2018 CSDMS meeting-028
Long-profile evolution of transport-limited gravel-bed rivers
Transport-limited gravel-bed rivers are ubiquitous across Earth's upland environments. Sediment transport processes, while notoriously difficult, are better-understood than bedrock erosion, meaning that solutions to transport-limited river long profiles can help us gain a physics-based toehold into landscape evolution. Here we demonstrate how the coupling of equations for gravel transport, channel morphodynamics, and simple flow hydraulics that produce steady-state river profiles and show how they respond to changes in climate and tectonics. This coupled set of equations is analytically solvable for special cases, and we have also developed efficient semi-implicit numerical solutions that can solve millions of years of landscape evolution in seconds. Gravel-bed rivers become steeper as the sediment-to-water supply ratio increases, and become less concave as uplift rates (relative to input sediment supply and valley dimensions) increase. These distinctive responses allow us to use transport-limited gravel-bed rivers as recorders of climatic versus tectonic influence on river systems.