Application of Vertical Electrical Sounding to Investigate the Groundwater Potential in Abak Local Government Area, Akwa Ibom State, Nigeria

Abstract

The vertical electrical sounding (VES) method has been used to characterize the aquifer in part of Abak Local Government Area, Akwa Ibom State, Nigeria. Thirteen (13) electrical sounding were taken in three transect using ABEM Terrameter (SAS1000). The maximum current electrode spread ranged between 1000 m and 2000 m. The VES field data obtained were interpreted using the WinResist programme to generate the final model for layer resistivity and thickness. Dar Zorrouk parameters, transmissivities and kσ values were also determined.  Apart from the topsoil, the underlain layers have sizeable thicknesses that can host groundwater.  The transverse resistance ranges from 31725.72 – 387732.5 Ωm2 and the average value is 119750.46 Ωm2. The longitudinal conductance ranges from 0.0053864 – 0.049078 Ω-1 and the average value is 0.05215 Ω-1. The transmisivity ranges from 394.848 to 728.852 m2/day and the average value of 548.82 m2/day was obtained. The Kσ - value ranges from 0.0010 to 0.0128 (Ωday)-1 and the average value was 6.43 x 10-3 (Ωday)-1. The Kσ values show that the area studied has fresh water that is in abundance in fine-coarse grained sands. The water table map shows the pattern of water flow in the study area and this can be used for groundwater contamination study.