Study of groundwater sustainability in Gurgaon district Haryana

Abstract

Groundwater is an important source of water for domestic, agricultural, and industrial requirements. Gurgaon district, which is economic capital of Haryana state, stands at very critical juncture due to its alarming decrease in ground water levels. As surface water potential is not promising in the district, there is increased dependence on ground water for meeting almost all types of water requirements. Gurgaon district is located between 76040" E to 77015" E longitude and 28010" N to 28032" N latitude and have geographical area of 1254.62 Sq. Km with an average elevation of 220 meters for its four blocks viz. Gurgaon, Sohna, Farukhnagar and Pataudi. The share of rural population is 64.42% of the total population and agriculture is the predominant occupation of the majority of the people in Gurgaon district. The main source of the irrigation is tube-well, which irrigates about 96.8% of the total irrigated area. Indiscriminate use of underground water for agricultural and other uses has depleted the ground water to the level of over exploited category. The agriculture in Gurgaon district started transforming in sixties and seventies due to advent of electrification and green revolution. Due to high use of natural and artificial resources, the production and productivity of the district noticed a marked increase. Though, the development of tubewell irrigation has contributed significantly to the increase in food production and reduction in poverty, sustainable development and management of this resource has posed many challenges in recent years. Strategically located Gurgaon district and especially Gurgaon city and block, at a distance of thirty-two kilometers from Delhi, it is an important town of N.C.R. and forms a part of Delhi Metropolitan Area. It is challenged by a very fast growth rate with increasing construction activities for residential and commercial activities which has added fuel to fire. Major problems associated with the ground water development and management are over exploitation of ground water, water logging and salinity, ground water pollution and ultimately precise evaluation of ground water potential. Continual debate on falling water table and deteriorating soil health has prompted general public, farmers, scientists and policy makers to rethink. Presented research is major attempt in this direction to suggest sustainable solutions to offer mentioned problems. Thirty five years period ranging from 1974 to 2008 has been used for the analysis of all data. Total period under consideration was divided into five year average scenarios. For each scenario of average of five years, water balance was carried out for water budget year viz. June of current period to June of next period. In this time period, two stress periods were considered viz. June to September (120 days Monsoon Period) and October to next June (245 days Non-Monsoon Period). Monsoon stress period was simulated at four time steps (end of each month) and non-monsoon period was simulated at eight time steps (end of each month) when used with MODFLOW model. Thus 1974 to 2008 period was divided into seven five year average time periods, and each period was divided into two stress periods giving total 14 stress periods (7×2) and 84 time steps (7×12). Block was considered as basic unit for all calculations as per the guidelines of central ground water board. Future prediction for year 2025 and 2050 has also been carried out for planning purpose. Intense competition among user’s viz. agriculture, industry, and domestic is main force driving natural resources in unsustainable manner. Therefore major objective of research was to prepare integrated ground water resource roadmap indicating gradual development of ground water resources, its present and prospects in terms of quantity, depth and locations considering above users. Thorough analysis of rainfall data, geomorphologic features, topography, landform characteristics, soil characteristics and natural land cover of Gurgaon district was carried out as first step. Groundwater is an integral part of the environment, and hence cannot be looked upon in isolation. Therefore blockwise water balance of Gurgaon district was carried out using all components of input and output. Input parameters considered in groundwater system were rainfall, recharge due to rainfall and recharge due to irrigation. Output parameters also called as pumping or withdrawal parameters considered were domestic water use, agricultural water use, industrial water use, domestic and other animal’s water use and institutional water use. Standard professional methods like central ground water board methods for recharge estimation, Priestley-Taylor method for crop water requirement estimation were used for calculation of input and output calculations. Proper assessments of groundwater recharge and pumping at past, present and future is of paramount importance in the management of groundwater resources in optimal manner. For this and to represent data spatially we used Modflow model (Version 5.3.1 © Chiang, W. H. and Kinzellbach, W., 1991-2001). MODFLOW, a modular three- dimensional finite difference groundwater flow model developed by the U. S. Geological Survey simulates saturated flow in three dimensions. MODFLOW is probably the most widely used, tested and verified model today because of its versatility and an open structure. Total Gurgaon district area of 1254.62 km2 was modeled using 102 column and 66 rows making total grid cell number of 6732, in which 3861 cells were coming within the boundary of Gurgaon district. Each grid cell had 570.03 m length by 570.03 m width making 324934.20 m2 area. Ground water observation well data for about 75 wells evenly spread all over the geographic area of Gurgaon district was utilized for the analysis. Then input of model parameters viz. storage coefficient (0.011) and effective porosity (0.16) were given and transmissivity was specified as the model calculated value. Then results were obtained for aquifer parameters viz. storage coefficient, and transmissivity using pump tests and average value of Theis’ Method, Cooper-Jacob Method, Chow’s Method solutions and recovery test. MODFLOW model was calibrated to match the observed drawdown with model calculated drawdown using different values of aquifer parameters. Using this calibrated model and water balance inputs of 35 years averaged over five year period, recharge, pumping, balanced water as well as horizontal exchange at various time developmental stages and potential were estimated. Calibrated model was also utilized for future prediction for 2025 and 2050 for monsoon and non-monsoon periods as well as for various management decisions like situation under normal rainfall conditions, effect of water conservation assisted recharge and roof top harvested water recharge on drawdown of groundwater resources of Gurgaon district. For identification of potential ground water recharge sites, first of all water extraction pattern and water deficit area were identified. To obtain these contours of water drawdown at the end of each five year average period was carried out. These contours were then superimposed on the three dimensional mesh wire diagram of water table head of corresponding water withdrawal. For preparation of 3-D diagram help of Surfer was taken. Human activities, such as ground water withdrawal, irrigation etc. change the natural flow pattern, and these changes must be accounted for sustainable solutions. Therefore studying the water withdrawal contour diagrams, flow pattern was identified. In addition to this, studying water withdrawal contours and flow pattern, potential sites of water recharge for water conservation schemes on large scale were identified. Study of ground water sustainability of Gurgaon district, Haryana thus gives quantitative and spatial information on different components of ground water resources, their net and potential availability, block wise plans of water balance and various measures for sustainability of groundwater resources. Substantial study over sufficient long duration will result in significant saving of time and cost. This information is very useful in narrowing down the target areas for identifying recharge sites and understanding flow patterns. The spatial information generated on past, present and future prospects, depth & quantity at single site will help the planners and decision makers for devising sound and feasible ground water development plans.