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Journal Articles Earth Surface Processes and Landforms Year : 2012

An opportunity to connect the morphodynamics of alternate bars with their sedimentary products

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Abstract

Field investigations that help clarify local sedimentary processes involved in the migration of alternate bars as a consequence of flood events are lacking. A simple approach combining scour chains, stratigraphy and frequent bathymetric surveys is proposed to connect the dynamics of free migrating alternate bars present in disconnected channels of large sandy-gravelly rivers with their sedimentary products and vice versa. The results show that the spatial distribution of bars before a flood partly governs the scour and fill processes and that the sediment transport rates vary significantly on a single cross-section. This can be due to preferential axes of the migration of the bars determined by their location on the crosssection, the bank direction and the discharge. The approach allows the reconstruction of local sedimentary processes involved in alternate bar migration by combining maximum scour depths reached during a flood with frequent channel bed topography surveys and post-flood stratigraphy. It is also possible to distinguish deposited and preserved sediments compared with sediments by-passed during the flood.

Dates and versions

insu-00666083 , version 1 (03-02-2012)

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Stéphane Rodrigues, Nicolas Claude, Philippe Jugé, Jean-Gabriel Bréhéret. An opportunity to connect the morphodynamics of alternate bars with their sedimentary products. Earth Surface Processes and Landforms, 2012, 37, pp.240-248. ⟨10.1002/esp.2255⟩. ⟨insu-00666083⟩
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