Land%20Cover%20Change%20and%20Climate%20Change%20Effects%20on%20Streamflow%20in%20Puget%20Sound%20Basin,%20Washington - PowerPoint PPT Presentation

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Land%20Cover%20Change%20and%20Climate%20Change%20Effects%20on%20Streamflow%20in%20Puget%20Sound%20Basin,%20Washington

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Title: Land%20Cover%20Change%20and%20Climate%20Change%20Effects%20on%20Streamflow%20in%20Puget%20Sound%20Basin,%20Washington


1
Land Cover Change and Climate Change Effects on
Streamflow in Puget Sound Basin, Washington
  • Lan Cuo1, Dennis Lettenmaier1, Marina Alberti2,
    Jeffrey Richey3
  • 1 Department of Civil and Environmental
    Engineering, University of Washington
  • 2 Department of Urban Design and Planning,
    University of Washington
  • 3 Department of Chemical Oceanography,
    University of Washington
  • February 21, 2007
  • University of Washington

2
  • Background
  • Early settlement started in the mid 1800s in
    the Puget Sound Basin.
  • Population has increased by 17 times since
    1900.
  • 70 of Washington state population lives in
    the Puget Sound Basin.
  • Land cover change is mainly caused by logging
    and urbanization.
  • Temperature is changing in the Puget Sound.
  • Objectives
  • How does land cover change affect streamflow
    in the Puget Sound Basin?
  • How does temperature change affect streamflow
    in the Puget Sound Basin?

3
Methodology
  • Study Area - Puget Sound Basin
  • Area 30,807 sqr.km
  • Bounded by the Cascade
  • and Olympic Mountains
  • Maritime climate, annual precipitation 600 mm -
    3000 mm, October April
  • Land cover 82 vegetation
  • 7 urban
  • 11 other

4
Methodology
  • Generate forcing data and land cover maps for the
    study area.
  • Calibrate hydrology model.
  • Study land cover change effects by removing the
    long term trend in temperature.
  • Study climate change effects using temperature
    regime detrended to 1915, temperature regime
    detrended to 2002, and historical temperature
    regime.

5
Methodology
  • Model Distributed Hydrology Soil Vegetation Model
  • Interception
  • Evapotranspiration
  • Snow accumulation and melt
  • Energy and radiation balance
  • Saturation excess and infiltration excess
    runoff
  • Unsaturated soil water movement
  • Ground water recharge and discharge

6
Forcing Data Basin Averaged Historical Annual
Precipitation
Eastern Puget Sound Basins
7
Forcing Data Basin Averaged Historical Annual
Precipitation
Western Puget Sound Basins
8
Forcing Data Basin Averaged Historical Annual
Tmin
Eastern Puget Sound Basins
9
Forcing Data Basin Averaged Historical Annual
Tmin
Western Puget Sound Basins
10
Forcing Data Basin Averaged Historical Annual
Tmax
Eastern Puget Sound Basins
11
Forcing Data Basin Average Historical Annual
Tmax
Western Puget Sound Basins
12
Data 2002 Land Cover Map (Alberti et al., 2004)
Land Cover Types Proportion ()
Dense urban (gt75 impervious area) 2.41
Light-mediu urban (lt75 impervious area) 3.97
Bare ground 0.42
Dry ground 1.30
Native grass 0.05
Grass/crop/shrub 5.36
Mixed/deciduous forest 32.19
Coniferous forest 36.41
Regrowth vegetation 0.61
Clear cuts 0.50
Snow/rock/ice 7.85
Wetlands 0.34
Shoreline 0.13
Water 8.46
13
Data Reconstructed 1883 land cover
Land Cover Types Proportion ()
Light-mediu urban (lt75 impervious area) 0.40
Grass/crop/shrub 7.43
Mixed/deciduous forest 29.61
Coniferous forest 48.23
Snow/rock/ice 6.38
Water 7.96
  • Source
  • Department of Interior, Density of
    Forests-Washington Territory, 1883
  • 2. Historical records of Puget Sound county
    population development

14
Results Calibration
15
Results Calibration
16
Results Monthly Statistics of Calibrated and
Measured Streamflow
Basin (gage) Observation Mean (cms) Simulation Mean (cms) Correlation Coefficient RMSE (cms) Model Efficiency
Cedar (12115000) 7.93 8.22 0.88 2.78 0.77
Deschutes (12078720) 0.97 0.99 0.89 0.41 0.80
Green (12104500) 12.03 12.42 0.86 4.96 0.67
Nisqually (12083000) 10.31 9.96 0.87 3.99 0.73
Puyallup (12094000) 12.12 12.36 0.78 4.33 0.54
Snohomish (12141300) 35.05 33.74 0.88 10.48 0.75
Stillaguamish (12161000) 32.48 32.91 0.81 11.74 0.58
Duckabush (12054000) 11.72 9.94 0.87 4.19 0.69
Quilcene (12052210) 4.34 4.03 0.81 2.17 0.64
Hamma Hamma (12054500) 10.40 10.27 0.82 3.91 0.65
Skokomish (12056500) 14.84 14.93 0.88 5.04 0.77
17
Results Land Cover Change Effects Seasonal Flow
Eastern Puget Sound Basins
18
Results Land Cover Change Effects Seasonal Flow
Western Puget Sound Basins
19
Results Land Cover Change Effects Seasonal Flow
71 urbanization
Urbanization Affected Gages
64 urbanization
31 urbanization
20
Results Mean Annual Streamflow
Basin (gage) 1883 Land Cover (cms) 2002 Land Cover (cms) 2002 vs. 1883 Change ()
Cedar (12115000) 6.66 7.06 6
Deschutes (12078720) 0.98 1.06 8
Green (12104500) 10.61 11.70 10
Nisqually (12083000) 10.26 11.58 13
Puyallup (12094000) 11.54 12.40 7
Snohomish (12141300) 29.46 31.85 8
Stillaguamish (12161000) 30.77 31.44 2
Quilcene (12052210) 2.29 2.75 20
Duckabush (12054000) 9.01 10.18 13
Hamma Hamma (12054500) 8.90 9.86 11
Skokomish (12056500) 13.24 14.87 12
Springbrook Creek (12113346) 0.27 0.33 22
Upper Mill Creek (12113349) 0.37 0.46 24
21
Results Daily Peak Flow
Eastern Puget Sound Basins
22
Results Daily Peak Flow
Western Puget Sound Basins
23
Results Daily Peak Flow
71 urbanization
Urbanization Affected Gages
64 urbanization
31 urbanization
24
Mann-Kendall Trend Analysis on Measurement and
Model Residuals for Upland Gages
Annual Maximum Daily Peak Flow (AMDPF)
Gage Location Gage Start Period End Period Confidence level Slope
Cedar river near Cedar falls 12115000 1945-10-1 2002-9-30 - 0.03
Duckabush river near Brinnon 12054000 1938-7-1 2002-9-30 0.9 0.40
NF Skokomish at Hoodsport 12056500 1925-10-1 2002-9-30 - 0.02
SF Skykomish at Index 12133000 1922-2-1 1982-9-30 - 0.14
SF Stillaguamish at Granite Falls 12161000 1928-8-1 1980-11-30 0.6 1.20
  • No significant trend was found in monthly
    and annual streamflow at the above gages.
  • Although model simulation shows increase
    trend in AMDPF and annual streamflow for upland
    basins, the trend might not be statistically
    significant.

25
Climate Change Effects Seasonal Flow
Eastern Puget Sound Basins
26
Climate Change Effects Seasonal Flow
Western Puget Sound Basins
27
Climate Change Effects Seasonal Flow
71 urbanization
Urbanization Affected Gages
64 urbanization
31 urbanization
28
DJF winter months, JJA summer months
Basin (gage) Detrended 1915 vs. Historical Detrended 1915 vs. Historical Detrended 2002 vs. Historical Detrended 2002 vs. Historical
DJF JJA DJF JJA
Cedar (12115000) -25 18 33 -21
Green (12104500) -10 7 10 -7
Nisqually (12083000) -9 14 7 -9
Puyallup (12094000) -8 7 9 -6
Snohomish (12141300) -6 -3 6 3
Stillaguamish (12161000) -10 9 10 -8
Quilcene (12052210) -3 11 2 -7
Duckabush (12054000) 1 -5 -1 5
Hamma Hamma (12054500) 2 -9 -2 9
Skokomish (12056500) 2 -15 -2 14
Deschutes (12078720) 0 -4 0 4
Springbrook Creek (12113346) -0.3 -0.5 0.3 1
Upper Mill Creek (12113349) -0.2 -0.8 0.4 1
29
Climate Change Effects Daily Peak Flow
Eastern Puget Sound Basins
30
Climate Change Effects Daily Peak Flow
Western Puget Sound Basins
31
Climate Change Effects Daily Peak Flow
71 urbanization
Urbanization Affected Gages
64 urbanization
31 urbanization
32
Climate Change Effects Mean Annual Flow Change
Basin (gage) Detrended 1915 vs. Historical Detrended 2002 vs. Historical
Cedar (12115000) -3 3
Deschutes (12078720) -0.2 0.2
Green (12104500) -0.4 0.5
Nisqually (12083000) -0.9 0.9
Puyallup (12094000) -0.7 0.7
Snohomish (12141300) -0.7 0.8
Stillaguamish (12161000) -0.3 0.3
Quilcene (12052210) -0.2 0.2
Duckabush (12054000) -0.5 0.5
Hamma Hamma (12054500) -0.5 0.4
Skokomish (12056500) -0.7 0.7
Springbrook Creek (12113346) -0.4 0.6
Upper Mill Creek (12113349) -0.3 0.5
33
Mann-Kendall Trends of Raw Measurement
Combination of Climate Change Effects and Land
Cover Change Effects
Gages Maximum Daily Peaks Maximum Daily Peaks Monthly Q Monthly Q Annual Q Annual Q
Confidence level Slope Confidence level Slope Confidence level Slope
12115000 - -0.06 0.95 -0.02 0.95 -0.03
12054000 0.60 0.27 - 0.003 - 0.01
12056500 0.90 0.52 0.90 0.02 0.80 0.02
12133000 - 0.89 0.80 0.10 - 0.06
12161000 0.60 1.17 0.60 0.04 0.60 0.06
For upland basins, land cover is not a dominant
effect in changing streamflow.
34
Pacific Decadal Oscillation (PDO)
  • Positive phase () warmer and dryer climate
  • Negative phase (-) colder and wetter climate
  • In upland basins, PDO perhaps play a more
    important role than land cover change effects.

35
Conclusions
  • In upland basins, fall, winter and spring
    streamflows are higher under current land cover
    condition because of lower ET. Summer streamflow
    is lower in 2002 scenario because of less water
    storage in the basin.
  • On average, mean annual streamflows are slightly
    higher under current land cover condition which
    might not be statistically significant.
  • Peak flows are affected by the combination of ET
    and infiltration excess runoff. Peak flows tend
    to be higher under current land cover condition
    for most basins.
  • Chances of getting peak flows are higher under
    current land cover condition.

36
Conclusions
  • Climate change mainly affects upland basins where
    snow occurs. Temperature change mainly affects
    seasonal distribution of streamflow. Warmer
    temperature regime tends to generate higher
    winter flow but lower summer flow due to less
    snow occurrence, early snow melt and less basin
    snow storage.
  • Simulation shows that land cover change might be
    more important than climate change in affecting
    the streamflow in lowland urbanizing basins.
  • Trend study in upland gauged stations shows that
    land cover change is not the dominant factor that
    influences peak flows, monthly and annual flows
    in the upland basins.
  • Regional climate system such as PDO perhaps plays
    a more important role in affecting streamflow in
    the upland basins.

37
Thank You !
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