ABSTRACT
This chapter provides background to the fluvial response to more recent environmental change. Geomorphic research on response to floods in southern Africa points to fluvial systems that undergo cyclical changes, responding to drought and flood cycles that not only affect sediment dynamics and channel morphology but also the riparian vegetation that has its own geomorphic effects. Sediment routing from the hillslopes to the channel, and along the channel, has become more efficient, changing colluvial and alluvial buffers into transfer zones of sediment and water. The examples of environmental change demonstrate how human impact results in degradation of the fluvial system through catchment erosion, changing flows or direct impacts on the channel and riparian zone. Future environmental change is likely to impact southern African fluvial systems in a number of ways. Future scenarios can be both negative and positive depending largely on the capacity to implement sound environmental policies.
