Orange River

Tributary system

The upper Orange River is fed by numerous tributaries that originate in the highlands of Lesotho and South Africa. Among the principal upper tributaries are the Caledon River, Little Caledon River, Kraai River, Kornetspruit, and Senqunyane River, many of which drain the Maloti Mountains before joining the main channel.

These tributaries provide much of the Orange River's annual discharge because the highest precipitation in the basin occurs over the mountainous catchments of Lesotho. Snowfall and seasonal rainfall contribute significantly to streamflow during the austral summer.

Several upper tributaries are regulated by reservoirs associated with the Lesotho Highlands Water Project, which supplies water to South Africa while generating hydroelectric power for Lesotho.

Dams

• Armenia Dam
• Egmont Dam
• Gariep Dam
• Newberry Dam
• Vanderkloof Dam
• Welbedacht Dam
• Knellport Dam
• Kalkfontein Dam
• Teirpoort Dam
• Mohale Dam
• Katse Dam
• Rustfontein Dam

History

Etymology

Some of the earliest precolonial inhabitants called the river ǂNūǃarib, referring to its black colour, or sometimes just Kai !Arib ("Great River"), from which is derived the Afrikaans version Gariep, and translation "Groote Rivier". The early Dutch name for the river was just that translation, Groote Rivier, meaning "Great River". The river was named the Orange River by Colonel Robert Gordon, commander of the United East India Company (VOC) garrison at Cape Town, on a trip to the interior in 1779. Gordon named the river in honor of William V of Orange. A popular but incorrect belief is that the river was named after the supposedly orange color of its water, as opposed to the color of its tributary, the Vaal River, which name is derived from the name ǀHaiǃarib "pale river" (vaal being Afrikaans for pale or grey). Since the end of apartheid, the name "Gariep" has had greater favor in official correspondence in South Africa, although the name "Orange" has greater international recognition. In Lesotho, where the river rises, it is known as the Senqu River, derived from the original Khoemana name.

The Eastern Cape Geographical Names Committee has advertised its intention to consider a name change from the colonial name, for that portion of the river that forms the border between the Eastern Cape and the Free State, with suggestions being IGqili or Senqu. The advertisement placed in the Aliwal Weekblad newspaper states that the "present name is perceived to have a strong association with the history of colonial subjugation and has therefore no place under the current democratic dispensation."

The Grootslang

In South African folklore, the Orange River is often associated with the Grootslang, a mythical being resembling a giant serpent, which is often connected to the river's alluvial diamonds. The Grootslang is described as living in a gem-filled cave connected to the Orange River by a natural pipe through which the diamonds gradually enter the river. Other sites said to be lairs of the creature include the pool beneath the King George Cataract at Aughrabies Falls, which is also said to be a source of diamonds, and a large rock in the middle of the river itself. In this version of the legend, the Grootslang is also said to prey on cattle from the river's banks.

Economy

As the primary source of water for the majority of South Africa, the Orange River plays a crucial role in supporting agriculture, industry, and mining. To assist in this, two large water schemes have been created, the Orange River Project and the Lesotho Highlands Water Project. Historically, the river played an important role in the South African diamond rush, with the first diamonds in the country being discovered in alluvial deposits on the Orange. Today, commercial diamond mines operate along the final stretch of the Orange River and around its mouth, while oil and gas prospecting rights and permits have been granted to several companies.

Because of the lack of dangerous animals and high water levels during summer, the river is used for recreational canoeing and rafting. Orange River rafting has become very popular with many companies using their camps along the river from which to operate. The most popular trips are four-day and six-day river trips that take place either along the gorge below the Augrabies Falls or along the Richtersveld area.

Orange River Project

The Orange River Project (ORP) was one of the largest and most imaginative projects of its kind in South Africa. It was constructed by Hendrik Verwoerd's government at the height of the apartheid era. The ORP was built to exploit the waters of the Orange River—which, without the Vaal River, represents some 14.1% of the total runoff in South Africa—and in the process, to satisfy an increasing demand for water. The main objectives of the project were:

• to stabilise river flow,
• the generation and transmission of hydroelectric power,
• to provide a reliable water supply for users in the Orange River basin, and
• to give a new lease on life to water-deficient areas in the Eastern Cape, such as the Great Fish and Sundays River valleys.

The Gariep Dam near Colesberg is the main storage structure within the Orange River. From here, the water is supplied in two directions, westward along the Orange River (via hydroelectric power generators) to the Vanderkloof Dam and southward through the Orange-Fish Tunnel to the Eastern Cape.

Hydroelectricity

Eskom operates hydroelectric power stations at both the Gariep Dam and the Vanderkloof Dam. The hydroelectric power station at the Vanderkloof Dam was the first power-generation station in South Africa situated entirely underground. The towns Oviston and Oranjekrag were established to facilitate the construction and operation of the new infrastructure.

Irrigation

Irrigation in the vast area downstream of the Vanderkloof Dam, which has turned thousands of hectares of arid veld into highly productive agricultural land, was made possible by the construction of the Gariep and Vanderkloof Dams. Old established irrigation schemes such as those at Buchuberg, Upington, Kakamas, and Vioolsdrif have also benefitted because regulation of the flow is now possible. On the Namibian side of the river, Aussenkehr produces grapes with the help of water from the Orange.

In recent years, the wine-producing areas along the Orange River have grown in importance. Irrigation in the Eastern Cape has also received a tremendous boost, not only from the additional water being made available, but also owing to improvement in water quality. Without this improvement, the citrus farmers along the Lower Sundays River would almost certainly have continued to suffer losses of productivity.

Lesotho Highlands Water Project

The Lesotho Highlands Water Project was conceived to supplement the water supply in the Vaal River System. Water is delivered to South Africa by means of the delivery tunnel which passes under the Lesotho South Africa border at the Caledon River, and then under the Little Caledon River south of Clarens in the Free State, and discharges into the Ash River about 30 kilometres (19 mi) further to the north. The scheme became viable when water demands in Gauteng reached levels that could no longer be supported economically by alternative schemes such as the Tugela River-Vaal River pumped storage scheme, which used the Sterkfontein Dam, located near Harrismith in the Free State.

Alluvial diamonds

In 1867, the first diamond discovered in South Africa, the Eureka Diamond, was found near Hopetown on the Orange River. Two years later, a much larger diamond known as the Star of South Africa was found in the same area, causing a diamond rush. This was soon eclipsed by the diamond rush to mine diamonds directly from kimberlite at Kimberley in 1871, although alluvial diamonds continued to be found in the Orange. Today, several commercial diamond mines operate on the last stretch of the river, as well as the beaches around its mouth. Diamond mines also operate on the middle stretch of the river.

Rafting and canoeing

During the temperate months of March and April, given good rains and the sluices of the dams being open, a canoeist (or rafter) can easily travel 30 kilometres (19 mi) per day. The lower reaches of the river are most popular, because of the spectacular topography. Commercial tours are available, and these expeditions depart from the border town of Vioolsdrif.

Wildlife

The Orange River has no large animals. It lies outside the range of the Nile crocodile, and although hippopotami were once abundant, they were hunted to extermination in the 19th century. The Orange River has a relative paucity of species diversity. Surveys from 1995 to 2001 in the Lower Orange River found 19 different fish species from eight different families. The two non-native species recorded in the surveys were Cyprinus carpio and Oreochromis mossambicus, the latter of which had increased rapidly in abundance since the early 1980s. Another exotic species, rainbow trout, is found in the river headwaters in Lesotho.

Seven species are endemic to the Vaal-Orange River system:

• Rock-catfish (Austroglanis sclateri)
• Maluti redfin or Maloti minnow (Pseudobarbus quathlambae)
• Namaquab barb (Barbus hospes)
• River sardine (Mesobola brevianalis)
• Smallmouth yellowfish (Labeobarbus aeneus)
• Largemouth yellowfish (Labeobarbus kimberlyensis)
• Orange River Mudfish (Labeo capensis)