African Wildlife & Environment Issue 85

CONSERVATION

water resources, has no Directorate of Reservoir Management to coordinate appropriate stewardship of our dams. The Department does not have a single qualified reservoir limnologist in its employ. Curiously, the National Aquatic Ecosystem Health Monitoring Programme neither mentions the terms ‘reservoir’ nor ‘dam’! Sadly, but certainly not inexplicably,

South Africa has 586 man-made reservoir lakes, storing approximately thirty-two billion litres of water or 66% of the Mean Annual Runoff (MAR). As much as 76% of the total storage capacity has been shown to have impaired water quality as a result of elevated nutrient levels – originating largely from the aforementioned inadequately-treated sewage effluents.

Central Hartbeespoort Dam showing extensive Salvinia coverage during July 2022 (Photograph: John Wesson)

reservoir limnology remains the Cinderella of South African aquatic sciences. So when and how did this egregious situation arise? Towards the end of the 1980s there was a noticeable decrease in both financial and human resources allocated to South African limnology, particularly in terms of the study and administration of reservoir lakes. This was partly underpinned by the Department’s startling perception that eutrophication was not a priority issue! A review of the North American literature at that time might have suggested to departmental planners, however ill-advisedly, that eutrophication was considered to be ‘resolved,’ largely through legislative initiatives and engineering solutions applied to municipal wastewater treatment. This was, however, a far cry from the reality in South Africa. At that time in the northern hemisphere, lake management emphasis was shifting to focus on exotic

There is a general consensus in South Africa that wastewater treatment is in a very dire state, with eutrophication acknowledged as the primary threat to water quality and the health of the nation’s reservoirs and, by extension its population. Cyanobacterial blooms and cyanotoxins are common, as are vast swathes of floating invasive plants such as water hyacinth. From this brief background one could assume that South Africa has a national reservoir management programme that is cohesive, well developed, and academically supported. It may, then, come as a shock to learn that South Africa has no such programme, that none of our academic institutions teach reservoir limnology as a career subject, and that the Department of Water & Sanitation (the ‘Department’), the custodian of our

28 | African Wildlife & Environment | Issue 85 (2024)