Quantifying Changes in Water Levels and Storm Eff ectsNovember 7, 2011

VULNERABILITY AND RESILIENCE OF COASTAL

ESTUARIES AND COMMUNITY

INFRASTRUCTURE TO CLIMATE CHANGE

Joe Hamman, Research AssistantDept. of Civil and Environmental EngineeringUniversity of Washington

Alan F. Hamlet, Research Assistant Professor JISAO/CSES Climate Impacts GroupDept. of Civil and Environmental Engineering, University of Washington

Sea Level Quantify sea-level rise downstream of estuaries Explore relationships between PNW regional sea

level and observed global climate patterns

PROJECT GOALS

Hydrology Simulate hydrologic changes upstream of

estuaries Describe changes in runoff and flood behavior

Impacts on Estuaries Combine hydrologic and sea level changes to

quantify estuarine water levels and occurrences of flooding, inundation, and other high/low water extremes

Hydrologic Modeling Use naturalized flows developed by the

Variable Infi ltration Capacity Model (VIC) for the Columbia Basin Climate Change Scenarios Project

Reservoir Modeling Simulates flood control operations at

major reservoirs Hydrodynamic Modeling

Combine regulated flows with daily sea level predictions to simulate water surface elevations along the lower river

Integrate with GIS based digital elevation models to quantify extent of flooding and inundation

Statistical / Regression Based Model Develop simple regression relationships

between atmospheric variables and predicted regulated floods to simulate estuarine water elevations

PROJECT PLAN

Hydrologic Model (VIC)

Reservoir Operations

Model

Hydrodynamic Models

Statistical / Regression

Model

Harmonic Tidal Predictions

Meteorological Regression

Model

Hydrology

Sea Level

Impacts

Change in Dominant Run-off Timing Mixed Rain and Snow Basins experience

higher flows in fall/winter months and reduced flows in spring/summer months**

Snow dominant basins transition towards hydrographs resembling present day mix rain and snow basins

Increased Flood Magnitudes Mean estimated future 100 year flood is

about 30% higher than the historical (Skagit at Mt. Vernon, A1B)

98% confidence that Q100 will increase

PREDICTED HYDROLOGIC CHANGES

Snow Dominant

Mixed Rain and Snow

Local Sea Level Change Observed Rates: ±2 mm yr -1

Negative rates explained by crustal deformation

Global Sea Level Rise (IPCC AR4) 1961-2003: 1.8 ± 0.5 mm yr -1

20th Century: 1.7 ± 0.5 mm yr-1

Global Trends Sea Level PNW experiencing global

average

OBSERVED SEA LEVEL CHANGES

1900 1920 1940 1960 1980 20006900

6950

7000

7050

7100

7150

7200

Trend = 1.9862 mm/year

Seattle

Sea Level

Trend

1920 1940 1960 1980 20006800

6850

6900

6950

7000

7050

7100

7150

7200

Trend = 0.59574 mm/year

Victoria

Sea Level

Trend

1940 1960 1980 20006800

6850

6900

6950

7000

7050

7100

7150

7200

Trend = 1.0106 mm/year

Friday Harbor

Sea Level

Trend

1940 1960 1980 20006800

6850

6900

6950

7000

7050

7100

7150

7200

Trend = -1.7995 mm/year

Neah Bay

Sea Level

Trend

1900 1920 1940 1960 1980 20006900

6950

7000

7050

7100

7150

7200

Trend = 1.9862 mm/year

Seattle

Sea Level

Trend

1920 1940 1960 1980 20006800

6850

6900

6950

7000

7050

7100

7150

7200

Trend = 0.59574 mm/year

Victoria

Sea Level

Trend

1940 1960 1980 20006800

6850

6900

6950

7000

7050

7100

7150

7200

Trend = 1.0106 mm/year

Friday Harbor

Sea Level

Trend

1940 1960 1980 20006800

6850

6900

6950

7000

7050

7100

7150

7200

Trend = -1.7995 mm/year

Neah Bay

Sea Level

Trend

Global Sea Level Rise

IPCC 2007

Church et al., 2004

UW CIG for Puget Sound Low Prob. / High Impact:

55 cm by 2050 128 cm by 2100

High Prob. / Low Impact: 8 cm by 2050 16 cm by 2100

IPCC scenario based projections

Daily Sea Level calculated using: Harmonic constants (NOAA) Regression analysis to

predict anomalies

PREDICTED SEA LEVEL CHANGES

1980 2000 2020 2040 2060 2080 2100 21200

100

200

300

400

500

600

700

A1B B1Projections of mean global sea level in mm relative to 1990s levels for

30-yr period surrounding the period of interest

A1B B12020s 68 692040s 141 1322080s 332 274

data from Hunter, 2010

1920 1940 1960 1980 20003500

4000

4500

5000

5500

Time (years)

Sea

Lev

el (m

m)

Historic Level

CC Level - 2080s A1B

Sea Level, Seattle, WA

PUTTING IT ALL TOGETHER

9/25

/05

10/1

5/05

11/4

/05

11/2

4/05

12/1

4/05

1/3/

0610

12

14

16Port Townsend, WA

(MHHW)

MHHW MHHW + 1.6'

MH

HW

(ft

)

9/25

/05

10/1

5/05

11/4

/05

11/2

4/05

12/1

4/05

1/3/

060

10000

20000

30000

40000

50000

60000Skagit River at Concrete

Historical CC

Daily F

low

(cfs

)

Incorporate hydrology and sea level models into existing hydrodynamic models USGS

DELFT2D/3D USACE/FEMA

HEC-RAS / FLO-2D

Use models to investigate Changing river dynamics Impacts of larger flood

magnitudes and sea level rise

Examine coincidence of flooding and high tides Using the “synthetic”

future climates, develop joint probability distributions that describe the likelihood of coincident flooding and high tides.

Role of global climate patterns, such as ENSO, in regional sea level Can we make inferences

on future climates by observing past El Nino years?

OTHER ANGLES

-2 0 2 4-200

-100

0

100

200

300

400Port Townsend, WA 1/1972-12/2009

JanuaryFebruaryMarch

Nino3.4 Index

Mean S

ea L

eve

l (m

m)

Theoretical joint probability of exceedence (10 %-90 %).

Loganathan et al., 1987

Complete Nisqually Reservoir ModelDevelop time series approximations of historical and

future sea level near study estuaries Incorporate hydrology and sea level models into

existing hydrodynamic modelsValidate models using water levels measures within

the tidally influenced estuariesQuantify flooding / inundation using GIS approach

WHAT’S LEFT TO DO?

QUESTIONS?

THANK YOU

Skagit River 3,000 sq. mi., 5 major

reservoirs operated by Seattle Public Utilities and Puget Sound Energy

Nisqually River 750 sq. mi, 2 major reservoirs

operated by Tacoma Power

STUDY STATS

0 80 160 240 32040Kilometers

¯Nisqually River

Skagit River

CANADA Historical Scenario Based on observed

temperature and precipitation data

Climate Change Scenarios A1B – Represents

unconstrained growth B1 – Represents rapid

growth with an ecological focus

Climate Models Echam5 climate model

for 2040s and 2080s

Apri l 1 SWE has predominantly decreased: Most dominant in mixed snow-

rain basins, Upward trends are generally due

to increased precipitation, When changes in temperature

are isolated, nearly all trends are negative,

PNW SWE decreases 0.14% yr -1 from 1916 to 2003.

Freshwater infl ow has changed over the period 1948-2003: Total annual inflow declined 13

percent, Snowmelt timing shifted earlier

by 12 days (2.1 days per decade),

The fraction of annual flow entering Puget Sound during the summer months decreased 18 percent.

OBSERVED HYDROLOGIC CHANGES

Hamlet, 2005

Snover et al., 2005

OBSERVED HYDROLOGIC CHANGES