Geo-electrostratigraphic assessment of aquifer potential, protectivity, and pliable level of vulnerability within a coastal milieu

Abstract

Geo-electro stratigraphic assessments of aquifer potentiality, protectivity, and pliable level of vulnerability within a coastal milieu were undertaken with geo-electrical technology. The vertical electrical soundings were undertaken at 20 locations and the 2D electrical resistivity tomography surveys were undertaken at five locations within the study area. Results obtained from these geo-electrical surveys coupled with hydro-geophysical investigations within the area indicated the presence of four geo-electric layers: motley topsoil, sandy clay, fine sand, and coarse sand. The geo-stratigraphic data assessed groundwater potentiality, protectivity, and vulnerability to contamination with measures of transverse resistance, hydraulic conductivity, transmissivity, hydraulic diffusivity, aquifer storativity, and longitudinal conductance. Geo-hydraulic characterization indicated mean aquifer resistivity of 554.6 Ωm, mean aquifer conductivity of 0.0004 S/m, mean longitudinal conductance of 0.67 Ω−1, mean transverse resistance of 5601.7 Ωm2, mean hydraulic conductivity of 3.5 m/day, mean transmissivity of 283 m2/day, mean storativity of 0.0002, and mean hydraulic diffusivity of 1 × 105 m2/day. The results indicated that the region's groundwater potential ranged from medium to high. Longitudinal conductance values indicated that the aquifer protective capacity ranged from moderate to poor. Geo-electrical technology was therefore found to be an effective methodology for delineating aquifer potentiality, protectivity, and vulnerability within the vulnerable coastal aquifer system.