Geophysical Approach to Groundwater Resource Appraisal in Afe Babalola University, Ado-Ekiti, Southwestern Nigeria

• Oluwaseun S. OGUNGBEMI

  Department of Geology, Afe Babalola University, Ado-Ekiti, Ekiti State, Nigeria

  Author

This study investigates the groundwater potential of Afe Babalola University, Ado-Ekiti, Southwestern Nigeria, using the Vertical Electrical Sounding (VES) technique of the electrical resistivity method with a Schlumberger electrode configuration. Eight VES stations were occupied to delineate the subsurface lithological units and evaluate aquifer potential. The interpreted results indicated the presence of four to five geoelectric layers with the following ranges of resistivity and thickness: topsoil, 52.4–789.4 Ω·m and 0.3–0.8 m thick; sandy-clay/lateritic horizon, 25.9–1,338.6 Ω·m and 1.5–8.0 m thick; weathered layer, 10.7–142.8 Ω·m and 7.3–22.1 m thick; and fresh basement, 172.8–2,862 Ω·m with effectively infinite thickness. Longitudinal conductance values range between 0.05 and 0.75 mhos, indicating moderate to good overburden protective capacity across 70% of the study area. Transverse unit resistance values (1200–3000 Ω·m) reflect variable aquifer potentials, with relatively lower values suggesting zones of enhanced groundwater occurrence. The coefficient of anisotropy (λ), ranging from 1 to 4, delineates subsurface inhomogeneities and structural controls influencing groundwater accumulation. Geo-electric sections and resistivity maps identified the weathered/fractured basement as the primary aquifer unit, with the most prospective groundwater zones located at VES 1 and VES 2, corresponding to areas of high overburden thickness and moderate resistivity. These zones also exhibit good to moderate aquifer protection from surface contaminants. The study validates the reliability of electrical resistivity methods in groundwater appraisal and provides a scientific basis for sustainable groundwater development and management within the university. It is recommended that groundwater abstraction, waste disposal, and subsurface infrastructure be confined to zones with adequate protective capacity to ensure long-term water security.

• FJET_12_83_76

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