Abstract Title

Session S-02A: Future Salish Sea Water Quality

Proposed Abstract Title

Sensitivity of Circulation and Biogeochemical Response in Puget Sound to Sea Level Rise and Future Climate Loads

Keywords

Marine Water Quality

Location

Room 615-616-617

Start Date

30-4-2014 1:30 PM

End Date

30-4-2014 3:00 PM

Description

Assessments using future climate conditions based on the Intergovernmental Panel on Climate Change emissions scenario (A1B) have shown that hydrology of major rivers and freshwater runoff from multiple watersheds to Puget Sound, Washington, will be affected. In general, higher winter floods and lower summer flows coupled with future sea level rise have the potential to impact circulation and estuarine exchange. The effects on water properties such as temperature profiles, salinity gradients, and biogeochemical interactions are of interest due to concern over loss of coastal brackish habitats and potential impairment of water quality. In this paper we present a sensitivity analysis using the Puget Sound Georgia Basin hydrodynamic and biogeochemical model based on unstructured grid Finite Volume Coastal Ocean Model (FVCOM) framework and the CE QUAL-ICM model water quality kinetics. Effects of modified hydrology, sea level rise, and nutrient loads corresponding to years 2020, 2040, and 2070 are compared with baseline conditions from 2006. We examine potential large scale changes to the seasonal net transport through the various sub-basins within Puget Sound and also provide a relative comparison of key water quality parameters such as dissolved oxygen, nutrients, and algae. Simulation results indicate that the circulation and biogeochemical cycles within the Puget Sound Georgia Basin system are dominated by the strong estuarine exchange inflow from the Pacific Ocean. This exchange flow into Puget Sound is predicted to increase in response to the future forcing conditions resulting in higher influx of nutrient rich saline water from the Pacific Ocean. Although the magnitude of the predicted response in the main basin and deeper reaches of Puget Sound is relatively small, we note that higher nutrient loads in the intertidal zones and the shallow stratified reaches could lead to conditions suitable for algae blooms and exacerbate the low DO levels in the future.

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Apr 30th, 1:30 PM Apr 30th, 3:00 PM

Sensitivity of Circulation and Biogeochemical Response in Puget Sound to Sea Level Rise and Future Climate Loads

Room 615-616-617

Assessments using future climate conditions based on the Intergovernmental Panel on Climate Change emissions scenario (A1B) have shown that hydrology of major rivers and freshwater runoff from multiple watersheds to Puget Sound, Washington, will be affected. In general, higher winter floods and lower summer flows coupled with future sea level rise have the potential to impact circulation and estuarine exchange. The effects on water properties such as temperature profiles, salinity gradients, and biogeochemical interactions are of interest due to concern over loss of coastal brackish habitats and potential impairment of water quality. In this paper we present a sensitivity analysis using the Puget Sound Georgia Basin hydrodynamic and biogeochemical model based on unstructured grid Finite Volume Coastal Ocean Model (FVCOM) framework and the CE QUAL-ICM model water quality kinetics. Effects of modified hydrology, sea level rise, and nutrient loads corresponding to years 2020, 2040, and 2070 are compared with baseline conditions from 2006. We examine potential large scale changes to the seasonal net transport through the various sub-basins within Puget Sound and also provide a relative comparison of key water quality parameters such as dissolved oxygen, nutrients, and algae. Simulation results indicate that the circulation and biogeochemical cycles within the Puget Sound Georgia Basin system are dominated by the strong estuarine exchange inflow from the Pacific Ocean. This exchange flow into Puget Sound is predicted to increase in response to the future forcing conditions resulting in higher influx of nutrient rich saline water from the Pacific Ocean. Although the magnitude of the predicted response in the main basin and deeper reaches of Puget Sound is relatively small, we note that higher nutrient loads in the intertidal zones and the shallow stratified reaches could lead to conditions suitable for algae blooms and exacerbate the low DO levels in the future.