Geo-Electric Study for Groundwater Development in Ikunri Estate, Kogi West, Southwestern Nigeria

Abstract

A total of fifteen (15) vertical electrical soundings (VES) were conducted at Ikunri estate with the aim of having an idea about the overburden thickness, determining the geoelectric layers and locating depths that are of hydrologic significance. The vertical electrical soundings (VES) were performed using Schlumberger array with half current electrode separation (AB/2) varying from 1m to 65m.  The geo-electric parameters obtained from the sounding curves revealed 3-layer, 4-layer and 5-layer earth models. The 3-layer model constitutes 80% of the coverage area while the 4- layer and 5-layer models constitute 6.67% and 13.33% respectively.  All the models showed that the subsurface are distinguishable into the topsoil, clay /sandy-clay, weathered/fractured basement rock, and the fresh basement rock. The thickness of the weathered and/or the fractured basement ranges from 1.5m to 9.5m and these are the aquifers in the area. The resistivity values of the weathered/the fractured basement ranged from 21.2-494.9 Ωm. Based on the isopach and basement relief maps, the study area was zoned into high, intermediate and low groundwater potential. The study revealed that basement depressions mostly constitute high groundwater potential zones. It will serve as a guide on the groundwater potential of the area and expected to assist in future development of groundwater resources in the area.