Geophysical Investigation for Groundwater Potential in Mamu Area, Southwestern Nigeria

Geophysical investigation for groundwater potential of Mamu, South Western Nigeria was carried out with the aim of delineating suitable site for groundwater development. Vertical electrical sounding using Schlumberger configuration was used to delineate the sub-surface geology of the study area. Ten VES stations were probed within the study area and the data obtained were interpreted through partial curve matching and computer iteration method. The interpreted data indicate 3-4 geoelectric layers, namely top soil, clayey sand/sandy clay, lateritic cap rock, fractured/weathered/fresh basement. The resistivity of 1st layer ranges from 61.6-503.5 Ωm, 2nd layer has resistivity value ranging from 69.9-3504.0 Ωm, the 3rd layer has the resistivity between 149.5-2964.4 Ωm and in the 4th layer the resistivity ranges from 116.50-6052.4 Ωm. It is believed that there is a correlation between large depth to bedrock and high conductance of geoelectric layers. Based on these, VES 1, 2, 5 and 8 has high potential for groundwater development because of their large overburden thickness and low resistively values.