<P> Much of the runoff is lost through flood spillage, so that the available surface water resources are estimated at 14 km3 / year only . Although groundwater is limited due to geologic conditions, it is extensively utilised in the rural and more arid areas . Available groundwater is estimated at 1 km3 / year . The main rivers of South Africa are fairly small compared to the large rivers of the world: For example, the discharge of the Nile River alone is about six times higher than the available surface water resources from all South African rivers together . </P> <P> The main rivers are the Orange River draining to the Atlantic Ocean, the Limpopo River, the Incomati River, the Maputo River, the Tugela River, the Olifants River (Limpopo), and the Breede River . The Incomati, Maputo, Thukela and Limpopo all drain to the Indian Ocean . South Africa's most important rivers are transboundary: The Orange River is shared with Botswana, Namibia and Lesotho, the "water tower" of Southern Africa . The Limpopo - Olifants river basin is shared with Botswana, Zimbabwe and Mozambique, which lies the furthest downstream . International commissions of all riparian countries have been set up to manage these transboundary water resources . Potential future water resources are seawater desalination or the transfer of water from the Zambezi River . </P> <P> Total annual water withdrawal was estimated at 12.5 km3 in 2000, of which about 17% was for municipal water use . In the northern parts of the country, both surface water and groundwater resources are nearly fully developed and utilised . In the well - watered southeastern regions of the country significant undeveloped and little - used resources exist . The Gauteng area around Johannesburg, which is very water scarce, receives water from various dams in the area such as the Vaal Dam and imports water from the Orange River system through the Lesotho Highlands Water Project, in particular from the Katse Dam . Cape Town receives its drinking water from an extensive system of rivers and dams, including the Berg River Dam . </P> <P> In South Africa, the town Garden Route, George faced water shortages and had decided on an IPR strategy (2009 / 2010), where final effluents from its Outeniqua WWTP are treated to a very high quality through UF and disinfection prior to being returned to the main storage facility, the Garden Route Dam, where they are combined with current raw water supplies . This initiative augments the existing supply by 10,000 m per day, approximately one third of the drinking water demand . The process configuration includes the following treatment processes: drum screen, UF, and chlorine disinfection . Provision has been made for powdered activated carbon (PAC) addition at George WTW, if required as an additional operational barrier . </P>

Where does south africa's water come from