Geoelectric Investigation of The Hydrological Characteristics of the Fractured Basement Complex Over Igem City in Ibadan, Nigeria

This study was carried out to establish a baseline geo-physical data and hydrological characteristics using the Schlumberger arrangement (a vertical electrical sounding) and drillers log from the study area. Vertical Electrical Sounding (VES) data were acquired from 4 locations evenly distributed around International Gospel Evangelical Mission (IGEM) city and her environs. This was an attempt to obtain useful information on the aquifer distribution within the area and hence delineate possible depths boreholes could be drilled for potable and sustainable water supply. The first aquifer consist of fine-grained sand formation at a depth between 1.60 - 8.70m and thickness between 1.60 and 7.10m. The first aquifer consist medium-topsoil, weathered basement and fresh basement formation and occurs at a depth, between 1.60 -8.70m. Prospective groundwater exploration was therefore recommended in the second aquifer at a depth, between 1.60 -8.70m to enhance sustainable and potable water supply in IGEM city and her environs. The basement thickness was considered adequate for any overlying pressure from the camp to locate effective water. The results obtained from the VES curves show a typical three layer model in all the parts. The area cannot experience any ground water failure, these layers include the topsoil, clayey weathered layer/partly weathered basement and the fresh/crystalline basement. It has been discovered from this study that the weathered/fractured zone are deeply seated and will not have any adverse effect on the structures that will be placed in the nearest future. The area is not likely to experience any ground water problem as the low resistivity weathered zone thickness is high enough for reasonable accumulation of water.