Hydrogeophysical crystalline aquifer characterization in the Ajumako–Enyan–Essiam District, Ghana
摘要
The Ajumako–Enyan–Essiam district is infamously dependent on groundwater. The district is experiencing a water deficit due to surface water bodies drying up and water demand increasing. Consequently, the suitability of the electromagnetic approach for groundwater exploration was evaluated. Ten profiles were used for the electromagnetic method survey. Points were selected on the profiles for VES and borehole drilling. The range of conductivity values was 22–80 mS/m, the range of resistivity values was 31.7–2599.0 Ωm, the range of depth to basement rock was 7.8–48.8 m, and the range of geoelectric layer thicknesses was 1.1–44.7 m. The range of borehole depth was 35–60 m, the range yield was 13–60 l/min, the range of specific capacity was 0.692–18.81 m3/day/m and the range of transmissivity was 0.404–30.744 m2/day. The lithology of the area was laterite, weathered granite, fresh granite, and fractured granite. The area has a complex and highly heterogeneous hydrogeological environment. The fractured granite was the main aquifer in the district. The high consistency between the electromagnetic method, vertical electrical sounding, and borehole data interpretations showed the effectiveness of the electromagnetic method for groundwater exploration in the area.