CHANGES IN URBAN RESIDENTIAL LAND IN THE RIETSPRUIT CATCHMENT, SOUTHERN TRANSVAAL

Abstract

Informal settlements have become an important and rapidly-expanding component of urban development in South Africa. In the Rietspruit catchment, south-west of Johannesburg, average growth rates in urban land cover of up to 2.7 km² per year (1972–1991) were measured from satellite images. Aerial photographs show that in 1991 more than a third of the residential land consisted of informal housing. Elevated concentrations of dissolved nitrogen, phosphorus and faecal coliforms in the Rietspruit point to a possible eutrophication and health risk.