ORANGE RIVER PROJECT Vaal r Riet-Modder iet de Douglas Weir R Mod Douglas Catchment Jacobsdal BLOEMFONTEIN ORANGe–FISH TRANSFER TUNNEL e P ng Tierpoort South Africa Ora Riet River Marksdrift Canal Dam Caledon-Bloemfontein O r Pipeline an Orange-Riet Riet ge Canal Kalkfontein P Knellpoort Ramah Branch Dam Tienfontein N P Dam Canal Scheiding P n o Welbedacht d le Ca Dam Vanderkloof 0 50 100km Dam Orange Gariep Dam Aliwal North LOCATION Orange River Orange-Fish Catchment Tunnel The Orange–Fish transfer tunnel runs from Gariep Dam on the Orange River to Grassridge Dam located in the upper reaches of the Great Fish River. Molteno Grassridge DESCRIPTION Dam Great Fish Tarka Nqweba Dam Cradock (formerly Komandodrif Due to the severe stress the Eastern Cape underwent for many years, partly due to water shortages and exacerbated Graaf Reinet Dam Van Ryneveld’s Lake Arthur by salinisation and siltation occurring in the reservoirs, the Orange–Fish Tunnel was constructed, together with a Pass Dam) Sundays River Elandsdrift Weir network of canals, weirs and balancing dams, restoring and enabling thousands of hectares of irrigation. The Catchment Somerset East Cookhouse Tunnel Town and city Great Fish River De Mistkraal Orange–Fish Tunnel was completed in 1975 and is the key structure by which water is delivered from the Gariep River and dam Sund ays Weir Catchment S t Fish m Grea Pipeline al Dam to the Teebus Spruit and the Great Brak River and from there to the valley of the Great Fish River and the Darlington l Fish Skoenmakers Canal Sundays River valley. The tunnel has a length of 82,8 km, a diameter of 5,35 m, and maximum capacity of Canal Dam Tunnel Grahamstown 54 m3/s. An intake tower in the lake some 20 km from Gariep Dam heads the tunnel through the Suurberg plateau. Catchment boundary P Port Alfred Diversion weir n e a PORT ELIZABETH O c PURPOSE P Pump station I n d i a n The Orange–Fish Transfer Tunnel (from map produced by The purpose of the tunnel is to divert water to the Eastern Cape for irrigation, urban (including Grahamstown and ORASECOM/SA Dept of Water Affairs) Nelson Mandela Metropole) and industrial use. Due to siltation, the capacities of dams in these two river basins became greatly reduced and arable land had to be de-scheduled prior to construction of the tunnel. PHYSICAL INFORMATION Canal name Length (km) Capacity (m3/s) Orange–Fish Tunnel 83 54.