Fluvial systems cover much of the Earth’s surface; they convey water, sediments, and essential nutrients from the uplands to the sea, intermittently transferring these materials from the river channel to the adjacent floodplain. The routing of sediment and water through the channel network initiates complex process-form interactions as the river bed and banks adjust to changes in flow conditions. Despite their ubiquity, little is known about the landform-driven morphodynamic interactions taking place within the channel that ultimately determine patterns of sedimentation and changes of channel form. Furthermore, an understanding of how these process-form interactions scale with the size of the fluvial system is also currently lacking. Recent technological advances now afford us the opportunity to study and to quantify these process-form interactions in detail across a range of spatial and temporal scales. This session aims to bring together interdisciplinary researchers working across field, experimental, and numerical modelling approaches who are advancing methods and providing new insights into: (i) sediment transport and morphodynamic functioning of fluvial systems, (ii) evaluating morphological change at variable spatial and temporal scales, such as at event vs. seasonal scales, and (iii) investigating the sedimentology of these river systems. We particularly welcome applications which investigate the morphodynamic response of fluvial systems in all types and sizes and we specifically would like to encourage submissions from early career researchers and students.

Public information:
To those authors (or co-authors) who wish to participate in the chat-based session, please prepare yourselves to answer the following question:
- Who are you and what are your research topic and the key message of your research? -

Sedimentary features are the result of a complex interplay between the erosion, transport and deposition of grains under the action of a current - unidirectional, oscillatory, combined or multidirectional. Each sedimentary structure represents a palaeo-surface expression, and therefore they contain a record of the geomorphology driven by the flow conditions, provided that one understands how to invert and read this history. Evidence for sedimentary processes have been identified on Earth but also on other planetary bodies, based on observations of geomorphic features and stratigraphy.

Bedforms and other sedimentary features are generated in a wide variety of environments, including: aeolian wind-driven transport, rivers, estuarine, lacustrine and deltaic settings, pyroclastic currents, sub- and pro-glacial environments, shorelines and continental shelves, offshore storms, turbidity currents and subaqueous mass flows, deep-sea currents and extra-terrestrial bodies.

This session will host contributions regarding many aspects of the complex interaction between flow, bedforms and sedimentary structures on Earth and planetary surfaces, from their description to interpretation, and from modelling to experiments to field quantification, with studies ranging across differing spatial and temporal scales, from large-scale organisation patterns down to the grain-scale, as well as the palaeo-dynamic and morphodynamic aspects of control and feedback between flow, sediment transport and bedform evolution, on Earth and on Mars.

The varied contributions from field, laboratory, theoretical, and numerical approaches are intended to advance our knowledge of how to decipher the information contained in terrestrial and extra-terrestrial sedimentary bedforms, and help foster fruitful discussions between sedimentologists, geomorphologists, hydrologists, physicists and all researchers working on understanding bedform dynamics and their sedimentary products.

Obtaining quantitative information on the spatial pattern of soil redistribution during storms and on the spatial sources supplying sediment to rivers is required to improve our understanding of the processes controlling these transfers and to design effective control measures. It is also crucial to quantify the transfer or the residence times of material transiting rivers along the sediment cascade, and to reconstruct the potential changes in sources that may have occurred at various temporal scales. During the last few decades, several sediment tracing or fingerprinting techniques have contributed to provide this information, in association with other methods (including soil erosion modelling and sediment budgeting). However, their widespread application is limited by several challenges that the community should address as priorities.
We invite specific contributions to this session that address any aspects of the following:
• Developments of innovative field measurement and sediment sampling techniques;
• Soil and sediment tracing techniques for quantifying soil erosion and redistribution;
• Sediment source tracing or fingerprinting studies, using conventional (e.g. elemental/isotopic geochemistry, fallout radionuclides, organic matter) or alternative (e.g. colour, infrared, particle morphometry) approaches;
• Investigations of the current limitations associated with sediment tracing studies (e.g. tracer conservativeness, uncertainty analysis, particle size and organic matter corrections);
• Applications of radioisotope tracers to quantify sediment transit times over a broad range of timescales (from the flood to the century);
• The association of conventional techniques with remote sensing and emerging technologies (e.g. LiDAR);
• Integrated approaches to developing catchment sediment budgets: linking different measurement techniques and/or models to understand sediment delivery processes.