TY  - JOUR
A1  - Wickert, Andrew D.
A1  - Schildgen, Taylor F.
T1  - Long-profile evolution of transport-limited gravel-bed rivers
T2  - Earth surface dynamics
N2  - 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.
Y1  - 2019
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/51062
SN  - 2196-6311
SN  - 2196-632X
VL  - 7
IS  - 1
SP  - 17
EP  - 43
PB  - Copernicus
CY  - Göttingen
ER  -