Long-profile evolution of transport-limited gravel-bed rivers
- 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 channelAlluvial 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.…
Verfasserangaben: | Andrew D. WickertORCiDGND, Taylor F. SchildgenORCiD |
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URN: | urn:nbn:de:kobv:517-opus4-425718 |
DOI: | https://doi.org/10.25932/publishup-42571 |
ISSN: | 1866-8372 |
Titel des übergeordneten Werks (Englisch): | Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe |
Schriftenreihe (Bandnummer): | Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe (680) |
Publikationstyp: | Postprint |
Sprache: | Englisch |
Datum der Erstveröffentlichung: | 13.03.2019 |
Erscheinungsjahr: | 2019 |
Veröffentlichende Institution: | Universität Potsdam |
Datum der Freischaltung: | 13.03.2019 |
Freies Schlagwort / Tag: | alluvial river; basin geometry; bedrock incision models; channel changes; flow; grain-size; landscape response; sediment transport; size distribution; stream-power |
Ausgabe: | 680 |
Seitenanzahl: | 27 |
Quelle: | Earth Surface Dynamics 7 (2019), pp. 17–43 DOI 10.5194/esurf-7-17-2019 |
Organisationseinheiten: | Mathematisch-Naturwissenschaftliche Fakultät |
DDC-Klassifikation: | 5 Naturwissenschaften und Mathematik / 55 Geowissenschaften, Geologie / 550 Geowissenschaften |
Peer Review: | Referiert |
Publikationsweg: | Open Access |
Lizenz (Deutsch): | CC-BY - Namensnennung 4.0 International |
Externe Anmerkung: | Bibliographieeintrag der Originalveröffentlichung/Quelle |