Grootdraai Dam is a combined gravity and earth-fill type dam located on the

Vaal River The Vaal River ( ; Khoemana: ) is the largest tributary of the Orange River in South Africa. The river has its source near Breyten in Mpumalanga province, east of Johannesburg and about north of Ermelo and only about from the Indian Ocean. ...

, near Standerton,

Mpumalanga Mpumalanga () is a province of South Africa. The name means "East", or literally "The Place Where the Sun Rises" in the Swazi, Xhosa, Ndebele and Zulu languages. Mpumalanga lies in eastern South Africa, bordering Eswatini and Mozambique. It ...

, South Africa. It was established in 1981.

Background

Grootdraai Dam is a composite structure comprising a central concrete gravity section 360 m long and two earthfill flanks giving a total crest length of 2180 m and a maximum wall height of 42 m above lowest foundation level. The dam was completed in 1982 and was built primarily to support the water needs of the

SASOL Sasol Limited is an integrated energy and chemical company based in Sandton, South Africa. The company was formed in 1950 in Sasolburg, South Africa and built on processes that were first developed by German chemists and engineers in the early ...

I, II and III coal to petrol plants at Secunda, Eskom's

Tutuka Power Station Tutuka Power Station in Mpumalanga, South Africa, is a coal-fired power plant operated by Eskom. It is a twin sister to Duvha Power Station. History The first unit at Tutuka was commissioned in June 1985 and the last went online in June 1990. ...

as well as the

Matla Power Station Matla Power Station in Mpumalanga, South Africa, is a coal-fired power plant operated by Eskom and consuming the output from the Matla coal mine. History Construction started in 1974, and the last unit was commissioned in July 1983. In 1981 ...

Duvha Power Station Duvha Power Station in Mpumalanga, South Africa, is a coal-fired power plant operated by Eskom. The tall chimneys at Duvha are the second and third tallest structures in Africa, only a chimney located at the Secunda CTL plant is taller. History ...

Kendal Power Station Kendal Power Station is a coal-fired power station in Mpumalanga, South Africa. It is sited in a coal-mining area; one of its sources is AEMFC's coal mine at Vlakfontein, near Ogies. History Design Kendal was built between 1982 and 1993. The fi ...

and

Kriel Power Station Kriel Power Station in Mpumalanga, South Africa, is a coal-fired power plant operated by Eskom. It is located about 4 km from Matla Power Station just outside the town of Kriel (Emalahleni Local Municipality, Mpumalanga Emalahleni Local M ...

located on the coal fields in the adjacent Olifants River basin. The dam also provides some flood attenuation for Standerton and stores up to 100 million m³/annum pumped into the upper reaches of the Vaal River basin from Heyshope Dam in the Usutu River basin. The hazard potential of the entire dam construction has been ranked high (3). During the serious drought of 1983, the water resources in the adjacent

Komati River The Komati River, also known as the Inkomati River or Incomati River (in Mozambique, from Portuguese Rio Incomati), is a river in South Africa, Eswatini and Mozambique. Originating in north-western Eswatini, it is joined by the Crocodile Rive ...

and Usutu River basins were badly depleted, leading to serious concerns that the water supplies to various power stations could be affected. Any water shortages to the power stations would be disastrous for South Africa since 80% of the country's electricity is dependent on water from the Komati-Usutu-Vaal system. It was estimated that the newly completed (1982) Grootdraai Dam would empty within a matter of months and an emergency scheme was therefore initiated to pump water upstream over a distance of 202 km to Grootdraai Dam from

Vaal Dam The Vaal Dam in South Africa was constructed in 1938 and lies 77 km south of OR Tambo International Airport. The lake behind the dam wall has a surface area of about and is 47 meters deep. The Vaal Dam lies on the Vaal River, which is one ...

. The emergency scheme involved constructing 7 weirs, each with numerous pumps capable of pumping a total of 1 million m³/day. Although the emergency scheme was never used, it was completed and received an award for the Most Outstanding Civil Engineering Achievement of 1983 from the South African Institute of Civil Engineers.

References

{{reflist
List of South African Dams
from the Department of Water Affairs Dams in South Africa Dams completed in 1981 Buildings and structures in Mpumalanga

Background

See also

References