| Roodeplaat Dam | |
| Name Official: | Roodeplaat Dam |
| Dam Crosses: | Pienaars River |
| Res Name: | Roodeplaat Dam Reservoir |
| Location: | Near Pretoria, Gauteng |
| Country: | South Africa |
| Owner: | Department of Water Affairs |
| Dam Length: | 351 m |
| Dam Height: | 55 m |
| Dam Type: | A |
| Purpose: | Irrigation |
| Res Capacity Total: | 43 472 000 m3 |
| Res Catchment: | 684 km2 |
| Res Surface: | 403 ha |
| Construction Began: | 1955 |
| Opening: | 1959 |
| Coordinates: | -25.6208°N 28.3714°W |
| Location Map: | South Africa |
Roodeplaat Dam is a concrete arch dam situated in South Africa on the Pienaars River (also known along parts of its length as the Moretele River and Moreleta Spruit[1]), a tributary of the Crocodile River, which flows northwards into the Limpopo River. The dam is a warm monomictic impoundment with stable thermal stratification during the summer.[2]
Roodeplaat Dam was originally an irrigation dam, and soon became popular for recreation. Later it became an important source for Magalies Water, a state-owned water board that supplies potable water to a large area north of Pretoria.[3] The hazard potential of the dam has been ranked high.[4] [5]
Roodeplaat Dam's catchment contains a large part of the rapidly expanding municipality of Tshwane, which includes Pretoria. Two sewage treatment works feed treated effluent to the dam, resulting in highly eutrophic conditions comparable with those experienced in Hartbeespoort Dam. These conditions were already apparent in the mid-1970s[2] and have not improved.[6] Consequences of eutrophication include blooms of algae and cyanobacteria, and dense mats of water hyacinth (Eichhornia crassipes).
The Department of Water Affairs' Resource Quality Information Services directorate is housed on the banks of Roodeplaat Dam, near the wall.[7] This section is responsible for national monitoring of the surface water resources of South Africa.