The incipient motion of sediment in a channel with model emergent vegetation

Judy Q. Yang, Hayoon Chung, Heidi M. Nepf

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In a bare channel (without vegetation), the incipient velocity for sediment motion, Ucrit, has historically been related to the mean bed shear stress (t) or friction velocity (U* = (t/ρ)1/2). More recent studies, however, suggest turbulence also plays a role. This paper examines whether the onset of sediment motion in a vegetated channel is correlated with U*, or turbulence (kt). Images collected with a digital camera were interrogated with a particle-tracking code to measure sediment transport for different vegetation density and channel velocity. The trend in sediment transport with channel velocity was used to identify Ucrit for each stem density. The values of U* and kt were estimated at Ucrit. However, none of these parameters produced a constant threshold across all stem density and bare bed. We construct a new metric representing the peak turbulent velocities impinging on the bed that produces a constant threshold value for all cases.

Original languageEnglish (US)
Title of host publicationRiver Flow - Proceedings of the International Conference on Fluvial Hydraulics, RIVER FLOW 2016
EditorsGeorge Constantinescu, Marcelo Garcia, Dan Hanes
PublisherCRC Press/Balkema
Pages932-936
Number of pages5
ISBN (Print)9781138029132
DOIs
StatePublished - 2016
Externally publishedYes
EventInternational Conference on Fluvial Hydraulics, RIVER FLOW 2016 - St. Louis, United States
Duration: Jul 11 2016Jul 14 2016

Publication series

NameRiver Flow - Proceedings of the International Conference on Fluvial Hydraulics, RIVER FLOW 2016

Other

OtherInternational Conference on Fluvial Hydraulics, RIVER FLOW 2016
CountryUnited States
CitySt. Louis
Period7/11/167/14/16

Bibliographical note

Publisher Copyright:
© 2016 Taylor & Francis Group, London.

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