GROUNDWATER EXPLORATION USING 2-D GEOELECTRICAL RESISTIVITY IMAGING

ABSTRACT

Electrical resistivity imaging investigations have been carried out in University of Benin Teaching Hospital Ugbowo, Benin City in other to locate groundwater water resources, estimate its depth and delineate the lithologies of the subsurface layer.

2-D electrical resistivity imaging technique using dipole-dipole profiling and vertical electrical sounding were carried out using an ABEM SAS 300 C terrameter. The field survey was conducted along three profile of 300m each which provided a continuous information of the resistivity imaging below the surface using dipole dipole array. One vertical electrical sounding data was collected along one traverse which is at right angle to the dipole dipole traverses. The data collected were processed and interpreted using DIPRO software for computer assisted iterations.

The result obtained from inversion show that the lithology is made up of top soil and intermittent lateritic clay and sand which have varying thicknesses and resistivities which ranges from about 324Ωm to 4684Ωm. The aquiferous zone was observed to lie between  depth of about 60m to 85m due to the low resistivity in that zone. Hence the study area  holds  good prospect for groundwater by virtue of its  thick layer.