Event Title
Using seasonality and particle tracking to trace Intermediate Water in the Strait of Georgia
Presentation Abstract
The Strait of Georgia is a complex system of basins and waterways within the Salish Sea that receives the majority of Greater Vancouver’s wastewater via riverine input and effluent outfalls. It can be nominally divided into three constituent water masses: (1) a riverine surface layer; (2) a deep oceanic layer; and (3) an intermediate layer, composed of a mixture of the surface and deep waters. The intermediate water (IW) layer is the largest layer volumetrically and a primary component of the region’s subsurface estuarine circulation, yet a comprehensive understanding of the system has proved challenging. Here, we use two methods to assess the circulation pathways. The first method uses a synthesis of hydrographic observations to determine seasonal cycles in IW mass characteristics and exploits the spatial variation in seasonal cycle phase and amplitude to age the water mass, infer circulation and mixing, and understand the transport and eventual fate of IW in the Strait of Georgia. The second method uses particle tracking techniques implemented using SalishSeaCast model velocity outputs to similar effect. The IW circulation is found to be more complex than previously anticipated, with a direct alteration of circulation via inputs to the north of the region, a distinct cyclonic flow in the primary basin, and a strong inflowing boundary current on the eastern shores. Furthermore, we find evidence that wastewater tracer concentrations downstream of major effluent outfalls are consistent with our inferences of IW pathways.
Session Title
Track: Contaminants, Plastics, Microplastics, Toxicology & Stormwater – Posters
Conference Track
Contaminants, Plastics, Microplastics, Toxicology & Stormwater
Conference Name
Salish Sea Ecosystem Conference (2020 : Online)
Document Type
Event
SSEC Identifier
2020_abstractID_4627
Start Date
21-4-2020 9:00 AM
End Date
22-4-2020 4:45 PM
Genre/Form
conference proceedings; presentations (communicative events); posters
Subjects – Topical (LCSH)
Water currents--Salish Sea (B.C. and Wash.); Water--Pollution--Point source identification--Salish Sea (B.C. and Wash.)
Geographic Coverage
Salish Sea (B.C. and Wash.)
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Format
application/pdf
Included in
Fresh Water Studies Commons, Marine Biology Commons, Natural Resources and Conservation Commons, Terrestrial and Aquatic Ecology Commons
Using seasonality and particle tracking to trace Intermediate Water in the Strait of Georgia
The Strait of Georgia is a complex system of basins and waterways within the Salish Sea that receives the majority of Greater Vancouver’s wastewater via riverine input and effluent outfalls. It can be nominally divided into three constituent water masses: (1) a riverine surface layer; (2) a deep oceanic layer; and (3) an intermediate layer, composed of a mixture of the surface and deep waters. The intermediate water (IW) layer is the largest layer volumetrically and a primary component of the region’s subsurface estuarine circulation, yet a comprehensive understanding of the system has proved challenging. Here, we use two methods to assess the circulation pathways. The first method uses a synthesis of hydrographic observations to determine seasonal cycles in IW mass characteristics and exploits the spatial variation in seasonal cycle phase and amplitude to age the water mass, infer circulation and mixing, and understand the transport and eventual fate of IW in the Strait of Georgia. The second method uses particle tracking techniques implemented using SalishSeaCast model velocity outputs to similar effect. The IW circulation is found to be more complex than previously anticipated, with a direct alteration of circulation via inputs to the north of the region, a distinct cyclonic flow in the primary basin, and a strong inflowing boundary current on the eastern shores. Furthermore, we find evidence that wastewater tracer concentrations downstream of major effluent outfalls are consistent with our inferences of IW pathways.
