Climate Change and Sea Level Rise Impacts on Puget Sound

Angela GroutMarine & Sediment Assessment Group

Water and Land Resources Division Science Seminar – November 29, 2005

Talk Outline

Sea Level RiseSea Level Rise

Water QualityWater Quality

Implications for Marine EcosystemsImplications for Marine Ecosystems

Vertical Land Movement Rates

in Western Washington

• Uplift occurs on northern outer coast and southern outer coast near Columbia River

• Subsidence occurs in most of Puget Sound and most of southern outer coast

Friday Harbor sea level trend

From 1935 to the present, water level at the Friday Harbor gauge has been rising at about the global average.

Lyles et al. (1988)

Seattle sea level trend

From 1900 to the present, water level at the Seattle gauge has been rising at about 2X the global average.

Lyles et al. (1988)

Neah Bay sea level trend

From 1935 to the present, water level at the Neah Bay gauge has been trending down.

Lyles et al. (1988)

Barometric Pressure Effects

Short term low pressure cells allow water level to rise: up to 2.0 ft on 22 Nov 2001 at Tacoma

1991 2001 2011 2021 2031 2041 2051 2061 2071 2081 20910

10

20

30

40

50

60

70

Sea

Le v

el R

ise

(cm

)

Eastern Pacific

Equatorial Atlantic

NW Atlantic

Arctic Ocean

Regional Changes in Sea Level

Source: Canadian Climate Change Model

Local Sea Level Rise ScenariosCanning (1991)

Effects and Implications of Sea Level Rise

• Inundation of low-lying coastal areas• Increased coastal flooding• Increased rates of coastal erosion• Loss of coastal wetlands• Changes in tidal prism and salinity of embayments• Rise in coastal water table• Changes in stormwater/wastewater outfall

hydraulics

Sea Surface Temperature at Race Rocks

From Snover et al. 2005

Long-term warming trend of 1.7oF (0.9oC) since 1921 and 1.8oF (1.0oC) since 1950.

Since 1985 ↑ ≈ 0.85oC

Preliminary Temperature Trends at

King County Beach Sites (1985-present) Mean = +0.047 oC/yr

Since 1985 ↑ ≈ 0.94oC

Preliminary Temperature Trends Offshore(1998-present)

Temperature Trends at KSBP01 (1998-2005)

0

50

100

150

200

0 0.05 0.1 0.15

Increase in Temperature per Year (deg C)

Dep

th (m

)

Other Parameters Currently Under Study for Trends

• Salinity – Positive trends observed at beach and offshore sites

• Dissolved Oxygen – No trends observed offshore

• Nutrients• Fecal Coliform/Pollutants

Stratification IndexHigh ΔSigma-t = Strongly Stratified Water ColumnLow ΔSigma-t = Weakly Stratified Water Column

KSBP01 Stratification Index(Delta sigma-t = max - min)

02468

101214161820

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05

Delta

sig

ma-

t

Stratification IndexHigh ΔSigma-t = Strongly Stratified Water ColumnLow ΔSigma-t = Weakly Stratified Water Column

KSBP01 Stratification Index(Delta sigma-t = max - min)

02468

101214161820

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05

Delta

sig

ma-

t

Drought Conditions

Stratification IndexHigh ΔSigma-t = Strongly Stratified Water ColumnLow ΔSigma-t = Weakly Stratified Water Column

KSBP01 Stratification Index(Delta sigma-t = max - min)

02468

101214161820

Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04 Jan-05

Delta

sig

ma-

t

Drought Conditions

Snowpackabove normal

KSBP01 Stratification Index

02468

101214161820

1998 1999 2000 2001 2002 2003 2004 2005

Delta

sig

ma-

tJanFebMarAprMayJunJulAugSepOctNovDec

Newton et al. 2003 – Weak stratification → More sluggish circulation → Increased residence time of water in Puget Sound

Water Column Most Stable in Spring/Summer Months

Implications for ecosystem-level processes!

↓ precip (snowpack) → ↑ surf salinity → ↓ stratification

1) Either: low DO less likely (↑ mixing rates) OR low DO more likely (↑ residence time)

2) Changes in the timing and/or intensity of phytoplankton blooms could result in a mismatch of PP blooms with zooplankton emergence → possible impact on trophic transfer and biota recruitment success

3) Decreased circulation would increase residence time of contaminants and pollutants in Puget Sound.

4) Implications for transport/retention of planktonic larvae & ichthyoplankton.

RecommendationsMore baseline and environmental variability data

Monitoring focused on long-term

Characterization of physical, chemical & biological processes and the connections between them

Engagement of public interest

Acknowledgements

• Douglas Canning, Ecology

• Eric Grossman, Western Coastal and Marine Geology Program, USGS, Santa Cruz, CA

• Tom Georgianna, WLRD