2d Geoelectric Evaluation and Imaging of Aquifer Vulnerability of Dump Site at Ozoro Isoko South Lga of Delta State

Abstract

The Electrical resistivity survey was carried out to evaluate the aquifer vulnerability of a dumpsite in Ozoro Isoko South LGA of Delta State. Four Schlumberger vertical electrical soundings with maximum electrode separation of 350m and four dipole-dipole were carried out at a dumpsite. The data were presented as VES curves interpreted quantitatively by computer iteration using the Resist Software to obtain the first order geoelectric parameters. The vertical electrical sounding data were presented as VES curves interpreted quantitatively by computer iteration using the Resist Software to obtain the first order geoelectric parameters. The dipole-dipole data were present as Inverted 2D resistivity structure by computer inversion using DIPROfWin Software. The results of the geoelectric investigation have revealed five geoelectric layers namely the lateralitic topsoil, sandy clay soil, fine coarse sand, medium coarse sand and coarse sand that are in agreement with the actual lithology encountered from the hand dug well logs close to the dumpsite. The overburden protective capacity in an area was evaluated using the total longitudinal unit conductance values. The generated longitudinal conductance showed poor protective capacity (<0.1mhos) in all parts of the study area. The inverted 2D resistivity structure shows movements of leachate down toward the aquifer indicating that the aquifer is not protected. The low value of the protective capacity makes the aquifer in the study area vulnerable to contamination from the dumpsite.

Keywords: Aquifer vulnerability, Ozoro, 2D imaging, dumpsite, lithology