ABSTRACT
Sediment in river channels is transported as wash load and bed-material load. Wash load is fine sediment (usually <0.062 mm) that is transported in permanent suspension and is not found in appreciable quantities on the bed. Bed-material load is composed of coarser bed sediment that is transported by traction and saltation as bed-load and in intermittent suspension as suspended bed-material load. The relative importance of bed-load and suspended bed-material load (herein ‘suspended-load’) in sand-bed channels affects many aspects of channel morphology, including the form of sand dunes on the bed. Dunes are ubiquitous features in sand-bed rivers and estuaries and play an integral role in the relationships between boundary layer flow structure and sediment transport (ASCE, 2002).
