Using DHSVM to Study Land Cover Change and Temperature Change Effects on Streamflow in

Puget Sound Drainage

Lan Cuo and Dennis Lettenmaier

July 26 2006

• Objectives1. land cover change effects: ~100 years

ago, current and 100 years later

2. Climate change effects (mainly T)

• Background

• Methodology

• Results

• Problems

• Future Work

Background• Study Area

Puget Sound Drainage• Bounded by the Cascade

and Olympic Mountains• 41,439 sqr.km• 80% land, 20% water• Temperate rainforest ecosystem• Western Hemlock, Douglas fir,

Subalpine forest, and Alpine Medows

• Steep slope: mollisol-ultisol-alfisol

Gentle slope: Inceptisol-mollisol-spodosal

Nearly level: inceptisol-mollisol-histosol

http://wa.water.usgs.gov/projects/pugt/images/studymap.gif

Population in 1900

0

20000

40000

60000

80000

100000

120000

City/T

own

Islan

d Cou

nty

Jeffe

rson

Cou

nty

King C

ounty

Kitsap

Cou

nty

Mas

on C

ounty

Pierce

Cou

nty

San Ju

an C

ount

y

Skagit

Cou

nty

Snoho

mish C

ount

y

Thurs

ton C

ount

y

Wha

tcom C

ount

y

Background

• Population

Population in 2000

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

City/T

own

Islan

d Cou

nty

Jeffe

rson

Cou

nty

King C

ounty

Kitsap

Cou

nty

Mas

on C

ounty

Pierce

Cou

nty

San Ju

an C

ounty

Skagit C

ount

y

Snoho

mish

Cou

nty

Thurs

ton

County

Whatc

om C

ounty

King county had almost 18 times more population in 2000 than 1900.

Source: Washington State Office of Financial Management

SkagitStillaguamishSnohomishCedarGreenPuyallupNisquallyDeschutesQuilceneHammahammaDosewallipsDuckabushSkokomish

Dam source: Washington State Department of Ecology

Background• Upland basins

Methodology• Model Structure

DHSVM Components

Interception Evapotranspiration

Energy and radiation balance

Unsaturated soil water movement

Saturation excess and infiltration excess runoff

Ground water recharge and discharge

Snow accumulation & melt

Methodology• Forcing Data 1-16th degree Tmin, Tmax, precipitation and

wind speed grids. Used 33 stations from 1927 to 2003

Mean monthly precipitation comparison between PRISM and 1-16th grid

Accumulated monthly precipitation comparison between stations, 1-8th grid and 1-16th grid over the Cedar Basin

Annual precipitation (mm)

Annual mean Tmax (C)

Annual mean Tmin (C)

• 2002 Land Cover Map in Puget Sound (Marina, 2004)

Fixing problems:Filled no data values and clouds location with reference to CCAP 2000land cover map.

Supplement north and south portion with CCAP 2000 and GAP 1991 land cover map.

Problems:1. Clouds, no data values.2. Incomplete in the north and south portion of Puget Sound

•Modified Land Cover TypesLand Cover Types Percentage

Dense urban (>75% impervious area) 1.20

Light-mediu urban (<75% impervious area) 2.23

Bare ground 0.70

Dry ground 1.03

Native grass 0.02

Grass/crop/shrub 7.36

Mixed/deciduous forest 30.04

Coniferous forest 32.78

Regrowth vegetation 0.48

Clear cuts 0.70

Snow/rock/ice 6.77

Wetlands 0.28

Shoreline 0.09

Water 16.32

Methodology• Pilot Study Areas

• Upland

Cedar Basin

Methodology• Pilot Study Areas• Lowland Urban basins

Mill Creek

Spring Brook Creek

Land cover Springbrookcreek basin

(22 km2)

Mill creek Earthworks Park basin (6.4 km2)

Mill creekbasin (15 km2)

Dense urban 32.59 25.83 46.78

Ligth-medium urban 31.34 32.51 24.98

Bareground 0.83 0.43 0.76

Dry ground 2.24 1.85 1.79

Grass/crop/shrub 7.79 8.86 8.86

Mixed/deciduous forest 22.49 26.23 14.45

Coniferous forest 2.54 4.00 1.72

Water 0.12 0.22 0.33

Land cover types and percentage in urbanized basins.

12113346 Gage (Spring brook creek)

12113347 Gage (mill creek at Earthworks Park)

12113349 Gage Location and Surround (Mill creek at mouth)

Results - Streamflow Calibration in Cedar Basin

A. Cedar River (1945-1985 )

Daily statistics:Observation Mean = 7.50 cmsSimulation Mean = 7.50 cmsCorrelation Coefficient = 0.86RMSE = 3.92 cmsModel Efficiency = 0.67

B. Rex River (1945-1985)

Daily statistics:Observation Mean = 2.93 cmsSimulation Mean = 2.48 cmsCorrelation Coefficient = 0.81RMSE = 2.15 cmsModel Efficiency = 0.23

C. Taylor Creek (1956-1985)

Daily Statistics:Observation Mean = 2.80 cmsSimulation Mean = 2.78 cmsCorrelation Coefficient = 0.87RMSE = 1.18 cmsModel Efficiency = 0.73

Results – Streamflow Validation period : 1985-2003

A. Cedar River

Daily statistics:Observation Mean = 6.87 cmsSimulation Mean = 6.97 cmsCorrelation Coefficient = 0.84RMSE = 4.54 cmsModel Efficiency = 0.60

B. Rex River

Daily Statistics:Observation Mean = 2.69 cmsSimulation Mean = 2.29 cmsCorrelation Coefficient = 0.78RMSE = 2.42 cmsModel Efficiency = 0.15

C. Taylor Creek

Daily Statistics:Observation Mean = 2.63 cmsSimulation Mean = 2.65 cmsCorrelation Coefficient = 0.85RMSE = 1.40 cmsModel Efficiency = 0.65

Urban Basin Streamflow Simulation

Simulation Period: 1995-10-1 to 2003-9-30. Time step: 1 hourMill Creek at Earthworks Park, area 2.49 sq.mile (6.4 sq.km)

Urban Basin Streamflow Simulation

Mill Creek Basin area 5.63 sq.mile (14.6 sq.km)

Urban Basin Streamflow Simulation

Spring brook creek basin 8.44 sq.mile (21.9 sq.km)

Green River Basin Simulation

Daily Statistics:Observation Mean = 10.85 cmsSimulation Mean = 10.39 cmsCorrelation Coefficient = 0.84RMSE = 7.69 cmsModel Efficiency = 0.56

Map ID Creator Published Year

Uw001* USGS 1902

Uw017* USGS 1898

Uw029* USDA 1910

Topo063* USGS 1900

Topo064* USGS 1900

Uw083 USGS 1898

Uw102 Department of Interior 1883

Uw073 USGS 1898

Uw072 USGS 1898

Uw054 USGS 1899

Reconstruction of Historical Land Cover Map

Map of Washington Showing Classification of Lands 1902 (USGS)

Re-construction Strategy• Geo-reference land cover maps.• Digitize land cover types ( 5 maps)• Make a composite historical map of land cover types for timber

industry• Transform historical timber industry land cover types to Alberti

Marina’s land cover types by using census data, DEM. Crittenden 1997; Harlow et al. 1979: Maple tree grows up to 1000 ft in

B.C Canada.

• Timber industry land cover types Transformed land cover types• Cut areas/ Timberless /Burned areas Light-medium urban (?)

Grass/crop/shrub (?)Bareground (?)Dry ground (?)Clear-cuts (?)

• 0-100,000 feet B.M. per acre Coniferous forest (?) Mixed/deciduous forest (?)

Problems

• Good calibration in one basin does not guarantee good simulations in the other basins.

• Critical issue for urban basin is to get correct basin area. Stream channels on topo map are need to get the outline of basin.

Future Work

• Write a urban basin study report.• Search or make lowland urban basins.• Simulate streamflow in Puget Sound

basins• Generate historical land cover map for

DHSVM• Study current and historical land cover

change effects• Study climate change (mainly Ta) effects

Special thanks to:Matt WileyChunmei

BerntAlan

Questions?