A Geo-Electrical Survey for Groundwater Exploration in a Part of the Basement Complex Terrain, Ilorin Metropolis Northcentral Nigeria
Keywords:
Geo-electrical, Investigation, Resistivity, Aquifer, Basement Complex, IlorinAbstract
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Investigation and determination of groundwater potential is an important procedure for addressing the problem of acute water shortage. In order to achieve this purpose, a geo-electrical resistivity survey involving vertical electrical sounding (VES) technique for groundwater exploration was carried out at Oke-Adini area, Ilorin. A total of twelve (12) VES stations with the current electrode maximum separation of 100 m were completed. The field data obtained was first subjected to a conventional partial curve matching before being interpreted with the computer iteration techniques using the WinGlink and WinResist software. The results revealed four layers comprising of the top soil with resitivity values ranging from 190 to 900 Ωm while the thickness ranges from 0.44 to 1.15 m. The weathered basement has resistivity values ranging from 54.1 to 150 Ωm while the thickness ranges from 2.0 to 17 m. The fractured basement resistivity values ranges from 5.7 to 503.4 Ωm with 1.51 to 50.8m in thickness. The resistivities of the fresh basement is above 700 Ωm. The obtained resistivity analysis and pseudo section curves shows that VES station 3, 6, and 7 exhibited low resistivities value and high overburden thickness in the weathered rock layer from all survey conducted and therefore, recommended has being most suitable target for borehole tube drilling.