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Fine‐Sediment Erosion and Sediment‐Ribbon Morphodynamics in Coarse‐Grained Immobile Beds

Trevisson, Michele 1; Eiff, Olivier 1
1 Institut für Hydromechanik (IFH), Karlsruher Institut für Technologie (KIT)

Abstract:

In rivers, fine sediments are often transported over immobile coarse grains. With low sediment supply, they tend to aggregate in longitudinal ribbons. Yet, the long-term evolution of such ribbons and the influence of immobile grains on the erosion of fine sediments are still not well understood. Flume experiments without sediment supply were therefore performed to investigate the erosion of an initially uniform fine-sediment bed covering an immobile bed of staggered spheres through topographic and flow measurements. The topographic measurements yielded the spheres' protrusion above the fine sediment (P) and revealed long-lived ribbons with ridges and troughs. The ridges are the main long-term sediment source as the troughs are quickly eroded to a stable bed level resulting from the spheres' sheltering. The ridges stabilize with a spacing of 1.3 effective water depths, their number resulting from the integer number of wavelengths fitting into the effective channel width which excludes side-wall accumulations. The ridges' erosion is damped by the local upflow of secondary current cells, which displaces the strongest sweep events above the bed. ... mehr


Verlagsausgabe §
DOI: 10.5445/IR/1000153774
Veröffentlicht am 16.12.2022
Originalveröffentlichung
DOI: 10.1029/2021WR031837
Scopus
Zitationen: 2
Dimensions
Zitationen: 2
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Hydromechanik (IFH)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 11.2022
Sprache Englisch
Identifikator ISSN: 0043-1397, 1944-7973
KITopen-ID: 1000153774
Erschienen in Water Resources Research
Verlag John Wiley and Sons
Band 58
Heft 11
Seiten Art.: e2021WR031837
Vorab online veröffentlicht am 14.11.2022
Schlagwörter sediment erosion, rough beds, sediment ribbons, secondary currents, open-channel, ridge morphology
Nachgewiesen in Web of Science
Scopus
Dimensions
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