Geophysical mapping of groundwater aquifers beneath the Central Region of Ghana

Abstract

Geophysical data were used to map groundwater aquifers beneath two towns in Central Region of Ghana. The geophysical data include electromagnetic, electrical resistivity profiling and vertical electrical sounding. The results revealed that, the surveyed areas are underlain by three to four layers. The resistivity values of the first layer ranges between 71.93 to 2399.70 Ωm and the average value of 617.46 Ωm. The layer thickness ranges between 0.48 – 7.42 m with an average value of 1.73 m. The second layer has the resistivity values between 41.96 to 1996.12 Ωm with an average value of 678.19 Ωm. The thickness of the second layer is 1.77 – 20.87 m with an average thickness of 9.26 m. The third layer which in some towns served as the bed rock has resistivity values between 298.91 to 861250.57 Ωm and an average value of 87473.04 Ωm. The layer thickness ranges between 6.00 to 18.39 m with an average value of 13.89 m. The fourth layer has the resistivity values between 915.78 to 2066.15 Ωm with an average value of 1647.44 Ωm. The depth to aquifer within the study area is between 0.48 to 7.42 m. The average aquifer thickness within the study area is 14.78 m. The results of this study were used to determine the drilling locations for groundwater in the region.