The Implications of Subsurface Resistivity Variations at Alvan Ikoku Federal University of Education, Owerri, Southeastern Nigeria (Published)
This study investigates the implications of subsurface resistivity variations at Alvan Ikoku Federal University of Education, Owerri, Southeastern Nigeria, utilizing vertical electrical sounding (VES) techniques. The research aims to characterize the subsurface geology and assess groundwater potential within the Benin Formation, which is of late Cretaceous to Paleocene age. Eleven VES stations employing the Schlumberger array were conducted, and data were modeled using IPI2Win software to delineate geoelectric layers. Results revealed topsoil resistivities ranging from 203 Ω·m to 250,000 Ω·m at an average thickness of 1.31 m, indicating variability in surface materials. Middle layer resistivities varied from 16.5 Ω·m to 260,000 Ω·m, corresponding to sandy-clay, clayey-sand, sand/gravel, and sandstone at greater depths, indicative of a predominantly sandy subsurface. The aquifer resistivities ranged from 1,795 Ω·m at CKC to 134,777 Ω·m at the Nursery School, suggesting zones of high permeability. The average electrical conductivity was found to be (7.4496 x 10-6) S/m, implying low dissolved ion content in groundwater. Aquifer thickness varied from 36 m to beyond 142 m, with transverse resistances from (1.168174 x 105) Ω·m² to (1.53511003x 108) Ω·m², indicating high lateral resistance and prolific groundwater flow. The aquifer is semi-confined beneath a sandy-clay overburden that offers natural protection from contamination. These findings have significant implications for sustainable groundwater development and management within the university campus.
Keywords: Aquifer, Benin formation, Investigation, implication of subsurface, resistivity variations, vertical electrical sounding