Application of Electrical Resistivity Tomography for the Delineation of Ground Water Potential at Southern Part of Maikunkele Town, Niger State, Nigeria.

Abstract

Vertical Electrical sounding (VES) and 2-D Electrical Resistivity Tomography (ERT) were used to study the groundwater potential for effective development and management in Maikunkele, Niger State, Nigeria. Thirty (30) VES points were examined using Schlumberger configuration with current electrode spacing ranging from 2.0 to 200 m. The VES data obtained were interpreted using WinResist computer software. Furthermore, 2-D ERT with a 10 m interval between two sounding points was applied using a dipole-dipole configuration. The 2-D inversion modelling of the Dipoledipole data was interpreted using RES2DINV(R) software. The VES results revealed a heterogeneous subsurface geologic sequence probe to 20.20 m and beyond. The variation in lithology consisted of Lateritic soil/sand/clay/sandy-clay/clayey-sand/topsoil with resistivity varying from 115 Ωm to 1237 Ωm and underlay by a layer of clay with resistivity varying from 41 to 461 Ωm. The third layer was a continuation of clay of resistivity ranging from 15.62 to 100 Ωm while the fourth layer in some VES points was a combination of gravely sand with resistivity varying from 2674 to 4271 Ωm with a high resistivity at the basement bedrock of 7920-16541 down to infinity. The VES results indicate that VES points A5, B4, C5 and D5 have a promising aquifer potential. The fractured layer has a thickness of 20-46 m and a resistivity value ranging from 27.2 Ωm to 409.4 Ωm. The presence of groundwater in some parts of Maikunkele was determined and that was correlated with existing borehole logs for proper sitting and development.