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Transport Modelling to River. Management: A Case in the Fraser River, Vancouver,. BC, Canada. Albert Leung, Jim Stronach and Jordan Matthieu ...
Linking Hydrodynamics and Sediment Transport Modelling to River Management: A Case in the Fraser River, Vancouver, BC, Canada Albert Leung, Jim Stronach and Jordan Matthieu

Background and Facts

Background and Facts - Part of a multi-partner collaboration program between PMV, -

DFO, SCH, BCMOTI, local interest groups, First Nations, municipalities and cities Other key players: BCMOE and Environment Canada Local Channel Dredging Contribution Program – Collaboration Project

• • • • •

Cannery Channel: Approx. 130,000 m3 removed in 2014 Sea Reach: Approx. 160,000 m3 removed in 2014 Deas Slough: 60,000 m3 removed in 2014 Ladner Harbour*: 300,000 m3 combined in 2014 and 2015 Others

Background and Facts

Dredgeate Disposal Method - Disposal Methods: Ocean Disposal and In-river Dispersal - Ocean disposal: No clear benefits except for acting as a -

repository for the dredged materials from the river In-river dispersal: cost, time and environmental benefits

In-river Dispersal - Method: Dredged materials piped and dispersed at a selected location close to a dredge site

Background and Facts

In-river Dispersal - Financial and Time Benefit: No need to barge-load and ship to an ocean disposal site which might not be close-by.    Save time and money

In-river Dispersal • Environmental benefits: Can be treated as a mean to reinitiate the movement of the sediment that is already in the rivers instead of taking it out of the system entirely; maintain sediment supply to the flats.

In-river Disposal - Considerations - Navigation : permanent accumulation sediment in the river not desirable

In-river Disposal - Considerations

- PCB: very persistent organic compound; been banned in Canada for several decades; preferentially associated with fine particles; potential to the Southern Resident Killer Whale.

In-river Disposal - Considerations Sedimentation: minimal alteration to the sedimentation regime, or like-on-like deposition

Modelling Study Modelling tools: - In-house, three dimensional hydrodynamic model, H3D, coupled with sediment transport model - Double nested model: Strait of Georgia (rectilinear) and Fraser River (curvilinear) from Sand Heads to Douglas Island - Model driven by water level, river flow and density structures at the boundaries and meteorological conditions in the domain

Modelling Study Model assumed dredging operations in the fall:

Modelling Study Time of Operation: - Sea Reach (Sep 20 – 29) - Cannery Channel (Oct 6 – 15) - Deas Slough (Oct 22 – Nov 2)

Modelling Study – Nat. Riv. Sed. Phy. Properties

Modelling Study – Dredgeate Physical Properties

Modelling Study – Discharge Characteristics - D50 = 14 microns; D90 = 39 microns - Fine Sediment Concentration in Slurry = 5,300 mg/L (Sea Reach); 92,750 mg/L (Ladner Reach); 143,100 mg/L (Deas Slough)

Modelling Study – Sediment Plume in Fraser River

Modelling Study – Sediment Plume in SOG – Low T

Modelling Study – Sediment Plume in SOG – High T

Modelling Study – Natural Fine Sed. Deposition

Modelling Study – Dredgeate Fine Sed. Deposition

Modelling Study – Dredgeate Coarse Sed. Deposition Start of freshet

Modelling Study – Dredgeate Coarse Sed. Deposition 10 day after start of freshet

Modelling Study – Dredgeate Coarse Sed. Deposition 20 day after start of freshet

STFATE – Point Grey Ocean Disposal Site

STFATE – Point Grey Ocean Disposal Site Ladner Harbour Clay Fraction: 7.5 mins after dumping

STFATE – Point Grey Ocean Disposal Site Ladner Harbour Clay Fraction: 80 mins after dumping

Questions, Comments and Follow-up? - Albert Leung ([email protected]) - Jim Stronach ([email protected]) - Jordan Matthieu ([email protected])

Questions, Comments and Follow-up?