Abstract
Resistivity survey was carried out in some parts of Nsukka and Igbo Eze south local government areas of Enugu State, in order to evaluate the groundwater conditions of the area. The area is devoid of surface water and lack of proper knowledge of the aquifer has affected the extraction and development of groundwater in the area since it is the major source of water. Resistivity, thickness, depth, curve frequencies and Dar-Zarrouk parameters were determined. The result revealed a total of three to five geoelectric layers with the range of resistivity and thickness values as; topmost layer: 121.6 - 2155.3 Ωm and 0.9 - 3.6 m; second layer: 794.4 - 4823.5 Ωm and 5.2 - 24.0 m; third layer: 1226.6 - 4703.1 Ωm and 29.3 - 175.0 m; fourth layer: 4261.2 - 20998.8 Ωm and the fifth layer is undefined in most of the vertical electrical sounding (VES) stations. The Dar-Zarrouk parameters computed show the longitudinal conductance to range from 0.01 - 0.09 mhos with a mean value of 0.029 mhos. The curve types obtained from the study were; KH, H, AA, KHA, AAA. The transverse resistance ranges from 17048.82 - 863269.68 Ωm2 with 271805 Ωm2 as the mean value. The aquifer layers show resistivity range of 1226.6 - 7087.6 Ωm with thickness range of 13.4 - 175.0 m and are composed mainly of sandstone. The contour maps drawn show the variation of aquifer parameters and Dar-Zarrouk parameters. The study area was generally delineated as having a poor protective capacity as a result of the low values of longitudinal conductance of the aquiferous layers, but high transmissivity and permeability which suggest high groundwater potential.
Key words: Groundwater conditions, Nsukka and Igbo Eze south, protective capacity, transmissivity, permeability, aquiferous layers.
