Abstract EN:

8 major inter bassin tranfers (IBT) have transformed the Orange River into a "Plumbing system". This thesis shows that theses IBTs have been built mainly for political and geopolitical reasons during the Apartheid era. But there was no general planning and each project was discussed at the highest political level. These IBT have been highly criticised for the damages they cause on the river ecology. But the river was far to be in a pristine state when they were built in the 1970s : significant modifications in the river channel have been taking place at a local level, especially in the irrigated areas of the middle reaches. The central hypothesis of this thesis is that of IBT cannot be properly understood without considering their interaction with the environmental impacts of small weirs, levees and canals. It is also absolutely necessary to understand the regional settings in order to judge the spatial effects of IBTs. With the dismissal of apartheid in 1994, IBTs seem to be doomed. But il could be very difficult for the ANC government to buillt a new Orange river, combining environmental protection and economic development, without framing a inventive mangement strategy for IBTs.