Underground water exploration of Oleh, Nigeria using the electrical resistivity method

A geophysical investigation was carried out in Oleh, Nigeria to determine the groundwater potential and the geological structure of the area. The method employed in this study was the Vertical Electrical Sounding (VES) using the Schlumberger configuration. The data obtained were interpreted by computer iteration process and results when compared with lithologic log from existing borehole indicate a four layered formation. The first aquifer identified in this study is located along the second layer with resistivity ranging from 347.4 to 1137 Ωm and depth ranging between 2.0 and 3.7 m. Analysis of this layer shows that this aquifer is unconfined and prone to pollution since it underlay’s a loose and clayey sand formation that is very thin. The second aquifer is a viable potable water formation with resistivity range of 416.7 to 1459.2 Ωm and a thickness range of 12.0 to 14.9 m. The depth of the aquifer ranges from 21.8 to 29.7 m. Boreholes for potable groundwater are therefore recommended within the forth layer because of its quality and viability.   Key words: Groundwater, electrical resistivity sounding, aquifer, water formation.