(23) Advances in simulating fluvial sediment transport at basin-scale
Albert J. Kettner
CSDMS, INSTAAR, University of Colorado, Boulder CO, 80309,
Recently significant advances have been made in estimating fluvial sediment transport that involves glacial processes, floodplain dynamics and tectonic forcings. Models to quantify the amount of sediment transported by a single or multiple
river to the ocean have bee developed for decades. Field observations are difficult and costly to obtain, so that predictive models are still neede t estimate the flux of sediment, which importantly influences the downstream coastal, deltaic, and marine environments.
Existing empirical models estimate sediment fluxes per river drainage basin by incorporating easy to obtain inputs: drainage basin properties (drainage area, relief, lithology) and climatological parameters (precipitation, temperature). first order approach incorporates glacial erosion processes to be able to simulate fluvial fluxes ove glacial-‐interglacial timescales. These first-‐generation models calculat solely the suspended sediment flux at the rivermouth (1D) and definitely d not reflect all processes that interact with the terrestrial sediments. However the impact of long-‐ term climate change or human interaction o the landscape are well captured.
Recen advance make it possible to simulate global fluvial fluxes throughout a drainage basin (2D) a 6-‐arc minute resolution (i.e. the WBMsed model). B increasing the spatial dimension we now can identify sediment hotspots (sources and sinks) i th terrestrial landscape and keep track of sediment routing through a rive system. Furthermore, the WBMsed model i able to capture th process of deposition of sediments i floodplains during pea floods; it thus dynamically reduces the sediment load ultimately reaching the ocean. Another major advance is incorporating the impact of seismic activity on the sediment fluxes to the ocean. Data analyzes reveal tha th Peak Ground Acceleration (PGA), globall available index for seismic activity, has a significant impact on sediment fluxes. Earthquakes
appear to increase the total sediment flux up to factor 2, even fo area that ar not
known for their tectonic activity (e.g. Europe).
Future advances should more focus on simulating fluvial transport of different