Aquifer depths and thickness in Ogba/Egbema/Ndoni local government area of Rivers State, Nigeria from vertical electrical soundings

Most parts of the world depend on groundwater for domestic and other uses. Different geophysical methods can be used to exploit these groundwater. In this study aquifer depths and thickness spread in parts of Ogba/Egbema/Ndoni Local Government Area of Rivers State, Nigeria have been determined from 30 vertical electrical sounding survey. An ABEM Terrameter (SAS 300C) was used with Schlumberger array configuration of maximum electrode spread of 500 m. The data were analyzed with an IP2WIN ID software to obtain the strata resistivities, geoelectric layers, aquifer depths and thickness from which the isopach and iso-resistivity maps of the region were obtained. The results show two to four layer formations with resistivity values ranging from 350 to 3895 . Aquifer depths of between 20 m to 75 m and thickness varying from 17 m to 48 m. The isopach map indicates that regions in the north-central part of the study area have shallower aquifer thickness with an average value of 25 m while in the other parts of the study area, the average value is 41 m. The iso-resistivity contour maps at depth intervals of 50 m, 100 m, 150 m and 200 m reveal the trending of the resistivity values for these depths across the region. The general results indicate that the study area has productive aquifers of reasonable thickness at moderate depths from 20 m as in the other parts of the Niger delta region, therefore portable boreholes can be drilled from this depth.