Impacts of lower Fraser River geometry on the Fraser River plume
Presentation Abstract
The Southern Strait of Georgia is dominated by the Fraser River plume. Salinity, turbidity, currents, phytoplankton are all, to first order, different in the plume and out of the plume. Thus the position and extent of the plume exerts strong controls on spatial variability. Modelling the exact position of the plume is difficult and it may be partially stochastic. However, it is clear that the bathymetry and geometry of the lower river and coastal nearshore strongly impact its position. Many of the key aspects have been constructed and/or modified in the last 100 years. These include the dredging of the river, the Steveston Jetty, the Iona Spit, the coal port and Tsawwassen Ferry Terminal. In this presentation we will describe the Fraser River plume as simulated by the SalishSeaCast model of the Salish Sea, evaluate it against data and describe how it is impacted by numerical choices. Then we will use the model to investigate the impacts of bathymetry and geometry changes on the position and extent of the plume. We will explain the observed differences in terms of the strength and phasing of the tides in the lower river and on the mud flats compared to the those in the deep Strait of Georgia. Using estimates of pre-modification lower Fraser River, we will present our simulations of the plume location 100 years ago.
Session Title
Integrated Coastal Climate Change Modeling for Salish Sea Planning: Part I
Conference Track
SSE5: Climate Change: Impacts, Adaptation, and Research
Conference Name
Salish Sea Ecosystem Conference (2018 : Seattle, Wash.)
Document Type
Event
SSEC Identifier
SSE5-511
Start Date
6-4-2018 9:30 AM
End Date
6-4-2018 9:45 AM
Type of Presentation
Oral
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Regions of freshwater influence--Washington (State)--Fraser River
Geographic Coverage
Fraser River (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Impacts of lower Fraser River geometry on the Fraser River plume
The Southern Strait of Georgia is dominated by the Fraser River plume. Salinity, turbidity, currents, phytoplankton are all, to first order, different in the plume and out of the plume. Thus the position and extent of the plume exerts strong controls on spatial variability. Modelling the exact position of the plume is difficult and it may be partially stochastic. However, it is clear that the bathymetry and geometry of the lower river and coastal nearshore strongly impact its position. Many of the key aspects have been constructed and/or modified in the last 100 years. These include the dredging of the river, the Steveston Jetty, the Iona Spit, the coal port and Tsawwassen Ferry Terminal. In this presentation we will describe the Fraser River plume as simulated by the SalishSeaCast model of the Salish Sea, evaluate it against data and describe how it is impacted by numerical choices. Then we will use the model to investigate the impacts of bathymetry and geometry changes on the position and extent of the plume. We will explain the observed differences in terms of the strength and phasing of the tides in the lower river and on the mud flats compared to the those in the deep Strait of Georgia. Using estimates of pre-modification lower Fraser River, we will present our simulations of the plume location 100 years ago.
