Sediment Transport and Channel Morphology: Implications for Fish Habitat

This chapter reviews the basic principles of sediment transport in streams, channel classification, mountain channel morphology, and associated implications for fish spawning habitats. Local sediment transport processes construct the differing channel morphologies, which are often opportunistically used by spawning fish. Sediment load in streams can be transported in various ways. Dissolved load corresponds to material transported in solution with the fluid, whose concentration depends primarily on the geochemical character of basin geologic materials, and the dissolution of these materials by groundwater flow. Sediment sources in river basins can be distinguished as two types for timescales ranging from individual floods to many flood seasons. Sediment resting on the streambed will move, or become entrained, when the overlying fluid pressure, or shear stress, exceeds some threshold value. Lumped empirical or semi-empirical expressions have been widely used to compute bedload transport rates. Sediment transport and channel morphology are important components of physical habitat for aquatic biota in rivers.