ABSTRACT
Rivers shape a high proportion of arid lands despite the fact that runoff frequency is low. Riverine landforms are as attractive as in other environments, offering low angle surfaces, accessible building aggregates and local water sources. Flood events are, however, often damaging if not devastating. Prediction is made difficult by the cellular nature of rain storms, and by the importance of factors such as in-channel transmission losses. Besides this, erosion-rates are extreme, so that material transfers even without human interference with the landscape mean significant soil losses on water catchment slopes and considerable sedimentation problems along water ways and behind impoundment structures.
