Sediment transport and channel morphology in mountain rivers
Fluvial morphodynamics are characterized by the coupling between sediment supply, storage, and transport, as well as between flow resistance and bed morphology. However, the relationships between these characteristics vary across fluvial landscapes. Specifically in steep channels, the threshold for motion has been shown to change significantly in space and time, and possibly with slope, and observed sediment transport rates are lower than predicted based on classic equations developed for lowland channels. Macro-roughness elements including large-wood structures complicate estimates of flow resistance and boundary shear stress, and hillslope-channel coupling adds to system disorder. The poor performance of traditional sediment transport approaches consequently limits the utility of channel evolution models to predict the morphology of steep mountain rivers – the lower boundary control of mountainous terrain evolution.
This session welcomes field, experimental, theoretical, and modelling efforts aimed at improving (1) our understanding of the morphodynamics of mountain river channels, as well as (2) predictive models for sediment transport in mountainous channels. In addition, we welcome studies spanning a range of spatial scales, from the grain to landscape scale.