Electrical Resistivity Survey for Groundwater Potential and Estimation of Clay Deposit in Aragba-Okpe, Okpe Local Government Area, Delta State Nigeria

Abstract

Electrical resistivity survey employing Vertical Electrical Sounding techniques of Schlumberger arrangement were carried out at seven (7) fairly distributed stations with 154 Vertical Electrical Soundings in Aragba-Okpe. The data obtained from the field were plotted on a log-log graph and interpreted qualitatively by inspection and quantitatively by partial curve matching. The results obtained were improved with the aid of computer iteration using the Winresist Software to delineate the thickness and depth of each layers as well as the resistivity value. These layers were grouped together in to geologic depth intervals known as the Geoelectric sections for interpretations. Using knowledge of both the local geology of Aragba-Okpe and the resistivity of the layers, the Geoelectric sections were interpreted. The study revealed that boreholes for sustainable water supply could be drilled to a depth of 30 m in Aragba-Okpe, However, the fifth layer within Aragba Primary School, Aragba Secondary School and Oviri Aragba Road (VES 1, 5 and 7) are the best locations for sustainable water supply
 The overburden protective capacities of the aquifer in Aragba-Okpe were evaluated using the Dar-zarrouk parameters. The result also revealed poor aquifer protection ratings of less than 0.1 in all the stations. The groundwater in Aragba-Okpe is therefore not protected and prone to contamination in the event of pollution.