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), a tributary of the Crocodile River, which flows northwards into the

Limpopo River The Limpopo River rises in South Africa and flows generally eastward through Mozambique to the Indian Ocean. The term Limpopo is derived from Rivombo (Livombo/Lebombo), a group of Tsonga settlers led by Hosi Rivombo who settled in the mount ...

. The dam is a warm monomictic impoundment with stable thermal stratification during the summer.Walmsley RD, Toerien DF, Steyn DJ. An Introduction to the Limnology of Roodeplaat Dam. Journal of the Limnological Society of South Africa. 1978;4(1):35–52.

Use

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. The hazard potential of the dam has been ranked high.

Water quality

Roodeplaat Dam's catchment contains a large part of the rapidly expanding : municipality of

Tshwane The City of Tshwane Metropolitan Municipality (also known as the City of Tshwane) () is the metropolitan municipality that forms the local government of northern Gauteng Province, South Africa. The Metropolitan area is centred on the city of P ...

, which includes

Pretoria Pretoria () is South Africa's administrative capital, serving as the seat of the executive branch of government, and as the host to all foreign embassies to South Africa. Pretoria straddles the Apies River and extends eastward into the foot ...

. Two sewage treatment works feed treated effluent to the dam, resulting in highly

eutrophic Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytoplank ...

conditions comparable with those experienced in

Hartbeespoort Dam Hartbeespoort Dam (also known as ''Harties'') is an arch type dam situated in the North West Province of South Africa. It lies in a valley to the south of the Magaliesberg mountain range and north of the Witwatersberg mountain range, about 35 ki ...

. These conditions were already apparent in the mid-1970s and have not improved. Consequences of eutrophication include blooms of

algae Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from ...

and cyanobacteria, and dense mats of

water hyacinth ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range.Eichhornia crassipes ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range.List of dams and reservoirs in South Africa A ''list'' is any set of items in a row. List or lists may also refer to: People * List (surname) Organizations * List College, an undergraduate division of the Jewish Theological Seminary of America * SC Germania List, German rugby union ...

References

{{reflist Crocodile River (Limpopo) Dams in South Africa Dams completed in 1959