South Africans finally warned about eutrophication

4 October 2012

In something of a very rare first, the South African Department of Water Affairs has issued a statement warning about the risks associated with widespread eutrophication and toxic algal blooms.  Apparently this admission came in response to questions posed by an opposition political party (at least they are doing their job!).

Farmers Weekly reports that:

With summer ahead, the Department of Water Affairs (DWA) has warned of the high risk of excessive algal blooms and water hyacinth in a number of eutrophic and hyper-eutrophic dams. 

Algal blooms may result in the death of aquatic life due to oxygen depletion; changes in the taste, colour and odour of potable water; and filter blockages at water purification plants. It also poses a hazard to livestock and irrigation farmers. DWA minister Edna Molewa said most dams in the Crocodile West-Marico water management areas (WMAs) were eutrophic to hyper-eutrophic, including Hartbeespoort, Roodeplaat, Rietvlei, Klipvoor, Bospoort, Bon Accord and Moroka Dams. 

Others dams include Erfenis, Allenmanskraal and Koppies in the Middle Vaal WMA and Spitskop and Krugersdrift in the Lower Vaal WMA. In the Mvoti to Umzimkulu WMA, Nagle, Inanda and Shongweni Dams are listed, along with Laing, Kariver, Nahoon and Bridledrift Dams in the Mzimvubu to the Keiskamma WMA. 

Theewaterskloof Dam in the Western Cape and Loskop Dam in Mpumalanga, known to be eutrophied systems, were not included in the list, which Molewa provided in response to parliamentary questions from DA shadow minister, Gareth Morgan.

All of the dams are major supply dams and the risks they pose have been highlighted in numerous documents, posts and presentations by this author, over many years.

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