EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Few floods govern decades of suspended sediment flux in German upland rivers

Jan Henrik Blöthe1 and Thomas Hoffmann2
Jan Henrik Blöthe and Thomas Hoffmann
  • 1University of Freiburg, Institute of Environmental Social Science and Geography, Freiburg, Germany (
  • 2Bundesanstalt für Gewässerkunde, 56068 Koblenz, Germany

Sediment yield from lowland rivers around the globe is often dominated by suspended sediment that also acts as a carrier for pollutants and contaminants. Achieving a deeper understanding of the suspended sediment dynamics is important for river management, but often complicated by short or discontinuous time-series and scattered surveying locations. However, suspended sediment transport is highly variable in space and time, calling for decadal observations that reflect this variability. Here we make use of >130,000 measurements on water discharge (Q) and suspended sediment concentration (SSC) from twelve stations that drain large parts of the central German uplands, to investigate the spatiotemporal variability in suspended sediment flux. 
The data has been collected during working days between 1965 and 2018 in context of the suspended sediment monitoring conducted by the Federal Waterways and Shipping Administration (WSV). The contributing catchments of the twelve monitoring stations range between 2500 and 22000 km2 and cover observation periods between 27 and 53 years. 
Despite roughly similar topographic and climatic conditions, average specific (suspended) sediment yield (SSY) varies between ~6 and ~29 t km2 yr-1. Highest specific yields are observed for those catchments that drain the escarpment of the Swabian cuesta landscape. Even more pronounced than the spatial variability is the interannual variability in sediment yield, with SSY for very wet years exceeding SSY for dry years more than tenfold. Separating the hydrograph into base-flow and event-flow components, we find that sediment export during event-flows accounts for 60 to 85% of the long-term SSY, with individual floods accounting for more than 90% of the annual sediment export. We conclude that high specific (suspended) sediment yields in the central German uplands are conditioned by rapidly responding catchments (i.e. large fraction of event-flow contribution) with highly erodible lithologies of the Swabian cuesta landscapes.

How to cite: Blöthe, J. H. and Hoffmann, T.: Few floods govern decades of suspended sediment flux in German upland rivers, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12056,, 2021.


Display file