Delineation of Groundwater Potential Zones for Hard Rock Region in Karnataka Using AHP and GIS

The satellite based technology adopting the efficacy of Geographical Information System (GIS) plays a dynamic role in groundwater exploration, assessment and management. The current study investigated the demarcation of groundwater potential zones by integrating RS, GIS and Multi-Criteria Analysis for the hard rock terrain of Gundihalla watershed which lies in Bellary district of Karnataka, India. The thematic layers incorporated in this research includes the Geomorphology, Soil, Drainage Density, Lineament Density, Rainfall, and Slope. Saaty's Analytical Hierarchy Process was used to determine the weights and ranks of all the thematic layers and the significant classes within each layer. All the thematic layers were then integrated to create the groundwater potential zonation map for the study area. The resulting map was categorized into five different groundwater potential zones, viz., 'very good,' 'good,' 'moderate,' 'poor' and 'very poor.' The area coverage of these zones in the study region are: 263 km(2) (18.76%), 332.3 km(2) (23.7%), 327 km(2) (23.3%), 238 km(2) (17%) and 229 km(2) (16.3%) respectively.