The rainwater that was trapped and channelled by the hill at Tsabong has, for thousands of years, been a renowned source of 'sweet' water in an area otherwise plagued with few and brackish water sources. It has allowed humans, their livestock and wildlife to survive in the arid Kalahari of southwestern Botswana.

Pits have been dug for hundreds, perhaps thousands of years, prolonging the presence of water well into the dry season. In more recent times, these and other watering points have become foci around which settlements have developed.

This has made the water less accessible to wildlife and the area around the pans denuded and degraded from overgrazing, remobilising previously vegetated, stable dunes.



Inappropriate management of the Orange–Senqu's catchment has resulted in erosion in Lesotho's sensitive rangelands contributing high sediment loads to the river system. At Mount Moorosi, stone walls are built by community volunteers to stop further erosion and rehabilitate rangelands above the Senqu River.

Mamasako Lesotsa volunteers her labour three days a week to fight soil erosion, clear invasive bushes and plant seeds of indigenous, nutritious grass on common lands where she is one of many villagers who graze their livestock.



Forty years ago, Prosopis was introduced to areas of Namibia and South Africa as a fodder plant. However, it proved to be aggressively invasive in the drier, western areas of the Orange–Senqu River basin, outcompeting indigenous riparian vegetation, and impeding surface flow and groundwater recharge.

Prosopis is, however, a potentially valuable source of wood. Henk Kempen, who lives in Leonardville on the Black Nossob River, recognised that this pest could be turned into a profit and create much-needed employment, while addressing the environmental problems it causes. A small grant provided seed funding for community involvement and job creation through felling trees for charcoal, wood and construction timber.

Burning or treating the stumps of felled trees ensures, that they do not re-grow or coppice. Currently, his business keeps between 17 and 22 people employed and recently supplied wood used to reconstruct Swakopmund's historical jetty.

South Africa


Of all water demand on the Orange–Senqu system in 2010, about 93% came from South Africa, of which 70% was from the irrigation sector. Historically and currently, the Orange–Senqu and its tributary Vaal system has provided the source of water, minerals and energy on which economic development has been based.

Water supply required to meet demands of the Witwatersrand economic hub and those of large-scale irrigation schemes further downstream has been assured through the construction of numerous dams and a series of transfer schemes, mostly on the upper Orange–Senqu and Vaal river systems. It is consequently regarded as the most developed river system in southern Africa.