Hydrogeophysical Investigation of Groundwater Potential in Ugbowo Area of Edo State Using Electrical Resistivity Method

Abstract

A hydrogeophysical investigation of groundwater potential was conducted in the Ugbowo area of Edo State, Nigeria, using Electrical Resistivity Method to characterize the subsurface lithology and evaluate groundwater potential. A Global Positioning System (GPS) receiver was used to obtain the geodetic coordinates of the VES station, which is located at latitude 6° 28′ 48.36″ N and longitude 5° 35′ 17.16″ E. The geology of the study area is predominantly composed of the Benin Formation, which underlies approximately 95% of the region. Vertical Electrical Sounding (VES) was performed at one station using the SAS 300C ABEM Terrameter with the Schlumberger array configuration and a maximum electrode spacing of 147 m. The acquired data were processed and interpreted using the IPI2WIN software. The resulting geoelectric model revealed six subsurface layers with apparent resistivity values ranging from 391.51 Ωm to 5836.9 Ωm and depths extending from 1.41 m to 85.23 m. The lithologic units identified include lateritic topsoil, clay, gravel, cemented sandstones, and fine- to coarse-grained sands of varying thicknesses. The aquifer units were predominantly confined and showed good correspondence with lithologic logs from existing boreholes within the study area. A high resistivity lateritic layer was found to dominate the upper subsurface. The Vertical Electrical Sounding (VES) results indicate the presence of an aquifer with a resistivity of 783.37 Ωm, located directly below the fifth layer in the study area. This potential aquifer suggests that the area may be suitable for groundwater development. Based on these findings, it is recommended that drilling contractors consider this information before borehole construction to enhance the efficiency and success of groundwater exploration.