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?
