Application of the electromagnetic and the electrical resistivity methods in groundwater exploration in the Tolon-Kumbungu District of the Northern Region of Ghana

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Geophysical exploration for groundwater has been carried out in seven communities the Tolon-Kumbungu District of the Northern Region of Ghana. This is to locate good yielding wells to be fitted with handpumps to supply the communities with potable water. This study came about as collaboration between NARMSAP/GAP of World Vision Ghana and the Physics Department of the Kwame Nkrumah University of Science and Technology, Kumasi, in the quest to establish the effectiveness of some geophysical techniques in groundwater prospecting in the Tolon-Kumbungu District. The object is to provide safe drinking water in a hydrogeologically difficult terrain and at low cost to the Ground Rural Water Project. The communities involved are Gbullung, Woribogu, Gun, Nyorong, Yoggu, Nyankpala-Tuunayili and Nyerishegu. These communities are mostly located in the South-Eastern part of Tolon and are all guinea worm endemic areas that have no access to potable water. The project area lies in the Lower Voltaian Sedimentary Basin. The geophysical techniques involved were the Electromagnetic (EM) survey for ground profiling with the EM 34-3 ground conductivity meter and the dipole-dipole configuration in Vertical Electrical Sounding (VES) with the Swedish ABEM SAS 300C resistivity equipment. Results show that major aquifers are confined to hard, fractured sandstone formation. No water was found for weathered zone or fresh rock aquifers. Analysis of data also revealed several thin-bedded sequences of between 4 m and 10 m thickness of sandstone, mudstone, shale, siltstone and their intercalations to be the dominant formations here. Groundwater was confined to between 25 m and 45 m with major aquifers occurring approximately between 34 m and 45 m depths. Groundwater availability to beyond 55 m was not possible. The potential success rate is estimated at 75%. The surveys show conclusively that the EM method and the dipole-dipole array in VES when combined is an effective tool for the location of groundwater in the survey area of the Tolon-Kumbungu District. It is therefore recommended that the EM method be used for the ground profiling to be followed by the dipole-dipole method for the VES.
A thesis submitted to the College of Science, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the award of Master of Science in Physics, 2004