Application of Electrical Resistivity Method for Aquifer Characterization in the Crystalline Basement Complex of Kaduna North Lga, Kaduna State, Nigeria

Abstract

The exploitation of groundwater requires an understanding of the hydrogeological characteristics of subsurface aquifers within basement terrains. This study employed a geophysical investigation using the Vertical Electrical Sounding technique to determine subsurface geological formations and evaluate aquifer depth and thickness for groundwater potential. The survey involved injecting current into the ground through current electrodes using the Schlumberger array configuration. Sixteen VES stations were occupied, with electrode separation varying from 1 to 100 meters, to investigate geo-electrical characteristics. Field data were manually computed and processed using computer software. A Mc Ohm-EL resistivity meter was used for data acquisition, while IPI2Win software was applied for interpretation. Results revealed three to four geo-electric layers consisting of sandy or clayey topsoil, weathered basement, fractured basement, and fresh basement. Topsoil resistivity values ranged from 0.523 to 183 Ωm with thicknesses between 0.217 and 5.326 meters. Aquifer resistivity values ranged from 14.4 to 5182 Ωm, with an average thickness of 15.435 meters. Fractured layers showed resistivities between 18.04 and 7222 Ωm at depths of 1.48 to 32.3 meters, while fresh bedrock resistivities ranged from 58.52 to 9412 Ωm. Borehole locations identified at VES stations 6, 12, and 14, and compliance with recommended depths was advised.