Hydrogeophysical Investigation of Aquifer Vulnerability and Groundwater Potential in Igbo-Eze North, Enugu State

Groundwater supply in Igbo-Eze North Local Government Area of Enugu State is under increasing pressure from population growth, agricultural demand, and potential contamination from unregulated land use. This study conducts a hydrogeophysical investigation of aquifer vulnerability and groundwater potential in the area using vertical electrical sounding (VES) and geospatial analysis. A total of forty VES stations were established across the study area using the Schlumberger array with maximum half-electrode spacing of 200 m. Apparent resistivity data were processed using IPI2Win software, and the resulting layer models were interpreted in the context of the regional geological framework. Layer resistivities and thicknesses were used to compute Dar Zarrouk parameters, including longitudinal conductance (protective capacity) and transverse resistance. Four to six geoelectric layers were identified across the study domain. Groundwater-bearing zones occur within the fractured basement complex at depths ranging from 35 m to 95 m. Longitudinal conductance values below 0.1 mhos in the northern zones indicate poor aquifer protection, suggesting elevated vulnerability to surface-derived contamination. Isoresistivity and isopach maps delineate preferred zones for borehole siting and reveal spatial patterns in aquifer productivity. The study identifies three high-potential groundwater zones suitable for large-scale water development. These results provide a scientific basis for groundwater resource planning in Igbo-Eze North and demonstrate the effectiveness of the VES method in characterizing basement aquifer systems in Enugu State.

Keywords: vertical electrical sounding, aquifer vulnerability, Dar Zarrouk, groundwater potential, Igbo-Eze North