Refine
Has Fulltext
- yes (1)
Year of publication
- 2019 (1)
Document Type
- Postprint (1)
Language
- English (1)
Is part of the Bibliography
- yes (1)
Keywords
- alluvial river (1)
- basin geometry (1)
- bedrock incision models (1)
- channel changes (1)
- flow (1)
- grain-size (1)
- landscape response (1)
- sediment transport (1)
- size distribution (1)
- stream-power (1)
Institute
- Mathematisch-Naturwissenschaftliche Fakultät (1) (remove)
Alluvial and transport-limited bedrock rivers constitute the majority of fluvial systems on Earth. Their long profiles hold clues to their present state and past evolution. We currently possess first-principles-based governing equations for flow, sediment transport, and channel morphodynamics in these systems, which we lack for detachment-limited bedrock rivers. Here we formally couple these equations for transport-limited gravel-bed river long-profile evolution. The result is a new predictive relationship whose functional form and parameters are grounded in theory and defined through experimental data. From this, we produce a power-law analytical solution and a finite-difference numerical solution to long-profile evolution. Steady-state channel concavity and steepness are diagnostic of external drivers: concavity decreases with increasing uplift rate, and steepness increases with an increasing sediment-to-water supply ratio. Constraining free parameters explains common observations of river form: to match observed channel concavities, gravel-sized sediments must weather and fine – typically rapidly – and valleys typically should widen gradually. To match the empirical square-root width–discharge scaling in equilibrium-width gravel-bed rivers, downstream fining must occur. The ability to assign a cause to such observations is the direct result of a deductive approach to developing equations for landscape evolution.