Water, Sewage & Effluent May-June 2017 - Page 28

Retaining walls alongside the river to prevent future erosion of the waterway. T he Hartbeesspruit Waterway runs through the Hillcrest Campus of the University of Pretoria, which is home to the LC de Villiers Sports Grounds and the High Performance Centre (HPC), a major elite sports facility in South Africa. Established in 2002, the HPC has become the preferred location for the pre-departure camps of South African national sporting teams, in addition to being selected by several international federations as their preferred specialisation centre. “Therefore, it is imperative that the waterways in the vicinity of the training facilities are managed such that flood events do not damage them or affect their use,” comments Shaun Chamberlain, function manager: dams & hydro at SMEC South Africa. The design work involved hydraulic modelling of the waterway, while the actual restoration work included construction of a new 13m-wide spillway at the original farm dam as the dam’s previous spillway had been outflanked, and re-shaping of the dam basin to encourage a diverse ecology. While restoration of the farm dam was the focus of the project, other existing erosion issues had been caused by the fast-flowing river and needed attention. These included two scour holes, each about 1.5m deep, which were repaired and filled with rip-rap to prevent further erosion and to slow the flow downstream. SMEC South Africa also designed and implemented repairs to the Loffelstein retaining walls alongside the river to prevent future erosion of the waterway, and a debris grate at 26 Water Sewage & Effluent May/June 2017