Research
Fawale O, Oladipo OI
Abstract
A detailed geoelectrical resistivity survey involving Vertical Electrical Sounding (VES) was carried out for groundwater exploration at the Continuing Education Centre of the Federal Polytechnic Ado-Ekiti, Nigeria. This was in view of the possibility that more entrepreneurship and skill acquisition centers could be sited within the study center of the school and the need to secure the place from acute water shortage for students, researchers and entrepreneurship instructors. The area lies within the crystalline basement complex of South-western Nigeria and bounded by Latitude 5.17°N-5.25°N and Longitude 7.58°E-7.67°E. The survey was carried out using PELI 1300 portable terameter while a total of 10 (Ten) VES with 10 m station interval in three even profiles were completed. Global Positioning System (GPS) equipment was used to locate the stations on the ground. The result of the interpretations revealed the presence of four geo-electric layers in the study area. The top lateritic soil has resistivity values ranging between 54.9 Ωm to 82.6 Ωm and thickness of 0.3 m to 1.89 m, the sandy clayey has a resistivity ranging between 9.44 Ωm to 9.48 Ωm with thickness of 0.133 m to 7.74 m, the weathered basement has a resistivity value ranging from 14.6 Ωm to 834 Ωm with thickness of 0.56 m to 15.1 m, while the fractured basement has resistivities greater than 900 Ωm. The analysis of the resistivity and the thickness map revealed that the main aquifer unit in the area was the weathered and highly fractured layers which were prominent among VES 2, VES 4, VES 5 and VES 10 with low resistivities which may be recommended and suitable for a highly proficient target for groundwater prospecting.