268-Delineation of Groundwater Prospect Zones Using Remote Sensing and GIS Techniques A Case Study.

Abstract

A systematic planning of groundwater development using modern techniques is essential for the proper utilization and management of this precious but shrinking natural resource. With the advent of powerful and high-speed personal computers, efficient techniques for water management have evolved, of which RS, GIS and GPS are of great significance. West Medinipur district in West Bengal, India is suffering from water shortages for both irrigation and domestic purposes. In the present study, an attempt has been made to delineate and classify possible groundwater prospect zones in the West Medinipur district of West Bengal using integrated Remote Sensing (RS) and GIS techniques. The thematic layers considered in this study are lithology, landform, drainage density, recharge, soil, slope and surface water body, which were prepared using the IRS-1D imagery and conventional data. All these themes and their individual features were then assigned weights according to their relative importance in groundwater occurrence and the corresponding normalized weights were obtained using Saaty's analytical hierarchy process. The thematic layers were finally integrated using ArcView software to yield groundwater prospect map of the study area. Thus, three different groundwater prospect zones viz., 'good', 'moderate' and 'poor' were identified. The area covered by 'good' groundwater potential zone is about 1400 km2 (15% of the total area). The eastern portion and some small patches in the central and northern portions of the study area fall under 'moderate' groundwater potential zone, which encompasses an area of 5400 km2 (55%). However, the groundwater potential in the western, southwestern and parts of northeastern portions of the study area is 'poor' encompassing an area of about 3000 km2. Moreover, the average annually exploitable groundwater reserve in the 'good zone' is estimated to be 401 MCM, whereas it is 1334 MCM for the 'moderate' zone and 397 MCM for the 'poor' zone. Finally, it is concluded that the RS and GIS techniques are very efficient and useful for the identification of groundwater prospect zones.