Eichhornia crassipes
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 and have not improved. Consequences of eutrophication include blooms of algae and cyanobacteria, and dense mats of water hyacinth ("Eichhornia crassipes").