Hydrogeophysical characterization of the Lower White Volta River Basin of Ghana using electromagnetic technique
摘要
The Lower White Volta River Basin (LWVRB) is known to have frequent borehole drilling failures. The basin is experiencing water scarcity due to the drying up of surface water bodies and frequent borehole drilling failures. Hence, the suitability of the electromagnetic method for groundwater exploration was evaluated. Ten communities were selected within the basin for the electromagnetic data collection. In each community, two sets of two 400-m-long parallel profiles spaced 15 m apart and oriented perpendicularly were used. Four out of the ten communities were selected for electrical resistivity tomography to verify the electrometric method. The study revealed that the basin is generally made of laterite, dry sandstone, shale, mudstone, saturated sandstone, and siltstone from top to bottom. The groundwater resource of the basin is controlled by secondary porosity and permeability. The electromagnetic method has proven effective for groundwater exploration in the basin. The study showed that the presence of crossover and relatively high peak-to-trough amplitude indicates the presence of structural features. The traceability of structural features across several parallel traverses confirms the presence of such features. A good correlation between the interpreted electromagnetic data, borehole data, and electrical resistivity tomography data demonstrates the effectiveness of the electromagnetic technique in identifying potential borehole drilling sites in the basin.