GIS Based Delineation of Groundwater Prospective Zones Using AHP Techniques in Jaldhaka Watershed, Cooch Behar District, West Bengal

Geographic Information Systems (GIS)-based studies have emerged as a rapid and efficient tool for groundwater exploration, providing valuable insights into resource availability for future development. In this study, the groundwater prospective zones (GWPZ) of Jaldhaka River watershed from the north-eastern part of India are delineated, deploying a combined approach, integrating Remote Sensing (RS), GIS and Analytical Hierarchy Process (AHP) techniques. Eight thematic layers of lithology, land use and land cover (LULC), Geomorphology, drainage density, soil, rainfall, lineament density and topographic wetness index (TWI) were generated and analysed. The AHP method was used to assign weightage values to the sub-classes within the thematic layers, considering their specific characteristics and their relative influence over groundwater recharge in the area. The resulting GWPZ (Groundwater Prospect Zone) map was categorized into four classes: high, moderate, low, and very low potential zones. These potential classes cover 11% (103 sq. km), 65% (610 sq. km), 21% (197 sq. km), and 3% (28 sq. km) of the study area, respectively. The precision of the groundwater potential zone map was validated against existing well data available from government and ground truth information. The wells falling in the ‘low’ to ‘very low’ prospective classes had lesser yield (10 to 50 lpm) than the others, while those belonging to the ‘moderate’ to ‘high’ zones showed higher yield (~100 lpm), conforming to the successful validation.