GEOPHYSICAL INVESTIGATION OF GROUNDWATER POTENTIALS OF OKE-BADAN ESTATE, IBADAN, SOUTHWESTERN NIGERIA

Abstract

Electrical resistivity survey using Schlumberger vertical electrical sounding (VES) field technique was carried out at Oke-Badan, Akobo area, Ibadan, Southwestern Nigeria. The dominant rocks comprise suites of quartzschist and pegmatite. The traverse length i.e AB/2 is 100m while the distance of separation between the VES station is 100m.

A maximum of four geoelectric layers were delineated from the vertical electrical sounding. The geoeletrical sections for the study area were: the topsoil, the clayey sand, sandy clayey, shale/clay basement, and the fresh basement. Computer modeling using WinGLink program was used for the iteration to obtain the geoelectrical parameters. Interpretations of VES data were used to generate 2D basement relief / topography map, weathered layer resistivity map showing groundwater potential zones, overburden thickness map and aquifer unites) thickness

map using computer software. The groundwater potential zones were identified in which poor, moderate and good zones are classified with respect to the prospects of finding groundwater in the study area. The study reveals that the weathered and fractured horizons that occur in the southeastern part, as a ridge at northeastern part and as an isolated patch at the western part of the area constitute the productive water - bearing zones referred to as good groundwater

potential aquifers.