Bankfull shear velocity predicts embeddedness and silt cover in gravel streambeds

River Research and Applications
By: , and 

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Abstract

Excess fine sediment (<2 mm) deposition on gravel streambeds can degrade habitat quality for stream biota. Two measures of fine sediment deposition include embeddedness and silt cover (<62.5 μm). Embeddedness measures fine sediment in interstitial pore spaces, whereas silt cover, primarily deposited during low flows, measures fine sediment draped on the streambed's surface. Here, we demonstrate that a baseline level of embeddedness and a maximum value of silt cover can be predicted from bankfull shear velocity, which can be estimated from river channel and streamflow characteristics, independently of knowing the sediment supply. We derive an equation for bankfull shear velocity that only requires knowing bankfull flow, channel width, and channel slope, which can be readily obtained in the United States from freely available, remotely sensed data. We apply this methodology to data collected at 30 sites in the Piedmont region of Virginia and North Carolina. This work is an important step in developing statistical models of stream ecosystems in which geophysical variables can predict embeddedness and silt cover, which commonly limit biotic assemblages.

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Publication type Article
Publication Subtype Journal Article
Title Bankfull shear velocity predicts embeddedness and silt cover in gravel streambeds
Series title River Research and Applications
DOI 10.1002/rra.3878
Volume 38
Issue 1
Publication Date October 28, 2021
Year Published 2022
Language English
Publisher Wiley
Contributing office(s) Coop Res Unit Leetown
Description 10 p.
First page 59
Last page 68
Country United States
State North Carolina, Virginia
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