Columbia River Basin Water Supply
and Demand Forecast for 2030
Presented 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 Team
Dr. Jennifer Adam
Assistant Professor, Civil and Environmental Engineering
Dr. Claudio Stöckle
Professor and Chair, Biological Systems Engineering
Dr. Michael Brady
Assistant Professor, School of Economic Sciences
Dr. Michael Barber
Professor and Director, Washington Water Research Center
Dr. Kiran Chinnayakanahalli
Post-Doctoral Associate, Washington Water Research Center
Chad Kruger
Director of Center for Sustaining Agriculture & Natural Resources (CSANR)
Roger Nelson
Research Associate and Programmer, Biological Systems Engineering
Kirti Rajagopalan
PhD Student, Civil and Environmental Engineering
Shifa Dinesh
PhD Student, Civil and Environmental Engineering
Georgine Yorgey
Associate 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-ofstream water user
Diverse crop mix
Modeling Approach
Models Used
VIC
CropSyst
Hydrology
Cropping Systems
Liang et al, 1994
Stockle and Nelson 1994
Overview of Framework
VIC-CropSyst Model
VIC
CropSyst
1. Weather (D)
2. Soil
Soil layer depths
Soil water content
3. Water flux (D)
Infiltrated water
4. Crop type
Irrigation water = Crop
Water Demand /irrigation
efficiency
Sow date
Crop interception capacity
Crop phenology
Crop uptake (D)
Water stress (D)
Current biomass (D)
Crop Water demand (D)
Harvest day
Crop Yield
D – communicated daily
VIC-CropSyst Coupling Approach
T
Ir
IP
I
T0, T1, T2, IP,
Wd
Q
Q01
Daily Tmin, Tmax,
Ws, RH, SR, I
Q12
Redistribute I,
W0, W1 and W2
to CropSyst
layers
W0,W1, W2
CropSyst
Qb
VIC
T – Transpiration
IP – Interception
capacity
I – Infiltration
Ir – irrigation
Wd- Water demand
Q – Runoff
Q01 – Drainage from
0 to 1
Q02 – Drainage from
0 to 2
Qb – Baseflow
W0 – water content in 0
W1 – water content in 1
W2 - water content in 2
Tmin, Tmax – daily
minimum and maximum
temperature
Ws – wind speed
RH – Relative humidity
SR – Solar radiation
Invoking CropSyst within VIC gridcell
CropSyst is
invoked
Crop 2
Crop 1
Non-Crop
Vegetation
VIC grid cell
(resolution=1/16°)
(~ 33 km2)
CropSyst is
invoked
Crops Modeled
Major Crops

Grape, Juice

Other Pastures
Grape,
Juice

Winter Wheat

Grape, Wine

Grass hay

Spring Wheat

Pea, Green

Bluegrass

Alfalfa

Pea, Dry

Hay

Barley

Sugarbeet

Rye grass

Potato

Canola

Corn

Corn, Sweet
Generic Vegetables
 Onions

Pasture


Apple


Lentil/Wheat type
Oats

Bean, green
Asparagus

Rye

Carrots

Barley
Cherry

Squash

Bean, dry

Lentil

Garlic

Bean, green

Mint

Spinach

Hops

Berries
Caneberry

Blueberry

Cranberry
Other Tree fruits

Pear

Peaches
The Reservoir Model (ColSim)
(Hamlet et al., 1999)
Reservoir Operating Policies
Physical System
of Dams
and Reservoirs
1980
1979
1978
1977
1976
1975
1974
1973
1972
900000
800000
700000
600000
500000
400000
300000
200000
100000
0
1971
Flow (cfs)
VIC Streamflow Time Series
Reservoir Storage
Regulated Streamflow
Flood Control
Energy Production
Irrigation Consumption
Streamflow Augmentation
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
#
* #
*
#
*
#
*
#
*
#
*
#
* #
*
#
*
#
*
#
*
#
*
#
*
#
*
#
*
*
*##
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
Integration with Economics
Inputs
Future Climate
Scenario
Water
Management
Scenario
Economic
Scenario
Modeling Steps
Outputs
Biophysical Modeling:
VIC-CropSyst, Reservoirs, Curtailment
•Crop Yield (as
impacted by climate
and water
availability)
•Adjusted Crop
Acreage
1.
2.
•Selective
Deficit
Irrigation
3.
Economic Modeling:
Agricultural Producer Response
4.
Water Supply
Irrigation Water
Demand
Unmet Irrigation Water
Demand
Effects on Crop Yield
Model Scenarios: Low, Middle, High

Climate Change Scenarios




Water Management 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
Additional Storage Capacity
Cost Recovery for Newly Developed Water Supply
Economic Scenarios


International Trade
Economic Growth
The UW CIG Supply Forecast
http://www.hydro.washington.edu/2860/
Slide courtesy of Alan Hamlet
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
Historical
Yakima Supply
and Demand
Future:
Hadcm_B1
Historical
Walla Walla
Supply and
Demand
Future:
Hadcm_B1
Impacts on Irrigation Demand

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%)
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 and
downscaling 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 water
proportions 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
- Change in some crop yield
- Trees does not show significant change
- Results are for full irrigation
Crop type
Corn
Spring Wheat
Winter Wheat
Alfalfa
Apples
Cherry Orchard
Potatoes
Grapes
Percent change (tons/hectare)
-12.9
7.7
25.1
10.0
0.0
0.0
-9.1
0.0
Crop Mix Information
for the Columbia River Basin


United States
Department of
Agriculture (USDA)
Washington State
Department of
Agriculture (WSDA)
Yakima Reservoir Model
Instream
flow targets
Monthly Inflows
Total System of Reservoirs
(capacity 1MAF approx.)
from VIC-CropSyst
Objectives:
•Reservoir refill by June 1st
•Flood space availability
Gauge at Parker
Irrigation demand from
VIC/CropSyst
Curtailment rules
Proratable water rights prorated
according to Total Water Supply Available
(TWSA) calculated each month