Development and Application of a Watertable Model for the Assessment of Waterlogging in Irrigated Semi-arid Regions
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Development and Application of a Watertable Model for the Assessment of Waterlogging in Irrigated Semi-arid Regions Ajay Singh
Received: 3 April 2012 / Accepted: 17 September 2012 / Published online: 26 September 2012 # Springer Science+Business Media Dordrecht 2012
Abstract Direct measurement of groundwater recharge is nearly impossible. So there are various direct and indirect methods and sophisticated models have been used for its estimation. However, the use of multiple approaches has been recommended to estimate the groundwater recharge since each individual approach is associated with some limitations. In many cases, different approaches complement each other and help refine the conceptual model of recharge processes. In this study, a simple watertable model, which is a combination of the groundwater budget and watertable fluctuation, was developed. The model is unique, simple, cost effective, and easy to apply. The model requires input parameters that are readily available or obtainable and which can be accurately measured. The model was applied to estimate the seasonal long–term (30 years, e.g., from 1981 to 2011) groundwater recharge of a canal command located in Jhajjar district of Haryana State (India), where watertable is rising. The results were analysed to provide an overview of the process dynamics that led to watertable rise in the command area. The calculated watertable depths reasonably matched with the observed ones for all the seasons which were confirmed by the high R–squared value of 0.963. The mean error and root mean squared error were low at –0.0068 and 0.2548 m, respectively, while the model efficiency was 0.83. Different water management alternatives were studied to examine the effect of variation in model parameters on its output. Among the alternatives studied, increased tubewell draft had a higher impact on the overall water balance followed by reduced rice area and canal lining, respectively. Keywords Watertable model . Water resources . Hydrological budget model . Watertable fluctuation method . Groundwater recharge . Waterlogging
A. Singh (*) Agricultural and Food Engineering Department, Indian Institute of Technology, Kharagpur, West Bengal 721302, India e-mail: [email protected] Ajay. Singh e-mail: [email protected]
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A. Singh
1 Introduction Accurate and reliable estimation of groundwater recharge is essential for efficient and sustainable groundwater management in arid and semi–arid regions as water resources are critical to economic development in these areas (de Vries and Simmers 2002; Safavi et al. 2010; Sherif et al. 2012). However, recharge is difficult to estimate (Sekhar et al. 2004; Scanlon et al. 2006) in these areas. Many different approaches exist for estimating recharge (Allison et al. 1994; Healy and Cook 2002; Rushton et al. 2006; Lee et al. 2008; Manghi et al. 2009; Singh 2011; Xu et al. 2011). However, the amount of information that is required depends on the complexity of the method. For example, some methods require extensive fieldwork, while
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