Electrical resistivity investigation of the groundwater potential in Oloruntedo Community, Abeokuta, Ogun State, Nigeria

Abstract

Groundwater is that water found beneath the surface of the earth which serves as a predominant source of water for human endeavours. The aim of the study was to determine viable aquiferous zones to investigate the groundwater potential using resistivity technique (specifically Vertical Electrical Soundings) in Oloruntedo Community Obantoko, Odeda Local Government area, Abeokuta, Ogun State. The highly resolution PASI Earth resistivity meter, Model 16 GL geophysical equipment was used to acquire the groundwater location. Relatively six (6) Vertical electrical soundings were carried out via Schlumberger array. The VES data generated were processed and interpreted using partial curve matching method and computer iteration techniques. The result shows four geo- electric sections with varied thicknesses and resistivity. The resistivity of the top soil ranges between 181 ohm-m and 1460.6 ohm-m, the resistivity of clay varies between 31.8 ohm-m and 789.8 ohm-m, the resistivity of the fresh basement ranges from 1049.3 ohm-m and 8961.5 ohm-m which was the only layer observed in one of the (6) VES points. The resistivity of weathered basement ranges from 90.6 ohm-m and 388.2 ohm-m, the resistivity of highly weathered ranges from 13.6 ohm-m and 49.1 ohm-m and lastly the resistivity of the lateritic sand which was only observed in one of the (6) VES points is 294.4 ohm-m. The results show that a drilling depth of 50m is feasible at VES 6, 40m depth borehole at VES 4 and 5, while 20m depth borehole at VES 1, 2 and 3 respectively is feasible in the study area. VES 6 station has the highest groundwater potential, secondly by VES 4 and 5 while VES1, 2 and 3 imprint a low groundwater zone in the study area. The study confirms that Electrical resistivity technique is a good method in identifying groundwater potential zones in an area.