# Gariep Dam

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.

## Name

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 (the longest river in South Africa).

## Location

The dam is on the Orange River about 48 kilometres (30 mi) north-east of Colesberg and 208 kilometres (129 mi) south of Bloemfontein. It is in a gorge at the entrance to the Ruigte Valley some 5 kilometres (3.1 mi) east of Norvalspont. The dam crest is some 1300 m (4250 ft) above sea level.

## Dimensions

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 5,340,000 megalitres (5,340 hm$^3$) and a surface area of more than 370 square kilometres (140 sq mi) when full. The hydro-electrical power station houses four 90 MW generators.

## Design type and contractors

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.

## Rivers and spruits flowing into the dam

* Orange River
* Caledon River
* Brakspruit
* Broekspruit
* Oudagspruit
* Palmietspruit
* Slykspruit

## Water consumption, outflow, derivative usages and diversions

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.

### Orange–Fish Water Scheme

The scheme diverts water from the Orange River to the Great Fish River valley.
* Great Fish River Valley, then via Grassridge Dam, ElandsDrift Wier, Cookhouse Tunnel, De MistKraal Weir into
* Sundays River Valley (Canals and Tunnels Scheme) North-West of Port Elizabeth, then via Darlington Dam, Korhaansdrift Weir, Canal, Scheepersvlakte Balancing Dam, Bulk water Pipeline to
* Port Elizabeth, Nooitgedracht Water Treatment Works, since 1992 with water from the Sundays River Valley (See External links for more video documentaries on construction and drone footage for canal system.)

### Orange-Fish River Tunnel

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.

### Gariep hydroelectric power plant

A 360 MW hydroelectric power plant is one is run by Eskom. Four 90 MW hydro turbines (which are remotely controlled from Gauteng)

## Gallery

* Gariep Dam overflowing in January 2011
* Sunset at Oviston Nature Reserve on the dam's southern shores
* Road sign heading for the dam wall
* View over the lake
* Forever Holiday Resort at Gariep Dam