Columbia River Basin Water Supply and Demand Forecast for 2030Presented by: Keyvan Malek, Washington State University

Contributors:

J.C. Adam, K. Chinnayakanahalli, K. Rajagopalan, R. Nelson, M.E. Barber, C. Stockle, M. Brady, G. Yorgey, S. Dinesh, C. Kruger

Washington State University

Presented at:

2nd annual PNW Climate Science Conference, Seattle

Sep, 2011

WSU Modeling TeamDr. Jennifer AdamAssistant Professor, Civil and Environmental Engineering

Dr. Claudio StöckleProfessor and Chair, Biological Systems Engineering

Dr. Michael BradyAssistant Professor, School of Economic Sciences

Dr. Michael BarberProfessor and Director, Washington Water Research Center

Dr. Kiran ChinnayakanahalliPost-Doctoral Associate, Washington Water Research Center

Chad KrugerDirector of Center for Sustaining Agriculture & Natural Resources (CSANR)

Roger NelsonResearch Associate and Programmer, Biological Systems Engineering

Kirti RajagopalanPhD Student, Civil and Environmental Engineering

Shifa DineshPhD Student, Civil and Environmental Engineering

Georgine YorgeyAssociate in Research, Center for Sustaining Agriculture & Natural Resources (CSANR)

Outline of Talk

Goals Background Modeling Approach Results Conclusions

Goals

To project 2030s water supply and demand in the Columbia River Basin Agricultural and Municipal demands considered

To study the effect of climate change on agriculture (crop water demand, crop yield, cropping pattern)

Background

Columbia River Water resources

sensitive to climate change

Economic value of agriculture (5 billion $ in WA)

Irrigation largest out-of-stream water user

Diverse crop mix

Modeling Approach

Models Used

VIC Hydrology

Liang et al, 1994

CropSystCropping Systems

Stockle and Nelson 1994

Overview of Framework

VIC-CropSyst Model

1. Weather (D)

2. SoilSoil layer depths

Soil water content

3. Water flux (D)Infiltrated water

4. Crop type

Irrigation water = Crop Water Demand

/irrigation efficiency

Sow dateCrop interception

capacityCrop phenologyCrop uptake (D)Water stress (D)

Current biomass (D)Crop Water demand

(D)Harvest dayCrop Yield

VIC CropSyst

D – communicated daily

T – TranspirationIP – Interception capacityI – InfiltrationIr – irrigationWd- Water demandQ – RunoffQ01 – Drainage from 0 to 1Q02 – Drainage from 0 to 2Qb – BaseflowW0 – water content in 0W1 – water content in 1W2 - water content in 2Tmin, Tmax – daily minimum and maximum temperatureWs – wind speedRH – Relative humiditySR – Solar radiation

Qb

Q12

T

IP

Redistribute I, W0, W1 and W2 to CropSyst layers

Q

Q01

W0,W1, W2

T0, T1, T2, IP, Wd

I

CropSyst

VIC

Ir

Daily Tmin, Tmax, Ws, RH, SR, I

VIC-CropSyst Coupling Approach

Invoking CropSyst within VIC gridcell

Crop 1

VIC grid cell(resolution=1/16°)(~ 33 km2)

Crop 2

Non-Crop

Vegetation

CropSyst is

invoked

CropSyst is

invoked

Crops Modeled

Winter Wheat Spring Wheat Alfalfa Barley Potato Corn Corn, Sweet Pasture Apple Cherry Lentil Mint Hops

Grape, Juice Grape, Wine Pea, Green Pea, Dry Sugarbeet Canola

Onions Asparagus Carrots Squash Garlic Spinach

Generic Vegetables

Grape, Juice Grass hay Bluegrass Hay Rye grass

Oats Bean, green Rye Barley Bean, dry Bean, green

Other Pastures

Lentil/Wheat type

Caneberry Blueberry Cranberry

Pear Peaches

Berries

Other Tree fruits

Major Crops

Physical Systemof Damsand Reservoirs

Reservoir Operating Policies

Reservoir StorageRegulated StreamflowFlood ControlEnergy ProductionIrrigation ConsumptionStreamflow Augmentation

0100000200000300000400000500000600000700000800000900000

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

Flow

(cfs

)

VIC Streamflow Time Series

The Reservoir Model (ColSim) (Hamlet et al., 1999)

Slide courtesy of Alan Hamlet

ColSim Reservoir Model (Hamlet et al., 1999) for Columbia Mainstem

Model used as is, except for

Withdrawals being based on VIC-CropSyst results

Curtailment decision is made part of the reservoir model

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Green triangles show the dam locations

Curtailment Rules (Washington State)Curtailment based on instream flow targets Columbia Mainstem Lower Snake Central Region (Methow, Okanogan, Wenatchee) Eastern Region (Walla Walla, Little Spokane,

Colville)

Prorated based on a calculation of Total Water Supply Available

Yakima

Biophysical Modeling:VIC-CropSyst, Reservoirs,

Curtailment

• Crop Yield (as impacted by climate and water availability)

• Adjusted Crop Acreage

• Selective Deficit Irrigation

1. Water Supply2. Irrigation Water

Demand3. Unmet Irrigation

Water Demand4. Effects on Crop

Yield

Economic Modeling:Agricultural Producer

Response

Water Management Scenario

Future Climate Scenario

Inputs Modeling Steps Outputs

Integration with Economics

Economic Scenario

Model Scenarios: Low, Middle, High Climate Change Scenarios

HADCM_B1, CCSM_B1, CGCM_B1, PCM_A1B, IPSL_A1B Hybrid Delta Downscaling Approach (2030s climate) GCMs and Emission Scenarios chosen for

low/middle/high precipitation and temperature change combinations

Water Management Scenarios Additional Storage Capacity Cost Recovery for Newly Developed Water Supply

Economic Scenarios International Trade Economic Growth

http://www.hydro.washington.edu/2860/ Slide courtesy of Alan Hamlet

The UW CIG Supply Forecast

Application of the UW CIG Water Supply Forecast

WSU is building directly off of the UW water supply forecasting effort (Elsner et al. 2010) by starting with these tools that were developed by UW Climate Impacts Group: Implementation of the VIC hydrology model over the

Pacific Northwest at 1/16th degree resolution Reservoir Model, ColSim Historical climate data at 1/16th degree resolution Downscaled future climate data at 1/16th degree

resolution By explicitly incorporating irrigation water

demand into this framework, we can explore the coupled dynamics between water supply and water demand

Results

- Supply Forecast- Irrigation Demand Forecast

Supply in 2030s for the Columbia River Basin (at Bonneville- the outlet of Columbia river basin)

Annual flows are projected to increase by 3% Summer flows are projected to decrease by

16%

Note: The above numbers are based on an average of all 5 future climate scenarios considered

Water Supply Entering

Washington• Eastern: increasing• Western: decreasing

Top: 2030 Flow (cfs)Bottom: Historical Flow (cfs)

Snake River and Columbia River Supplies (Entering Wasington)

Snake river Columbia river

Irrigation and Municipal Demands by Watershed in Washington State

Yakima Supply and Demand

Historical

Future: Hadcm_B1

Walla WallaSupply and Demand

Historical

Future: Hadcm_B1

Projected demand for 2030s (middle climate change and economic scenarios):

Columbia River Basin Scale

Average annual “top of the crop” irrigation demand increases from 10.7 MAF to 11.8 MAF (increase of 10%)

Washington State

Average annual “top of the crop” irrigation demand increases from 4.9 MAF to 5.5 MAF (increase of 12%)

Impacts on Irrigation Demand

Dam-Regulated Supply versus Demand for Columbia River Basin (at Bonneville)

2030 results are for- HADCM_B1 climate scenario- average economic growth and trade

Note: Supply is reported prior to accounting for demands

Conclusions

Supply: we see a small increase (3%) in annual supply in the 2030s But, summer supplies (when there is irrigation

demand) decreases about 16% Demand: we see a significant increase in annual

irrigation demand (10% for the entire Columbia River Basin) in the 2030s

Increased irrigation demand, coupled with decreased seasonal supply poses difficult water resources management questions, especially in the context of competing in stream and out of stream users of water supply.

Acknowledgements

Many thanks to members of the University of Washington Climate Impacts and Land Surface Hydrology Groups Alan Hamlet Marketa Elsner Pablo Carrasco Se-Yeun Lee Dennis Lettenmaier

Funding was provided by the Washington State Department of Ecology

THANK YOU!

Uncertainties

1-Future climate (due to GCMs, greenhouse emission scenarios anddownscaling approach)

2-Model structure (VIC-CropSyst)

3-Water management and economic scenarios

4-Cropping pattern - discrepancy between multiple data sources

5-Irrigation supply – poor data on groundwater and surface waterproportions of the supply

6-Irrigation methods a)No information for upstream states b)Conveyance loss is not explicitly modeled (This is a proportion of the demand at each WRIA)

Change in Crop Yield

Crop typePercent change (tons/hectare)

Corn -12.9Spring Wheat 7.7Winter Wheat 25.1

Alfalfa 10.0Apples 0.0

Cherry Orchard 0.0Potatoes -9.1Grapes 0.0

- Change in some crop yield - Trees does not show significant change

- Results are for full irrigation

Crop Mix Informationfor the Columbia River Basin

United States Department of Agriculture (USDA)

Washington State Department of Agriculture (WSDA)

Yakima Reservoir Model

Irrigation demand from VIC/CropSystCurtailment rules

Proratable water rights prorated according to Total Water Supply Available (TWSA) calculated each month

Monthly Inflows

from VIC-CropSyst

Total System of Reservoirs (capacity 1MAF approx.)

Objectives:

• Reservoir refill by June 1st

• Flood space availability

Instream flow

targets

Gauge at Parker