Application of the electrical resistivity tomography (ERT) method in identifying high groundwater potential sites in the Atebubu municipality of Ghana

The people of Atebubu municipality depend almost entirely on groundwater for their daily water needs since they are not served with treated water from the Ghana Water Company Limited (GWCL). The municipality has been battling with perennial potable water crisis for the past few decades as supply from the groundwater sources is erratic. This paper used the electrical resistivity tomography (ERT) technique in the gradient and Wenner array configurations to access subsurface groundwater information leading to possible sustainable groundwater potential locations. The results show resistivity values ranging from 5 to 2212 Ωm across the profiles. Possible clay contents have resistivity distributions ranging from 5 to 98.6 Ωm and dominate the shallow subsurface and top layers in most cases. Distribution of the moderately low resistivity 100 to 506 Ωm also suggest that the water table for sustainable boreholes and wells could be found at deeper depths with only few portions stretching to the shallow subsurface. Rocks that are expected to exist at these depths are phyllites, sandstone, siltstone or arkose. The high to very high resistivity values which are interpreted as competent rock formations were observed predominantly at both deeper depth and the shallow subsurface.