Intrinsic Geo-electric Characterization and Geomorphological Valuation for Groundwater Recharge Potentiality: Implications for Groundwater Sustainability

Abstract

This study investigates groundwater recharge (GWR) potential in a region characterized by varied lithology, topography, and geophysical properties by integrating geophysical parameters (resistivity, longitudinal conductance, transverse resistance, resistivity coefficient, and electrical anisotropy) with geo-morphological factors (topography and slope). Vertical electric souding (VES) data was acquired from thirty-eight (38) locations in the study area using Schlumberger array, pre-processed manually by means of partial curve matching and refined using 1D forward modeling to obtain layer resistivity, thickness and secondary geo-electric characteristics. Results indicate the southeastern, eastern, and central regions as primary recharge zones, characterized by permeable sandy and gravelly lithologies (100–150 ohm-m), low longitudinal conductance (0.01–0.38 S), and high transverse resistance (>7465 Ωm²). These areas, coupled with deep, weathered bedrock (notably migmatite-biotite gneiss, RC 0.41–0.99) and high anisotropy (1.50–3.06), exhibit enhanced storability, fracturing, and secondary porosity, forming critical recharge hotspots and the flat topography further facilitates infiltration. Conversely, clay-rich zones (S >0.5 S) in parts of the northeast and east; and steep southwestern ridges pose constraints due to low permeability and accelerated runoff, respectively. Despite lacking quantitative recharge estimates and local precipitation data, this study provides a robust framework for identifying recharge hotspots, offering critical insights for sustainable groundwater management in water-scarce regions. The study underscores the importance of targeted water management strategies, for optimizing GWR in less favorable areas. Recommendations include managed aquifer recharge and runoff management to enhance GWR in less permeable areas.