A drainage basin is an extent of land where water from rain and melting snow or ice drains downhill into a body of water, such as a river, lake, reservoir, estuary, wetland, sea or ocean. The drainage basin includes both the streams and rivers that convey the water as well as the land surfaces from which water drains into those channels, and is separated from adjacent basins by a drainage divide.

The drainage basin acts like a funnel, collecting all the water within the area covered by the basin and channelling it into a waterway. Each drainage basin is separated topographically from adjacent basins by a geographical barrier such as a ridge, hill or mountain, which is known as a water divide.

Other terms that are used to describe a drainage basin are catchment, catchment area, catchment basin, drainage area, river basin, water basin and watershed.

The drainage basins in South Africa do not correspond with the Water Management Areas, and have the letters A, B, C, D, E, F, G, H, J, K, L, M, N, P, Q, R, S, T, U, V, W, and X. The Area A comes close to the same area that the Limpopo WMA seems to cover. Apart from these letters they seem to have no name referring to them. What seems to be the case though is that each area refers to some major river systems and their tributaries (a region for each major river system).

List of drainage basins

Code[A]NameArea km2Gross capacity x103m3Nr. regionsMajor riversDrains toNotes
A1,2849Limpopo RiverIndian Ocean[B]
B1,5029Olifants RiverLimpopo River
C7,9419Vaal RiverOrange River[C][D]
D11,1058Orange River (below Gariep Dam), Kraai RiverSouth Atlantic
E1284Olifants River (above confluence with the Doring River), Groot RiverSouth Atlantic
F6Buffels RiverSouth Atlantic
G4455Berg River, Diep River, Eerste River, Verlorevlei River, Bot River, Klein River, Uilkraal RiverSouth Atlantic
H1,0249Hex River, Kingna River, Breede River (below Brandvlei Dam), Tributaries of the Sonderend River above theewaterskloof DamIndian Ocean
J2004Touws River, Gamka River, Olifants River, Langtou River, Weyers River
K1839Little Brak River, Great Brak River, Karatara River, Knysna River, Keurbooms River, Bloukrans River, Lottering River, Storms River, Sandrif River, Groot River, Tsitsikamma River, Klippedrift River, Kromme River, Seekoei River, Kabelkous RiverIndian Ocean
L2199Baviaanskloof River, Kouga River, Lower Gamtoos River
M123Swartkops River, Maitland River, Van Stadens RiverIndian Ocean
N2274Sundays River (below Darlington Dam, and above Vanrynevelds Pass Dam), Skoenmakers River (below Skoenmakers Canal Outlet), Gats RiverIndian Ocean[D]
P4Bushmans River, Kowie River, Kariega RiverIndian Ocean
Q1319Great Fish River, Little Fish River, Tarka River, Vlekpoort River, Lake ArthurIndian Ocean[D]
R2115Buffels River, Kwenxura River, Kwelera River, Gonubie River, Nahoon River
S6107White Kei River (above Xonxa Dam), Indwe River (above Lubisi Dam), Swart Kei River (above Klipplaat River confluence), Klipplaat River (above Waterdown Dam), Oxkraal River (above Oxkraal Dam), Thorn River, Thomas River, Tsomo River, Kwa-Qokwama River, Mbokotwa River, Kubisi River (above Wriggleswade Dam), Toise River, Xilinxa River (above Xilinxa Dam)
T2489Slang River, Xuka River, Mtata River (above Mtata Dam), Tsitsa River, Pot River, Mooi River, Inxu River, Wildebees River, Gatberg RiverIndian Ocean
U8068Mgeni River, Mvoti RiverIndian Ocean
V1,1107Tugela River, Mooi River, Sundays River, Bushmans RiverIndian Ocean[B]
W3,2837Umfolozi River, White Umfolozi River, Black Umfolozi River, Pongola River, Mkuze RiverIndian Ocean
X1,0494Nkomati River , Crocodile River

See also

References

  1. ↑ "Drought impact mitigation and prevention in the Limpopo River Basin". Natural Resources Management and Environment Department. Retrieved 6 February 2010.
  2. ↑ "Thukela Water Project --> Background". Department of Water Affairs (South Africa). Retrieved 6 February 2010.
  3. ↑ "FISH-SUNDAYS TRANSFER SCHEME". Department of Water Affairs (South Africa). Retrieved 6 February 2010.
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