the three colorado rivers: the physical, legal, and economic allocation — richard rushforth,...

The Three Colorado Rivers: The Physical, Legal, and Economic Allocation

Richard Rushforth, PhD StudentDr. Benjamin RuddellIra A. Fulton Schools of EngineeringArizona State University

2015 UCOWR/NIWR/CUAHSI Annual Conference16 June 2015

A Bit of History• Colorado River Compact (1922)

• Allocated 7.5 million acre feet per year (MAFY) to the Upper and Lower Colorado River Basins in the United States and allocated 1.5 MAFY to Mexico (16.5 MAFY)

Basin State

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0Allocation (MAFY)

UpperBasin

Colorado

Utah

Wyoming

New Mexico

LowerBasin

California

Arizona

Nevada

Mexico Mexico

3.900

1.700

1.000

0.850

4.400

2.850

0.300

1.500

http://static.trunity.net/files/174201_174300/174244/colorado-river-module-sect-2-ag5.png

Jumping to the Present93 years of economic growth and prosperity coupled with water resources development and planning has resulted in:

Tenfold increase in the population of Colorado River Basin states 3 of the 10 largest US cities depend on the Colorado River; 10 of the top 50

Regional business patterns have resulted in tightly coupled and circular regional trade networks within the Southwest United States

However, historic drought threatens the availability to water in the Colorado River.

• Shortage on the Colorado could occur as early as 2016, but likely in 2017 (Central Arizona Project)

Given that, how can we measure the likely impacts of shortage on the Colorado River Basin states?

Source: Central Arizona Project (2015), “Colorado River Shortage”. URL: http://www.cap-az.com/index.php/departments/planning/colorado-river-programs/colorado-river-shortage

Virtual Water as a Tool to Measure Hydroeconomic Connectivity• For states within the Colorado River Basin, water is a shared natural

resource that is stored in central reservoirs and distributed through hundreds of miles of aqueducts and large scale diversion projects.

• Therefore water in the Colorado River Basin is rival: use of water in one area the basin legally and physically precludes use elsewhere, especially in a different Lower Basin location.

• Virtual water transfers within the Colorado River Basin represent an outsourcing of consumption of water to a rival water user within the basin, and a voluntary hydroeconomic reallocation of basin water resources.

Virtual water Transfers in the US• Dang et al. (2015) estimate agricultural virtual water flows within the

United States as 256 MAF• California is the 2nd largest recipient of agricultural virtual water (22 MAF) in the

US and 6th largest source of virtual water (10.5 MAF).• CA largest source of blue virtual water in milled products; UT (3rd) and NM (4th)• CO 6th largest source of blue virtual water in cereals; California 10th

• Rushforth and Ruddell (2015, in review) found Phoenix metro area virtual water flow to be highly regional, focused in southwest US

• Virtual water inflows 3.34 MAF; Virtual water outflows 2.09 MAF

• Arizona a net exporter (29,813 AF) of virtual water through electricity grid

Dang, Q., Lin, X., & Konar, M. (2015). Agricultural virtual water flows within the United States. Water Resources Research, 51(2), 973-986.Rushforth and Ruddell. (2015, In Review). Intra-Metropolitan Water Dependency: A Case Study of Water Footprints and Virtual Water Flows in the Phoenix Metropolitan Area.Scott, C. A., & Pasqualetti, M. J. (2010). Energy and water resources scarcity: Critical infrastructure for growth and economic development in Arizona and Sonora. Nat. Resources J., 50, 645.

The National Water-Economy Database• County-to-county virtual water flows for the United State

• Blue Water• 43 Commodity Types• 5 Economic Sectors

Data• US Commodity Flows – Freight Analysis Framework (FAF3) from Oak Ridge

National Labs• USGS Water Use of the Nation• US Census, Economic Census• USDA National Agricultural Statistics Survey

MethodsData from the National Water Economy Project (NWEP) were used to calculate virtual water flows and a water footprint balance for each Colorado River Basin state and county.1. Virtual Water Flows Within the Colorado River Basin States

• A commodity flow based virtual water model for the United States based on regional shares of population, agriculture, and employment.

• Two Techniques• By Total State Area• By Colorado River planning areas

2. Calculating a Complete Water Footprint Balance for the Colorado River Basin and sub-geographies.• Water footprint balance (E) calculated for each municipality using direct (U) and virtual water

flows (V) with the Embedded Resources Accounting Framework

Virtual Water Transfers Between and Within CRB StatesBasin State

-1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0Virtual Water Flow (MAF)

UpperBasin

ColoradoExportImportBalance

UtahExportImportBalance

WyomingExportImportBalance

NewMexico

ExportImportBalance

LowerBasin

ArizonaExportImportBalance

CaliforniaExportImportBalance

NevadaExportImportBalance

-0.060

5.5105.450

1.5901.590

0.000

-1.000

1.5900.580

0.6300.620

0.000

-0.210

2.3702.160

0.8502.040

1.1800.150

0.2700.110

Inter- and Intrastate Virtual Water TransfersBasin State

-1.6 -1.2 -0.8 -0.4 0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 4.8Virtual Water Flow (MAF)

UpperBasin

Colorado

Interstate ExportInterstate ImportCircularBalance

Utah


Wyoming


NewMexico


LowerBasin

Arizona


California


Nevada


-0.060

1.1401.080

4.360

0.3200.320

1.2600.000

-1.000

1.0500.050

0.530

0.1000.090

0.5200.000

-0.210

0.7200.510

1.640

0.2601.440

0.5901.180

0.0200.1400.1200.110

What goods are responsible for virtual water flow in the Colorado River Basin?• Virtual water transfers in the Colorado River Basin are largely from

agricultural activities, followed by industrial activites.• At the commodity level, cereal grains, agricultural products, and

animal feed are responsible for the largest virtual water flows

Rank Commodity Virtual Water Flow (MAF) % of Total Flow

1 Cereal grains 6.46 50%2 Other ag prods. 2.39 19%3 Animal feed 1.72 13%4 Milled grain prods. 0.64 5%5 Nonmetal min. prods. 0.3 2%… Remainder 1.36 11%… Total 12.87 100%

Commodity Classification

Virtual Water Flow (MAF) % of Total Flow

Agriculture 11.21 87%Industrial 1.24 10%Livestock 0.29 2%Mining 0.13 1%Total 12.87 100%

A Virtually Adjusted Colorado River Allocation

At the Colorado River Basin scale, these virtual water transfers create a virtual water reallocation of a common resource; fresh surface and groundwater within the Basin.

State1922 Allocation

(MAF)

Net Water Footprint

(MAF) % AdjustmentColorado

UtahWyoming

New MexicoArizona

CaliforniaNevada

3.91.71

0.852.854.40.3

3.841.69

00.842.615.610.42

-2%0.00%-100%

-1%-9%27%38%

Source Basin Destination BasinVirtual Water Flow

(MAF)Upper Basin Upper Basin 1.36Upper BasinLower Basin

Lower Basin -1.29Upper Basin -0.21

Lower Basin Lower Basin 0.85

• Adjusted Upper Basin Allocation: 6.42 MAF• Adjusted Lower Basin Allocation: 8.58 MAF

Which Transfers Are the Largest?

RankOrigin State

Destination State

Virtual Water Flow (MAF)

1 WY CO 0.902 CO CA 0.643 AZ CA 0.624 CO AZ 0.265 CO UT 0.18

• The largest virtual water transfers within the CRB are intra-state transfers, at local scales

• Except for California, Nevada• The largest interstate virtual water

transfer is Wyoming to Colorado.• The largest interbasin virtual water

transfer is from Colorado (upper) to California (lower).

Who Imports and Who Exports?• Counties with large population centers

tend to be virtual water importers.• However, some urban counties are still

large virtual water exporters (e.g., Maricopa County, AZ)

• Agricultural counties tend to be virtual water exporters.

Rank County NameExport(MAF)

Import(MAF)

Balance(MAF)

12345

El Paso County, ColoradoMaricopa County, Arizona

Los Angeles County, California

Utah County, UtahDenver County, Colorado

0.020.660.220.090.04

0.951.571.040.590.48

0.930.910.830.510.44

…

137138139140141

Gunnison County, ColoradoMontrose County, Colorado

Rio Grande County, ColoradoLa Paz County, ArizonaYuma County, Arizona

0.320.360.330.380.64

0.020.060.020.010.07

-0.3-0.3

-0.31-0.37-0.57

Does CRB Virtual Water Stay in the Basin?

How will drought impact virtual water trade in the Colorado River Basin?

• (Left) Social network of each CRB state’s top two virtual water sources within the CRB (not including intrastate flows).

• Colorado followed by Arizona are the most connected hubs in the CRB virtual water trade network.

• Shortage on the river has the potential to impact one of the most important virtual water nodes in the CRB.

Conclusions• A virtual water assessment allows for analysis of how water in shared catchment

is distributed through economic activity rather than water infrastructure.• This represents the net water impact on the basin, which can be greater or lesser than

actual diversions.

• In the CRB, the largest virtual water transfers are intrastate (rural to urban), but large transfers exist between neighboring states and between basins

• WY CO virtual water transfer is 0.90 MAF• CO CA virtual water transfer is 0.64 MAF• AZ CA virtual water transfer is 0.62 MAF

• Finally, the Upper Basin subsidizes the water use of the Lower Basin through virtual water transfers.

• Upper Basin Lower Basin virtual water transfer is 1.29 MAF

the three colorado rivers: the physical, legal, and economic allocation — richard rushforth,...

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