Estimation of aquifer geohydrodynamic properties using the Inverse Slope method

This study is aimed at estimating aquifer geohydrodynamic properties of the hinterland aquifers of Obot Akara Local Government area for groundwater development in the area. A total of 12 Vertical Electrical Soundings (VES) was conducted in the area with the use of the Schlumberger electrode configuration with maximum current electrode separation of 600. The acquired data were interpreted using the modified Inverse Slope Method (ISM) to obtain the primary geoelectric parameters of the various lithological and hydrogeological units penetrated by the current in the area. The areais shown to comprise 3 to 4 geoelectric layers, with the third layer constituting the economical exploitable aquifer. The thickness of this layer varies from 54.4 to 129.5 m with an average value of 86.7 m while its bulk resistivity varies from 396.0 to 3333.3Ωm with an average value of 1425.5 Ωm. These two primary aquifer parameters were used in conjunction with empirical relations in literature to estimate the geohydrodynamic properties of the hinterland aquifers in the area. The estimated properties are pointers to the fact that aquifers in the area are very productive.