Geoelectrical Investigation of Groundwater Resources at Ikpoba Okha Local Government Area, Edo State, Nigeria

Geophysical survey involving the use of resistivity sounding method was recently carried out to investigate the geoelectrical layers of groundwater resources in Obaretin, Iyanomon and Orhionmwonbor, both in Ikpoba Okha Local Government Area of Edo State, Nigeria. Three vertical electrical sounding (VES) locations were visited in the study area, VES 12 in Obaretin, VES 28 in Iyanomon and VES 14 in Orhionmwonbor. The vertical electrical sounding was done using the Schlumberger electrode array configuration and the linear filter method of interpretation was adopted. A correlation of the interpreted curves with the lithologic log from the borehole sections in the study area suggests that the major lithologic layers penetrated are laterite, clay, sand (sandstone) and sandy clay from basic depth interval as shown by the geoelctric section. The sandstone layer which is the aquifer zone lies between the depth of 59.80m to 85.80m for VES 12, 63.16m to 89.36m in VES 28 and 69.36m to 95.37m for VES 14. Therefore, the depth to water table in the study area has a maximum drill depth within the range of 60m (199.8ft) to 100m (333ft).