EGU2020-4079
https://doi.org/10.5194/egusphere-egu2020-4079
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Long-profile evolution of transport-limited gravel-bed rivers: Implications for sediment and landscape dynamics

Andrew Wickert1 and Taylor Schildgen2,3
Andrew Wickert and Taylor Schildgen
  • 1Saint Anthony Falls Laboratory and Department of Earth & Environmental Sciences, University of Minnesota, Minneapolis, United States of America (awickert@umn.edu)
  • 2GFZ German Research Centre for Geosciences, Potsdam, Germany
  • 3Institute of Geosciences, University of Potsdam, Potsdam, Germany

Gravel-bed rivers cross and sculpt Earth's upland regions. Field, flume, and theoretical studies together provide governing equations for these rivers. Building upon this rich background, we quantitatively link catchment-scale hydrology, sediment transport, and morphodynamics into a model of river long-profile change over time. We focus on the transport-limited case (i.e., alluvial rivers), as most rivers around the world expend the majority of their geomorphic work by moving sediment rather than eroding the underlying substrate. Morphologically, this "transport-limited" category includes all alluvial rivers as well as those bedrock rivers for which bedrock erosion is easy relative to sediment transport. This model provides predictions for how such systems respond to changes in water supply, sediment supply, and base level – which are often linked to climate, land use, and tectonics. After deriving the central equation for long-profile evolution, we demonstrate that river concavity is strongly determined by the attrition rate of gravel, which can occur by either hillslope weathering or downstream fining. This dependency creates the potential for significant feedbacks between climate, tectonics, lithology, and river morphology. Furthermore, the equation predicts that oscillations in sediment and water supply will lead to net river incision when compared to steady means of both quantities. If true, this theoretical prediction could help to explain the near-ubiquitous presence of river terraces around the world.

How to cite: Wickert, A. and Schildgen, T.: Long-profile evolution of transport-limited gravel-bed rivers: Implications for sediment and landscape dynamics, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4079, https://doi.org/10.5194/egusphere-egu2020-4079, 2020

This abstract will not be presented.