Geophysical assessment of groundwater potential in Divine Estate, Sango Ota, Southwestern Nigeria

Ezennubia, Valentine and Bello, Rereloluwa and Samuel, Uwem-Umoh and Daniel, Oladimeji T (2025) Geophysical assessment of groundwater potential in Divine Estate, Sango Ota, Southwestern Nigeria. World Journal of Advanced Engineering Technology and Sciences, 16 (1). pp. 240-253. ISSN 2582-8266

This study evaluates the groundwater potential of Divine Estate, Sango Ota, southwestern Nigeria, through geophysical investigation using the Vertical Electrical Sounding (VES) method. Sixteen VES points were surveyed with the Schlumberger electrode configuration (AB/2 = 100 m) to delineate subsurface conditions affecting groundwater occurrence. The area, situated within the Dahomey Basin, experiences persistent water scarcity and frequent borehole failures. Geoelectric interpretation revealed a three-layer structure comprising topsoil, weathered/fractured basement, and fresh basement rock. The dominant curve type is H (68.75%), with minor occurrences of K, KH, A, HQ, and HA types (each 6.25%), indicating varying subsurface conditions with H-type curves suggesting favorable groundwater zones. Overburden thickness ranges from 0.8 to 25.7 m (mean: 1.9 m), which is significantly below the 20–30 m threshold for reliable groundwater development. Transverse resistance varies between 71 and 9,591.4 Ωm², implying spatially variable aquifer transmissivity. Longitudinal conductance (0.001–0.625 Ω⁻¹) indicates poor aquifer protective capacity, raising concerns about contamination vulnerability. Integrated analysis of aquifer resistivity, overburden thickness, and Dar-Zarrouk parameters identified high groundwater potential zones at VES stations 2, 7, and 8, where moderate resistivity weathered layers (51–209 Ωm) occur at drillable depths (10–13 m). The findings highlight limited groundwater potential across much of the estate due to shallow overburden and resistive basement conditions. The study recommends strategic borehole placement, adoption of integrated water supply solutions, and rigorous aquifer protection to address the estate’s water supply challenges sustainably.