South Africa Physical informa became greatly reduced andarable landhadtobede-scheduledprior toconstruction tunnel. ofthe Nelson Mandelaetropole) tworiverbasins ofdamsinthese capacities the andindustrialuse.Duetosiltation, Grahamstown urban(including Cape forirrigation, The Eastern watertothe and tunnelistodivert purposeofthe Purpose of capacity maximum and 5,35 m, of diameter 54 m3/s. a An intake tower 82,8 km, in the of lake length some 20 kma from has Gariep tunnel Dam heads The the tunnel valley. through River the Suurberg Sundays plateau. TeebusDam tothe Great Spruitandthe Brak Riverandfrom there Great ofthe valley tothe F Orange–F network ofcanals,weirsandbalancingdams,restoring ofhectares thousands andenabling The ofirrigation. occurring andsiltation by salinisation reservoirs, inthe Orange– the F andexacerbated severeDue tothe duetowatershortages formany years,partly stress Cape underwent Eastern the Description reaches Great ofthe F The Orange–F Loca Orange–Fish Tunnel Canal name tion ish Tunnel wascompleted key in1975andisthe structure bywhichwaterisdelivered from Gariep the Orange–Fish TransferTunnel Orange RiverProjec ish transfer tunnelrunsfrom Orange GariepDamonthe RivertoGrassridge upper Damlocatedinthe ish River. tion Length (km) t 83 ish Tunnel wasconstructed, a with together Capacity (m 3 /s) 54 ish Riverandthe ORASECOM/SA DeptofWaterAffairs) The Orange–FishTransferTunnel(from mapproduced by

O 0 ra n Douglas Weir P ge Marksdrift Douglas Pump station Diversion weir Catchment boundary Tunnel Canal Pipeline River anddam Town andcity 50 N Orange River P

Catchment

Van Ryneveld’s O

r

a

Ramah Branch n (formerly Nqweba Dam g

Pass Dam) e V a

Canal a l Orange-Riet 100 R Canal ie Sundays River t km Catchment Darlington Graaf Reinet P Dam

Scheiding

S

u Jacobsdal

n

d

a Vanderkloof

y M s De Mistkraal o Riet River

Somerset East d d Dam Canal e Orange-Fish r Weir Kalkfontein Tunnel

Dam Great Fish Great

R

i

Grassridge

e t

Riet-Modder

P S Catchment

m Dam

PORT ELIZABETH a

Cradock l

l

Lake Arthur Tierpoort F

Elandsdrift Weir i

Great Fish River s

h Dam Gariep Cookhouse Tunnel Dam Catchment Skoenmakers Tarka G Komandodrif

r

Canal e

a

t Knellpoort

F Dam

BLOEMFONTEIN i

Grahamstown

s h Dam Molteno

I

n Caledon-Bloemfontein

d

Orange i Ca P a led Aliwal North Aliwal o n n Pipeline Welbedacht Port Alfred P

O Tienfontein

c Dam e a n