Geo-electric assessment for groundwater potential at permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi, Kebbi State North Western, Nigeria

Abstract

Vertical Electrical Soundings (VES) afford fast and economical measurements used in geophysical exploration. VES was used for groundwater exploration at the permanent site of Waziri Umaru Federal Polytechnic, Birnin Kebbi. Eighteen (18) Vertical Electrical Sounding (Schlumberger array, maximum AB/2 distance 100 m) were performed, data were acquired using ABEM terrameter (SAS 300c), to determine the geoelectric units in the subsurface stratigraphy as well as to delineate groundwater potential in the area via electrical resistivity soundings. Field data collected was analyzed using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity in ohm-meter. Data was interpreted in terms of the resistivity and thickness of subsurface layers. Results indicates that three to five (3-5) distinct layers in the study area namely; top soil which is mainly sand, clayey sand/loose sand, sandy clay/fine sand and clay unit were delineated. The result also revealed that water bearing formation exists in the third layer in some identified VES locations i.e VES 3, VES5, VES13 and VES14 with very good aquifers, with thickness and corresponding resistivity values of 40.5, 37.5, 45.8, 60 m and 173, 148, 222 and 432 Ωm respectively. The electrical resistivity data, therefore gives reasonable accurate results that can be used to understand stratigraphy and sedimentary configuration in ground water exploration.