Water Supply and Sanitation in South Africa - Water Resources and Water Use

Water Resources and Water Use

Water availability in South Africa varies greatly in space and time. While the West is dry with rainfall only during the summer and as low as 100mm, the East and Southeast receive rainfall throughout the year with an average of up to 1,000mm. Total annual surface runoff is estimated at 43 to 48 km3, depending on the source. However, 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 utilized 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. 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.

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 utilized. On the contrary, 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.