Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada
Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada
A benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate (ϵ) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f-5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10-3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate (ws) scaled with the friction velocity (u*) in the form ws/u* = D*/8. The median size of resuspended aggregates (df) scaled inversely with dissipation (ϵ) in the form df = 5 × 10-6ϵ-0.24m, which is close to the relationship found in the literature.
Sand transport, Suspension, cohesive sediment, erodibility, flocculation, roughness, sediment, sediment dynamics, shear, turbulence dissipation
691-707
Kassem, Hachem
658efa7a-a02c-4b29-9d07-5d57e95a4b51
Sutherland, Terri F.
012af7c5-4bec-4867-8c06-c8fff186fbec
Amos, Carl
d0a18a13-bccd-4fdc-8901-aea595d4ed5c
8 July 2021
Kassem, Hachem
658efa7a-a02c-4b29-9d07-5d57e95a4b51
Sutherland, Terri F.
012af7c5-4bec-4867-8c06-c8fff186fbec
Amos, Carl
d0a18a13-bccd-4fdc-8901-aea595d4ed5c
Kassem, Hachem, Sutherland, Terri F. and Amos, Carl
(2021)
Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada.
Journal of Coastal Research, 37 (4), .
(doi:10.2112/JCOASTRES-D-20-00135.1).
Abstract
A benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate (ϵ) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f-5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10-3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate (ws) scaled with the friction velocity (u*) in the form ws/u* = D*/8. The median size of resuspended aggregates (df) scaled inversely with dissipation (ϵ) in the form df = 5 × 10-6ϵ-0.24m, which is close to the relationship found in the literature.
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Hydrodynamic Controls on the Particle Size of Resuspended Sediment from Sandy and Muddy Substrates in British Columbia, Canada
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Accepted/In Press date: 12 January 2021
e-pub ahead of print date: 23 March 2021
Published date: 8 July 2021
Additional Information:
Funding Information:
We would like to thank the Canadian Coast Guard crew of the CCGS Vector for providing a support vessel platform for the flume deployments and sediment grab survey. Thanks go to the Fisheries and Oceans Canada crew (Shane Petersen, Nicola Cook, Jason Thompson, Jennifer Whyte, and Marina Galvao) for assisting with both the project-and lab-based work. This project was supported by two Fisheries and Oceans Canada funding programs: Ecosystem Research Initiative (project: Strait of Georgia Benthic-Pelagic Coupling (2008-2010) and the Program for Aquaculture Regulatory Research (project: PARR-2011-P-21).
Publisher Copyright:
© Coastal Education and Research Foundation, Inc. 2021.
Keywords:
Sand transport, Suspension, cohesive sediment, erodibility, flocculation, roughness, sediment, sediment dynamics, shear, turbulence dissipation
Identifiers
Local EPrints ID: 447018
URI: http://eprints.soton.ac.uk/id/eprint/447018
ISSN: 0749-0208
PURE UUID: d6ba4e92-5053-447a-abe8-74301577795c
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Date deposited: 01 Mar 2021 17:35
Last modified: 17 Mar 2024 03:33
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Author:
Terri F. Sutherland
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