VES Based Groundwater Potential Zone Mapping in Radhapuram Taluk, Tirunelveli District, Tamil Nadu

This study evaluates groundwater potential zones in the southern Tirunelveli District, Tamil Nadu, using Vertical Electrical Sounding (VES) surveys at forty-two locations in hard rock terrain. Geoelectrical interpretation revealed two to four subsurface layers comprising topsoil, weathered rock and sand, sand–clay mixtures, and jointed rock formations. Integration of 2D pseudo-cross sections and 3D resistivity modeling delineated productive aquifers at VES stations 1, 21, 25, 37, 38, and 41, validated by nearby well data. Additional promising horizons were identified at VES 3, 6, 15, 17, 18, 30, and 38 within the 10–15 m depth range, with resistivity values of 25–610 Ω m. Aquifer thickness varies from 0.6 to 43 m across the study area. Approximately 40% of the region shows groundwater potential, while saline intrusion was observed near the Nambiyar River, particularly at stations 19, 30, and 35 with resistivity <10 Ω m. Overall, the results confirm that VES combined with 3D modeling is a reliable tool for aquifer delineation, and water supply schemes should be implemented alongside monitoring and recharge measures to mitigate saline ingress.