Vertical Electrical Sounding (VES) was conducted to explore the groundwater potential in Mando, located within the Crystalline Basement Complex of Nigeria. Four VES traverses were investigated employing the Schlumberger configuration with a maximum half current electrodes separation of 90m. WINRESIST software was employed for the iteration and inversion processes of computing resistivities, depths and thicknesses of the various layers and the curve types. The results show that the area is characterized by four to five geoelectric subsurface layers inferred differently at the VES traverses. An unconfined shallow aquifer zone is delineated. This potential groundwater aquifer zone found at all the VES locations has shallow overburden depth ranging between 7.1–10.9m with coarse-grained sand columns having thicknesses ranging between 6.0–9.6m. These results suggest that groundwater occurrence in Mando lies within the weathered overburden (WO) composed of coarse-grained sands which forms a level below the loose clayey laterite. These WO consist of sands or gravels derived from the weathering of the crystalline rocks. Based on these results, it is suggested that boreholes for sustainable groundwater supply in the study area should be drilled to a depth of about 10.0m. Though, this falls within the unconfined shallow aquifer zone, however, it has potentials for groundwater occurrence but may be susceptible to contamination. It is recommended that geoelectrical logging and other hydrogeological analyses be conducted to properly delineate prolific aquifers and determine the Total Dissolved Solids (TDS) to avoid possible contamination in the water before any borehole(s) are completed for potable groundwater supply.
Keywords: Vertical Electrical Sounding, Aquifer, Groundwater, Crystalline Basement Complex, Mando.