Delineation of Groundwater Aquifer and Subsurface Structures of Some Selected Areas in Chikun Local Government Area of Kaduna State, Nigeria using Electrical Resistivity

This study is aimed at delineating groundwater aquifer and subsurface structures of some selected areas within Chikun local government area of Kaduna State, Nigeria, using the Vertical Electrical Sounding (VES) method. To obtain the electrical resistivity values of the subsurface within the study area, electric current was conducted into the ground through two current electrodes while measuring the corresponding values of the potential difference using two potential electrodes. VES was conducted in twenty (20) different stations and was named profiles A, B, C and D with each having five stations with several layers, and four Vertical Electrical Sounding curves which were A, H, Q and QH were obtained. The results obtained from Vertical Electrical Sounding (VES) revealed the aquifer was at depths 7.3 m, 0.141 m 22.7 m, and 14 m for VES A, B, C and D respectively. Results from the 2D map revealed low resistivity within the weathered basement and fracture basement with resistivity values ranging between 1.929 – 885 Ωm which correlates with the results obtained from the VES. The reflection coefficient (r) was used to determine the aquifer protective capacity of the study area and the isoresistvity map depicted that 7% was good (with r values ranging between 0.8 – 4.9), 43% was moderate (with r values ranging between 0.2 - 0.79), 33% was weak (with r values ranging between 0.10 - 0.19) and 17% was poor (with r values <0.10). Aquifer with low reflection coefficient values (r<0.8) favors groundwater potentiality but with high vulnerability to contamination. The study area has an aquiferous zone characterized by fractures and porosity aiding groundwater permeability and storage.