HS9.7/GM7.7/SSP3.1.17/SSS7.10Revisiting techniques for quantifying sources and travel times of fine sediment from catchment to coast (co-organized)
|Convener: Hugh Smith | Co-Conveners: Will Blake , Philip Owens , Olivier Evrard|
Research into the sources of fine sediment in river catchments has expanded rapidly over the last two decades. Sediment tracing or fingerprinting studies use various physical and chemical properties of soil and sediment to discriminate sources and estimate contributions to fine material delivered downstream. However, recent work has raised important questions concerning (i) the selection of soil physical and chemical properties for use in discriminating sources and (ii) the potential for non-conservative behaviour of properties during downstream transfer. There is a need to revisit key assumptions associated with sediment fingerprinting with a view to further develop this technique.
The timescales associated with contemporary sediment delivery processes have also been the subject of recent attention. To date, studies have used differences in the radioactive decay rates of several fallout radionuclides to quantify the travel or residence times of fine sediment in river systems over timescales relevant to river basin management (days to decades). Data on sediment travel times can provide a critical temporal dimension to fine sediment budgets based on source tracing, erosion and sediment yield measurements and/or modelling.
Contributions to this session may address any aspect of fine sediment source tracing/fingerprinting and approaches for quantifying sediment travel times as well as studies incorporating these techniques into catchment sediment budgets. Key themes may include:
• Applications of sediment source fingerprinting techniques with reference to key assumptions
• Selection of tracer properties and identification of the physical or chemical basis for the discrimination of sediment sources
• Identification of novel tracer properties for future application
• Potential for changes to tracer properties during transport
• New methods for the statistical treatment of tracer data and applications of different un-mixing models
• Approaches for dealing with uncertainty in estimates of source contributions to downstream sediment
• Techniques for quantifying sediment travel times over timescales relevant to river basin management
• Integrated approaches to sediment budgeting: linking catchment source information with sediment travel times, erosion and sediment yield monitoring or modelling