Assessment of Groundwater Potential in Ankobra River Basin

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Ankobra river basin is endowed with many rich natural resources. The mining activities in the basin and the proposed hydropower generation on the Ankobra river as well as oil discovery in the western region would lead to the establishing of new industries in the basin. These would certainly lead to potential population growth. As a result of these developments, there would be stress on surface water resources and therefore there would be demand for groundwater. A research was carried out to assess groundwater potential in the river basin as alternative source to surface water supply. Hydrogeological data was used to evaluate the groundwater storage in the basement complex, regolith. The relevant aquifer characteristics or parameters (extent of the study area, thickness of the groundwater zone in the regolith, the porosity and specific capacity of the aquifer zones) were used to compute total groundwater storage and recoverable storage. The groundwater contribution to streamflow was computed using mean monthly discharge data from the filled data and a hydrograph drawn. The baseflow was then determined from the hydrograph separation using the straight line method. The groundwater potential in the Ankobra basin is 45.82x 109m3 while the recoverable groundwater storage is 29.39x 109 m3. The baseflow computed was 13.75m/s. Investigations into groundwater chemistry with particular reference to physico-chemical parameters (quality) was analysed, the constituents fall within the acceptable limits of the Ghana Standard Board (GSB) for drinking water standard and are satisfactory for human consumption. However, Tamso, Wantenem, Gyaman, and Beyin communities exceeded the GSB's recommended values of pH (6.5-8.5) and Chloride (250mg/l) respectively for drinking water standard.  
Thesis submitted to the Department of Civil Engineering, Kwame Nkrumah University of Science and Technology in partial fulfillement of the requirement for the degree of Master of Science.