Observing, Measuring and Modelling Sediment Transport and Bedform dynamics

Daniel Vázquez Tarrío

There are clear feedbacks and interplays between particle entrainment, sediment transport and bed structuration in natural rivers. For instance, sediment supply and the differential mobility of different grain-sizes influences the type of bedforms that emerge. Similarly, bed structures and channel morphologies influence hydraulics and sediment transport rates. Consequently, the sedimentological functioning of rivers is largely controlled by the physical processes driving sediment transport and bedform dynamics. However, there remain open questions on how sediment transport, bed structuration and macro-bedforms coevolve in rivers. In this session, we seek for contributions focusing on the measurement and quantification of sediment transport processes and bedform dynamics in rivers, focusing at the local and reach scales. Contributions that combine different methodologies (field, flume experiments, numerical modelling) and/or try to link the short-term sediment transport dynamics to the sediment records preserved through fluvial stratigraphy are particularly welcomed.

Sediment Connectivity: Advances in Research and Application

Simone Bizzi, Christopher Hackney, Andrew Wilcox

Sediment connectivity is a central concept used to understand geomorphic processes, source-to-sink sediment routing, and the sensitivity of landscapes to disturbances.  Emerging remote sensing technology and smart sensors are providing unprecedented opportunities to quantify sediment connectivity in terms of fluxes, type and provenance and to generate sediment budgets from the reach to the network scale. These improved observations inform modeling efforts, especially those at the network or basin scales, but the scarcity of sediment transport data presents persistent challenges for model validation.

The functional links between sediment connectivity, resulting river types, and associated geomorphic processes linking river channels, floodplains and hillslopes have been extensively debated in literature but mostly by qualitative evidences and arguments. Novel frameworks to assess sediment connectivity and budgets allow a more detailed quantification of these functional links and open up the possibility to measure landscape/river sensitivity to changes in water and sediment fluxes. Indeed, the concept of sediment connectivity increasingly represents an essential ingredient to guide modern river basin management. 

This session welcomes contributions addressing any aspect of sediment budgeting or connectivity, in particular: i) sediment connectivity models at basin or network scale and their validation; ii) sediment budgeting techniques; iii) exploring links between sediment connectivity and landscape geomorphic processes; iv) examples where sediment connectivity understanding supports river and landscape management