Efficacy of hydrological investigation in Karumeniyar river basin, Southern Tamil Nadu, India using vertical electrical sounding technique: A case study

In the Karumeniyar river basin, the groundwater demand increases for irrigation, industrial and larger per capita needs, and the recent year's groundwater table is drastically falling due to both natural and anthropogenic activities. In this context, a study on geophysical vertical electrical sounding (VES) using Schlumberger configuration has been carried out across 72 locations in the Karumeniyar river basin to demarcate the subsurface geoelectrical parameters and to identify the groundwater potential zone along with aquifer protective capacity. The acquired data were inverted using the 1D (resistivity variation with respect to depth) inversion approach IPI2Win demonstrated the presence of three to six subsurface geoelectrical layers in the study area with H type sounding curve being dominant. Furthermore, the deciphered result from VES is cross-validated with lithology data of four wells in the study area. Based on the interpreted results the parameters such as longitudinal conductance, overburden thickness, reflection coefficient and basement resistivity were calculated. It revealed that 36 VES location signifies good to moderate aquifer protective capacity. According to the reflection coefficient value and overburden thickness, the basin was divided into four distinct groundwater potential zones as high (42%), medium (38%), low (15%) and very low (5%). The inverse Distance Weighting (IDW) interpolation method is adopted to generate the spatial distribution maps in ArcGIS environment. The findings of the present study provide the vital geo-database for groundwater potential zones in the Karumeniyar river basin and have important implications for designing, intendance and management of sustainable groundwater resources. • Vertical Electrical Sounding method is a noninvasive, low cost and effective method for locating groundwater potential zone. • It measures the vertical wise variation of subsurface resistivity distribution based on surface measurement. • This technique provides a quantitative evaluation of different subsurface layers.