Hydrogeologic Survey Using Electrical Resistivity Method for Sustainable Water Supply Development in Parts of Owerri, Southeastern Nigeria

Electrical resistivity method for evaluation of groundwater potential in the Owerri North was carried out based on aquifer transmissivity obtained using Dar Zarouk parameters and pumping test data. Twenty vertical electric soundings (VES) were carried out in this study. The field data were acquired using the Omega-500 resistivity meter and interpreted using Advanced Geoscience Incorporation (AGI) 1D resistivity inversion software. Five of the VES stations were sited near existing boreholes from which pumping test data were acquired. Transverse resistance and Longitudinal conductance were determined, which together with hydraulic conductivity derived from pumping test data enabled the estimation of aquifer transmissivity and its variation in the study area. The aquiferous layers are composed mainly of sands and sandstones. Resistivity values varied with depth and ranges from 0.10Ωm to 1208.50Ωm. The aquifer depth varied from 8.50m to 67.07m. The aquifer thickness varied across the study area from a value of 8.32m around ChukwumaNwoha to 199.42m measured at Agbala. Areas having high aquifer thickness also have corresponding high Transmissivity values and so have high groundwater potential. High transverse resistance above 10000Ω were observed in areas around Owaelu, while low values of 3100Ω and less were observed in areas such as Emekuku. Areas around VES 6, 11 and 15 are underlain by high Longitudinal conductance aquifer materials. Transmissivity values are fairly high and varied from 264m2/day at Azaraegbelu to 276m2/day at Shoprite Egbu. The study revealed that the study area has good prospect for sustainable groundwater supply.