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TitleModelling seabed shear stress, sediment mobility and sediment transport in the Bay of Fundy
AuthorLi, M Z; Hannah, C G; Perrie, W A; Tang, C C L; Prescott, R H; Greenberg, D A
SourceCanadian Journal of Earth Sciences vol. 52, no. 9, 2015 p. 757-775, https://doi.org/10.1139/cjes-2014-0211
Year2015
Alt SeriesEarth Sciences Sector, Contribution Series 20130082
PublisherNRC Research Press
Documentserial
Lang.English
Mediapaper; on-line; digital
File formatpdf; html
ProvinceEastern offshore region; New Brunswick; Nova Scotia
NTS11E/05; 11E/06; 20O; 20P/04; 20P/05; 20P/12; 20P/13; 21A/05; 21A/12; 21A/13; 21A/14; 21B; 21G/01; 21G/02; 21G/03; 21G/08; 21H/01; 21H/02; 21H/03; 21H/04; 21H/05; 21H/06; 21H/07; 21H/08; 21H/09; 21H/10; 21H/11; 21H/15; 21H/16
AreaBay of Fundy; Chigneto Bay; Minas Basin; Minas Channel; Cobequid Bay; Southern Bight; Brier Island; Grand Manan Island; St. Mary's Bay; Saint John Harbour; Passamaquoddy Bay; Cape Chigneto; Cape D'Or
Lat/Long WENS -68.0000 -63.2500 46.0000 43.1667
Subjectsmarine geology; surficial geology/geomorphology; bedforms; bedform movement; submarine transport; sediment transport; shear stress; marine sediments; sediment transport; sediment stability; energy resources; tidal power; tides; currents; tidal currents; resource management; oceanography; models; grain size analyses; erosion; deposition; water circulation patterns; bathymetry; seabottom topography; sediment distribution; waves; shear velocity; sediment load; eddies; seabed disturbance
Illustrationslocation maps; geophysical images; models; sketch maps
ProgramRenewable Energies, Environmental Geoscience
ProgramOffshore Geoscience
ProgramClean Energy Fund
AbstractInformation about seabed stability and sediment dynamics is part of the fundamental geoscience knowledge required for the extraction of tidal energy in the Bay of Fundy and for the integrated management of the Bay. Waves, tidal currents, and wind-driven and circulation currents were obtained from oceanographic models to assess the wave and current processes for the broader Bay of Fundy. The wave and current outputs were coupled with observed grain size in a sediment transport model to predict, for the first time, the seabed shear stresses, sediment mobility, and sediment transport patterns for the entire Bay. The root mean square tidal current, highest in the upper Bay (>1.4 m·s-1), is reduced to moderate in the central Bay (0.5-0.8 m·s-1) and decreases further in the outer Bay (0.2-0.5 m·s-1). The maximum tidal current occurs in the Minas Passage and is >5 m·s-1. The mean significant wave height, in contrast, is the greatest in the outer Bay (~1.3 m) and gradually decreases to the northeast in the central and upper Bay (<0.5 m). Seabed shear in the Bay of Fundy is mostly due to tides, and wave effects are only important in coastal areas. The strongest mean shear velocity of 10 cm·s-1 occurs in the Minas Passage area. Strong shear velocity of 4-5 cm·s-1 also occurs in Minas Basin, in the central Bay, and in the narrows around Grand Manan Island. Sediment mobilization in the Bay of Fundy is predominantly by tidal current. Mobilization frequency is >30% of the time over most of the Bay and reaches 100% of the time in some areas. The maximum total-load sediment transport rate under spring tide can reach ~5 kg·m-1·s-1 and is to the northeast during flood and to the southwest during ebb. Net sediment transport flux, however, is dominantly to the northeast and reaches 2 kg·m-1·s-1. Eddies of net transport are found to occur around headlands and at the narrows of Grand Manan Island, largely due to the occurrence of eddies of residual tidal flows. The regional distribution of substrate types and bedform fields and patterns of seabed erosion and deposition are well correlated with tidal current strength and sediment transport patterns.
Summary(Plain Language Summary, not published)
Regional understanding of the tidal current strength and sediment transport flux and direction forms part of the fundamental geoscience knowledge required for environmental impact assessment for tidal energy development in the Bay of Fundy. Predictions of waves, tidal and ocean currents were used in a sediment transport model to predict the seabed shear stresses, sediment mobility, and sediment transport pattern for the broader Bay of Fundy. The maximum tidal current, greater than 5 m s-1, occurs in narrow channels in the upper bay. The wave height, in contrast, is the greatest in the outer bay. Sediment mobilization is predominantly by tidal current with frequencies >30% of time over most part of the bay. Net sediment transport flux is dominantly to the northeast and reaches 5 kg m-1 s-1. The distribution and characteristics of substrate types and major bedform fields are well correlated with tidal current strength and sediment transport patterns.
GEOSCAN ID292665