Electrical resistivity mapping of aquiferous zones within Gudi-takalau Area of Birnin Kebbi, Nigeria

Abstract

Domestic water supply in Birnin Kebbi metropolis, Kebbi State of Nigeria comes majorly from groundwater. Birnin Kebbi is underlain by the sedimentary rock of Gwandu formation Northwestern, Nigeria. The zone constitutes the easternmost segment of the extensive Sokoto basin. A two-electrode (D.C) electrical resistivity survey was carried out at Gudi-Takalau area of Birnin Kebbi metropolis, Nigeria with the aim of determining the aquiferous zones within the Gudi-Takalau for future borehole drilling. Data obtained from the eleven Vertical Electrical Sounding (VES) station sounded were interpreted using the IPI2win resistivity and surfer V.12 software. An interpretation model was designed by sounding at a borehole site of known lithology log. The interpreted result suggested the existence of two major random geoelectric sections consisting of three to four subsurface layers: the top soil clay (the alluvium cover) with a resistivity range of 20Ωm to 450Ωm and thicknesses range of 3.5m to 10.5m, overlaying the weathered sandstone with a resistivity range of 450Ωm to 3000Ωm at a depth range of 3.5m to 20.4m. Other Sub-layers were identified as weathered, fractured and fresh zones and were also detected and interpreted as aquifers. Finally, regions of high groundwater potentials were identified as VES 04, 01, 09 and 08. A borehole of depth 3.4m to 38.5m is recommended.

Keywords: Mapping, Geoelectric Layers, Two-Electrode Resistivity Survey, Fractured and Aquifer