Borehole Rehabilitation: A Case Study in the Dunkwa Mining Town

Abstract

Rehabilitation works were carried out on boreholes in the Dunkwa Mining town in the Central Region of Ghana. These works were carried out because the boreholes had lost their original yields due to clogging, corrosion and encrustation and had been abandoned for a long time. The cost of drilling a new well and assessing the productivity of the well is $4,500 which is more expensive that carrying out rehabilitation works which is cheaper, about $800. Also, the initial yields of the boreholes were very high according to the feasibility report which is not a common characteristic of the rocks in the area. Camera inspection followed by rehabilitation, pre and post pumping tests were carried out to assess whether there has been an improvement in their yield after the exercise and that the yield obtained will be adequate for a water supply design. Results show that all the boreholes had an improvement in their yields (57.19 - 259.80 %) after the rehabilitation. It can therefore be concluded that rehabilitation is effective in restoring boreholes to their original yields. Organisations drilling boreholes to communities can take advantage of rehabilitation of the existing boreholes located in the communities which are high yielding, thereby reducing project implementation cost.

Keywords: Borehole Rehabilitation, Borehole Yields, Borehole Camera Inspection, Pumping Test