Orange–Fish River Tunnel
The Orange–Fish Tunnel is an irrigation tunnel in central South Africa.
For many years, large areas in the Eastern Cape experienced severe water shortages because of little rainfall in the arid Karoo. The situation was aggravated by the reduction in capacity of many of the existing dams due to heavy silt deposits.
The Orange-Fish Tunnel, together with its network of canals, weirs and balancing dams, has enabled these areas to be restored and has made the irrigation of thousands of hectares of additional land possible. The main purpose of the tunnel is to divert water from the Gariep Dam to the Eastern Cape for irrigation, household and industrial use.
It diverts water from the Orange River to the Great Fish River and the semi-arid areas of Eastern Cape province.
The inlet tower at 30°41′26″S 25°45′46″E / 30.69056°S 25.76278°E takes water from the Gariep Dam at Oviston: the name Oviston is an acronym based on the Afrikaans Oranje-VISrivier TONnel. After traversing under the Suurberg mountain plateau, it releases the water to the Teebus Spruit (tunnel outlet at 31°25′22.5″S 25°38′14″E / 31.422917°S 25.63722°E), to the Groot Brak River and onwards to the valleys of the Great Fish River and the Sundays River.
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