A Hydrogeophysical Appraisals for Surficial Aquifer Potentials of Sedimentary Basin of SW Nigeria

Abstract

This study presents the use of geoelectrical method in assessing the surficial aquifer potentials of the multi-layered sedimentary basin of South Western Nigeria. The 18 Vertical Electrical Sounding (VES) covering the sedimentary basin was conducted using the schlumberger electrode array. Methodology and data evaluation includes zoning the basin according to their geological formations and rock types. Field resistivity data were inverted into one and two dimensions with IPI2Win Software. The inversion were done to obtain both lateral and vertical layer distribution of beds in the vadose zone, depth to water levels, identification of lithological types and thicknesses and presence of aquifers. Four to six lithological layers were delineated general for the basin from the interpretation of the data inversions. Results showed that vadose sediment compositions include porous sandstones, limestones, shales and topsoils. Transverse conductance from the study correlated with the aquifer transmissivity which suggest possibility of good yield. This study has shown the importance of surface resistivity in aquifer parameters and potentials estimations.