Improving the quality of raw water supply to Potchefstroom / E. Le Roux

• Main Author: Le Roux, Ebenhaezer
• Published: North-West University 2009
• Online Access: http://hdl.handle.net/10394/790

Water management challenges in the Mooi River catchment are becoming increasingly complex due to an increase in the demand of water users combined with the current and historic negligent pollution of water. In this regard, the illegal discharge of effluent by major water users, especially the gold mines, is the most prominent. A clear demonstration of the growing complexity and urgency of the situation in the Mooi River catchment, is the existing Memorandum of Understanding (MOU) between the Gauteng regional office of the Department of Water Affairs and Forestry (DWAF) and the Potchefstroom Local Municipality. This MOU calls for inter aha the following: integrated monitoring of the Wonderfontein Spruit and Mooi River catchments and the commencement of a risk assessment to users downstream of the Wonderfontein Spruit. The Potchefstroom Local Municipality is currently reliant on the Mooi River as its sole source of raw water for the supply of drinking water to its citizens. Unfortunately, water quality in the Mooi River catchment is impacted on by water from its Wonderfontein Spruit tributary, primarily due to constant pollution by goldmining industries and associated abandoned infrastructures and deposits in the Wonderfontein Spruit region. The discharge of polluted underground mine water within the Wonderfontein Spruit catchment, combined with the underground flooding of some abandoned mines, has resulted in the pollution of both the surface water of the downstream river system, as well as the underlying dolomitic water resources, adversely affecting the beneficial use of water in the Mooi River catchment. The following reasons enhance the complexity of the abovementioned situation even further, as it minimises the chances of successful remediation and restoration: 1) not only has it been demonstrated that there is interaction between the surface streams of the Wonderfontein Spruit and its associated dolomitic ground water compartments; 2) but it has also been demonstrated that the sediments of the Wonderfontein Spruit tributary and its downstream dams are continually enriched with heavy metals and radionuclides, which could be released into the downstream water under certain uncontrollable circumstances, resulting in a significant deterioration in the water quality of all downstream users, including the City of Potchefstroom. This study therefore questions the sustainability of the current situation, and recognises its vulnerability and possible health risk. This study supports the need to take action in line with the precautionary principle of the National Environmental Management Act, No 107 of 1998, which advocates that a "risk-averse and precautionary approach" be followed. The feasibility of the following alternative solution is considered: Diverting the Wonderfontein Spruit towards an area downstream of the Potchefstroom raw water abstraction points in order to ensure an improved raw water quality supply for Potchefstroom. The feasibility study of the diversion is concluded in section 5, and comes to the following preliminary conclusion: The Wonderfontein Spruit diversion would indeed be a feasible option to be considered for improving the raw water quality of Potchefstroom, due to the following reasons: The proposed diversion will improve the current situation by minimising the contamination potential of the Potchefstroom raw water by the Wonderfontein Spruit at Turffontein; and improve on the current raw water quality available to Potchefstroom; and minimise the potential health risk of the current situation, as has been considered by previous studies (see section 1); and provide a feasible alternative water use (namely agriculture) for the diverted water from the Wonderfontein Spruit at Turffontein. However, the study also notes that the following factors also have to be taken into consideration, as they might have an influence on the feasibility of the abovementioned proposal, despite the abovementioned water quality advantages: As the diversion would influence water-availability, water availability should also be taken into consideration: the study recommends that a water-needs assessment be conducted, in order to contemplate on the feasibility of dedicating the Klerkskraal Dam as a water resource exclusively for Potchefstroom. The current lack of monitoring data on key water quality parameters of the Wonderfontein Spruit at Turffontein, were also regarded as a priority to be addressed, as the outcome of such monitoring data could influence the feasibility of the abovementioned proposal for agricultural purposes, and also the sustainability of the current situation. Alternatives to this solution are briefly described in Addendum 5 of this study. These alternatives basically consider the following: leaving the current situation as it is (the "No Go" option); utilising supplementary water (for example Rand Water or dolomitic water); or dedicating the Klerkskraal Dam as the sole raw water resource for Potchefstroom. Various other recommendations were made, and are listed in Section 6 of this study === Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2005.