Columbia River Basin Water Supply and Demand Forecast for the 2030s

Jennifer C. Adam, Assistant ProfessorCivil and Environmental EngineeringWashington State University

WSU Modeling TeamCivil and Environmental EngineeringJennifer Adam, Assistant ProfessorMichael Barber, Professor and Director of Washington Water CenterKiran Chinnayakanahalli, Postdoctoral AssociateKirti Rajagopalan, PhD StudentShifa Dinesh, PhD Student

Biological Systems EngineeringClaudio Stöckle, Professor and ChairRoger Nelson, Research AssociateKeyvan Malek, PhD Student

School of EconomicsMichael Brady, Assistant ProfessorJon Yoder, Associate ProfessorTom Marsh, Professor and Director of IMPACT Center

Center for Sustaining Agriculture and Natural ResourcesChad Kruger, DirectorGeorgine Yorgey, Research Associate

Background

The economic, ecologic, and cultural well being of Washington's Columbia River Basin depends on water

Irrigation largest water user

Economic value of agriculture (5 billion $ in WA)

Water resources sensitive to climate change

Better understanding of future range in supply and demand needed to guide investment decisions

Goals

To project 2030s water supply and (agricultural and municipal) demand in the Columbia River Basin

WA Dep. of Ecology Report to State Legislature (November, 2011)

Linked WSU Study Components

1. Regional survey of Columbia River Basin water managers

2. Biophysical modeling of historical and future supply and irrigation demand

3. Economic analyses of domestic and international factors driving agricultural production

4. Municipal demand forecast 5. Hydropower review

Modeling Integration:*Surface Hydrology*Cropping Systems*Water Management*Economics

Modeling Approach

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 WSU added elements for handling agriculture:

integrated crop systems and hydrology irrigation withdrawals from reservoirs, and including

some smaller reservoirs, curtailment modeling economic modeling of farmer response

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

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

Model Calibration/Evaluation Calibration:

Streamflows (we used calibration from Elsner et al. 2010 and Maurer et al. 2002)

Crop Yields (using USDA NASS values) Irrigation Rules (using reported irrigated

extent by watershed) Evaluation:

Streamflows (Elsner et al. 2010 and Maurer et al. 2002)

USBR Diversions from Bank’s Lake (for Columbia Basin Project)

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) (UW

CIG) 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

1. Columbia Basin-Scale and Columbia Mainstem

2. Example Watershed-Scale1. Yakima2. Walla Walla

Results Draft

Water Supply Entering

Washington• Eastern: increasing• Western: decreasing

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

Water Supply Entering Columbia Mainstem

• Eastern: increasing• Western: decreasing

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

Snake River and Columbia River Supplies

Snake River Columbia River

Regulated Supply vs 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

Regulated Supply and In-Stream Flow Requirements at Key Locations Future

(2030)Historical (1977-2006)

Note: Supply is reported prior to accounting for demands

Watersheds Included in Study

Out-of-Stream Demand by Watershed

Yakima

Yakima Supply

Yakima Demand

Yakima Supply and Demand

Historical

Hadcm_B1

Walla Walla

Walla Walla Supply

Walla Walla Demand

Walla WallaSupply and Demand

Historical

Hadcm_B1

Conclusions and Future Directions Changes in supply (average of all climate

scenarios) 3% increase in annual flow at Bonneville However, 16% decrease in summer flow at Bonneville

Changes in demand (middle econ and climate scenarios) 10% increase in agricultural demand over basin 12% increase in agricultural demand over state

Some watersheds more impacted than others 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.

Time Line on Report to State Legislature Outreach workshops in Spokane, Wenatchee, and

Tri-Cities (last month) Draft Legislative Report has been released:

http://www.ecy.wa.gov/programs/wr/cwp/wsu_supply-demand.html

Final Legislature Report by end of October: Responses to comments from workshops High/low economic scenarios Unmet demand due to curtailment

Full Technical Report by end of year: Impacts of climate change and curtailment on

crop yield Full economic scenarios

Longer-Term Directions

2016 Report to State Legislature, improvements that are being considered Groundwater dynamics Columbia-basin scale economics (not just

state-level) Fuller inclusion of climate change scenarios More ground-truthing

BioEarth

http://www.cereo.wsu.edu/bioearth/

• Overarching Goal: To improve the understanding of regional and decadal-scale C:N:H2O interactions in context of global change to better inform decision makers involved in natural and agricultural resource management.

Acknowledgements

Alan Hamlet and others at UW CIG Peer reviewers Bob Mahler, Ari

Michelson, Jeff Peterson Dana Pride WA Dep. 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 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)

Example WRIA Results: – Supply in WENATCHEE

Example WRIA Results - Demand in WENATCHEE

Example WRIA Results – Supply and Demand in WENATCHEE