Geoelectric investigation of the aquifer characteristics and groundwater potential in Kwale, Delta state, Nigeria

Subsurface geo-electrical survey using the electrical resistivity (VES) method and drillers logs were carried out in Kwale, Ndokwa West Local Government Area of Delta State in order to investigate the aquifer characteristics and ground water potential of the subsurface formations. Nineteen vertical electrical soundings were carried out within the town and its environment using the Schlumberger array configuration. The data was interpreted using the conventional curve matching and computer iteration method. The results reveal a five layer HKH, KQH and AKH type curves. The true resistivity of the top soil varies from 55-236Ωm while the thickness varies from 0.7-1.0m. The second layer has resistivity ranging from 37-627 and thickness ranging from 1.3-3.6m. This layer is composed of clay to sand. The third layer, which constitutes an aquifer, has resisitivity varying from 2.7 to 411Ωm while the thickness varies from 4-17m. It is composed of fine-grained sand. The fourth geoelectric layer has resistivity values ranging from 114 to 168Ωm while the thickness varies form 15 to 35m. This layer is composed of fine to mediumgrained sand. The soft layer has resistivity ranging from 326-2308Ωm. This layer is composed of medium coarsegrained soil and it constitutes an aquifer of very good quality groundwater. The average depth of this aquifer is between 30-40m. These results were correlated with lithological logs from boreholes drilled in the study areas and were found to be consistent.