Reviev of the Hartbeespoort Dam integrated biological remediation programme (Harties Metsi a me)

The purpose of this review is to assess Phase 1 of the Hartbeespoort Dam Integrated Biological Remediation Programme (HDRP) and to make recommendations for the future Phase II of the programme. The review benchmarks the HDRP against selected national and international benchmarks which are introduced as appropriate through the document. Hartbeespoort Dam is the hub of the economy in the area, supporting irrigation and mining as well as substantial residential and recreational developments around the Dam. The most important ecosystem service is the provisioning of water, through the storage that the Dam provides. The Dam further plays an important water regulation role. It is common cause that it has a waste assimilation role, as it traps nutrient pollution. A number of ancillary benefits exist, these include fishing for food, habitat for species, and a range of cultural services that include tourism, recreation and aesthetic services. As with other impoundments downstream from the Gauteng conurbation the dam has become highly eutrophic. Of great concern is the challenge of managing the effluent from the Gauteng. The institutional environment governing the management of effluents is complex and spread across different government structures. This, combined with the expense and difficulty of treating the effluents to a standard that will not impact the receiving environment, is one factor that has led to widespread eutrophication in the impoundments on the rivers draining Gauteng. Harding (2010) estimates conservatively that 35% of South Africa’s impounded water resources are seriously impaired (eutrophic to hypertrophic); a further 20-30% are incipiently problematical. All of the major impoundments in the economic heartland of the country, Gauteng, are grossly impaired. The full extent of the problem is unknown as no systematic comprehensive spatial surveys have been conducted. Matthews (2014) found that 62% of South Africa’s largest dams were highly nutrient enriched. The HDRP was designed to give effect to the recommendations made by the various research initiatives in order to reverse the trend of increasing eutrophication in the impoundment. The intention was, then, to repeat successful initiatives in other eutrophic impoundments and to investigate and implement, if suitable, additional remedial interventions.