Delineation of aquifers and evaluation of protective capacity using geoelectrical indices in the Vindhyan fringe belt, Mirzapur district, U.P., India

The purpose of this study is to locate groundwater-saturated aquifers in the Vindhyan fringe belt in the Mirzapur district of Uttar Pradesh, India, and evaluate their protection using geoelectrical indices. The Schlumberger electrode layout, with a maximum half-current distance between electrodes of 300 m, was used to perform three gradient profilings and six geoelectrical soundings. The inversion IPI2win program and the traditional partial curve matching approach were used for geoelectrical sounding data interpretation. Four to five geologic units are identified in the research region based on the interpretation of the geoelectrical sounding data. These are the top-surface soil, clay, kankar/laterite and sand, weathered sandstone, and compact sandstone. The research region is characterized by HA-type sounding curves, and the obtained findings suggest the presence of groundwater-saturated zones and cracks in the area. The weathered sandstone saturated with water shows resistivity ranges between 375.4 and 407.1 Ω-m and depth ranges from 96.8 to 97.6 m. Thematic maps were prepared for total longitudinal conductance, transverse resistance, overburden thickness, and electrical anisotropy. The protective capacity of the aquifer is measured using the transverse resistance (Tr) and longitudinal conductance (Lc) of the Dar Zarrouk parameters. Based on the longitudinal conductance of the aquifers, the results obtained indicate that the research region is dominated by a good aquifer protective capacity rating.