Bedload transport controls bedrock erosion under sediment-starved conditions

Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Bedrock erosion processes have been described with incision models that are widely applied in river-reach and catchment-scale studies. However, so far no linked field data set at the process scale had been published tha...

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Main Authors: A. R. Beer, J. M. Turowski
Format: Article
Language:English
Published: Copernicus Publications 2015-07-01
Series:Earth Surface Dynamics
Online Access:http://www.earth-surf-dynam.net/3/291/2015/esurf-3-291-2015.pdf
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author A. R. Beer
J. M. Turowski
author_facet A. R. Beer
J. M. Turowski
author_sort A. R. Beer
collection DOAJ
description Fluvial bedrock incision constrains the pace of mountainous landscape evolution. Bedrock erosion processes have been described with incision models that are widely applied in river-reach and catchment-scale studies. However, so far no linked field data set at the process scale had been published that permits the assessment of model plausibility and accuracy. Here, we evaluate the predictive power of various incision models using independent data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep bedrock stream section for a single bedload transport event. The influence of transported bedload on the erosion rate (the "tools effect") is shown to be dominant, while other sediment effects are of minor importance. Hence, a simple temporally distributed incision model, in which erosion rate is proportional to bedload transport rate, is proposed for transient local studies under detachment-limited conditions. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. For the event at hand, basic discharge-based models, such as derivatives of the stream power model family, are adequate to reproduce the overall trend of the observed erosion rate. This may be relevant for long-term studies of landscape evolution without specific interest in transient local behavior. However, it remains to be seen whether the same model calibration can reliably predict erosion in future events.
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spelling doaj.art-6203eed8c2474c6fb92037e290c27dce2022-12-21T18:25:36ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2015-07-013329130910.5194/esurf-3-291-2015Bedload transport controls bedrock erosion under sediment-starved conditionsA. R. Beer0J. M. Turowski1WSL Swiss Federal Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, SwitzerlandWSL Swiss Federal Institute for Forest, Snow and Landscape Research, 8903 Birmensdorf, SwitzerlandFluvial bedrock incision constrains the pace of mountainous landscape evolution. Bedrock erosion processes have been described with incision models that are widely applied in river-reach and catchment-scale studies. However, so far no linked field data set at the process scale had been published that permits the assessment of model plausibility and accuracy. Here, we evaluate the predictive power of various incision models using independent data on hydraulics, bedload transport and erosion recorded on an artificial bedrock slab installed in a steep bedrock stream section for a single bedload transport event. The influence of transported bedload on the erosion rate (the "tools effect") is shown to be dominant, while other sediment effects are of minor importance. Hence, a simple temporally distributed incision model, in which erosion rate is proportional to bedload transport rate, is proposed for transient local studies under detachment-limited conditions. This model can be site-calibrated with temporally lumped bedload and erosion data and its applicability can be assessed by visual inspection of the study site. For the event at hand, basic discharge-based models, such as derivatives of the stream power model family, are adequate to reproduce the overall trend of the observed erosion rate. This may be relevant for long-term studies of landscape evolution without specific interest in transient local behavior. However, it remains to be seen whether the same model calibration can reliably predict erosion in future events.http://www.earth-surf-dynam.net/3/291/2015/esurf-3-291-2015.pdf
spellingShingle A. R. Beer
J. M. Turowski
Bedload transport controls bedrock erosion under sediment-starved conditions
Earth Surface Dynamics
title Bedload transport controls bedrock erosion under sediment-starved conditions
title_full Bedload transport controls bedrock erosion under sediment-starved conditions
title_fullStr Bedload transport controls bedrock erosion under sediment-starved conditions
title_full_unstemmed Bedload transport controls bedrock erosion under sediment-starved conditions
title_short Bedload transport controls bedrock erosion under sediment-starved conditions
title_sort bedload transport controls bedrock erosion under sediment starved conditions
url http://www.earth-surf-dynam.net/3/291/2015/esurf-3-291-2015.pdf
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