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TitleSeabed disturbance and sediment mobility due to tidal current and waves on the continental shelves of Canada
AuthorLi, M ZORCID logo; Wu, Y; Hannah, C G; Perrie, W A
SourceCanadian Journal of Earth Sciences 2021 p. 1-24, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20200146
PublisherCanadian Science Publishing
Mediapaper; on-line; digital
File formatpdf
ProvinceBritish Columbia; Eastern offshore region; New Brunswick; Newfoundland and Labrador; Northern offshore region; Northwest Territories; Nova Scotia; Nunavut; Ontario; Prince Edward Island; Quebec; Western offshore region; Yukon
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 24; 25; 26; 27; 28; 29; 35; 36; 37; 38; 39; 46; 47; 48; 49; 57; 58; 59; 66; 67; 68; 69; 76; 77; 78; 79; 86; 87; 88; 89; 92; 93; 97; 98; 99; 102; 103; 107; 117; 120; 340; 560
Lat/Long WENS-141.0000 -40.0000 84.0000 40.0000
Subjectsmarine geology; surficial geology/geomorphology; geophysics; environmental geology; Science and Technology; Nature and Environment; Health and Safety; continental margins; continental shelf; marine sediments; sands; sediment dispersal; sediment transport; sediment stability; turbidity currents; tidal currents; shear stress; modelling; oceanography; sea ice; seismic waves; s waves; seismic velocities; Classification; Habitats
Illustrationslocation maps; geoscientific sketch maps; tables
ProgramMarine Geoscience for Marine Spatial Planning
Released2021 04 27
AbstractWaves and tidal currents can interact to produce strong seabed shear stress and mobilization of sediments on continental shelves. Modelled wave and tidal current data for a 3-year period were used in a combined-flow sediment transport model to simulate the seabed shear stresses and the mobilization of uniform medium sand on the continental shelves of Canada. The modelling results are presented to establish the first national framework of seabed disturbance and sediment mobility on the continental shelves of Canada. Strong waves and tidal currents on the Canadian continental shelves produce mean bed shear velocity >5 cm/s. Medium sand can be mobilized >50% of the time over many areas on the shelves. The mobilization by tidal currents occurs over 36% and by waves over 50% of the shelf area, demonstrating that mobilization of sediments is dominated by waves on the Canadian continental shelves. Combined shear stresses due to wave and tidal current interaction further increase sediment mobilization to over 68% of the shelf area. The spatial variation of the relative importance of wave and tidal disturbances allows classification of the continental shelves into six disturbance types. Innovative Seabed Disturbance (SDI) and Sediment Mobility (SMI) indices are proposed to quantify the seabed exposure to oceanographic processes and sediment mobilization, incorporating both the magnitude and frequency of these processes. The proposed SDI and SMI, together with the disturbance type classification, can be used as standard parameters to best quantify seabed disturbance and sediment mobility on other shelves of the world.
Summary(Plain Language Summary, not published)
Modelled waves and tidal currents for a 3-year period were used to model the movement of seabed sediments on the continental shelves of Canada. This modelling study establishes the first national framework of the magnitude and frequency of sediment mobilization, and shows that strong waves and tidal currents move sediment >50% of the time over many areas on the continental shelves. The results of the study are important for environmental assessments, planning for seabed infrastructure, and better understanding of seabed fisheries.

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