performance of existing schemes are among the main factors of the decline in irrigation growth and investment both by governments and farmers.

Increased competition for water between sectors already affects agriculture. Poor operation and maintenance of large public schemes has led to irrigation management transfer or increased participation of users through water users' associations. Socio-economic changes and water scarcity call for a transformation of irrigation by the adoption of measures to modify water demands and maximize efficiency in water use, to improve its economic, technical, and environmental performance, together with diversification of produce and cropping patterns, changes in management systems and structures, financial and fiscal

Paddy Water Management for Precision Farming of Rice 109

imperative that the available irrigation supplies be used efficiently. A small improvement of water use in rice production would result in significant water savings for other sectors. Traditionally rice is grown under continuous submergence or intermittent or variable ponding conditions depending on the farmer's choice and also on the available water resources. Continuous submergence with 5 to 7 cm of water is probably the best for irrigated rice considering all factors and extremely deep water resulted in poor growth and yield [2]. To evaluate the effect of ponding water depth on rice yield, the 9 cm of ponding water depth in Wagner's pots (a growth chamber 25 cm diameter and 30 cm height, filled with soil up to 15 cm depth) gave the optimum rice growth and yield [3]. Therefore, the importance of controlled water supply and monitoring is indispensable for the sustainability of rice

Performance assessment has been prioritized as the most critical element to improve irrigation management [4]. Various analytical frameworks, criteria and indicators are available to understand the factors that influence the performance of irrigation system and to quantify water delivery performance. Some of them are suitable to identifying reasons for poor performance and prescribing management and physical interventions to improve the performance. All performance indicators have their own strengths and weaknesses. Many performance indicators fail to quantify reliability, adequacy and equity aspects of water distribution although many performance indicators are useful for quantifying the water delivery for irrigation seasons. Many performance indicators are useful for post-season evaluation but they are not useful as management tools which can be used to keep track of irrigation delivery performance during a crop growing season. If a particular indicator is useful both as a management tool and as an indicator of the overall irrigation delivery performance for any given irrigation interval or season, its credibility is undoubtedly

Detailed reviews for the advantages and disadvantages for various performance assessment methodologies [5] emphasized the simplest indicator of evaluating water delivery performance and how tightly adequate water can be delivered to the fields. The available water supply and the water demand are the most crucial factors in irrigation planning, design and operation of an irrigation system. A performance indicator [6], which is called Relative Water Supply (RWS), is simply the ratio of irrigation supply and demand. Detailed application and weakness have been described for monitoring and assessing of irrigation water delivery performance for rice irrigation scheme using the RWS concept [7 & 8]; and further illustration on the use of the RWS concept based on field research [9 & 10]. The RWS concept has been widely used to assess the performance of irrigation systems. Indeed for paddy irrigation, quantifying of the upper bound value of RWS for oversupply condition is a difficult task due to the many variables that influence the performance of irrigated agriculture. Therefore, it is essential to have an appropriate tool with feasible options to

The water demand for rice irrigation is completely different from upland crops. To replenish the field water level up to the Maximum Ponding Water Depth (WSmaxj) for a particular period, the amount of water for the difference between the Maximum Ponding Water Depth (WSmaxj) and the Present Ponding Water Depth (WSj) is gradually delivered to the paddy fields. The RWS concept incorrectly characterizes irrigation delivery performance for not considering this amount of water (WSmaxj - WSj) in the denominator. Due to this, RWS

improve the performance of the irrigation supplies for rice production.

production, which varies enormously from region to region.

superior to the other performance measures.

sustainability. But rehabilitation programs are assuming increasing importance. Progress in modernization is slow when compared with other regions.

Scenarios for growth in water demand suggest that because of the projected increases in food demand, irrigated food production will need to increase significantly. Demand from other sectors will also increase because of economic development and increase in population. Nearly all countries in the region will need to invest considerable efforts and resources in a mixture of improved demand management of the water sector and interventions on the supply side to achieve the very considerable improvements in water use which are required. But approximately 1 billion people would live in regions of absolute water scarcity.

Therefore there is a need to improve water productivity as well as water use efficiency. Land preparation, land soaking for maintaining water level in the paddy fields and soil saturation require more water than plant transpiration. System and farm irrigation efficiency is quite low (in the range of 30 to 40%). A river basin perspective should be adopted, defining the boundaries of intervention (farm, system, river basin), paying attention to managing the return flows and to water quality. However, practices which minimize irrigation inflow are of a direct interest to farmers who receive less water and more costly water. In the long run, sustainability of irrigated agriculture will ensure sustainable environment for all human beings.

Environmental sustainability is very synonymous with precision farming or site-specific management. Precision farming requires quick soil spatial variability description for decision-making on the right input at the right place, at the right time and in the right amount or site-specific zone management. VerisEC sensor is used widely for spatial variability description and it relates to soil properties such as salt concentration, texture and cation exchange capacity (CEC), an indication of the soils potential to hold plant nutrients. It is a sensor to measure the ability of soil in conducting electrical current using rotating discs as electrodes, which penetrate 6 cm into the soil, while pulled through the field by a tractor and locations determined by GPS. For upland crops, farmers use VerisEC to measure ECa at shallow and deep depths for Nitrogen management and hardpan depth determination.

Land management zone delineation using soil electrical conductivity (MAZDEC) shortens the time taken to determine paddy soil variability, can be utilized for zoning of paddy fields, and helps rice farmers in site-specific application of their inputs. MAZDEC can complement a detailed soil series map and can be used as an estimator for soil physical and chemical properties. MAZDEC allows directed soil sampling to replace grid sampling, allows topping-up of the required nutrients at the needed rate at the right place and time. Each farmer will be able to quickly determine the soil management zones for variable application rates of seed, fertilizers, and water. Making this information available on-line to the farmers will be a major step in making available the benefits of new technologies.

### **2. Irrigation water management**

### **2.1 Research on rice irrigation water management**

In Malaysia, about 70% of the available water resources are consumed for rice production. Due to rapidly growing population and water competition among different sectors it is

sustainability. But rehabilitation programs are assuming increasing importance. Progress in

Scenarios for growth in water demand suggest that because of the projected increases in food demand, irrigated food production will need to increase significantly. Demand from other sectors will also increase because of economic development and increase in population. Nearly all countries in the region will need to invest considerable efforts and resources in a mixture of improved demand management of the water sector and interventions on the supply side to achieve the very considerable improvements in water use which are required. But approximately 1 billion people would live in regions of absolute

Therefore there is a need to improve water productivity as well as water use efficiency. Land preparation, land soaking for maintaining water level in the paddy fields and soil saturation require more water than plant transpiration. System and farm irrigation efficiency is quite low (in the range of 30 to 40%). A river basin perspective should be adopted, defining the boundaries of intervention (farm, system, river basin), paying attention to managing the return flows and to water quality. However, practices which minimize irrigation inflow are of a direct interest to farmers who receive less water and more costly water. In the long run, sustainability of irrigated agriculture will ensure

Environmental sustainability is very synonymous with precision farming or site-specific management. Precision farming requires quick soil spatial variability description for decision-making on the right input at the right place, at the right time and in the right amount or site-specific zone management. VerisEC sensor is used widely for spatial variability description and it relates to soil properties such as salt concentration, texture and cation exchange capacity (CEC), an indication of the soils potential to hold plant nutrients. It is a sensor to measure the ability of soil in conducting electrical current using rotating discs as electrodes, which penetrate 6 cm into the soil, while pulled through the field by a tractor and locations determined by GPS. For upland crops, farmers use VerisEC to measure ECa at shallow and deep depths for Nitrogen management and hardpan depth determination.

Land management zone delineation using soil electrical conductivity (MAZDEC) shortens the time taken to determine paddy soil variability, can be utilized for zoning of paddy fields, and helps rice farmers in site-specific application of their inputs. MAZDEC can complement a detailed soil series map and can be used as an estimator for soil physical and chemical properties. MAZDEC allows directed soil sampling to replace grid sampling, allows topping-up of the required nutrients at the needed rate at the right place and time. Each farmer will be able to quickly determine the soil management zones for variable application rates of seed, fertilizers, and water. Making this information available on-line to the farmers

In Malaysia, about 70% of the available water resources are consumed for rice production. Due to rapidly growing population and water competition among different sectors it is

will be a major step in making available the benefits of new technologies.

modernization is slow when compared with other regions.

sustainable environment for all human beings.

**2. Irrigation water management** 

**2.1 Research on rice irrigation water management** 

water scarcity.

imperative that the available irrigation supplies be used efficiently. A small improvement of water use in rice production would result in significant water savings for other sectors. Traditionally rice is grown under continuous submergence or intermittent or variable ponding conditions depending on the farmer's choice and also on the available water resources. Continuous submergence with 5 to 7 cm of water is probably the best for irrigated rice considering all factors and extremely deep water resulted in poor growth and yield [2]. To evaluate the effect of ponding water depth on rice yield, the 9 cm of ponding water depth in Wagner's pots (a growth chamber 25 cm diameter and 30 cm height, filled with soil up to 15 cm depth) gave the optimum rice growth and yield [3]. Therefore, the importance of controlled water supply and monitoring is indispensable for the sustainability of rice production, which varies enormously from region to region.

Performance assessment has been prioritized as the most critical element to improve irrigation management [4]. Various analytical frameworks, criteria and indicators are available to understand the factors that influence the performance of irrigation system and to quantify water delivery performance. Some of them are suitable to identifying reasons for poor performance and prescribing management and physical interventions to improve the performance. All performance indicators have their own strengths and weaknesses. Many performance indicators fail to quantify reliability, adequacy and equity aspects of water distribution although many performance indicators are useful for quantifying the water delivery for irrigation seasons. Many performance indicators are useful for post-season evaluation but they are not useful as management tools which can be used to keep track of irrigation delivery performance during a crop growing season. If a particular indicator is useful both as a management tool and as an indicator of the overall irrigation delivery performance for any given irrigation interval or season, its credibility is undoubtedly superior to the other performance measures.

Detailed reviews for the advantages and disadvantages for various performance assessment methodologies [5] emphasized the simplest indicator of evaluating water delivery performance and how tightly adequate water can be delivered to the fields. The available water supply and the water demand are the most crucial factors in irrigation planning, design and operation of an irrigation system. A performance indicator [6], which is called Relative Water Supply (RWS), is simply the ratio of irrigation supply and demand. Detailed application and weakness have been described for monitoring and assessing of irrigation water delivery performance for rice irrigation scheme using the RWS concept [7 & 8]; and further illustration on the use of the RWS concept based on field research [9 & 10]. The RWS concept has been widely used to assess the performance of irrigation systems. Indeed for paddy irrigation, quantifying of the upper bound value of RWS for oversupply condition is a difficult task due to the many variables that influence the performance of irrigated agriculture. Therefore, it is essential to have an appropriate tool with feasible options to improve the performance of the irrigation supplies for rice production.

The water demand for rice irrigation is completely different from upland crops. To replenish the field water level up to the Maximum Ponding Water Depth (WSmaxj) for a particular period, the amount of water for the difference between the Maximum Ponding Water Depth (WSmaxj) and the Present Ponding Water Depth (WSj) is gradually delivered to the paddy fields. The RWS concept incorrectly characterizes irrigation delivery performance for not considering this amount of water (WSmaxj - WSj) in the denominator. Due to this, RWS

Paddy Water Management for Precision Farming of Rice 111

The design discharge at the BRH at the elevation of full supply level (FSL) of 9.6 m is 30.6 m3/s. The average annual rainfall is about 1800 mm [14]. The highest annual evaporation in the area was found to be 1600 mm during 1990 to 2003. The highest amount of rainfall normally occurs in March-April and October-November for the off season and main season, respectively. The excess water throughout the drainage network is drained out to the sea.

> **Bernam River**

**360000**.000000

**BRH**

#


**370000**.000000

**Feeder Canal**

**Tengi River**

#

**360000**.000000

#

**Sawah Sempadan**

0 1 5 0 20 Kilometers

**370000**.000000

**380000**.000000

**390000**.000000

**400000**.000000

**410000**.000000

**420000**.000000

This condition is often found for excess rainfall in the main season.

**350000**.000000

**ISA II**

**340000**.000000

**2.3 Data collection and GIS database development** 

Scheme (TAKRIS) Malaysia

#

#

**Sungai Nipah**

#

**Pasir Panjang**

#

**Bagan Terap**

**340000**.000000

#

#

#

**ISA I**

**350000**.000000

Fig. 1. Irrigation Distribution Network in the 18,000 ha Tanjung Karang Rice Irrigation

Many years of reliable climatic data records are required to estimate different parameters for a proper irrigation water management. Data and related information were obtained from

#

**Sungai Leman**

**Sekinchan**

**Sungai Burong**

•

Tertiary Canal

**ISA III**

**Panchang Bedena**

**330000**.000000

#

**Legend** # SRainfall\_point CHO-MCanal\_point HWorks\_point TCanal\_polyline BRiver\_polyline FCanal\_polyline MCanal\_polyline CBlock\_region Compartment\_region **Area\_ha** 1804.13 2015.94 2192.52 2336.27 2610.77 2841.52 3653.29 3910.4

**330000**.000000

**380000**.000000

**390000**.000000

**400000**.000000

**410000**.000000

**420000**.000000

gives a wrong scenario to monitor irrigation water delivery performance [11]. To overcome this conflict, new indicators known as Rice Relative Water Supply (RRWS), Cumulative Rice Relative Water Supply (CRRWS) and Ponding Water Index (PWI) are introduced to evaluate the irrigation delivery performance especially for the paddy irrigation system.

To improve irrigation management with variable irrigation supplies, GIS is an essential element for modern information techniques and acts as the interface with the user. To promote more efficient ways of managing water in irrigated areas, modern GIS technique can be employed to collect, store, and process enhanced information on water use for crops, and to disseminate reliable and validated procedures. The modern GIS technique coupled with model can quickly guide the management in decision-making since the temporal and spatial dimensions could be studied at once. The GIS approach is particularly appropriate as it is the most efficient tool for spatial data management and utilization that allows understanding of the spatial variance [12]. GIS has been applied effectively for bringing spatial variability of soil, crop, water supply and environment in dealing with the complex problems for irrigation and water management [13]. GIS is one of the most simple and straightforward ways of providing a management tool for planning of water allocation policy in irrigation system. GIS together with its powerful spatial data management and analysis capabilities is therefore used to extend the scope of the estimation of irrigation delivery performance and its proper evaluation techniques for paddy irrigation system.

### **2.2 Study area**

The Tanjung Karang Rice Irrigation Scheme is located at about 30 25/ to 30 45/ N latitude and 1000 58/ to 1010 15/ E longitude in the state of Selangor Malaysia (Fig. 1). The total command area of the scheme is about 18,848 ha. Rice is grown two times in a year mainly from August to January (main- or wet season) and February to July (off- or dry season). The ponding water depth of up to 10 cm is maintained depending on the crop growth stage, farmer's attitude and available water resources. A unique feature of this irrigation scheme is that it is a run of the river type with no reservoir or dam to store water. The Bernam River is the only source for the irrigation supplies which is diverted at the Bernam River Headwork (BRH) into the feeder canal. Then water is conveyed into Tengi River and thence to the intake point of the main canal at Tengi River Headwork (TRH). The distance from BRH to TRH is about 36 km.

Irrigation water is delivered directly from the main canal to tertiary canals, which are spaced 400 m apart along the main canal. A standard irrigation block has a net command area of about 150-200 ha. Irrigation blocks receive water in their paddy plots direct from two tertiary canals. A pump house constructed in 1962 on the lower reaches of the Bernam River at Bagan Terap provides water supply for the northern portion of approximately 1000 ha. The command areas under pumping condition are not considered in this study. In order to get better utilization of available water resources, the scheme is divided into three irrigation service areas (ISA) where water delivery is staggered by one month starting from August in main season and February in off season. In this way, pre-saturation of the whole project area is completed within three months. The detailed features of the irrigation distribution networks and irrigation compartments under each irrigation service areas namely ISA I (Sawah Sempadan and Sungai Burong), ISA II (Sekinchan, Sungai Leman, Pasir Panjang and Sungai Nipah) and ISA III (Panchang Bedena and Bagan Terap) for the scheme are illustrated in Fig. 1.

gives a wrong scenario to monitor irrigation water delivery performance [11]. To overcome this conflict, new indicators known as Rice Relative Water Supply (RRWS), Cumulative Rice Relative Water Supply (CRRWS) and Ponding Water Index (PWI) are introduced to evaluate

To improve irrigation management with variable irrigation supplies, GIS is an essential element for modern information techniques and acts as the interface with the user. To promote more efficient ways of managing water in irrigated areas, modern GIS technique can be employed to collect, store, and process enhanced information on water use for crops, and to disseminate reliable and validated procedures. The modern GIS technique coupled with model can quickly guide the management in decision-making since the temporal and spatial dimensions could be studied at once. The GIS approach is particularly appropriate as it is the most efficient tool for spatial data management and utilization that allows understanding of the spatial variance [12]. GIS has been applied effectively for bringing spatial variability of soil, crop, water supply and environment in dealing with the complex problems for irrigation and water management [13]. GIS is one of the most simple and straightforward ways of providing a management tool for planning of water allocation policy in irrigation system. GIS together with its powerful spatial data management and analysis capabilities is therefore used to extend the scope of the estimation of irrigation delivery performance and its proper evaluation techniques for paddy irrigation system.

to 30 45/

E longitude in the state of Selangor Malaysia (Fig. 1). The total command

area of the scheme is about 18,848 ha. Rice is grown two times in a year mainly from August to January (main- or wet season) and February to July (off- or dry season). The ponding water depth of up to 10 cm is maintained depending on the crop growth stage, farmer's attitude and available water resources. A unique feature of this irrigation scheme is that it is a run of the river type with no reservoir or dam to store water. The Bernam River is the only source for the irrigation supplies which is diverted at the Bernam River Headwork (BRH) into the feeder canal. Then water is conveyed into Tengi River and thence to the intake point of the main canal at Tengi River Headwork (TRH). The distance from BRH to TRH is about 36 km. Irrigation water is delivered directly from the main canal to tertiary canals, which are spaced 400 m apart along the main canal. A standard irrigation block has a net command area of about 150-200 ha. Irrigation blocks receive water in their paddy plots direct from two tertiary canals. A pump house constructed in 1962 on the lower reaches of the Bernam River at Bagan Terap provides water supply for the northern portion of approximately 1000 ha. The command areas under pumping condition are not considered in this study. In order to get better utilization of available water resources, the scheme is divided into three irrigation service areas (ISA) where water delivery is staggered by one month starting from August in main season and February in off season. In this way, pre-saturation of the whole project area is completed within three months. The detailed features of the irrigation distribution networks and irrigation compartments under each irrigation service areas namely ISA I (Sawah Sempadan and Sungai Burong), ISA II (Sekinchan, Sungai Leman, Pasir Panjang and Sungai Nipah) and ISA III (Panchang Bedena and Bagan Terap) for the scheme are

N latitude and

the irrigation delivery performance especially for the paddy irrigation system.

The Tanjung Karang Rice Irrigation Scheme is located at about 30 25/

**2.2 Study area** 

to 1010 15/

illustrated in Fig. 1.

1000 58/

The design discharge at the BRH at the elevation of full supply level (FSL) of 9.6 m is 30.6 m3/s. The average annual rainfall is about 1800 mm [14]. The highest annual evaporation in the area was found to be 1600 mm during 1990 to 2003. The highest amount of rainfall normally occurs in March-April and October-November for the off season and main season, respectively. The excess water throughout the drainage network is drained out to the sea. This condition is often found for excess rainfall in the main season.

Fig. 1. Irrigation Distribution Network in the 18,000 ha Tanjung Karang Rice Irrigation Scheme (TAKRIS) Malaysia

### **2.3 Data collection and GIS database development**

Many years of reliable climatic data records are required to estimate different parameters for a proper irrigation water management. Data and related information were obtained from

Paddy Water Management for Precision Farming of Rice 113

For presaturation water depth, the DID recommendation of 20 mm/day is used. This would help to maintain the standing water depth of 100 mm for the normal irrigation period. The minimum standing water depth (SWmin) is maintained at 50 mm. The seepage-percolation

If part of the water requirement is met by utilization of rainfall during crop growing period,

where, ETj is EToj \* kc, SWj is the required standing water depth for a particular day, and SWj-1 is field water level at the beginning of irrigation supply on (j-1)-th day. The NIRj is determined as in Equation 3 when paddy fields remain in the condition SWj ≥ SWj-1. However, this condition is rare during peak water demand and it is possible only by storing a significant amount of rainfall in the paddy fields. The inequality between SWj and SWj-1 leads to different water balance scenarios as well as water allocation rules, which are determined mainly by SWj-1 that falls short or exceeds the required standing water depth. The conditions for the estimation of the net irrigation requirements are summarized in

NIRj = ETj + SPj - ERj

NIRj = 0 NIRj = 0

Qrs = Recommended demand and Qav = available discharge at the intake point of the main canal

Indicators and measures of irrigation water delivery performance are best when those can be used to evaluate the irrigation delivery performance and as management tool to keep track of the water delivery performance as the season progresses. In this regards, the RWS concept is appropriate and can be applied for paddy rice and upland rice or other crops. This discussion however is restricted mainly to paddy rice for characterizing the irrigation

Table 1. Net Irrigation Requirements for Different Water Balance Scenarios

**2.5 Assessment of the irrigation delivery performance for rice** 

NIR = ET + SP - ER + SW - SW j jjj j j<sup>−</sup>1 (3)

Net irrigation requirements (NIRj)

NIRj = ETj + SPj – ERj and SWj = (SWmin ≤ SWadj < SWj)

NIRj = ETj + SPj – ERj and SWj = (SWmin ≤ SWadj < SWj)

NIRj = 0 and SWj = (SWmin ≤ SWadj < SWj)

NIRj = ETj + SPj - ERj + SWj – SWj-1

NIRj = ETj + SPj - ERj + SWj – SWj-1

(SP) rate of 2-3 mm/day is considered throughout the growth period [14 and 15].

then the net irrigation requirement on a particular day is determined as:

Availability of irrigation supply condition with respect to demand

> Qrs ≤ Qav Qrs > Qav and ERj = 0

Qrs ≤ Qav Qrs > Qav and (ETj + SPj) ≠ ERj

> Qrs ≤ Qav Qrs > Qav

> Qrs ≤ Qav Qrs > Qav

delivery performance using the RWS concept.

SPj = seepage-percolation loss (mm/day)

IE = overall irrigation efficiency, which is assumed to be 45% ,[14].

ERj = effective rainfall (mm/day)

Kc = crop coefficient

Table 1.

Water balance condition

SWj = SWj-1

SWj < SWj-1

SWj > SWj-1

SWj-1 = SWadj

relevant government agencies such as the Tanjung Karang Rice Irrigation Scheme Authority (IADA) for different ISAs, the Department of Irrigation and Drainage (DID), Department of Agriculture (DOA), Department of Survey and Mapping Malaysia (JUPEM) and Malaysia Meteorological Department (MMD). The detailed configuration of the irrigation canals, irrigation head regulator, Constant Head Orifice (CHO) offtake structures and specifications, stage and discharge data for the main canal were obtained from the Irrigation and Drainage Authority of the Scheme and also from the DID Headquarters, Malaysia. Database development is the crucial task to bring all the information obtained into a GIS database. All the data were properly registered and assembled in GIS platform.
