Delineation of Aquiferous Formation Using 2-D Electrical Imaging Technique at Ukwuani, South - South Nigeria.

Abstract

An aquifer is a body that can hold large volumes of water and also transmit such volumes of water as a result of groundwater potential. To determine groundwater potential, a 2-D Electrical Resistivity Imaging (ERI) technique was carried out within the medium fine-grained formation of the Ukwuani kingdom, South-South, Nigeria. The study is undertaken to determine the thickness, lateral extent and depth of aquiferous formation within the study locations. The Abem Terameter SAS 300C was used for field data acquisition while employing the Wenner-Schlumberger electrode configuration. A 2-D set of apparent resistivity data was generated in different parallel and other orientations with electrode spacing of 5.0m. The four electrodes are positioned at (0m, 5m, 10m and 15), which corresponds to the (C1, P1, P2, C2) positions for the current (C1 andC2) and potential electrodes (P1 and P2) on the particular profile. In each case, the circuitry is completed by connecting the electrodes to the Abem Terameter SAS 300C via single-core cables. The collected resistivity data was processed and inverted using the RES2DINV software. A probing depth of 17.3m was attained over a profile length of 120m with a unit electrode spacing of 5m. The depth and thickness of investigation suggest that across the traverses and horizons, a viable and sustainable aquifer is best sought for at a depth to formation of about 15m with thicknesses in the range of 4.00m to 7.00m. The study area is a sandy environment with an unconfined aquifer characteristic.