Main Article Content
Abstract
Enugu State College of Education (Technical), located on Abakaliki Road in the Polo Park and Government Reserved Area district of Enugu, depends on groundwater for a substantial share of its institutional water demand, yet sits on one of the least favourable aquifer systems in southeastern Nigeria. This study appraised the groundwater potential, aquifer hydraulic parameters, and pollution vulnerability of the college site using geoelectric evidence. A desk-based hydrogeophysical assessment design was adopted, in which published vertical electrical sounding datasets from stations immediately surrounding the campus were compiled into a composite geoelectric model, from which Dar-Zarrouk parameters, aquifer hydraulic characteristics, and three vulnerability indices were computed. Results indicate a five-layer geoelectric sequence comprising lateritic topsoil, sideritic sandy siltstone, dry shale, a wet shale aquifer horizon, and compacted shale at depth. The aquifer occurs between 32 and 48 m, with thickness of 20 to 35 m and resistivity between 2 and 190 ohm-metres. Derived transmissivity of 1.6 to 35 square metres per day places the aquifer in the low to intermediate class, adequate for a single institutional borehole but not for high-yield abstraction. Total longitudinal unit conductance of the overburden was computed at 0.059 to 0.276 siemens, corresponding to poor to moderate protective capacity. The computed DRASTIC index of 76 and GOD index of 0.15 both indicate low intrinsic vulnerability, a result driven by the deep water table and low-permeability aquifer media, and one that conflicts with the protective capacity rating. The study reconciles this divergence, concludes that the campus faces a low-yield rather than a high-vulnerability groundwater problem, and specifies a confirmatory sounding programme.