| Gariep Dam | |
| Location Map: | South Africa |
| Name Official: | Gariep Dam |
| Dam Crosses: | Orange River |
| Res Name: | Gariep Dam Reservoir |
| Location: | Border of Eastern Cape and Free State, South Africa |
| Owner: | Department of Water Affairs |
| Dam Length: | 914m (2,999feet) |
| Dam Height: | 88m (289feet) |
| Dam Type: | AG |
| Construction Began: | 1965 |
| Opening: | 1971 |
| Res Capacity Total: | 5340000ML[1] |
| Res Surface: | 374km2 |
| Plant Operator: | Eskom |
| Plant Turbines: | 4 x 90MW |
| Plant Capacity: | 360MW (max) |
| Plant Annual Gen: | 889GWh[2] |
| Coordinates: | -30.6237°N 25.5066°W |
The Gariep Dam is located in South Africa, near the town of Norvalspont, bordering the Free State and Eastern Cape provinces. Its primary purpose is for irrigation, domestic and industrial use as well as for power generation. It the largest dam in South Africa.
The Gariep Dam, at its commission in 1971, was originally named the Hendrik Verwoerd Dam after Hendrik Verwoerd, the Prime Minister before and after 31 May 1961, when the country changed from the Union of South Africa to the Republic of South Africa. However, after the end of apartheid, the Verwoerd name was considered unsuitable. The name was officially changed to Gariep Dam on 4 October 1996. Gariep is Khoekhoe for "river", the original name of the Orange River.[3]
The dam is on the Orange River about north-east of Colesberg and south of Bloemfontein. It is in a gorge at the entrance to the Ruigte Valley some east of Norvalspont. The dam crest is some 1300 m (4250 ft) above sea level.
The wall is 88 m high and has a crest length of 914 m and contains approximately 1.73 million m³ of concrete. The Gariep Dam is the largest storage reservoir in South Africa. In South African English, 'dam' refers both to the structure and the water volume it retains. Gariep Dam has a total storage capacity of approximately 5340000ML and a surface area of more than when full. The hydro-electrical power station houses four 90 MW generators.
The structure is a concrete gravity-arch hybrid dam. This design was chosen as the gorge is too wide for a complete arch so flanking walls form gravity abutments to the central arch.
It was built by Dumez, a French construction company.
| Gariep Dam bridge | |
| Carries: | 14300 tons |
| Width: | Doubleway |
| Toll: | None |
It must be carefully managed by balancing the supply-and-demand of this water resource usage for its derivatives of electricity generation, irrigation(food) and municipal drinking water. There is trade off in the water usage for electricity and inter-basin transfer for water in other areas like Port Elizabeth.
The scheme diverts water from the Orange River to the Great Fish River valley.[5] [6]
At Oviston, on the south bank of the reservoir, is the inlet of the Orange-Fish River Tunnel, allowing water to be diverted to the Great Fish River and most of the Eastern Cape's western parts.
A 360 MW hydroelectric power plant is one is run by Eskom. Four 90 MW hydro turbines (which are remotely controlled from Gauteng)[11]