GROUNDWATER EXPLORATION USING 2D RESISTIVITY IMAGING AT NUHU BAMALLI POLYTECHNIC, ZARIA, KADUNA STATE, NIGERIA

Abstract

The groundwater resource of Nuhu Bamalli Polytechnic Zaria was investigated using 2D resistivity imaging. The data was collected using ABEM Terrameter SAS 4000 with an electrode selector along 35 profiles running orthogonally employing a dipole-dipole array with an equally spaced electrode of 5m. The apparent resistivity obtained from field was processed and interpreted using RES2DINV software to produce two two-dimensional images of the study area. The result of the inverted 2D resistivity imaging revealed that the site is predominantly of low resistivity values at the near surface, with sparsely high resistivity values at some places. The low resistivity values that range from 9 ohm-m to 142 ohm-m typify high clay content. The overburden thickness was found to be between 3m to 12 m depth with outcrops along profiles 10 and 21. The basement has a varying degree of weathering, and areas of withered/fractured zone were well pronounced along 11 profiles (profiles 2, 4, 7, 8, 10, 20, 21, 22, 26, 27, 31) at different depths. These areas of the withered/fractures zone could serve as a water-bearing zone (aquifer) in the study area.