A pre-feasibility study by DWA for the Ncwabeni Off-Channel Storage Project near Port Shepstone that was completed in February 2005, identified two alternative dam sites namely the D2 site on the Ncwabeni River and the D3 site on the Gugamela River. Capital costs and the UVRs associated with the two alternatives were found to be almost identical but Site D2 was preferred from environmental and social perspectives. Selection of the preferred option would therefore largely depend on costs associated with geotechnical conditions at the dam sites
(including the possibility of a fatal flaw at D2), availability of construction materials and slope stability.