J. Water Resource and Protection, 2010, 2, 585-591 doi:10.4236/jwarp.2010.26067 Published Online June 2010 (http://www. SciRP.org/journal/jwarp) Copyright © 2010 SciRes. JWARP A Novel Approach for Groundwater Budgeting Using GIS in a Part of Pondicherry Region, India Sivaraman Pethaperumal 2 , Sabarathinam Chidambaram 1 , Kandasamy Vijayaragavan 1 , Mohan Viswanathan Prasanna 3 , Kannan Anandavel 2 , Ulaganathan Karmegam 1 , Ramachandran Manivannan 1 , Paluchamy Anandhan 1 , Kesari Tirumalesh 4 1 Department of Earth Sciences, Annamalai University, Annamalai Nagar, India 2 State Groundwater Unit and Soil Conservation, Department of Agriculture, Pondicherry, India 3 School of Engineering and Science, Department of Applied Geology, Curtin University of Technology, Sarawak, Malaysia 4 Scientist D, Isotope Hydrology Division, BARC, Mumbai, India E-mail: chidambaram_s@rediffmail.com Received March 23, 2010; revised April 23, 2010; accepted May 6, 2010 Abstract The over extraction of groundwater from the coastal aquifers, result in reduction of groundwater resource and lowering of water level. In general, the depletion of groundwater level enhances the landward migration of saltwater wedge. Pondicherry is one such region with recent alluvium as the major formation. Since the study area forms a part of the coastal aquifer system this behaves as a fragile ecosystem. The present study has been attempted to calculate the extraction of water and to estimate the amount of recharge into this allu- vial aquifer by using groundwater level variations. The monthly water level fluctuation was observed during the study period (2000-2002) in eighteen locations. The maximum rise in groundwater level observed during 2000 was considered as the initial water level for the study and the subsequent decline in water level (draw down) was monitored monthly until the rising trend was noted. This indicates the fall in water level due to extraction. Later keeping the deepest draw down as the initial value increasing water level trend was studied until there was a notice of decline in groundwater level. This indicates as the rise in water level due to re- charge. This method of observation carried out at a single location was adopted for all eighteen locations. The spatial representation of these data for eighteen locations were carried out by using GIS and the area occupied by different groundwater level contours were calculated and the amount of water withdrawn/re- charged was estimated. The maximum recharge was noted in the central and the northern part of the study area when compared to the other regions. Similarly, the maximum discharge was noted in the northern and the southern part of the study area during the study period. Keywords: Water Level, Recharge, Groundwater Budget, GIS 1. Introduction Groundwater is one of the most important and scarce commodity. Groundwater exists in the geological forma- tions through which it can penetrate, be transmitted and stored beneath the surface. When the rate of infiltration is sufficient and the rocks are saturated to an appreciable thickness, then the groundwater becomes usable enough to yield useful supplies of water to wells, springs and stream. At present nearly 1/5th of all the water used in the world are obtained from the groundwater. Land use/ land cover pattern of Pondicherry and its surroundings were studied by using IRS 1C LISS III data [1]. The land use/land cover patterns were visually interpreted and di- gitized using ERDAS IMAGINE software. The study observed that agriculture area (52.89%) is dominant in Pondicherry and its surroundings, followed by settlement with vegetation (18.35%). The dependency of ground- water for the agricultural purpose has considerably in- creased in the recent past. Nearly about 80% of ground- water is used for agriculture. The quantification of the groundwater resources has become essential for water management. There are differebt methods for assessing the rate of recharge e.g., by using stable isotope, tra- cer techniques, groundwater modeling (thangarajan et al.) etc. Aquifer recharge studies using different isotopes for determination of infiltration capacities, permeability and in delineation of aquifer, inter connection were studied