Modelling of groundwater potential zone in hard rock-dominated drought-prone region of eastern India using integrated geospatial approach

Worldwide, the ever-increasing population and urbanization have put tremendous pressure on groundwater (GW). It has provoked the over-exploitation of groundwater and hindered the percolation of rainwater beneath the earth's surface in another way. The uncertainty of rainfall occurrence and over-exploitation of groundwater created the problem of water scarcity and decreased groundwater height significantly in the hard rock-dominated semi-arid regions. This study is designed to delineate groundwater potential zone (GWPZ) in the hard-rock terrain controlled Bankura district of West Bengal with the help of a knowledge-driven statistical technique, analytical hierarchy process (AHP), in remote sensing and GIS environment. The GWPZ map has been prepared by compiling nine groundwater controlling parameters: geology, geomorphology, slope, land use–land cover (LULC), rainfall, drainage density, soil texture, topographical wetness index (TWI) and lineament density. Among all the parameters, rainfall, geology, slope and LULC have played a dominant role in groundwater availability in the Bankura district, and the weightage of these parameters is 0.28, 0.20, 0.14 and 0.11, respectively. These four layers have facilitated to accumulation of groundwater potentiality in the Bankura district and surroundings. Our study of the GWPZ map revealed that 13.36, 33.80, 21.05, 19.02 and 12.77% of the area of the Bankura district is under very good, good, moderate, poor and very poor condition, respectively, for targeting GW in the future. Very high to high groundwater yielding spots are observed in valley fills, flood plains, vegetation-covered areas, agricultural land and low-lying areas of the study area. The result is evaluated by employing the receiver operation characteristics (ROC) and area under curve (AUC) technique using the well’s yield groundwater data, and this value (0.757) also displayed the reliability of this work. However, the GWPZ map of the hard rock-dominated Bankura district has been delineated successfully; the findings of this study can be useful to the planners, engineers and policymakers for proper utilization, evaluation and management of groundwater in this water-scarce semi-arid region to ensure its sustainable development.