Delineation of groundwater potential zones using vertical electrical sounding (VES) in a complex bedrock geological setting of the West Coast of India

Identification of groundwater potential zones (GPZ) is a tedious task in the area that receives high rainfall, undulating topography with high runoff and complex geological settings. The present study was performed in the Karli River basin, West coast of Maharashtra, India with the integration of Vertical Electrical Soundings (VES), Dar-Zarrouk Parameters (DZP) and resistivity models to know the depth to bedrock and identification of the groundwater potential zones. Therefore, 24 VES Schlumberger electrode configuration profiles were considered based on the topography, geology and geomorphology of the area. In VES method, three-layer models, QH type curve is dominant and in four layers HKH, KHA and KHK are the major curve types. The iso-apparent resistivity maps were prepared at depths ranging from 3 to 20 m by plotting the apparent resistivity values in comparison with 3D topographic model of VES locations. DZP was employed to delineate the depth of weathering and aquifer characteristics. As per geo-electric sections profile and 3D apparent resistivity model, VES locations 2, 4, 5, 6, 14, 15, 16, 17, 19 and 21 are the best suitable sites for GPZ. Moreover, VES 6, 11 and 22 are not favourable sites for GPZ because of the least weathered laterite exposed at these locations. The utmost VES occurred in the central part of the basin are the most suitable locations for GPZ due to presences water-saturated lineaments and paleochannels. The meticulous lineament and marking of paleochannels studies will be suggested for the more precise demarcation of GPZ in the study area.