HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Quantifying the morphological print of bedload transport

Abstract : Bedload and river morphology interact in a strong feedback manner. Bedload conditions the development of river morphology along different space and time scales; on the other hand, by concentrating the flow in preferential paths, a given morphology controls bedload for a given discharge. As bedload is a nonlinear response of shear stress, local morphology is likely to have a strong impact on bedload prediction when the shear stress is averaged over the section, as is usually done. This was investigated by comparing bedload measured in different bed morphologies (step-pool, plane bed, riffle-pool, braiding, and sand beds), with bedload measured in narrow flumes in the absence of any bed form, used here as a reference. The initial methodology consisted of fitting a bedload equation to the flume data. Secondly, the morphological signature of each river was studied as the distance to this referent equation. It was concluded that each morphology affects bedload in a different way. For a given average grain shear stress, the larger the river, the larger the deviation from the flume transport. Narrow streams are those morphologies that behave more like flumes; this is particularly true with flat beds, whereas results deviate from flumes to a greater extent in step-pools. The riffle-pool’s morphology impacts bedload at different levels depending on the degree of bar development, considered here through the ratio D84/D50 which is used as a proxy for the local bed patchiness and morphology. In braiding rivers morphological effects are important but difficult to assess because width is dependent on transport rate. Bed morphology was found to have negligible effects in sand bed rivers where the Shields stress is usually sufficiently high to minimize the non-linearity effects when hydraulics is averaged over the section.
Document type :
Journal articles
Complete list of metadata

Contributor : Migration Irstea Publications Connect in order to contact the contributor
Submitted on : Saturday, May 16, 2020 - 7:16:46 AM
Last modification on : Tuesday, September 7, 2021 - 3:54:53 PM

Links full text




A. Recking, Guillaume Piton, D. Vazquez, G. Parker. Quantifying the morphological print of bedload transport. Earth Surface Processes and Landforms, Wiley, 2016, 41 (6), pp.809-822. ⟨10.1002/esp.3869⟩. ⟨hal-02602034⟩



Record views