GEOPHYSICAL INVESTIGATION OF GROUNDWATER USING VERTICAL ELECTRICAL SOUNDING IN ADOLOR AREA BENIN CITY SOUTHERN NIGERIA.

ABSTRACT

The applicability of the technique for subterranean water research was ascertained by a geophysical exploration employing vertical electrical sounding in a sedimentary setting. In the Adolor outskirts of Benin City, Southern Nigeria, numerous geophysical methods were used for this investigation, including the Vertical Electrical Sounding (VES) approach. The goal of the research is to discover and investigate the groundwater layer's (aquifer's) depth. ABEM Terrameter with Schlumberger Configuration of electrode was used to acquire VES data. In this study, there are four VES points with cable lengths varying from 1 m to 316 m. There were two differences in the resistivity value range between the four VES points. Extremely low resistivity value, 0.5–0.9 Ωm, is considered to be the aquifer layer.The aquifer layer of research area divided into two types which are unconfined aquifer and confined aquifer.It was observed that water bearing formations was mainly wet sandstone. This was observed in VES 1(VES A) and VES 3(VES C). The depth of groundwater ranges from 42.61m to 102.7m with resistivities of aquiferous intervals ranging from  60.47Ωm to 7358 Ωm. In VES 2 and VES 4 ground water was not reached but it showed promising aquifer at greater depth.