Roodeplaat Dam is a concrete arch dam situated in South Africa on the

Pienaars River The Pienaars River is a river in South Africa. It is a tributary of the Crocodile River. A short section of this river is known as the Moretele River (i.e. approximately 20 km section between Haakdoornbult and the Klipvoor Dam). Tributarie ...

(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 mountaino ...

. The dam is a warm

monomictic Monomictic lakes are holomictic lakes that mix from top to bottom during one mixing period each year. Monomictic lakes may be subdivided into cold and warm types. Cold monomictic lakes Cold monomictic lakes are lakes that are covered by ice throu ...

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 Pr ...

, which includes

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

. 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 kil ...

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

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...

and

cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...

, 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 species, invasive outside its native range ...

''). The Department of Water Affairs' Resource Quality Information Services directorate is housed on the banks of Roodeplaat Dam, near the wall. This section is responsible for national monitoring of the surface water resources of South Africa. File:Roodeplaat Dam Water Hyacinth from watertower DSCN4904.JPG, File:Roodeplaat Dam-Water Hyacinths-02.jpg,

References

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

Use

Water quality

See also

References