RECLAMATION 


Managing Water in the West 


Colorado River Basin 

Water Supply and Demand Study 

Technical Report C ­ Water Demand Assessment 

U.S. Department of the Interior 

Bureau of Reclamation December 2012 
Mission Statements

The U.S. Department of the Interior protects America’s natural 

resources and heritage, honors our cultures and tribal communities, 

and supplies the energy to power our future. 

The mission of the Bureau of Reclamation is to manage, develop, 

and protect water and related resources in an environmentally and 

economically sound manner in the interest of the American public.
U.S. Department of the Interior

Bureau of Reclamation December 2012

Colorado River Basin 

Water Supply and Demand Study

Technical Report C — Water 

Demand Assessment

December 2012 C-iii

Contents

Page

1.0 Introduction .............................................................................................................. C-1

2.0 Background .............................................................................................................. C-4

2.1 State Water Planning...................................................................................... C-4

2.2 Other Studies .................................................................................................. C-4

2.3 Federally Recognized Tribes ......................................................................... C-5

2.4 Summary of Trends in Historical Water Use ................................................. C-6

2.5 Limitations of Historical Data and Future Commitments.............................. C-9

3.0 Water Demand Scenario Development Approach ................................................ C-10

3.1 Scenario Planning Approach.......................................................................... C-10

3.2 Quantification Approach ................................................................................ C-13

3.2.1 Quantification of Tribal Demand ....................................................... C-17

4.0 Results of Water Demand Scenario Quantification .............................................. C-18

4.1 Comparison of Demand Scenarios................................................................. C-18

4.1.1 Demographics and Land Use ............................................................. C-19

4.1.2 Technology and Economics ............................................................... C-19

4.1.3 Social and Governance ...................................................................... C-20

4.2 Summary Results of Scenario Quantification ................................................ C-20

4.3 Colorado River Water Demand by Geography .............................................. C-23

4.4 Colorado River Water Demand by Category ................................................. C-29

4.4.1 Agriculture ......................................................................................... C-29

4.4.2 Municipal and Industrial .................................................................... C-31

4.4.3 Energy ................................................................................................ C-33

4.4.4 Minerals ............................................................................................. C-35

4.4.5 Fish, Wildlife, and Recreation ........................................................... C-35

4.4.6 Tribal .................................................................................................. C-38

5.0 Mexico’s Allotment .................................................................................................. C-45

6.0 Reservoir Evaporation and other Losses ............................................................... C-45

6.1 Reservoir Evaporation ................................................................................... C-46

6.2 Phreatophyte Losses....................................................................................... C-47

6.3 Operational Inefficiencies .............................................................................. C-47

7.0 Approach for Incorporating Climate Change Effects on Demands .................... C-48

7.1 Climate Change Effects on Evapotranspiration ............................................. C-49

7.2 Climate Change Effects on Reservoir Evaporation ....................................... C-50

8.0 Limitations ................................................................................................................ C-51

9.0 References ................................................................................................................. C-52

Disclaimer ............................................................................................................................. C-55
Colorado River Basin 

Water Supply and Demand Study

C-iv December 2012

Tables

Page

C-1 Definition of Demand Categories and Their Associated Parameters ........................ C-15

C-2 Scenario Matrix of Typical Changes in Parameters Defined by the 

Water Demand Storylines .......................................................................................... C-16

C-3 Storylines Related to Tribal Water Use ..................................................................... C-17

C-4 Summary Results of Water Demand Scenario Quantification by 2060 .................... C-21

C-5 Upper Colorado River Basin Tribes, Lower Colorado River Mainstem 

 Tribes, and Tribes Served by Water Provided through the CAP ............................... C-39

C-6 Upper Colorado River Basin Tribal Rights and Tribal and State 

 Future Demands ......................................................................................................... C-42

C-7 Lower Colorado River Tribal Rights and Tribal and State Future Demands ............ C-44

Figures

Page

C-1 The Study Area .......................................................................................................... C-3

C-2 Historical Colorado River Water Consumptive Use and Loss by State, 

Mexico, Reservoir Evaporation, and Other Losses, 1971–2010 ............................... C-7

C-3 Historical Colorado River Water Consumptive Use and Loss by Basin, 

 Mexico, Reservoir Evaporation, and Other Losses, 1971–2010 ............................... C-8

C-4 Historical Colorado River Water Consumptive Use, Delivery to Mexico, 

 Reservoir Evaporation, and Other Losses, 1971–2010 .............................................. C-9

C-5 Scenario Development Process .................................................................................. C-12

C-6 Approach to Quantifying Demand Scenarios ............................................................ C-14

C-7 Study Area, Colorado River, and Change in Colorado River Demand ..................... C-24

C-8 Colorado River Basin Historical Use and Future Projected Demand, 

 Delivery to Mexico, Reservoir Evaporation, and Other Losses ................................ C-25

C-9 Colorado River Water Demand ................................................................................. C-26

C-10 Colorado River Water Demand by Category ............................................................. C-27

C-11 Change in Colorado River Water Demand from 2015 by Category .......................... C-28

C-12 Change in Colorado River Water Demand for Agriculture ....................................... C-30
Technical Report C — Water

Demand Assessment

December 2012 C-v 

Figures (continued)

Page

C-13 Change in Colorado River Water Demand for Municipal and Industrial .................. C-32

C-14 Change in Colorado River Water Demand for Energy .............................................. C-34

C-15 Change in Colorado River Water Demand for Mineral Production .......................... C-36

C-16 Change in Colorado River Water Demand for Fish, Wildlife, and 

Recreation .................................................................................................................. C-37

C-17 Colorado River Basin Tribes ..................................................................................... C-40

C-18 Colorado River Basin Tribal Diversion Rights and Diversion-Based 

Demand ...................................................................................................................... C-41

C-19 Reservoir Evaporative Losses .................................................................................... C-46

C-20 Historical Lower Basin Phreatophyte Use, 1971–2010 ............................................. C-48

C-21 Current Projected (A) Scenario Demands Adjusted for Future Climate 

 Change ....................................................................................................................... C-50

Appendices

C1 Water Demand Sub-Team Members

C2 Colorado Water Demand Scenario Quantification

C3 New Mexico Water Demand Scenario Quantification

C4 Utah Water Demand Scenario Quantification

C5 Wyoming Water Demand Scenario Quantification

C6 Arizona Water Demand Scenario Quantification

C7 California Water Demand Scenario Quantification

C8 Nevada Water Demand Scenario Quantification

C9 Tribal Water Demand Scenario Quantification

C10 Historical Consumptive Use and Loss Detail By State

C11 Modeling of Lower Basin Tributaries in the Colorado River Simulation System 

C12 Plausible Range of Parameters 

C13 Parameters Assigned to Each Scenario

C14 Water Demand Scenario Storylines

C15 Climate Change Effects on Water Demand and Losses

December 2012 C-vii

Acronyms and Abbreviations

ADWR Arizona Department of Water Resources

af acre-feet

afy acre-feet per year

AMA Active Management Area

ASCE American Society of Civil Engineers

Basin Colorado River Basin

Basin States Colorado River Basin States 

BC Blaney-Criddle 

CAP Central Arizona Project

CBER Center for Business and Economic Research

CIMIS California Irrigation Management Information System 

CRB Colorado River Board 

CRBPA Colorado River Basin Project Act

CRIT Colorado River Indian Tribes 

CRSS Colorado River Simulation System

CRWDA Colorado River Water Delivery Agreement

CU&L Reports Reclamation’s Consumptive Uses and Losses Reports

CVWD Coachella Valley Water District

CVWMP Coachella Valley Water Management Plan

CWCB Colorado Water Conservation Board 

DIT Demand Input Tool 

DWR Department of Water Resources (California); Division of Water 

Resources (Utah)

ESA Endangered Species Act 

gpcd gallons per capita per day

Harg Hargreaves

ICS Intentionally Created Surplus 

IID Imperial Irrigation District

ITA Indian Trust Asset 

ITCA Inter Tribal Council of Arizona 
Colorado River Basin 

Water Supply and Demand Study

C-viii December 2012

kaf thousand acre-feet

M&I municipal and industrial 

maf million acre-feet

Mexico United Mexican States

MWD Metropolitan Water District of Southern California

NIA Non-Indian Agriculture 

NIAR Non-Indian Agriculture Relinquished 

NWR National Wildlife Refuge

Partnership Ten Tribes Partnership 

PET potential evapotranspiration 

PM Penman-Monteith

PPR present perfected right

Prs-Tylr Priestley-Taylor

PVID Palo Verde Irrigation District

Reclamation Bureau of Reclamation

Secretary Secretary of the Interior

SNWA Southern Nevada Water Authority 

SRP Salt River Project

SSI self-served industrial 

Study Colorado River Basin Water Supply and Demand Study 

SWSI Statewide Water Supply Initiative

tribes federally recognized tribes

UMUR Ute Mountain Ute Reservation

UMUT Ute Mountain Ute Tribe 

USFWS U.S. Fish and Wildlife Service

USGS U.S. Geological Survey 

VIC Variable Infiltration Capacity
December 2012 C-1 

Technical Report C — 

Water Demand 

Assessment

Key Terms Used in this 

Technical Report

• Hydrologic Basin – the 

geographic region naturally 

draining to the Colorado River. 

• Adjacent Area – geographic 

regions outside the Colorado River 

hydrologic basin that receive 

Colorado River water. 

• Study Area – the hydrologic 

boundaries of the Colorado River 

Basin within the United States, 

plus the adjacent areas of the 

Basin States that receive Colorado 

River water.

• Demand – water needed to meet 

identified uses. 

• Diversion – water withdrawn 

from the river system.

• Return Flow – water diverted 

from and returned to the river 

system.

• Consumptive Use – water used, 

diminishing the available supply. 

• Non-consumptive Use – water 

used without diminishing the 

available supply.

• Loss – water unavailable for 

identified uses due to 

reservoir/channel evaporation, 

phreatophyte use, and operational 

inefficiencies.

• Other Supplies – water supplies 

other than Colorado River 

Simulation System (CRSS) 

simulated Colorado River water 

supplies that may meet demand.

• Parameter – a variable that 

affects a demand category (for 

example, population). 

• Colorado River Demand –

Colorado River demand as 

computed by Study Area demand 

minus other supplies. 

1.0 Introduction

The Colorado River Basin Water Supply and Demand 

Study (Study), initiated in January 2010, was conducted 

by the Bureau of Reclamation’s (Reclamation) Upper 

Colorado and Lower Colorado regions, and agencies 

representing the seven Colorado River Basin States

(Basin States) in collaboration with stakeholders 

throughout the Colorado River Basin (Basin). The 

purpose of the Study is to define current and future 

imbalances in water supply and demand in the Basin and 

the adjacent areas of the Basin States that receive 

Colorado River water over the next 50 years (through 

2060), and to develop and analyze adaptation and 

mitigation strategies to resolve those imbalances. The 

Study contains for major phases to accomplish this goal: 

Water Supply Assessment, Water Demand Assessment, 

System Reliability Analysis, and Development and 

Evaluation of Options and Strategies for Balancing 

Supply and Demand. 

Spanning parts of the seven states of Arizona, California, 

Colorado, New Mexico, Nevada, Utah, and Wyoming, 

the Colorado River is one of the most critical sources of 

water in the western United States. The Colorado River 

is also a vital resource to the United Mexican States 

(Mexico). It is widely known that the Colorado River, 

based on the inflows observed over the last century, is 

over-allocated and supply and demand imbalances are 

likely to occur in the future. Up to this point, this 

imbalance has been managed, and demands have largely 

been met as a result of the considerable amount of 

reservoir storage capacity in the system, the fact that the 

Upper Basin States are still developing into their 

apportionments, and efforts the Basin States have made 

to reduce their demand for Colorado River water. 

Concerns regarding the reliability of the Colorado River 

system to meet future needs are even more apparent 

today. The Basin States include some of the fastest 

growing urban and industrial areas in the United States. 

At the same time, the effects of climate change and 
Colorado River Basin 

Water Supply and Demand Study

C-2 December 2012 

variability on the Basin water supply has been the focus of many scientific studies which project 

a decline in the future yield of the Colorado River. Increasing demand, coupled with decreasing 

supplies, will certainly exacerbate imbalances throughout the Basin. 

It is against this backdrop that the Study was conducted to establish a common technical 

foundation from which important discussions can begin regarding possible strategies to reduce 

future supply and demand imbalances. The content of this report is a key component of that 

technical foundation and describes the Study’s assessment of water demand. 

The amount of water available and the progression of demand for water in the Basin (and the 

adjacent areas of the Basin States that receive Colorado River water) over the next 50 years are 

highly uncertain and dependent upon a number of socioeconomic and other factors. The potential 

impacts of future climate variability and climate change further contribute to these uncertainties. 

To analyze the future reliability of the Colorado River system, with and without adaption and 

mitigation strategies, projections of water supply and demand were necessary. These projections 

needed to be sufficiently broad to capture the plausible ranges of uncertainty in future water 

supply and water demand to ensure that the reliability of the Colorado River system was 

adequately analyzed.

The Water Demand Assessment examined the quantity and location of current and future water 

demands in the Study Area. These water demands were derived from the needs of various uses, 

including municipal and industrial (M&I) use, hydropower generation, recreation, and fish and 

wildlife habitat. In addition, losses in the Study Area due to evaporation and other factors were 

assessed. Because future water supply and demand throughout the Study Area are uncertain, 

scenarios were developed that are sufficiently broad to span that uncertainty, including the 

potential effects of future climate change. The water demand scenarios, coupled with water 

supply scenarios (see Technical Report B – Water Supply Assessment) were used to analyze the 

future reliability of the Colorado River system, with and without future adaptation and mitigation 

strategies. 

Numerous organizations participated in the Water Demand Assessment, including 

representatives of Reclamation, the Basin States, federally-recognized tribes (tribes), 

conservation organizations, and others interested in the Basin. A Water Demand Sub-Team was 

assembled to provide input and assist in completion of this report. Members of the Water 

Demand Sub-Team are listed in appendix C1. 

This technical report presents historical water demand in the Study Area, the Study’s approach to 

water demand scenario development and quantification, and the results of quantifying water 

demand for a range of future demand scenarios within the Study Area. The Study Area 

encompasses the hydrologic boundaries of the Basin within the United States, plus the adjacent 

areas of the Basin States that receive Colorado River water (figure C-1). Water demand is

presented by use category, including a compilation of demand information by tribe. 
Technical Report C — Water

Demand Assessment

December 2012 C-3 

FIGURE C-1 

The Study Area
Colorado River Basin 

Water Supply and Demand Study

C-4 December 2012 

2.0 Background 

2.1 State Water Planning

Each of the Basin States has a statewide water planning process in place for estimating future 

water supply and demand. These processes typically project demand based on planning regions 

that are associated with the hydrologic basins of that state. In most states, demand is developed 

based on parameters in a similar manner employed in the Study. For example, Wyoming’s Green 

River Basin Plan projects future M&I demand by projecting population under “low,” “medium,” 

and “high” growth scenarios provided by the Wyoming Division of Economic Analysis (States 

West Water Resources Corporation, 2001). These population data are coupled with per capita 

water use estimates to arrive at future M&I demand. Similarly, agricultural demand is based on 

projections of future irrigated crop acreage, estimates of crop irrigation requirements, and losses. 

Parameter and demand estimates for the Study were provided by the Basin States and were 

generally derived from the states’ planning processes or, in some cases, the planning of 

individual water agencies such as the Southern Nevada Water Authority (SNWA) and 

Metropolitan Water District of Southern California (MWD). Because the Basin States and 

agencies are tasked with water planning and management of their respective areas, they have the 

most detailed knowledge of current and potential future demand for Colorado River water. 

Because of this knowledge and planning responsibility, information developed and provided by 

these agencies was heavily relied upon in the completion of this assessment. Where appropriate, 

other regional data and studies were consider and used to augment the assessment. 

Appendices C2 through C8, (Colorado, New Mexico, Utah, Wyoming, Arizona, California, 

Nevada, respectively) of this technical report presents detail about the assumptions and data 

sources used for each state in this demand assessment. 

2.2 Other Studies

As part of the demand scenario quantification process, several studies were reviewed to provide 

information on the regional trends in water use or parameters affecting water use. 

This information was provided to the Basin States to assist in demand scenario quantification 

where local information may not have been available, or where the range of parameter 

characteristics had not been previously assessed in state or water agency plans. For example, in 

the development of demand projections for the San Juan planning area in New Mexico, it was 

found that the San Juan Regional Water Plan did not include a range of estimates of population 

for this region. To examine high- and low-growth scenarios, a range of population projections for 

New Mexico was developed from U.S. Census data. 

Regional and national studies consulted include: 

• Population Projections: U.S. Census Bureau Projections (U.S. Census Bureau, 2010), U.S. 

Population Projections 2005–2050 (Pew Research Center, 2010), and World Population 

Prospects 2010 Revision (United Nations Department of Economic and Social Affairs, 2010). 
Technical Report C — Water

Demand Assessment

December 2012 C-5 

• Municipal Water Use: North American Water Use Trends Since 1992 (Water Research 

Foundation, 2010), Residential Water Use Trends in North America (Rockaway et al., 2011), 

20x2020 Water Conservation Plan (California Department of Water Resources, 2010), Growing 

Toward More Efficient Water Use (U.S. Environmental Protection Agency, 2010) and 

Municipal Deliveries of Colorado River Basin Water (Pacific Institute, 2011). 

• Irrigated Acreage and Agricultural Water Use: Agricultural Resources and Environmental 

Indicators (U.S. Department of Agriculture, 2010) and Estimated Use of Water in the United 

States reports (U.S. Geological Survey, 2009). 

• Energy Water Use: Energy-Water Nexus, A Better and Coordinated Understanding of Water 

Resources Could Help Mitigate the Impacts of Potential Oil Shale Development, (General 

Accounting Office, 2010), State Electricity Profiles (U.S. Department of Energy, 2009). 

2.3 Federally Recognized Tribes

Tribes hold quantified rights to a significant amount of water from the Colorado River and its 

tributaries (approximately 2.9 million acre-feet [maf] of annual diversion rights). In many cases, 

these rights are senior in priority to those held by other users. Therefore, representing these rights 

and the associated demand was a critical component to assessing future water demand in the 

Basin. An additional component of future demand was an assessment of demands by tribes that 

have unquantified rights or claims. Where information on these unquantified rights or claims was

provided by tribes, it was included in the Study, as appropriate; however, this information is not 

reflected in future tribal water demand projections.1

Based on quantified rights and with additional input from tribes, future demand for water by 

tribes in the Basin was quantified by the Study. The term “quantified rights”, as used in the 

context of the Study, is defined as the quantity of water rights reserved by or granted to tribes by 

federal court decrees, state court decrees, treaties, agreements, and Executive Orders. 

The United States has a trust responsibility to protect and maintain rights reserved by or granted to 

tribes by federal court decrees, state court decrees, treaties, agreements, and Executive Orders. The 

Indian Trust Assets entitled to protection under the trust responsibility include tribes’ federally 

reserved water rights. A tribe may also have other off-reservation interests and concerns that must 

be taken into account.

Each tribe’s water rights determination is multifaceted and contains numerous provisions. The 

information in this report is limited to the United States’ obligations with regard to current and 

future Colorado River water delivery to tribes, including tributaries in the Upper Basin. 

The information in this report is not intended to provide an interpretation of the water rights of 

any tribe.

Throughout the Study, Reclamation met with tribes in the Upper Colorado River Basin, Lower 

Colorado River mainstem, and tribes served by water provided (directly or pursuant to exchanges) 

through the Central Arizona Project (CAP) facilities under contracts between tribes and the United 

States (see the Tribal discussion in the Colorado River Water Demand by Category section). In 

addition, Reclamation worked collaboratively with the Ten Tribes Partnership (Partnership), whose 

members have landholdings in the Upper and Lower Basins through which the Colorado River and 

 

1 Demands provided by the Navajo Nation include both quantified and unquantified rights. See Appendix C-9 for more detail. 
Colorado River Basin 

Water Supply and Demand Study

C-6 December 2012

various tributaries flow, as well as the Inter Tribal Council of Arizona (ITCA), whose members are 

the governments of 20 tribes with land in Arizona. Additional information on tribal rights and 

projected future demand is provided in appendix C9. 

2.4 Summary of Trends in Historical Water Use

Reclamation’s Consumptive Uses and Losses Reports2 (CU&L Reports) (Reclamation, 2005, 

2012a, 2012b, 2012c) and Colorado River Accounting and Water Use Reports (Reclamation,

1971–2011), and Reclamation estimates demonstrate an increasing trend in Colorado River water 

use over the historical period 1971 to 2011. Details of historical water use by state can be found 

in appendix C10. Study Area consumptive uses and losses (including deliveries to Mexico 

pursuant to the 1944 treaty3) have grown from approximately 13 maf to over 15 maf, an increase 

of about 14 percent. Figure C-2 shows historical Colorado River water use by each state, water 

use by Mexico, reservoir evaporation, and other losses. Figure C-3 shows the same information 

as figure C-2 grouped by Upper and Lower Basin, water use by Mexico, reservoir evaporation, 

and other losses. Figure C-4 presents historical Colorado River uses and losses by category.

From this figure, trends of increasing M&I water use and stable to decreasing agricultural water 

use can be seen, consistent with the population and irrigated acreage trends of the Southwest. 

M&I water use has increased over time as a result of continued population growth in the Basin 

States. The Basin States include some of the most rapidly growing areas of the United States and 

typically have had growth rates far exceeding the national average. While population growth has 

slowed in recent years, the projections for the region continue to remain higher than the national 

average (U.S. Census Bureau, 2010). Significant decreases in per capita water use, largely due to 

improvements in indoor fixtures and appliances, have partially offset the water demands 

associated with increases in population. 

Agricultural water use has been relatively stable in recent years, with some reductions likely due 

to the recent drought. Some reductions in irrigated acreage have occurred in the Basin, consistent 

with trends in the western United States, and appear to be associated with economic conditions, 

supply limitations, and pressures from urban encroachment due to land use changes and water 

transfers. Continued population growth is expected to continue these recent pressures on 

agriculture lands and water use.

Water use for energy purposes has grown over time, generally consistent with population 

growth. The growth in population has translated into increased energy demands in the Southwest 

with energy supply importation from other areas and expanding use of renewable energy. This 

growth in energy demands has been partially offset through federal and local energy 

conservation incentive programs. 

Because historical tribal water use was not explicitly recorded as part of consumptive uses and 

losses reporting, the tribal uses have been incorporated into other applicable categories.

However, for the projections of future demand, tribal demands are generally considered in a 

separate category.

 

2 Some states produce independent estimates of consumptive uses and losses. For consistency, Reclamation-estimated historical consumptive use 

and loss are presented in this technical report. 

3 Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande, Treaty between the United States and Mexico, 1944.
Technical Report C — Water

Demand Assessment

December 2012 C-7 

FIGURE C-2 

Historical Colorado River Water Consumptive Use1 and Loss by State, Mexico, Reservoir Evaporation2, and Other Losses3, 

1971–2010

1 Excluding consumptive use in Lower Basin tributaries. 

2 Reservoir evaporation losses are accounted differently in the Upper and Lower Basin. In the Upper Basin, reservoir 

evaporation losses are accounted as part of each state’s total uses. In the Lower Basin, reservoir evaporation losses 

are accounted separately from each state’s uses. Reservoir evaporation losses from Upper and Lower Basin 

reservoirs have been aggregated for this presentation.

3 Phreatophyte and operational inefficiency losses.

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Colorado

New Mexico

Utah

Wyoming

Arizona

California

Nevada

Mexico

Reservoir Evaporation

Other Losses
Colorado River Basin 

Water Supply and Demand Study

C-8 December 2012 

FIGURE C-3 

Historical Colorado River Water Consumptive Use1 and Loss by Basin, Mexico, Reservoir Evaporation2, and Other Losses3, 

1971–2010

1 Excluding consumptive use in Lower Basin tributaries. 

2 Reservoir evaporation losses are accounted differently in the Upper and Lower Basin. In the Upper Basin, reservoir 

evaporation losses are accounted as part of each state’s total uses. In the Lower Basin, reservoir evaporation losses 

are accounted separately from each state’s uses. Reservoir evaporation losses from Upper and Lower Basin 

reservoirs have been aggregated for this presentation.

3 Phreatophyte and operational inefficiency losses. 1,747 1,779 1,946 2,003 2,033 2,014 1,921 1,957 2,103 2,220 2,194 2,231 2,374 2,327 2,320 2,290 2,300 2,255 2,146 2,007

1,962

1,943

2,090

2,072

2,137

2,198

2,272

2,340

2,322

2,243

2,124

1,889

1,744

1,635

1,722

1,722

1,686

1,706

1,721

1,691

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,700

1,700

1,700

1,500

1,700

1,700

1,700

1,700

1,700

1,700

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,700

1,700

1,700

1,700

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,500

1,500

6,564 

6,515 

6,679 

6,835 

6,414 

6,028 

6,402 

5,810 

5,999 

6,047 

6,322 

5,643 

5,394 

5,895 

6,075 

6,274 

6,735 

7,092 

7,530 

7,658 

7,050 

6,630 

7,286 

7,360 

7,081 

8,027 

8,101 

7,621 

7,976 

8,025 

8,170 

8,407 

7,538 

7,384 

7,065 

7,411 

7,454 

7,521 

7,438 

7,379 

2,992 

3,067 

2,894 

3,230 

3,048 

2,954 

2,414 

3,284 

3,249 

3,185 

3,207 

3,237 

3,083 

2,999 

3,284 

3,191 

3,281 

3,709 

3,795 

3,580 

3,635 

3,788 

3,502 

4,001 

3,141 

3,588 

3,350 

3,434 

3,253 

3,693 

3,951 

3,532 

3,543 

3,298 

3,379 

3,564 

3,848 

3,909 

3,843 

3,739 

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Upper Basin

Lower Basin

Mexico

Reservoir Evaporation

Other Losses
Technical Report C — Water

Demand Assessment

December 2012 C-9 

FIGURE C-4 

Historical Colorado River Water Consumptive Use1, Delivery to Mexico, Reservoir Evaporation, and Other Losses2, 

1971–2010

1 Excluding consumptive use in Lower Basin tributaries. Distribution of use by category in some adjacent areas was 

estimated when historical reporting of use within those areas did not contain identical categories as those presented 

here. 

2 Reservoir evaporation losses are accounted differently in the Upper and Lower Basin. In the Upper Basin, reservoir 

evaporation losses are accounted as part of each state’s total uses. In the Lower Basin, reservoir evaporation losses 

are accounted separately from each state’s uses. Reservoir evaporation losses from Upper and Lower Basin 

reservoirs have been aggregated for this presentation.

3 Phreatophyte and operational inefficiency losses.

2.5 Limitations of Historical Data and Future Commitments

In the Upper Basin, some states estimate their consumptive uses and losses of Colorado River 

water using different methods from those used by Reclamation. Reclamation and the states are 

continuing to work collaboratively to resolve differences in these estimates. For consistency 

purposes, however, the CU&L Reports (and subsequently, the data presented in this report) use 

Reclamation’s methodologies to estimate consumptive uses and losses for all Upper Basin states, 

with the exception of New Mexico. The New Mexico Interstate Stream Commission provides 

historical consumptive uses and losses estimates to Reclamation for subsequent review and 

publication in the CU&L Reports. 

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Mexico

Reservoir Evaporation

Other Losses
Colorado River Basin 

Water Supply and Demand Study

C-10 December 2012

In the Lower Basin, Reclamation accounts for consumptive use on the mainstem using a 

“diversion minus return flow” methodology for all water users and publishes that information 

each year in the Water Accounting Reports. The CU&L Reports include information taken from 

the Water Accounting Reports for mainstem Lower Basin use and also estimate consumptive 

uses and losses in the Lower Basin tributaries (primarily the Little Colorado, Virgin, Bill 

Williams, and Gila rivers). The process of estimating Lower Basin tributary consumptive uses 

and losses has not received a great deal of attention in the past, and the quality of the resulting 

information has suffered (see appendix C11). Because of the issues and problems associated with 

the Lower Basin tributary consumptive uses and losses data, the historical consumptive uses and 

losses data presented in the following sections do not include data from the Lower Basin 

tributaries. 

Furthermore, Reclamation does not use consumptive uses and losses to compute natural flows on 

the Lower Basin tributaries for use in CRSS4. Specifically, CRSS uses historical inflows based 

on U.S. Geological Survey gaged records as estimates of natural flows for the Little Colorado, 

Virgin and Bill Williams rivers. In addition, the Gila River is not included in CRSS. In appendix 

C11, three commitments are made to engage in efforts independent of the Study to enhance the 

capabilities of CRSS: 1) to resolve and correct the methodological and data inconsistencies in 

CU&L Reports pertaining to all of the Lower Basin tributaries, in collaboration with the Basin 

States; and 2) to develop natural flows for the Little Colorado, Virgin, and Bill Williams rivers 

and to modify CRSS to use natural flows for those tributaries; and 3) to explore the feasibility 

and necessity of computing natural flows for the Gila River Basin and adding that tributary to 

CRSS. 

Although some limitations were imposed on the Study by this treatment of the Lower Basin 

tributaries, the Study was able to examine several important issues, including potential climate 

change impacts on the tributaries represented in CRSS, future demand scenarios on those 

tributaries, and future demand scenarios for the Colorado River from the Gila River Basin, 

factoring in other water supplies within that basin (see appendix C11).

3.0 Water Demand Scenario Development Approach

3.1 Scenario Planning Approach

A scenario planning approach was implemented to examine the uncertainty in future water 

supply and demand. Details of this approach are included in Technical Report A – Scenario 

Development. Scenarios are alternative views of how the future might unfold and were used to 

assist in evaluating the effect of key driving forces on future system reliability. Scenarios are not 

predictions or forecasts of the future. Rather, a set of well-constructed scenarios represents a 

range of plausible futures. 

The scenario planning process involved identifying the key driving forces (the factors that likely 

will have the greatest influence on the future state of the system and thereby the performance of 

the system over time), ranking the driving forces as to their relative importance and relative 

 

4 CRSS is the primary modeling tool used in the Study. It simulates the operation of the major Colorado River system reservoirs on a monthly 

time step and provides information regarding the projected state of the system in terms of output variables. Outputs include the amount of 

water in storage, reservoir elevations, releases from the dams, hydropower generation, the amount of water flowing at various points in the 

system, the total dissolved solids content, and diversions to and return flows from the water users in the system. See Technical Report G – 

System Reliability Analysis and Evaluation of Options and Strategies. 
Technical Report C — Water

Demand Assessment

December 2012 C-11

uncertainty, and associating the highly uncertain and highly important driving forces (critical 

uncertainties) with either water supply or water demand. The top third of figure C-5 provides a 

flowchart of this approach as implemented in the Study. 

The water demand scenarios were then constructed based on alternative views of future demand

for the Colorado River, considering those critical uncertainties relating to demand. This process 

took place generally following the procedure identified on the right hand side of figure C-5 

labeled “Demand” and included: 1) identification of critical uncertainties; 2) identification of 

parameter ranges (e.g., high and low growth for population); 3) developing storylines that 

provide a cohesive plausible narrative of the future; and 4) quantifying the storylines. The Water 

Demand Sub-Team provided input and helped complete these steps. Appendices C12 and C13 

present the range of parameters by scenario. 

The following scenarios resulted from this process and were used to assess the range of future 

demand: 

• Current Projected (A): Continuation of growth, development patterns, and institutions follow 

long-term trends

• Slow Growth (B): Slow growth with emphasis on economic efficiency 

• Rapid Growth (C1 and C2): Economic resurgence (population and energy) and current 

preferences toward human and environmental values 

• Enhanced Environment (D1 and D2): Expanded environmental awareness and stewardship 

with growing economy 

Complete narrative descriptions of the scenarios (storylines) are presented in appendix C14. 

Under the storylines, two logical branches or directions were considered for the Rapid Growth 

(C1 and C2) and Enhanced Environment (D1 and D2) scenarios. For example, population growth

or increasing energy needs and subsequent water demand could be partially offset by associated 

technological innovations influencing water use. The four storylines, with two branches, resulted

in a total of six water demand scenarios. 
Colorado River Basin 

Water Supply and Demand Study

C-12 December 2012

FIGURE C-5 

Scenario Development Process

 

Analysis & Strategy 

Development

Scenario 

Development 

Process Identify Driving Forces

Rank Driving Forces

Identify 

Critical Uncertainties

Frame the Question 

Associate Critical Uncertainties with

Water Supply and Water Demand

Quantify Scenarios

Identify Characteristics within 

each Critical Uncertainty

Analyze Supply 

Scenarios

Identify Parameters within 

each Critical Uncertainty

Develop 

Storylines

Supply Demand

Uncertainty_Flow_Diagram_rev10.ppt

No

Yes

Analyze Demand 

Scenarios

Combine 

Scenarios

No

Yes

Supply 

Scenarios

Document 

Supply

Scenarios

Demand 

Scenarios

Document 

Demand

Scenarios

Do the existing 

scenarios 

represent a 

sufficiently broad 

range of 

plausible 

futures?

Do the existing 

scenarios 

represent a 

sufficiently broad 

range of plausible 

futures?

Identify Parameter Ranges
Technical Report C — Water

Demand Assessment

December 2012 C-13

3.2 Quantification Approach

The scenario planning approach described previously provided the narrative framework for 

assessing Colorado River demand. Each of the scenarios was subsequently quantified through 

significant input from the Basin States, with additional input provided by tribes, U.S. Fish and 

Wildlife Service (USFWS) personnel, and conservation organizations. Demand for each scenario 

was quantified by estimating values for individual parameters (such as population, irrigated 

acreage, water use efficiencies, etc.) associated with storylines and specific scenario 

assumptions. 

Each Basin State considers many of these parameters in its evaluation of future demand 

projections for its state water planning efforts. Although many planning efforts consider 

alternative scenarios, in most cases those scenarios are not wholly consistent with those 

considered in the Study. To provide consistent demand assumptions with the scenarios 

considered in the Study, the Basin States provided estimates of future demand that align with the 

storylines. These estimates of scenario demand were initially based on existing planning efforts, 

with varying assumptions related to parameters as well as varying planning timeframes 

considered. The estimates were generally modified to reflect the broader range of plausible 

conditions desired in the Study. The trends and projections of population, and trends in water use 

efficiency and agricultural acreage from previous regional studies, were provided to the Basin 

States for consideration and utilized to varying extent in development of demand projections. 

However, in many cases the detail from these previous studies was not sufficient to develop 

planning-area-level estimates as required for the Study. It was also not possible within the scope 

of the Study to develop Basin-wide demand projections based on a fully consistent analytical 

method that would also include the important local differences in factors contributing to water 

demand. 

Consumptive demand for fish and wildlife needs were prepared by the USFWS to reflect the 

range of potential needs for wildlife refuges. 

The demand under each scenario was developed for each of six demand categories: agricultural, 

M&I, energy, mining, fish/wildlife/recreation, and tribal. Demand estimates were developed for 

specific planning areas within each state and then totaled for all planning areas to represent the 

Study Area demand for that state. 

Demand was first developed for areas that may be served by Colorado River water, independent 

of the source of supply. This demand is termed Study Area demand in this technical report; 

however, for many areas outside of the hydrologic basin, a portion of the Study Area demand is

satisfied by other supplies. To develop estimates of Colorado River demand, the Study Area 

demand was reduced by estimates of available supply from other sources. The distinction 

between Study Area demand and Colorado River demand is particularly important for areas such 

as southern California, portions of Arizona not served by mainstem Colorado River water, the 

Front Range of Colorado, the Wasatch Front of Utah, the San Juan-Chama service areas of New 

Mexico, and the Cheyenne region in Wyoming (figure C-1). For example, M&I demands in 

southern California are served by sources such as the State Water Project, Los Angeles 

Aqueduct, and local surface and groundwater sources that are intermingled with Colorado River 

water. In these areas, parameters such as irrigated acreage and population were developed and 

projected based on a specific geographic area rather than by supply source. As a result, the 

specific population potentially served by Colorado River water could not be directly determined. 
Colorado River Basin 

Water Supply and Demand Study

C-14 December 2012

Instead, the total population was used to estimate M&I demand for the geography, and 

information about the availability of other supplies was used to estimate the Colorado River 

demand. Colorado River demand was not limited to individual state apportionments but rather 

reflects projected water needs based on change in demand parameters over time.

Figure C-6 shows the general approach to quantifying a demand scenario. The storyline, shown 

at the top of figure C-6, was required to begin the approach. The parameter characteristics were

quantified for that particular storyline and used to quantify demand by category. Summing all the 

categories established the Study Area demand. Colorado River demand was calculated as the 

Study Area demand minus demand potentially met by other supplies. 

Other factors affecting future water demand, such as Mexico’s allotment and losses such as 

riparian use and reservoir evaporation, were not explicitly included in the scenario approach. 

These factors were included in the modeling supporting the system reliability analysis. Nonconsumptive demands were primarily represented through metrics associated with uses such as 

hydropower, recreation, and ecological resources, further discussed in detail in Technical 

Report D – System Reliability Metrics. 

FIGURE C-6 

Approach to Quantifying Demand Scenarios1

1 Mexico’s allotment and losses such as reservoir evaporation, phreatophyte losses, and operational inefficiencies, 

are not included in this approach but will be included in the modeling supporting the system reliability analysis.
Technical Report C — Water

Demand Assessment

December 2012 C-15

Table C-1 presents the demand categories, their definitions, and associated parameters collected 

or developed for the Study. The parameter data were collected through communication with and 

requests to the Basin States, tribes, USFWS, and conservation organizations. Information sought 

included changes in parameter data over time, such as population, that were used to develop 

demands by category. Where information on alternative futures was lacking, other references

were reviewed that provided indications of regional trends. 

TABLE C-1 

Definition of Demand Categories and Their Associated Parameters 

Demand Category Definition Parameters

Agriculture 

Water used to meet irrigation requirements 

of agricultural crops, maintain stock ponds, 

and sustain livestock

Irrigated acreage, irrigation efficiency

Municipal and 

Industrial 

Water used to meet urban and rural 

population needs, and industrial needs 

within urban areas

Population, population distribution, M&I 

water use efficiency, consumptive use 

factor

Energy Water used for energy services and 

development Water needs for energy generation

Minerals Water used for mineral extraction not 

related to energy services Water needs for mineral extraction

Fish, Wildlife, 

Recreation1

Water used to meet National Wildlife 

Refuge, National Recreation Area, state 

park, and off-stream wetland habitat needs

Institutional and regulatory conditions, 

social values affecting water use, 

Endangered Species Act-listed species 

needs, and ecosystem needs

Tribal Water used to meet tribal needs and 

settlement of tribal water rights claims 

Tribal use, settlements, and claims

1 This demand category represents the consumptive use portion of demand. Non-consumptive demands are considered in metrics, 

see Technical Report D – System Reliability Metrics. 

As part of the scenario quantification process, general relationships were used to relate the 

expected changes in parameters for each scenario in comparison to recent history consistent with 

each storyline. These are shown conceptually in table C-2. For example, it was anticipated that 

population will grow under all scenarios but will grow at a greater rate in the Rapid Growth 

(C1 and C2) scenarios when compared to the Current Projected (A) scenario. M&I per capita 

water use goes down in all of the scenarios (i.e. communities become more efficient), but the rate 

of decrease is greater in the Rapid Growth (C2) scenario as compared to the Rapid Growth (C1) 

scenario. In addition, the expected change in parameters may have substantial geographic 

differences. For example, although “Increased Demand” for minerals under the Rapid Growth 

(C1) scenario may be expected in general, some areas may have little or no capacity for minerals 

development. Therefore, although these general relationships are shown in table C-2, the specific 

quantification of the scenario includes important geographic differences at the state and 

individual planning area level. 
Colorado River Basin 

Water Supply and Demand Study

C-16 December 2012

TABLE C-2 

Scenario Matrix of Typical Changes in Parameters Defined by the Water Demand Storylines

In general, these represent parameter change from 2015 with growth as a blue “Up” arrow, no change as a yellow bar, or reduction as a green “Down” arrow. 

The size of the arrow represent larger or smaller change for a given parameter.

1 Self-served industrial demand (SSI) represents the demand of industries in a given area that have water supply systems independent of municipal systems.

Population

M&I Per 

Capita Use

Self Served

Industrial

Demand1

Agricultural

Irrigated 

Acreage

Agricultural

Per Acre 

Delivery

Energy

Water

Demand

Minerals

Demand

Fish,

Wildlife,

Recreation

Demand

Tribal

Demand

Current 

Projected 

(A)

Slow 

Growth 

(B)

Enhanced

Environment

(D2)

Rapid

Growth 

(C1)

Enhanced

Environment

(D1)

Rapid

Growth 

(C2)
Technical Report C — Water

Demand Assessment

December 2012 C-17

3.2.1 Quantification of Tribal Demand

As previously described, the storylines describe different ways the critical uncertainties, those 

factors determined to be the most critical and uncertain in estimating future demand, may unfold. 

Change in Water Availability due to Tribal Water Use and Settlement of Tribal Water Rights 

Claims was determined to be a critical uncertainty5. Table C-3 summarizes the storyline 

narrative from each demand scenario regarding this critical uncertainty.

TABLE C-3 

Storylines Related to Tribal Water Use 

Storyline Related to Tribal Water Use Scenario

Tribal use develops according to quantified rights and current use patterns. Current Projected (A)

Tribal use continues to develop but at slower than planned rates. Slow Growth (B)

Tribal use and development occur faster than currently planned. In addition, 

new tribal claims and settlements are realized. Rapid Growth (C1)

Tribal use and development occur faster than currently planned. In addition, 

new tribal claims and settlements are realized. Rapid Growth (C2)

Tribal use develops according to quantified rights and current use patterns. Enhanced Environment (D1)

Tribal use and development occurs faster than currently planned. In addition, 

new tribal claims and settlements are realized. Enhanced Environment (D2)

Comments from tribal entities indicated that the factors driving the trajectory of certain critical 

uncertainties (for example, changes in water needs for energy or changes in agricultural land use) 

are different from those that drive the uncertainty related to tribal water use. Specifically, tribal 

comments pointed out that factors such as increased population and economic development may 

not be the primary drivers for future tribal demands. Tribal governments exercise direct and 

immediate control over land use decisions and development on tribal trust lands, and these 

decisions may be independent of economic drivers. For example, under economic conditions 

where a private entity might choose to fallow land, a tribal government may keep land in 

production simply to cover irrigation assessment costs and/or to provide employment. After 

considering these comments, it was decided to change the storyline narratives related to tribal 

water use by removing economic factors. For example, the storyline for the Slow Growth (B) 

scenario was changed from “Tribal use continues to develop but at slower than planned rates due 

to economic conditions and pressure to reduce tribal expenditures or federal settlement

expenditures,” to “Tribal use continues to develop but at slower than planned rates.” 

In most cases, the quantification of tribal demand relied on information submitted by the 

Partnership for use in the Colorado River Interim Surplus Criteria Final Environmental Impact 

Statement (Reclamation, 2000) and used in the more recent Colorado River Interim Guidelines 

for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead Final 

Environmental Impact Statement (Reclamation, 2007). Some revisions to these projections were 

made, and alternative demand scenarios were quantified based on discussions with and 

 

5 For a list of all critical uncertainties associated with water demand and an explanation of how those critical uncertainties were developed, see 

Technical Report A – Scenario Development. 
Colorado River Basin 

Water Supply and Demand Study

C-18 December 2012 

information submitted by individual tribes, the Partnership, and the ITCA. Appendix C9 

describes in more detail the demand projections for each tribe with quantified Colorado River 

rights.

4.0 Results of Water Demand Scenario Quantification

The quantification of future water demand incorporated the scenario planning approach 

described earlier. This section presents the quantified demands that resulted from implementing 

this approach. It begins with a broad qualitative comparison of the demand scenarios, followed 

by a quantitative summary of the results. An overview of Study Area demand and Colorado 

River demand is provided, followed by a discussion of demand by geography (state and Basin 

level) and demand by category. In each of these sections, the demands are presented for all six 

scenarios. Details of the demand quantification for each state at the planning-area level are 

presented in appendices C2 through C8 (Colorado, New Mexico, Utah, Wyoming, Arizona, 

California, Nevada, respectively). Details of quantification for tribal demands are provided in 

appendix C9. 

4.1 Comparison of Demand Scenarios

This section presents a broad comparison of the demand scenarios across the Study Area. The 

comparison is presented in terms of the differences among driving forces, summarized at a 

category level, as described in the storyline for each scenario. The storylines are also provided in 

appendix C14 of this technical report. The driving force categories, Demographics and Land 

Use, Technological and Economics, and Social and Governance, contain multiple driving forces 

that were used to explore critical uncertainties that formed the basis of the storyline for each 

scenario. The development of the driving forces, category groupings, critical uncertainties, and 

storylines is discussed in more detail in Technical Report A – Scenario Development. 

The storylines discuss the future trajectory of both consumptive and non-consumptive demands. 

The scenario quantification presented in this technical report primarily focuses on consumptive 

demands, expressed through the categories M&I, Agricultural, Energy, Minerals, Fish, Wildlife 

and Recreation, and Tribal. This technical report does not compare non-consumptive demands, 

which are those that support the environment and recreational activities, across scenarios. Rather, 

the impact on flows supporting the environment and recreational activities was assessed across 

all scenarios through the evaluation of flow targets, characterized through ecological and 

recreational metrics. Ecological resources and recreational resources (for example, river and 

whitewater boating) metrics can be found in Technical Report D – System Reliability Metrics. 

The Study Area comparison provides the overarching context supporting the water demand 

quantification presented in this technical report. Relative to water use across sectors, these 

comparisons reflect differing levels of and interplay among changing societal values, economic 

drivers, and various types of resource constraints. An exception to this comparison is with 

respect to tribal demands. It was determined during the quantification process that the factors 

affecting tribal demands are not particularly well represented by the driving force categories 

established by the Study. For the most part, tribal demands are based on quantified rights in 

Current Projected (A), Slow Growth (B), and Enhanced Environment (D1) scenarios, but 

consider additional unquantified settlements or claims in tribal demands in the Rapid Growth 

(C1 and C2) and Enhanced Environment (D2) scenarios. Additionally, it is important to 
Technical Report C — Water

Demand Assessment

December 2012 C-19

recognize that the quantification of water supply and demand scenarios may compare differently 

at state and individual planning area levels. State level demands generally follow broad 

identifiable trends, whereas individual planning areas consider locally relevant information, 

plans, timelines, and constraints. 

4.1.1 Demographics and Land Use

Population growth and changes in land use are driven by economic growth, the continuance of 

currently planned agricultural water supply projects, conversion of agricultural land to urban 

land, and the phasing out of lower-economic-value crops in some areas. Population growth and 

land use parameters for each state correspond with different reference points based on state and 

local information and planning efforts reflecting long-term trends.

The Current Projected (A) and Enhanced Environment (D1) scenarios include population 

projections that are the central estimate from the projections used by the Basin States, whereas 

more rapid population projections support the Rapid Growth (C1 and C2) and Enhanced 

Environment (D2) scenarios. The Slow Growth (B) scenario contains lower population 

projections. Agricultural land use decreases across the entire Basin to varying degrees across all 

scenarios and at a greater rate under the Rapid Growth (C1 and C2) scenarios. However, in some 

Upper Basin planning areas both the Current Projected (A) and the Slow Growth (B) scenarios 

show increases in irrigated agricultural acreage by 2060.

4.1.2 Technology and Economics

The development and adoption of new technology and conservation programs supporting 

reductions in agricultural, energy, and M&I water demand are driven by investments at the local, 

state, and federal levels that will be brought about by changing societal values, economic drivers, 

and resource constraints. 

M&I water use becomes more efficient under all scenarios. The increase in efficiency is beyond 

current water efficiency programs and practices. The lowest increase in M&I water use 

efficiency occurs under the Slow Growth (B) scenario, and the largest efficiency increase occurs 

under the Enhanced Environment (D1 and D2) scenarios. Changing social values drive these 

efficiency increases by fostering a willingness to increase investments at the local, state, and 

federal levels in water conservation programs. The most modest efficiency increase under the 

Slow Growth (B) scenario stems from the slower rate at which society embraces additional new 

conservation programs or lacks resources to develop such programs. Changing social values, 

federal investment, and subsequent responses focused on conservation efforts results in the 

largest efficiency increase under the Enhanced Environment (D1 and D2) scenarios. 

Agricultural per-acre water delivery ranges from a modest increase under the Rapid Growth (C2) 

scenario to a modest decrease under the Enhanced Environment (D1) scenario. The primary 

reason for the small decrease under this scenario is favorable economic conditions coupled with 

changing social values, creating willingness and incentives to invest in agricultural water 

conservation. This investment leads to rapid adoption of new technologies, resulting in decreased 

agricultural demands due to increased agricultural water use efficiency. 

Water needs for energy development increase across all scenarios and range from the most 

modest increase under the Enhanced Environment (D1 and D2) scenarios to the greatest increase 

under the Rapid Growth (C1 and C2) scenarios. Water needs for energy expand relative to 

population growth and results in the highest demand under the Rapid Growth (C1) scenario. 
Colorado River Basin 

Water Supply and Demand Study

C-20 December 2012 

Under the Enhanced Environment (D1 and D2) scenarios, an emphasis on renewable energy 

requirements and investments in technologies that reduce water consumption associated with 

energy production and new development decreases projected water demands for energy 

production, despite a rapidly growing population featured under the Enhanced Environment (D2) 

scenario. 

4.1.3 Social and Governance

Changes in agricultural and M&I water use efficiency, in addition to the adoption of new 

programs to support ecological and recreational resources, are influenced by varying rates of 

institutional and regulatory changes assumed in the scenarios. 

Water use efficiency changes range from a continuation of present practices toward increased 

efficiency to a greater emphasis on efficiency based on social values. A continuation of present 

practices is assumed in the Current Projected (A) and Slow Growth (B) scenarios. The Enhanced 

Environment (D1 and D2) scenarios show larger increases in efficiency resulting from social 

values leading to greater investment; increased governmental regulations, agreements, and 

incentives promoting greater renewable energy use; and implementation of additional water 

conservation programs. 

All scenarios rely on the continued existence and further successful implementation of existing 

federal endangered species programs and policies. Additionally, the Enhanced Environment 

(D1 and D2) scenarios contemplate a future where changing social values drive public support 

for investments in additional programs and actions: supporting more certain recovery of listed 

species, keeping them from being re-listed, providing ecological flows sufficient to support a 

healthy river system, and enhancing recreational use of the river. The ecological flow targets, 

characterized using the flow metrics for these scenarios, are non-consumptive, and modeling 

identified shortfalls for quantified flow targets. Options and strategies, including those that 

increase supply, reduce demand, and/or modify operations, were considered to address the risks 

to Basin resources6. 

4.2 Summary Results of Scenario Quantification

Following the approach described earlier, values were developed for parameters and demands 

quantified for each of the scenarios. Table C-4 presents summary results for the demand 

scenarios considered in the Study. The table presents agricultural and M&I demand parameters 

for the Study Area, which distinguishes the scenarios, the resulting Study Area demand, and 

finally the Colorado River demand by category. 

About 40 million people are estimated to be in the Study Area by 2015. This number is expected 

to increase to between 49 and 77 million by 2060. The highest population growth is associated 

with the Rapid Growth (C1 and C2) and the Enhanced Environment (D2) scenarios. The Slow 

Growth (B) scenario has the lowest population growth of the scenarios (49 million by 2060), but 

still represents a growth of nearly 25 percent over 2015 estimates. 

 

6 Resources include water allocations and deliveries consistent with the apportionments under the Law of the River; hydroelectric power 

generation; recreation; fish, wildlife, and their habitats (including candidate, threatened, and endangered species); water quality including 

salinity; flow- and water-dependent ecological systems; and flood control. 
Technical Report C — Water

Demand Assessment

December 2012 C-21

TABLE C-4 

Summary Results of Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

 2015

2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 38.9–41.1 62.4 49.3 76.5 76.5 62.4 76.5

Change in per capita water usage (%), 

from 2015 – -9% -7% -9% -16% -19% -17%

Irrigated acreage (millions of acres) 5.4–5.5 5.1 5.2 4.6 4.6 5.0 5.0

Change in per-acre water delivery (%), 

from 20151 – +1% +2% +1% +3% 0% +3%

Study Area Demand (maf) 

Agricultural Demand 16.4–16.7 15.2 15.7 13.7 13.8 14.9 14.9

Municipal and Industrial Demand 8.4–8.8 12.5 10.2 15.1 13.9 11.0 13.7

Energy Demand 0.34–0.63 0.66 0.57 1.01 0.58 0.51 0.56

Minerals Demand 0.1–0.11 0.18 0.18 0.22 0.15 0.15 0.15

Fish, Wildlife, and Recreation Demand 0.16–0.23 0.08 0.08 0.08 0.10 0.16 0.16

Tribal Demand2 1.6–1.8 2.0 2.0 2.4 2.4 2.0 2.4

Total Study Area Demand3 27.3–27.8 30.6 28.7 32.5 30.9 28.7 31.9

Colorado River Demand (maf) 

Agricultural Demand 7.1–7.2 6.7 6.8 6.6 6.7 6.6 6.8

Municipal and Industrial Demand 3.4–3.5 5.1 4.5 6.2 5.2 4.8 5.4

Energy Demand 0.21–0.23 0.44 0.38 0.74 0.37 0.34 0.35

Minerals Demand 0.09–0.11 0.17 0.18 0.21 0.14 0.14 0.14

Fish, Wildlife, and Recreation Demand 0.15–0.21 0.06 0.07 0.06 0.08 0.15 0.15

Tribal Demand2 1.5–1.7 2.0 1.9 2.4 2.4 2.0 2.4

Total Colorado River Demand3 12.6–12.8 14.5 13.8 16.2 15.0 14.0 15.2

1 Does not include reductions associated with conservation and efficiency programs such as those in Imperial Irrigation District 

which are part of transfer agreements. 

2 Tribal demand within the state of Colorado is included in other demand categories.

3 Excludes Mexico’s allotment and losses (reservoir evaporation, phreatophytes, and operational inefficiencies). These factors will 

be included in the modeling supporting the system reliability analysis.

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, based primarily on passive or existing conservation 

targets, is expected to be 7 to 19 percent less in 2060 than in 2015. These reductions vary 

considerably across states and scenarios. In some regions, per capita water use rates are expected 

to drop by over 20 percent by 2060. 

Irrigated acreage is projected to continue to decrease through 2060 under all scenarios. Under 

the Rapid Growth (C1 and C2) scenarios, projected irrigated acreage is reduced by more than 

830,000 acres and by roughly 300,000 to 500,000 acres in the other scenarios. Although water 
Colorado River Basin 

Water Supply and Demand Study

C-22 December 2012 

use efficiency improvements are anticipated, some of the remaining irrigated land is expected to 

be more intensely cultivated or fully irrigated, resulting in little overall change in water delivery

per acre. 

Water demand for energy and mineral categories are projected to increase under all scenarios.

The growing need for energy (coal, solar, and oil shale) is projected to increase water demands. 

The largest increases are anticipated in Arizona, Colorado, and the California desert. Meanwhile, 

water needs for mineral extraction are projected to significantly increase in Wyoming, Colorado, 

and Arizona. 

Tribal demand is anticipated to increase over time as demand reaches quantified rights (in all 

scenarios), and demand beyond these quantified rights is realized in the Rapid Growth (C1 and 

C2) scenarios and the Enhanced Environment (D2) scenario. 

The Study Area demand ranges between 28.7 and 32.5 maf by 2060, with Colorado River 

demand7 ranging between 13.8 and 16.2 maf. Some of the increase in Study Area demand is 

projected to be met through increases in other supplies, primarily in Colorado and California. 

The increase in Colorado River demand from 2015 to 2060 is estimated to be between 1.2 and 

3.4 maf, with the Lower Basin making up about 60 percent of the increase. Of the total increase 

in Colorado River demand, for the growing categories, between 64 and 76 percent of the growth 

is contributed by the M&I demand category. The growth in energy, tribal, and mineral categories 

constitutes the remaining demand increase. 

Colorado River demand is calculated as Study Area demand less the demand projected to be 

supplied by other sources. The Study and the results presented in this technical report focus on 

the resulting Colorado River demand. Figure C-7 presents demands across the initial scenarios in 

three panels as follows: 1) Study Area demand with other supplies and Colorado River demand 

identified, 2) Colorado River demand, and 3) change in Colorado River demand by 

demand category. 

From the first panel, it can be seen that Study Area demand increases from about 28 maf in 2015 

to up to nearly 33 maf by 2060 in the highest scenario. The range in demand increase across 

scenarios in 2060, however, is projected to be as low as 1.2 or as high as 4.7 maf. When total 

Study Area demand is compared to Colorado River Demand, it can be seen that more than half of 

the Study Area demand is expected to be met by other supplies. 

Panel two depicts the range of Colorado River demand across scenarios. The Colorado River 

demand increases from about 12.6 to 12.8 maf in 2015 to between 13.8 and 16.2 maf in 2060 

(or 9 percent to 26 percent increase from 2015) depending on the scenario. The range across the 

highest and lowest scenarios is about 2.4 maf by 2060 or about a 17 percent spread between the 

Rapid Growth (C1) and the Slow Growth (B) scenarios. 

Panel three shows the projected change in Colorado River demand by specific demand categories 

for each scenario. Increase in the M&I demand category across all scenarios represents the 

greatest increase in demand. Tribal and energy demand categories also are projected to grow, but 

 

7 Mexico’s allotment and losses such as reservoir evaporation, phreatophyte losses, and operational inefficiencies are not part of this total. These 

factors will be included in the modeling supporting the system reliability analysis and have been included in figure C-2 to provide a more 

complete view of the total demand and losses in the Basin.
Technical Report C — Water

Demand Assessment

December 2012 C-23

the overall growth in Colorado River demand is projected to be partially offset by decreases in 

agricultural demand driven by reductions in irrigated acreage. 

Figure C-8 shows the historical Colorado River use and projected future Colorado River demand 

by scenario. This figure includes historical and future projected losses (consisting of reservoir 

evaporation and other losses) and deliveries to Mexico to provide a more complete view of the 

total demand and losses in the Basin. Factoring in Mexico’s allotment and losses, the Colorado 

River demand increases to between 17.7 and 20.1 maf in 2060. The range across scenarios in 

2060 (about 2.4 maf) is easily discernible in the figure, as is the relative similarity of overall 

demand in the Current Projected (A), Rapid Growth (C2), and Enhanced Environment (D2) 

scenarios. In addition, it appears that the quantified scenarios track with recent peaks in historical 

uses that likely represent the least supply limited conditions and could be an indication of 

historical demand. 

4.3 Colorado River Water Demand by Geography 

The Colorado River demand at three geographic levels is presented in figures C-9, C-10, and 

C-11. These figures show Study Area, Upper and Lower Basin, and individual state demand 

across the scenarios. The bars at the right in these figures show the relative contribution of each 

demand category to the total Colorado River demand at a point in time (2015, 2035, or 2060) in 

the Current Projected (A) scenario. In general, the category proportions remain relatively 

consistent across the scenarios. 

As described in the Quantification Approach, the scenario quantification approach entailed first 

quantifying the changes in parameters, such as population and agricultural acreage, and then 

using these quantified parameters to compute demand. For the purposes of the Study, the 

resulting demand was not limited by the Colorado River Compact apportionments. In this way 

the demand for Colorado River and tributary water were assessed in the context of overall Study 

Area demand and supplies available from other sources. 

As shown in figure C-9, the change in both magnitude and percentage of Colorado River demand 

varies considerably across the states. Colorado and Arizona show the greatest magnitude of 

overall growth in Colorado River demand from 2015 to 2060 across the scenarios, ranging 

between about a 0.2 to 1.2 maf increase by 2060 in Arizona and 0.14 to 0.64 maf in Colorado. 

The broad demand range across scenarios in these states is attributable to substantial growth in 

M&I demand, particularly in central Arizona and the Front Range of Colorado. Increase in tribal 

demand is also a significant contributor to the increases in Arizona. Demand in Nevada and 

California is projected to grow by about 0.2 to 0.35 maf primarily as the result of population 

growth. Demand in New Mexico, Utah, and Wyoming grows by about 0.1 to 0.2 maf under most 

scenarios. However, under the Rapid Growth (C1) scenario the growth is about 0.3 maf and 

0.4 maf in Utah and New Mexico, respectively. This additional growth in Utah is driven by a 

projected increase in population of nearly 4 million and per capita water use reductions not fully 

offsetting the rapid growth. In New Mexico, this growth is driven by population growth and 

tribal demands. 

 
Colorado River Basin 

Water Supply and Demand Study

C-24 December 2012 

FIGURE C-7 

Study Area, Colorado River, and Change in Colorado River Demand

0

5

10

15

20

25

30

35

2015 2035 2060

Million Acre- Feet

Study Area Demand

(demands do not include Mexico's allotment, reservoir evaporation, and other losses)

12.0

12.5

13.0

13.5

14.0

14.5

15.0

15.5

16.0

16.5

2015 2035 2060

Million Acre -Feet

Colorado River Demand

(demands do not include Mexico's allotment, reservoir evaporation, and other losses) 

Colorado River Demand

shown with solid color

Demandsthat may be met 

by Other Supplies shown

with off-white and colored 

border

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

2015 2035 2060

Million- Acre Feet

Change in Colorado River Demand, from 2015

(demands do not include Mexico's allotment, reservoir evaporation, and other losses)

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Technical Report C — Water

Demand Assessment

December 2012 C-25

FIGURE C-8 

Colorado River Basin Historical Use1 and Future Projected Demand1, Delivery to Mexico2, Reservoir Evaporation3, and 

Other Losses4

1 Excluding consumptive use in Lower Basin tributaries.

2 Assumed 1.5 maf delivery to Mexico 2012–2060. Modeling to support the system reliability analysis will project future deliveries to 

Mexico in accordance with the 1944 treaty. 

3 Median value of CRSS-simulated reservoir evaporation across supply and demand scenarios.

4 Other losses include phreatophyte and operational inefficiency losses. Future phreatophyte losses are computed by assuming 

1995–2008 average of 632 thousand acre-feet (kaf). Future operational inefficiency losses are computed as the sum of 109 kaf (the 

1990–2010 average bypass of return flows from the Welton-Mohawk Irrigation and Drainage District to the Cienega de Santa Clara 

in Mexico) and 7 kaf (computed by assuming the 1964–2010 historical average annual volume of non-storable flows delivered to 

Mexico [excluding flood years] is reduced by 90 percent due to the operation of Warren H. Brock Reservoir). 

0

5

10

15

20

25

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Million Acre-Feet per Year

Year

<-- Historical Projected->

*Quantified demand scenarios have been adjusted to include Mexico's allotment and estimates for future reservoir evaporation and other losses.

Historical Use

Delivery to Mexico

Reservoir Evaporation

Other Losses

Current Projected (A)*

Delivery to Mexico

Reservoir Evaporation

Other Losses

Slow Growth (B)*

Rapid Growth (C1)*

Rapid Growth (C2)*

Enhanced Environment (D1)*

Enhanced Environment (D2)*
Colorado River Basin 

Water Supply and Demand Study

C-26 December 2012 

FIGURE C-9 

Colorado River Water Demand1,2

1 Demands do not include Mexico’s allotment and losses such as reservoir evaporation. These factors will be included in the 

modeling supporting the system reliability analysis.

2 Tribal demand in Colorado, at the request of the Southern Ute Indian and Ute Mountain Ute tribes, is not separated from other 

categories in the state.

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and Recreation

Tribal

Category Legend (Right)

0

1

2

3

4

5

6

2015 2035 2060

KAF

Demand Legend

Current Projected (A) Slow Growth (B)

Rapid Growth (C1) Rapid Growth (C2)

Enhanced Environment (D1) Enhanced Environment (D2)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

2015 2035 2060

MAF

Lower Basin

Tribal

Tribal

Tribal

Municipal and Industrial

Municipal and Industrial

Municipal and Industrial

Agricultural

Agricultural

Agricultural

201520352060

0.0

2.0

4.0

6.0

8.0

10.0

12.0

2015 2035 2060

MAF

Upper Basin

0.0

1.0

2.0

3.0

4.0

2015 2035 2060

MAF

Utah

0.0

1.0

2.0

3.0

4.0

2015 2035 2060

MAF

Nevada

0.0

1.0

2.0

3.0

4.0

5.0

6.0

2015 2035 2060

MAF

California

0.0

1.0

2.0

3.0

4.0

2015 2035 2060

MAF

New Mexico

0.0

1.0

2.0

3.0

4.0

2015 2035 2060

MAF

Colorado

0.0

1.0

2.0

3.0

4.0

2015 2035 2060

MAF

Wyoming

0.0

1.0

2.0

3.0

4.0

5.0

2015 2035 2060

MAF

Arizona

12.0

12.5

13.0

13.5

14.0

14.5

15.0

15.5

16.0

16.5

2015 2035 2060

Million Acre-Feet (MAF)

Colorado River Demand 

UPPER BASIN

LOWER BASIN
Technical Report C — Water

Demand Assessment

December 2012 C-27

FIGURE C-10

Colorado River Water Demand by Category1,2

 1 Demands do not include Mexico’s allotment and losses such as reservoir evaporation. These factors will be included in the 

modeling supporting the system reliability analysis.

2 Tribal demand in Colorado, at the request of the Southern Ute Indian and Ute Mountain Ute tribes, is not separated from other 

categories in the state.

0

2

4

6

8

10

12

MAF

Upper Basin

2015 2035 2060 0

2

4

6

8

10

12

MAF

Lower Basin

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

MAF

Utah

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

MAF

Nevada

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

5.0

6.0

MAF

California

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

5.0

MAF

Arizona

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

MAF

New Mexico

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

MAF

Colorado

2015 2035 2060

0.0

1.0

2.0

3.0

4.0

MAF

Wyoming

2015 2035 2060

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

Million Acre-Feet (MAF)

Colorado River Demand

2015 2035 2060

Tribal

Tribal

Tribal

Municipal and Industrial

Municipal and Industrial

Municipal and Industrial

Agricultural

Agricultural

Agricultural

201520352060

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

UPPER BASIN

LOWER BASIN
Colorado River Basin 

Water Supply and Demand Study

C-28 December 2012 

FIGURE C-11

Change in Colorado River Water Demand from 2015 by Category1,2

 1 Demands do not include Mexico’s allotment and losses such as reservoir evaporation. These factors will be included in the 

modeling supporting the system reliability analysis.

2 Tribal demand in Colorado, at the request of the Southern Ute Indian and Ute Mountain Ute tribes, is not separated from other 

categories in the state. 

-1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

MAF

Upper Basin

2015 2035 2060 -1.0

-0.5

0.0

0.5

1.0

1.5

2.0

2.5

MAF

Lower Basin

2015 2035 2060

-0.5

0.0

0.5

1.0

MAF

Utah

2015 2035 2060

-0.5

0.0

0.5

1.0

MAF

Nevada

2015 2035 2060

-0.5

0.0

0.5

1.0

MAF

California

2015 2035 2060

-0.5

0.0

0.5

1.0

1.5

2.0

MAF

Arizona

2015 2035 2060

-0.5

0.0

0.5

1.0

MAF

New Mexico

2015 2035 2060

-0.5

0.0

0.5

1.0

MAF

Colorado

2015 2035 2060

-0.5

0.0

0.5

1.0

MAF

Wyoming

2015 2035 2060

-1,000

0

1,000

2,000

3,000

4,000

5,000

Thousand Acre-Feet per Year

Change in Colorado River Demand , from 2015

2015 2035 2060

Tribal

Tribal

Tribal

Municipal and Industrial

Municipal and Industrial

Municipal and Industrial

Agricultural

Agricultural

Agricultural

201520352060

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

UPPER BASIN

LOWER BASIN
Technical Report C — Water

Demand Assessment

December 2012 C-29

When demand by category is examined in figure C-10, the contribution of demand by category 

across the Upper and Lower Basins vary, with nearly equal agricultural and M&I demand in the 

Lower Basin and nearly two-thirds of the demand in the Upper Basin from agriculture. The 

category contribution to the total demand varies considerably across states as well, with no two 

states having comparable proportions of categories. 

Figure C-11 shows the change in Colorado River demand by category from 2015 for each 

scenario. In most scenarios, the M&I demand is the major driver contributing to future growth in 

demand. However, the M&I demand does not increase as significantly in the Slow Growth (B) or 

Enhanced Environment (D1) scenarios where either population growth is reduced or per capita 

water use is assumed to be substantially decreased, respectively. Tribal, energy, and minerals 

demands are also projected to increase in all scenarios, while Basin-wide reductions in 

agricultural demand are projected. The Upper Basin generally shows growth in all categories but 

is dominated by demand growth in the M&I category, while the Lower Basin shows dramatic 

growth in M&I demand (in most scenarios) and a significant reduction of agricultural demand. 

The reduction in fish and wildlife demand in the Lower Basin is caused by the cessation of 

mitigation water provided to the Salton Sea in California in accordance with the Colorado River 

Water Delivery Agreement8 (CRWDA), approved in 2003. 

4.4 Colorado River Water Demand by Category

4.4.1 Agriculture

Agricultural water demand is primarily driven by the extent of irrigated acreage and per-acre 

water delivery. Per-acre water delivery is the amount of water diverted per irrigated acre and 

includes components such as transmission and delivery losses (surface evaporation, riparian 

demand, and seepage), and on-farm losses that are made up of evaporation, tail water (return), 

and crop irrigation requirements. Each of these factors varies by location (precipitation, growing 

season, etc.), irrigation method, and crop type. 

Figure C-10 shows the demand by category and depicts the relative magnitude of the agricultural 

demand. Figure C-12 presents the change in agricultural demand for the Study Area, by Upper 

and Lower Basin, and by state. The figure also shows agricultural demand as a proportion of the 

total Colorado River water demand (right hand stacked bar graph). 

As can be seen from figure C-10 and figure C-12, agricultural water demand is the largest 

component of Colorado River demand. Demand for agricultural uses decreases through 2060 for 

all scenarios, dropping from about 57 percent in 2015 to between 41 and 49 percent of Colorado 

River demand in 2060, depending on the scenario. The reduction in the percentage contribution 

of agricultural demand results from both a decrease in the magnitude of agricultural water 

demand and increases in the magnitude of other categories of demand. The overall decrease is 

almost entirely due to a reduction in irrigated acreage, as per-acre delivery shows slight increases 

across all scenarios. 

 

8 Colorado River Water Delivery Agreement: Federal Quantification Settlement Agreement for Purposes of Section 5(B) of Interim Surplus 

Guidelines, October 10, 2003 (69 Federal Register 12202, March 15, 2004)
Colorado River Basin 

Water Supply and Demand Study

C-30 December 2012 

FIGURE C-12

Change in Colorado River Water Demand for Agriculture

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

2015 2035 2060

MAF

Lower Basin

201520352060

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

2015 2035 2060

MAF

Upper Basin

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

Utah

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

Nevada

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

California

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

New Mexico

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

Colorado

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

Wyoming

-0.6

-0.4

-0.2

0.0

0.2

2015 2035 2060

MAF

Arizona

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

2015 2035 2060

Million Acre-Feet (MAF)

Change in Colorado River Demand, From 2015

Agricultural

Agriculture is 55 - 57% of Colorado River demand*

Agriculture is 47 - 51% of Colorado River demand*

Agriculture is 41 - 49% of Colorado River demand*

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Legend

Category Plot 

(Right)

UPPER BASIN

LOWER BASIN

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Technical Report C — Water

Demand Assessment

December 2012 C-31

Agricultural demand decreases over time in the Lower Basin, but exhibits some increases in the 

Upper Basin in several scenarios. For the Lower Basin states, most of the decrease in agricultural 

demand occurs in Arizona, with a small amount of reduction in demand in California across all 

scenarios. Nevada does not report any agricultural use in any scenario. In the Upper Basin, an 

increase in agricultural demand occurs in most states. Increases in projected agricultural demand 

in Colorado have the greatest magnitude and are the most notable in the Enhanced Environment 

(D2) scenario; however, decreases occur in several other scenarios due to assumed decreases in 

future irrigated acreage. Slight increases in agricultural demand are projected in most scenarios 

in Utah and Wyoming. New Mexico agricultural demand ranges from no change to a nominal 

decrease. 

A strong driver for loss of agricultural acreage is urbanization, leading to physical loss of acreage 

and pressure for transfer of water. These factors are particularly important in Colorado and 

Arizona. Utah and Wyoming are continuing to actively develop agricultural lands under 

existing plans. 

4.4.2 Municipal and Industrial

M&I water demand was estimated from population and per capita water use, with the addition of 

SSI demand. The per capita water use is a measure of the amount of water produced or diverted 

per person in a given municipality or service area. Because this measure examines all water 

produced by a given municipality or service area, it often includes industrial, commercial, and 

institutional demand as well as residential demand. A number of factors may influence the M&I

water use of a given community, including the amount of industrial demand, climate, number of 

institutional facilities, accounting method for reuse, demographics, economic conditions, and 

number of visitors. These factors make comparisons among different locations challenging. 

The SSI demand represents the demand of industries in a given area that have independent water 

supply systems. Because these industries have water supplies independent from the urban areas, 

the demand is not directly related to population and per capita water use rates assumed for most 

M&I demand projections. 

Figure C-10 shows the demand by category and depicts the relative magnitude of the M&I 

demand. Figure C-13 presents the change in M&I demand for the Study Area, by Upper and 

Lower Basin, and by state. The figure also shows the M&I demand as a proportion of the total 

Colorado River water demand (right hand stacked bar graph). 

As can be seen from figure C-10 and figure C-13, M&I water demand is the second largest 

component of Colorado River demand. The M&I demand increases over the Study period for all 

scenarios, from about 27 percent in 2015 to between 33 and 38 percent of total Colorado River 

demand in 2060, depending on the scenario. The increase is primarily due to population increase 

because per capita water use is projected to decrease over time across all scenarios. The SSI

demand is less than 10 percent of total M&I demand. 
Colorado River Basin 

Water Supply and Demand Study

C-32 December 2012 

FIGURE C-13 

Change in Colorado River Water Demand for Municipal and Industrial

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

MAF

Lower Basin

201520352060

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

MAF

Upper Basin

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

Utah

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

Nevada

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

California

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

New Mexico

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

Colorado

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

Wyoming

-0.5

0.0

0.5

1.0

1.5

2015 2035 2060

MAF

Arizona

A

A

B

C1

B

C1

C2

C2

D1

D1

D2

D2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

2015 2035 2060

Million Acre-Feet (MAF)

Change in Colorado River Demand, From 2015

Municipal and Industrial

M&I is 27% of Colorado River demand*

M&I is 31 - 32% of Colorado River demand*

M&I is 33 - 38% of Colorado River demand*

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Legend

Category Plot 

(Right)

UPPER BASIN

LOWER BASIN

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Technical Report C — Water

Demand Assessment

December 2012 C-33

The M&I demand for Colorado River water increases over the Study period in both the Upper 

and Lower Basin, with about 19 to 33 percent of the increase occurring in the Upper Basin and 

67 to 81 percent of the increase occurring in the Lower Basin. In the Upper Basin, most of the 

increase in M&I demand for Colorado River water is due to projected population growth in the 

state of Colorado. The remaining increase in Upper Basin M&I demand is primarily in New 

Mexico and Utah, with only small increases in Wyoming. In the Lower Basin, about 50 percent 

of the increase in M&I demand occurs in Arizona, with the remaining 50 percent split between 

California and Nevada across all scenarios. 

Population is the most significant driver for increases in M&I demands. In the scenarios, per 

capita water use rates are projected to decrease in six of the seven Basin States and partially 

attenuate demand growth due to population increases alone. Per capita water use rates decrease 

in all states except in Wyoming, where rates are projected to increase slightly due to urbanization 

of rural areas.

4.4.3 Energy

Water demand for energy includes anticipated growth in most types of power generation and 

associated technologies, including thermoelectric, solar, geothermal, and oil shale. Water 

demand for energy uses can be estimated through known plans for new power plants or through 

applying a per capita energy water use factor. Power facilities, however, often serve areas remote 

from their locations and therefore potentially represent exports or imports of energy and water 

from the Study Area to meet these distributed needs. Therefore, while the link between 

population and energy demand exists, the effects on energy water demands are not always 

experienced in the same planning areas as the growth.

Figure C-10 shows the demand by category and depicts the relative magnitude of the energy 

water demand. Figure C-14 presents the change in energy demand for the Study Area, by Upper 

and Lower Basin, and by state. The figure also shows the energy demand as a proportion of the 

total Colorado River water demand (right hand stacked bar graph). 

As can be seen from figure C-10 and figure C-14, energy water demand is a small fraction of

total Colorado River demand. The water demand for energy is projected to increase over the 

Study period in all scenarios and in both the Upper and Lower Basins. The water demand for 

energy increases from about 1.7 percent of the total demand in 2015 to between 2.3 and 4.6 

percent of total demand in 2060, depending on the scenario. Between 31 and 56 percent of the 

increase in water demand for energy occurs in the Upper Basin and between 44 and 69 percent of 

the increase occurs in the Lower Basin. In the Upper Basin, between about 50 to 80 percent of 

the increase in energy demand over time is due to increases in Colorado, with the remaining 

increase in demand primarily split between Wyoming and Utah. In the Upper Basin, increases 

are due to expansion of thermoelectric power plants and oil shale production. In the Lower 

Basin, virtually all of the growth in water demand for energy occurs in California due to 

projected expansion of geothermal and solar projects. Projected increases in water demands for 

energy in Arizona represent only about 1 percent of the Lower Basin increase, and Nevada does 

not report any water demand for energy use in any of the scenarios. In general, most states have 

some portion of imported and exported electrical supply. Likewise, significant hydroelectric 

production capacity along the mainstem mitigates typical water demand for energy production. 
Colorado River Basin 

Water Supply and Demand Study

C-34 December 2012 

FIGURE C-14 

Change in Colorado River Water Demand for Energy

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Lower Basin

201520352060

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Upper Basin

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Utah

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Nevada

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

California

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

New Mexico

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Colorado

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Wyoming

0.00

0.05

0.10

0.15

0.20

0.25

0.30

2015 2035 2060

MAF

Arizona

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0.0

0.1

0.2

0.3

0.4

0.5

0.6

2015 2035 2060

Million Acre-Feet (MAF)

Change in Colorado River Demand, From 2015

Energy

Energy is 1.7 - 1.8% of Colorado River demand*

Energy is 2.1 - 3.4% of Colorado River demand*

Energy is 2.3 - 4.6% of Colorado River demand*

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Legend

Category Plot 

(Right)

UPPER BASIN

LOWER BASIN

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Technical Report C — Water

Demand Assessment

December 2012 C-35

4.4.4 Minerals

Water demand for mineral production was estimated through existing uses and known plans for 

mineral extraction in the Study Area. Water demand for mineral production varies considerably 

across the Study Area and can fluctuate significantly based on market prices for a given product. 

Figure C-10 shows the demand by category and depicts the relative magnitude of the mineral

water demand. Figure C-15 presents the change in mineral demand for the Study Area, by Upper 

and Lower Basin, and by state. The figure also shows mineral demand as a proportion of the total 

Colorado River water demand (right hand stacked bar graph).

As can be seen from figure C-10 and figure C-15, water demand for mineral extraction is a small 

fraction (less than 200,000 acre-feet per year [afy] Basin-wide) of the total Colorado River 

demand It increases from about 0.7 percent in 2015 to between 0.9 and 1.3 percent of Colorado 

River demand in 2060, depending on the scenario. The water demand for mineral extraction

increases for all scenarios and in both the Upper and Lower Basins. Similar increases in demand 

occur in the Upper and Lower Basins for Rapid Growth (C2) and Enhanced Environment (D1 

and D2) scenarios between 2015 and 2060. Greater increases in demand occur in the Upper 

Basin for Current Projected (A), Slow Growth (B), and Rapid Growth (C1) scenarios due to 

technology adoption assumptions. 

All increases in water demand for mineral production are due to increases in Colorado, 

Wyoming, and Arizona. 

4.4.5 Fish, Wildlife, and Recreation

Water demand for fish, wildlife, and recreation was estimated from existing agreements or 

known consumptive uses associated with this demand category. The demands in this category 

largely represent water needs for wildlife refuges, fish hatcheries, recreational facilities, and 

obligations for water delivery to the Salton Sea under the CRWDA. In the Lower Basin, the 

Cibola National Wildlife Refuge (NWR), Imperial NWR, Havasu NWR, and Lake Mead 

National Recreation Area have consumptive water rights and largely comprise the fish, wildlife, 

and recreation demand in the Lower Basin. Non-consumptive demands associated with fish, 

wildlife, and recreations, including in-stream flow requirements are represented through the 

metrics portion of the Study as presented in Technical Report D – System Reliability Metrics. 

Figure C-10 shows the demand by category and depicts the relative magnitude of the fish, 

wildlife, and recreation water demand. Figure C-16 presents the change in fish, wildlife, and 

recreation demand for the Study Area, by Upper and Lower Basin, and by state. The figure also 

shows the fish, wildlife, and recreation demand as a proportion of the total Colorado River water 

demand (right hand stacked bar graph). 

As can be seen from figure C-10 and figure C-16, fish, wildlife, and recreation water demand is a 

small fraction of Colorado River demand, and decreases from about 1.4 percent in 2015 to about 

0.4 to 1 percent of Colorado River demand in 2060 across all scenarios. The overall decrease in 

demand for Colorado River water for fish, wildlife, and recreation is driven by the terms of 

Exhibit B of the CRWDA, which phases out Salton Sea delivery obligations over time. As such, 

the change in demand is a result of the termination of a regulatory settlement, rather than a 

regional depiction of reductions in water allocated for fish, wildlife, and recreation demands. 
Colorado River Basin 

Water Supply and Demand Study

C-36 December 2012 

FIGURE C-15 

Change in Colorado River Water Demand for Mineral Production

0.00

0.02

0.04

0.06

0.08

0.10

2015 2035 2060

MAF

Lower Basin

201520352060

0.00

0.02

0.04

0.06

0.08

0.10

2015 2035 2060

MAF

Upper Basin

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

Utah

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

Nevada

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

California

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

New Mexico

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

Colorado

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

Wyoming

0.00

0.02

0.04

0.06

2015 2035 2060

MAF

Arizona

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0.00

0.02

0.04

0.06

0.08

0.10

0.12

2015 2035 2060

Million Acre-Feet (MAF)

Change in Colorado River Demand, From 2015

Minerals

Minerals is 0.7 - 0.8% of Colorado River demand*

Minerals is 1 - 1.3% of Colorado River demand*

Minerals is 0.9 - 1.3% of Colorado River demand*

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Legend

Category Plot 

(Right)

UPPER BASIN

LOWER BASIN

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Technical Report C — Water

Demand Assessment

December 2012 C-37

FIGURE C-16 

Change in Colorado River Water Demand for Fish, Wildlife, and Recreation

-0.12

-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

2015 2035 2060

MAF

Lower Basin

201520352060

-0.12

-0.10

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

2015 2035 2060

MAF

Upper Basin

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

Utah

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

Nevada

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

California

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

New Mexico

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

Colorado

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

Wyoming

-0.12

-0.08

-0.04

0.00

0.04

2015 2035 2060

MAF

Arizona

A

A

B

B

C1

C2

C1

C2

D1

D1

D2

D2

-0.10

-0.09

-0.08

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0.00

2015 2035 2060

Million Acre-Feet (MAF)

Change in Colorado River Demand, From 2015

Fish, Wildlife, and Recreation

Fish, Wildlife, & Recreation is 1.2 - 1.7% of Colorado River demand*

Fish, Wildlife, & Recreation is 0.4 - 0.9% of Colorado River demand*

Fish, Wildlife, & Recreation is 0.4 - 1% of Colorado River demand*

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Legend

Category Plot 

(Right)

UPPER BASIN

LOWER BASIN

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

No 

Change

No 

Change

N/A

N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin 

Water Supply and Demand Study

C-38 December 2012 

Fish, wildlife, and recreation demand increases over time in the Upper Basin and decreases

over time in the Lower Basin. The Upper Basin makes up about 30 percent of the fish, wildlife, 

and recreation demand in 2060, with the Lower Basin making up about 70 percent of demand. 

In the Upper Basin, all of the increase in fish, wildlife, and recreation water demand over time 

is due to increases in this category in Wyoming. Wyoming provides water for a number of 

wildlife refuges. Colorado, New Mexico, and Utah do not report any fish, wildlife, and 

recreation consumptive use in any of the scenarios. In the Lower Basin, all of the decrease in 

fish, wildlife, and recreation demand occurs in California. Arizona includes fish, wildlife, and 

recreation demand that varies by scenario but is constant over time. Nevada includes small fish, 

wildlife, and recreation demand that is constant over time and across scenarios. 

4.4.6 Tribal

Tribal water demand in the Study is largely based on the quantified rights and entitlements of 

tribes to Colorado River water as well as their anticipated future rate of use and development. A 

number of tribes in the Basin have unquantified rights and claims (Navajo Nation, Ute Mountain 

Ute Tribe, Havasupai Tribe, Hopi Tribe, Hualapai Tribe, Kaibab Band of Paiute Indians, Pascua 

Yaqui Tribe, San Carlos Apache Tribe, San Juan Southern Paiute Tribe, Tohono O’odham 

Nation, Tonto Apache Tribe, and Yavapai-Apache Nation), and although the demand for this 

water will be a factor impacting Basin-wide water availability, specific, reliable numbers are not 

presently available due to their unresolved status.

For the Study, tribes with quantified rights to Colorado River water were organized into three 

categories, presented in table C-5, based on location: Upper Colorado River Basin tribes, Lower 

Colorado River Mainstem tribes, and tribes served by water provided through the CAP. 

Figure C-17 displays the lands in the hydrologic Basin where tribes have rights or claims to 

Colorado River water. 

Figure C-18 summarizes Basin-wide, by Upper and Lower Basins, and by state, both the 

quantified Colorado River rights held by tribes as well as the tribal demand as a portion of those 

rights. Tables C-6 and C-7 present, by state, tribal diversion, depletion, and acreage entitlement 

as appropriate, as well as 2015, 2035, and 2060 projected tribal diversion and depletion, along 

with total state depletion under each scenario. It is important to note that in figure C-18 both 

tribal demand and rights are presented in terms of diversion and not depletion. This presentation 

was chosen to facilitate a comparison between demand and quantified rights for the mainstem 

tribes in the Lower Basin whose rights are quantified in terms of diversion entitlements. For a 

more detailed description of the rights and demands by tribe, see appendix C9. 

As seen in figure C-18, quantified tribal diversion rights comprise about 2.9 maf in the Basin, 

with about 1.36 maf of those rights in the Upper Basin and 1.58 maf in the Lower Basin. 

Quantified tribal rights are assumed to not vary by scenario or throughout the Study period. The 

majority of quantified rights are within Arizona, totaling approximately 1.4 maf. Tribal demands 

in Colorado, at the request of the Southern Ute Indian and Ute Mountain Ute Tribes, are not 

broken out from other categories in the state. Consequently, only the quantified right for these 

tribes (not the demand) is shown in these figures. There are no tribal rights or claims to Colorado 

River water in Wyoming. The figure also shows the tribal demand in terms of depletion as a 

proportion of the total Colorado River demand (right hand stacked bar graph). 
Technical Report C — Water

Demand Assessment

December 2012 C-39

TABLE C-5 

Upper Colorado River Basin Tribes, Lower Colorado River Mainstem Tribes, and Tribes Served by Water Provided 

through the CAP

Upper Colorado River Basin Tribes

Jicarilla Apache Nation New Mexico

Navajo Nation Arizona, New Mexico, and Utah

Southern Ute Indian Tribe Colorado

Ute Indian Tribe of the Uintah and Ouray Reservation Utah

Ute Mountain Ute Tribe Colorado, New Mexico, and Utah

Lower Colorado River Mainstem Tribes1

Chemehuevi Indian Tribe California

Cocopah Indian Tribe Arizona

Colorado River Indian Tribes Arizona and California

Fort Mojave Indian Tribe Arizona, Nevada, and California

Hopi Tribe Arizona

Quechan Indian Tribe Arizona and California

Tribes with Central Arizona Project allocations

Ak-Chin Indian Community Arizona

Fort McDowell Yavapai Nation Arizona

Gila River Indian Community Arizona

Pascua Yaqui Tribe Arizona

Salt River Pima-Maricopa Indian Community Arizona

San Carlos Apache Tribe Arizona

Tohono O'odham Nation Arizona

Tonto Apache Tribe Arizona

White Mountain Apache Tribe Arizona

Yavapai-Apache Nation Arizona

Yavapai-Prescott Tribe Arizona

1 The Zuni Indian Tribe has rights to Little Colorado River water in Arizona and the Moapa Band of Paiutes has rights to water in 

the Muddy River, Nevada. The modeling of these tributaries assumes future demand to be consistent with historical demand on 

these rivers. See appendix C9 for more information on the modeling of Lower Basin tributaries.
Colorado River Basin 

Water Supply and Demand Study

C-40 December 2012 

FIGURE C-17 

Colorado River Basin Tribes
Technical Report C — Water

Demand Assessment

December 2012 C-41

FIGURE C-18 

Colorado River Basin Tribal Diversion Rights (dotted line) and Diversion-Based Demand1,2,3

1 Tribal demand in Colorado, at the request of the Southern Ute Indian and Ute Mountain Ute tribes, is not separated from other 

categories in the state. 

2 The diversion and depletion associated with demand for the Ute Indian Tribe of the Uintah and Ouray Reservation is dependent 

upon the re-ratification of the Revised Ute Indian Compact of 1990 by the tribe and the State of Utah.

3 The diversion and depletion demands of the Navajo Nation from the Colorado River in the Upper Basin in New Mexico are not 

limited by the Navajo Nation San Juan River in New Mexico Water Rights Settlement; however, the Navajo Nation agrees to be 

bound by the terms of that settlement so long as the Settlement is effective. To the extent that the Navajo Nation demands exceed 

the amounts provided in the settlement, the Nation may seek to acquire water from other users or from sources other than the 

Colorado River to meet any unmet demands.

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

MAF

Lower Basin

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

MAF

Upper Basin

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

New Mexico

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

Arizona

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

California

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

Nevada

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

Wyoming

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

Utah

UPPER BASIN

LOWER BASIN

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

A

A

A

B

B

B

C1

C1

C1

C2

C2

C2

D1

D1

D1

D2

D2

D2

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

2015 2035 2060

Million Acre-Feet (MAF)

Colorado River Tribal Water Right and Demand

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2015 2035 2060

MAF

Colorado
Colorado River Basin 

Water Supply and Demand Study

C-42 December 2012

TABLE C-6 

Upper Colorado River Basin Tribal Rights and Tribal and State Future Demands

State

Tribal 

Diversion 

Entitlement 

(Water 

Right) (afy)

Tribal 

Depletion 

Entitlement 

(Water 

Right) (afy) Scenario

Tribal Demand 

(Diversion)

Tribal

Demand

(Depletion)

State 

Demand 

(Depletion)

Tribal Demand 

(Diversion)

Tribal

Demand

(Depletion)

State Demand 

(Depletion)

Tribal 

Demand 

(Diversion)

Tribal

Demand

(Depletion)

State 

Demand 

(Depletion)

2015 (afy) 2035 (afy) 2060 (afy)

CO 225,448 125,399 All Scenarios Tribal demand in Colorado is embedded in other demand categories within the state.

NM1 652,343 359,865 Current 

Projected (A) 543,280 299,470 600,020 652,926 359,730 703,035 658,546 363,195 754,100

Slow Growth 

(B) 543,280 299,470 600,020 652,926 359,730 673,386 658,546 363,195 692,615

Rapid Growth 

(C1) 554,904 305,710 606,260 745,316 409,775 757,963 961,439 525,795 979,209

Rapid Growth 

(C2) 554,904 305,710 605,005 745,316 409,775 694,229 961,439 525,795 830,724

Enhanced 

Environment 

(D1)

543,280 299,470 597,509 652,926 359,730 684,477 658,546 363,195 682,604

Enhanced 

Environment 

(D2)

554,904 305,710 602,586 745,316 409,775 678,361 961,439 525,795 784,559

UT 480,594 258,943 Current 

Projected (A) 480,594 258,943 999,059 480,594 258,943 1,081,531 480,594 258,943 1,153,500

Slow Growth 

(B) 316,354 170,451 910,566 447,747 241,245 1,032,775 480,594 258,943 1,084,253

Rapid Growth 

(C1) 506,798 272,045 1,012,161 560,470 298,881 1,141,323 637,286 337,289 1,277,455

Rapid Growth 

(C2) 506,798 272,045 1,011,093 560,470 298,881 1,116,488 637,286 337,289 1,222,092
Technical Report C — Water

Demand Assessment

December 2012 C-43

TABLE C-6 

Upper Colorado River Basin Tribal Rights and Tribal and State Future Demands

State

Tribal 

Diversion 

Entitlement 

(Water 

Right) (afy)

Tribal 

Depletion 

Entitlement 

(Water 

Right) (afy) Scenario

Tribal Demand 

(Diversion)

Tribal

Demand

(Depletion)

State 

Demand 

(Depletion)

Tribal Demand 

(Diversion)

Tribal

Demand

(Depletion)

State Demand 

(Depletion)

Tribal 

Demand 

(Diversion)

Tribal

Demand

(Depletion)

State 

Demand 

(Depletion)

2015 (afy) 2035 (afy) 2060 (afy)

UT 480,594 258,943 Enhanced 

Environment 

(D1)

480,594 258,943 997,295 480,594 258,943 1,059,226 480,594 258,943 1,109,080

Enhanced 

Environment 

(D2)

506,798 272,045 1,010,397 560,470 298,881 1,111,176 637,286 337,289 1,211,531

WY 0 0 All Scenarios No tribal entities in Wyoming receive Colorado River water.

AZ 0 0 Current 

Projected (A) 49,125 47,987 45,610 49,207 47,707 45,610 49,207 47,707 45,610

Slow Growth 

(B) 49,125 47,987 45,610 49,207 47,707 45,610 49,207 47,707 45,610

Rapid Growth 

(C1) 43,437 42,431 40,054 61,088 59,226 57,129 77,621 75,255 68,768

Rapid Growth 

(C2) 43,437 42,431 40,054 61,088 59,226 57,129 77,621 75,255 68,768

Enhanced 

Environment 

(D1)

49,125 47,987 45,610 49,207 47,707 45,610 49,207 47,707 45,610

Enhanced 

Environment 

(D2)

43,437 42,431 40,054 61,088 59,226 57,129 77,621 75,255 68,768

1 The diversion and depletion demands of the Navajo Nation from the Colorado River in the Upper Basin in New Mexico are not limited by the Navajo Nation San Juan River in New 

Mexico Water Rights Settlement; however, the Navajo Nation agrees to be bound by the terms of that settlement so long as the Settlement is effective. To the extent that the Navajo 

Nation demands exceed the amounts provided in the settlement, the Nation may seek to acquire water from other users or from sources other than the Colorado River to meet any 

unmet demands.

2 The diversion and depletion associated with the demand for the Ute Indian Tribe of the Uintah and Ouray Reservation is dependent upon the re-ratification of the Revised Ute Indian 

Compact of 1990 by the tribe and the State of Utah.
Colorado River Basin 

Water Supply and Demand Study

C-44 December 2012

TABLE C-7 

Lower Colorado River Tribal Rights and Tribal and State Future Demands

State

Tribal 

Diversion 

Entitlement 

(Water Right) 

(afy) Scenario

Tribal 

Demand 

(Diversion)

Tribal 

Demand 

(Depletion)

State 

Demand 

(Depletion)

Tribal 

Demand 

(Diversion)

Tribal 

Demand 

(Depletion)

State 

Demand 

(Depletion)

Tribal 

Demand 

(Diversion)

Tribal 

Demand 

(Depletion)

State 

Demand 

(Depletion)

2015 (afy) 2035 (afy) 2060 (afy)

AZ 1,411,968 Current Projected (A) 1,226,804 991,458 2,971,627 1,389,573 1,154,227 3,139,792 1,389,573 1,154,227 3,498,169

Slow Growth (B) 1,173,590 875,250 2,954,401 1,336,359 1,038,019 3,023,966 1,336,359 1,038,019 3,113,250

Rapid Growth (C1) 1,243,260 1,007,533 3,062,675 1,463,628 1,226,025 3,474,004 1,516,340 1,277,130 4,294,372

Rapid Growth (C2) 1,243,047 1,007,384 3,047,165 1,463,415 1,225,876 3,279,575 1,516,127 1,276,981 3,649,521

Enhanced 

Environment (D1) 1,226,804 991,458 3,060,138 1,389,573 1,154,227 3,281,506 1,389,573 1,154,227 3,478,115

Enhanced 

Environment (D2) 1,243,047 1,007,384 3,094,136 1,463,415 1,225,876 3,415,447 1,516,127 1,276,981 3,871,117

CA 156,522 Current Projected (A) 156,522 91,995 4,979,059 156,522 91,995 4,973,679 156,522 91,995 5,203,358

Slow Growth (B) 156,522 91,995 4,976,814 156,522 91,995 4,966,166 156,522 91,995 5,182,190

Rapid Growth (C1) 156,522 91,995 4,987,463 156,522 91,995 5,038,886 156,522 91,995 5,335,818

Rapid Growth (C2) 156,522 91,995 4,979,179 156,522 91,995 4,970,671 156,522 91,995 5,203,263

Enhanced 

Environment (D1) 156,522 91,995 4,975,136 156,522 91,995 4,955,416 156,522 91,995 5,167,686

Enhanced 

Environment (D2) 156,522 91,995 4,977,225 156,522 91,995 4,961,821 156,522 91,995 5,184,353

NV 12,534 Current Projected (A) 12,534 9,000 300,000 12,534 9,000 385,309 12,534 9,000 517,042

Slow Growth (B) 12,534 9,000 300,000 12,534 9,000 356,568 12,534 9,000 489,668

Rapid Growth (C1) 12,534 9,000 300,000 12,534 9,000 426,713 12,534 9,000 600,049

Rapid Growth (C2) 12,534 9,000 300,000 12,534 9,000 426,713 12,534 9,000 600,049

Enhanced 

Environment (D1) 12,534 9,000 300,000 12,534 9,000 385,309 12,534 9,000 517,042

Enhanced 

Environment (D2) 12,534 9,000 300,000 12,534 9,000 426,713 12,534 9,000 600,049
Technical Report C — Water

Demand Assessment

December 2012 C-45

Tables C-6 and C-7 show that in some states, tribal demand is already equal to (or in some cases 

above) the quantified right in 2015 under all scenarios. Demand beyond the quantified rights, as 

seen under the Rapid Growth (C1 and C2) scenarios and the Enhanced Environment (D2) 

scenario in Arizona, New Mexico, and Utah, include unquantified rights and claims provided by 

the Navajo Nation. In those states that include scenarios where tribal demand is less than the 

right (Arizona, Utah, and New Mexico) the demand grows to reach the right by 2060. Under all 

scenarios for all states, with the exception of Colorado where tribal demand is not separated from 

other demands within the state, tribal demand has met or surpassed the quantified tribal right

by 2060. 

These tables also demonstrate the importance of tribal water in Study Area demand. Tribal 

demand in the Study Area lags behind only M&I and agricultural demand. 

5.0 Mexico’s Allotment

Mexico has an allotment to Colorado River water under Article 10 of the 1944 Treaty (United 

States and Mexico, 1944 [T.S. 994]). Article 10 of the 1944 Treaty states the following:

“Of the waters of the Colorado River, from any and all sources, there are allotted to 

Mexico:

(a) A guaranteed annual quantity of 1,500,000 acre-feet (1,850,234,000 cubic meters) to 

be delivered in accordance with the provisions of Article 15 of this Treaty. 

(b) Any other quantities arriving at the Mexican points of diversion, with the 

understanding that in any year in which, as determined by the United States Section, there 

exists a surplus of waters of the Colorado River in excess of the amount necessary to 

supply uses in the United States and the guaranteed quantity of 1,500,000 acre-feet 

(1,850,234,000 cubic meters) annually to Mexico, the United States undertakes to deliver 

to Mexico, in the manner set out in Article 15 of this Treaty, additional waters of the 

Colorado River system to provide a total quantity not to exceed 1,700,000 acre-feet 

(2,096,931,000 cubic meters) a year. Mexico shall acquire no right beyond that provided 

by this subparagraph by the use of waters of the Colorado River system, for any purpose 

whatsoever, in excess of 1,500,000 acre-feet (1,850,234,000 cubic meters) annually. 

In the event of extraordinary drought or serious accident to the irrigation system in the 

United States, thereby making it difficult for the United States to deliver the guaranteed 

quantity of 1,500,000 acre-feet (1,850,234,000 cubic meters) a year, the water allotted to 

Mexico under subparagraph (a) of this Article will be reduced in the same proportion as 

consumptive uses in the United States are reduced. 

The quantification of demand scenarios did not include the assessment of future demand for 

Colorado River water within Mexico. Future deliveries to Mexico in accordance with the 

1944 Treaty were included in the System Reliability Analysis phase of the Study, which assessed

future imbalances within the Study Area.

6.0 Reservoir Evaporation and other Losses

Water loss categories were also defined for the Study; these are reservoir evaporation (water 

lost due to evaporation from reservoirs), phreatophyte use (water lost due to evapotranspiration 
Colorado River Basin 

Water Supply and Demand Study

C-46

by riparian vegetation along the Colorado River in the Lower Basin), and operational 

inefficiency9 (water unavailable for delivery due to operational inefficiencies in the Lower 

Basin).

Losses for a number of the large mainstem reservoirs are directly calculated by CRSS. Other 

reservoirs and phreatophyte use are accounted for in the analysis by using an average of 

historical use. 

6.1 Reservoir Evaporation

Reservoir evaporation varies annually, based on the surface area of a given reservoir and climatic

conditions. Annual evaporation for the larger Basin reservoirs (Lower Basin: Lake Mead, Lake 

Mohave, and Lake Havasu; Upper Basin: Morrow Point, Blue Mesa, Crystal, Fontenelle, 

Flaming Gorge, Navajo, and Lake Powell) is calculated monthly through model simulation based 

on simulated conditions. Evaporation from other reservoirs in the Basin States is estimated from 

historical losses. Figure C-19 presents historical losses due to reservoir evaporation. Average 

annual evaporative losses between 1971 and 2010 are about 2 maf and 1.8 maf between 2000 

and 2010. Declining evaporative losses can be attributed to lower average reservoir storage.

FIGURE C-19 

Reservoir Evaporative Losses 

 

9 Operational inefficiency losses include return flows from the Wellton-Mohawk Irrigation and Drainage District that are not allowed to return to 

the river due to salinity concerns and non-storable flows that are delivered to Mexico in excess of Treaty requirements.

0.00

0.50

1.00

1.50

2.00

2.50

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Million Acre-Feet per Year

Year

Upper Basin: Morrow Point

Upper Basin: Blue Mesa

Upper Basin: Flaming Gorge

Upper Basin: Lake Powell

Lower Basin: Lake Mead

Lower Basin: Lake Mohave

Lower Basin: Lake Havasu

Other Reservoir Evap
Technical Report C — Water

Demand Assessment

December 2012 C-47

6.2 Phreatophyte Losses

Phreatophytes are defined as deep-rooted plants that obtain water from the water table or in the 

vadose zone just above the water table. Phreatophyte losses are estimated for portions of the 

Lower Basin along the Colorado River mainstem and explicitly included in the water budget 

using those estimates. Phreatophyte losses in the Upper Basin are implicitly included in the water 

budget through the natural flow computations and therefore are not shown separately as losses. 

Since 1995, Reclamation has updated Lower Basin phreatophyte areas by comparing the current 

year Landsat summer satellite images to the previous year's images (spectral change detection 

methods). Reclamation field checks areas of spectral change to confirm that the change is 

actually due to change in land cover. The areas of land cover change are then mapped, and these 

maps are used to update the phreatophyte database. Reference evapotranspiration is calculated 

using the Penman-Monteith (PM) equation and applied to the phreatophyte database to arrive at a 

water demand. Further details can be found in the Lower Colorado River Accounting System 

reports (Reclamation, 2009). 

Before 1996, Davis Dam to Imperial Dam Lower Basin phreatophyte acreage was estimated, and 

the Blaney-Criddle (BC) model was used to estimate demand from 1971 to 1990 and a linear 

interpolation was employed from 1991 to 1994. Imperial Dam to Northerly International 

Boundary Lower Basin phreatophyte demand from 1971 to 1994 was estimated based on a 1995 

to 2008 linear relationship between phreatophyte demand at Davis Dam to Imperial Dam versus 

Imperial Dam to Northerly International Boundary. 

Historical and current phreatophyte use averages about 0.54 maf per year from 1971 to 2010 

and 0.64 maf per year from 2000 to 2010. Figure C-20 shows historical Lower Basin 

phreatophyte use.

6.3 Operational Inefficiencies

Operational inefficiency losses include return flows from the Wellton-Mohawk Irrigation and 

Drainage District that are not allowed to return to the river due to salinity concerns and nonstorable flows that are delivered to Mexico in excess of treaty requirements. 

Non-storable flows that were delivered to Mexico in excess of the 1944 Treaty over the period of 

1964 to 2009 averaged 74,000 afy, excluding years when flood control releases were made from 

Lake Mead or flooding on the Gila River. The construction of the Warren H. Brock Reservoir is 

expected to reduce this quantity by about 90 percent to 7,000 afy. 
Colorado River Basin 

Water Supply and Demand Study

C-48

FIGURE C-20

Historical Lower Basin Phreatophyte Use, 1971–2010

7.0 Approach for Incorporating Climate Change Effects 

on Demands

Technical Report A – Scenario Development identified “changes in stream flow variability” and 

“trends and changes in climate variability” (for example, temperature, precipitation, etc.) as the 

most important and most uncertain of the critical uncertainties. Because of their importance, 

these critical uncertainties were considered separately from other driving forces and were

considered across all future demand scenarios when matched with the Downscaled General 

Circulation Model (GCM) Projected water supply scenario. Future demands may be affected by 

climate change, primarily due to changes in ambient temperature and the amount and distribution 

of precipitation. The Study addressed possible effects of changing temperature and precipitation 

on evapotranspiration, which affected agriculture and outdoor M&I demand, and phreatophyte 

and reservoir evaporation losses. 

As noted, projection of future climate conditions is uncertain, and these uncertainties are further 

described in Technical Report B – Water Supply Assessment. There are varying methods for 

projecting future climate conditions, and new science and methods are continually being 

developed. The methods chosen for the Study represent one suite of available techniques. 

0

100

200

300

400

500

600

700

800

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Phreatophytes: Davis to Parker

Phreatophytes: Parker to Imperial

Phreatophytes: Imperial To NIB
Technical Report C — Water

Demand Assessment

December 2012 C-49

Possible changes in demand related to climate change that were not evaluated in the Study 

include changes in water demand for energy production, changes to environmental flow 

requirements associated with increasing ambient temperature, and changes in crop type. 

Regarding water demand for energy production, the additional variability in water demands for 

energy due to climate change would likely be small compared with the overall uncertainty in 

future energy demands. For environmental flows, insufficient data currently exist to quantify 

new habitat and species flow needs due to climate change. Changes in crop type are highly 

uncertain, and there are insufficient data to understand how crop type will change in response to 

changes in temperature and precipitation. 

7.1 Climate Change Effects on Evapotranspiration 

Reclamation has historically used an empirically based approach, the BC or modified BC

method, for calculating consumptive uses and losses in the Basin. As part of the hydrologic 

modeling for the Study, a more physically based method, PM, was used to estimate potential 

evapotranspiration (PET) under varying climatic conditions. A detailed analysis of these two 

methods and a description of the approach for incorporating climate information for adjusting 

demands are presented in appendix C15. 

Reclamation used the Variable Infiltration Capacity (VIC) hydrologic model to estimate

hydrologic responses in the Basin for the purposes of estimating water supply under changing 

climate conditions. The VIC model incorporates the PM method for estimating PET in the daily 

water balance calculations. PET results from Reclamation’s VIC modeling were used in the 

Study to estimate the effects of climate change on demand. PET estimates may vary widely 

among various methods, but the PM method has been shown to estimate actual 

evapotranspiration from lysimeter and field studies most accurately (American Society of Civil 

Engineers, 2005; Jensen et al., 1990; and Hill et al., 1983). Different PET methods have been 

found to produce different results under similar climate change assumptions (McKenney and 

Rosenberg, 1993; Kingston et al., 2009; Bormann, 2011). It was found that the BC method 

produced the highest PET sensitivity to climate warming (greatest increase in PET per degree of 

warming) compared to four other methods for computing PET. The PM method produced 

changes in PET of approximately 2 to 3 percent per degree Celsius warming. This sensitivity was 

larger than that estimated under the Priestly-Taylor method and lower than that under the 

Hargreaves method; however, results were generally within 1 percent of these two methods. 

Conversely, the BC method, when simulated under identical meteorological conditions, suggests 

a change of almost double that in the other methods. 

In order to be consistent between the calculations used to generate water supply scenarios, the 

PM method, as implemented in the VIC model, was used to adjust agricultural, outdoor M&I 

demands, phreatophyte losses, and reservoir evaporation rates due to climate change. Details on 

the methods used to construct the climate index factors for adjusting demands and losses under 

climate change are included in appendix C15. The mean change in evapotranspirative demand is 

on the order of 4 percent by 2060 as compared to demands without changes in climate. Using the 

methods described in appendix C15 and applying the projected changes to all agricultural, 

outdoor M&I, and phreatophyte demands results in a total demand increase of over 500 kaf per 

year by 2060. These changes are projected to evolve over time with a warming climate, and 

could be higher or lower depending on the climate projection, but the magnitude of the climate 

impact to demands is expected to be substantial. 
Colorado River Basin 

Water Supply and Demand Study

C-50

Figure C-21 presents the factors as applied to the Current Projected (A) scenario demands 

excluding Mexico’s allotment, reservoir evaporation10, and other losses11 (corresponding with 

the Colorado River demand shown in table C-4). The thick red line represents the average annual 

demand as adjusted for the climate change scenarios. This line can be compared to the 

unadjusted demands (thick black line). The thinner lines represent the adjustments associated 

with individual climate traces. Similar adjustments were made to each of the demand scenarios 

when coupled with the GCM projected supply scenarios. 

FIGURE C-21

Current Projected (A) Scenario Demands Adjusted for Future Climate Change

7.2 Climate Change Effects on Reservoir Evaporation 

Reservoir evaporation will be affected by changes in temperature and rainfall in a similar 

manner to that for PET. Evaporation from mainstem reservoirs was calculated by estimating 

reservoir surface area and applying monthly unit net evaporation rates (evaporation minus 

precipitation). For the supply scenario representing climate change, projections of open 

water surface evaporation rates and precipitation were taken from the VIC model (see 

 

10 Climate change effects on reservoir evaporation are adjusted dynamically through CRSS simulations.

11 Phreatophytes are included in the “other losses” category. Losses due to phreatophytes are adjusted for climate change using similar methods 

as those proposed for agricultural irrigation. 

12

12.5

13

13.5

14

14.5

15

15.5

16

16.5

17

2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 2065

Million Acre-Feet per Year

Year

Baseline

Average Climate Change
Technical Report C — Water

Demand Assessment

December 2012 C-51

Technical Report B – Water Supply Assessment) to adjust historical evaporation rates to 

reflect the changes in climate. The details of the climate factors that were used to modify 

reservoir evaporation are described in appendix C15. 

8.0 Limitations 

The projection of future demands for Colorado River water is inherently uncertain. Many factors 

influence the demand for water in each of the categories described in this technical report. 

Population, water use efficiency, agricultural markets, policy and regulations, social values, 

availability of other supplies, and other factors will all change in the future. This technical report

describes the uncertainty in projecting future conditions through the use of alternative scenarios. 

The scenarios capture a view of future demands under only “external” factors and do not include 

activities by water management entities that may affect demand. Actual demands in the future 

will be the result of both external factors and more-direct, active management, just as demands

were in the past. Active management is considered in the options and strategies portion of the 

Study. 

The quantification of scenarios relied predominantly on state-provided information guided by the 

storylines. Each state projects water demands in a slightly different manner and level of 

complexity, and relies on different data sources. The trends and projections of population, and 

trends in water use efficiency and agricultural acreage from previous regional studies, were 

provided to the Basin States for consideration and utilized to varying extent in development of 

demand projections. However, in many cases the detail from these previous studies was not 

sufficient to develop planning area level estimates as required for the Study. It was also not 

possible within the scope of the Study to develop Basin-wide demand projections based on a 

fully consistent analytical method that would include the important local differences in factors 

contributing to water demand. The demands presented in this technical report are a compilation 

of this information in the most consistent form possible. However, there are areas of difference 

with respect to treatment of data, reference points, assumptions, and computation methods. 

Evaluations were performed as part of the Study, and it is known that areas of difference 

continue to exist due to planning approach differences. 

The demand assessment did not explicitly include the effects of markets and pricing on water 

demand. However, the driving forces related to technology and economics were considered in 

the development of the water demand scenarios. The increasing scarcity costs of water price 

elasticity effects on demand may have been considered implicitly by the Basin States in the 

quantification of their water demand projections and the assumed levels of M&I and agricultural 

water conservation. Consideration of additional water conservation, with drivers related to 

environmental, social, and economic factors, was included in the development of options and 

strategies (see Technical Report F – Development of Options and Strategies). However, explicit 

consideration of the economic and pricing impacts on water demand was beyond the scope of the 

Study. 

Feedback of water shortage or climatic factors on population and population distribution was not 

explicitly considered in Study. While it has been suggested that some regions of the Basin may 

experience future climate conditions so extreme as to affect population migration changes, 

explicit consideration of these effects was considered too speculative for the Study. However, the 
Colorado River Basin 

Water Supply and Demand Study

C-52

range of population projections considered in the Study is believed to be sufficiently broad for 

exploring future Colorado River water demand. 

Although these limitations exist, the Study represents a comprehensive, Basin-wide evaluation of 

future demands for the Colorado River Basin. Future planning efforts will improve upon these 

methods and limitations. 

9.0 References 

American Society of Civil Engineers. 2005. The ASCE Standardized Reference 

Evapotranspiration Equation. EWRI of ASCE Standardization of Reference 

Evapotranspiration Task Committee. Final Report. 

Bureau of Reclamation (Reclamation). 1971–2011 Colorado River Accounting and Water Use 

Reports. Retrieved from http://www.usbr.gov/lc/region/g4000/wtracct.html#Decree. 

Bureau of Reclamation (Reclamation). 2000. Colorado River Interim Surplus Criteria Final 

Environmental Impact Statement.

Bureau of Reclamation (Reclamation). 2005. Upper Colorado River Basin Consumptive Uses 

and Losses Report As Revised After Peer Review 1971 to 1995. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2007. Colorado River Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2009. Lower Colorado River Accounting System 

Evapotranspiration and Evaporation Calculations, Calendar Year 2008. Technical 

Memorandum No. 86-68210–2009-09. 

Bureau of Reclamation (Reclamation). 2012a. Colorado River Basin Consumptive Uses and 

Losses Report 1996–2000. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012b. Upper Colorado River Basin Consumptive Uses 

and Losses Report 2001–2005. Retrieved August, from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012c. Provisional Upper Colorado River Basin 

Consumptive Uses and Losses Report 2006–2010. Retrieved August, from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/pdfs/cul2006-2010prov.pdf. 

Bormann, H. 2011. “Sensitivity analysis of 18 different potential evapotranspiration models to 

observed climatic change at German climate stations.” Climatic Change. 104:729-753. 

California Department of Water Resources. 2010. 20x2020 Water Conservation Plan.

General Accounting Office. 2010. Energy-Water Nexus, A Better and Coordinated 

Understanding of Water Resources Could Help Mitigate the Impacts of Potential Oil 

Shale Development. 
Technical Report C — Water

Demand Assessment

December 2012 C-53

Hill, R. W., E. L. Johns, and D. K. Frevert. 1983. Comparison of Equations used for Estimating 

Agricultural Crop Evapotranspiration with Field Research. U.S. Department of the 

Interior, Bureau of Reclamation. Page 242. 

Jensen, M.E., R.D. Burman, and R.G. Allen. 1990. “Evapotranspiration and Irrigation Water 

Requirements.” American Society of Civil Engineers – Manuals and Reports on 

Engineering Practice – No. 70. 

Kingston, D.G., M.C. Todd, R.G. Taylor, J.R. Thompson, and N.W. Arnell. 2009. “Uncertainty 

in the estimation of potential evaporation under climate change.” Geophys Res Lett

36:L20403. doi:10.1029/2009GL040267. 

McKenney, M.S. and N.J. Rosenberg. 1993. “Sensitivity of some potential evapotranspiration 

estimation methods to climate change.” Agricultural and Forest Meteorology, 64, 81-

110. 

Pacific Institute. 2011. Municipal Deliveries of Colorado River Basin Water.

Pew Research Center. 2010. U.S. Population Projections 2005–2050.

Rockaway, T, P. Comes, J. Rivard, and B. Kornstein. 2011. Residential Water Use Trends in 

North America.

States West Water Resources Corporation. 2001. Green River Basin Water Planning Process. 

Prepared for Wyoming Water Development Commission Basin Planning Program. 

Prepared in association with Boyle Engineering Corporation, Purcell Consulting, P.C., 

Water Right Services LLC, and Watts and Associates, Inc. February. 

United Nations Department of Economic and Social Affairs. 2010. World Population Prospects 

2010 Revision.

U.S. Census Bureau. 2010. U.S. Census Bureau Projections. 

U.S. Department of Agriculture. 2010. Agricultural Resources and Environmental Indicators.

U.S. Department of Energy. 2009. State Electricity Profiles. 

U.S. Environmental Protection Agency. 2010. Growing Toward More Efficient Water Use. 

U.S. Geological Survey. 2009. Estimated Use of Water in the United States.

U.S. Secretary of Interior. 2003. Colorado River Water Delivery Agreement: Federal 

Quantification Settlement Agreement.

Water Research Foundation. 2010. North American Water Use Trends Since 1992.

Technical Report C — Water

Demand Assessment

December 2012 C-55

Disclaimer

The Colorado River Basin Water Supply and Demand Study (Study) is funded jointly by the Bureau of 

Reclamation (Reclamation) and the seven Colorado River Basin States (Basin States). The purpose of 

the Study is to analyze water supply and demand imbalances throughout the Colorado River Basin and 

those adjacent areas of the Basin States that receive Colorado River water through 2060; and develop, 

assess, and evaluate options and strategies to address the current and projected imbalances. 

Reclamation and the Basin States intend that the Study will promote and facilitate cooperation and 

communication throughout the Basin regarding the reliability of the system to continue to meet Basin 

needs and the strategies that may be considered to ensure that reliability. Reclamation and the Basin 

States recognize the Study was constrained by funding, timing, and technological and other limitations, 

and in some cases presented specific policy questions and issues, particularly related to modeling 

and interpretation of the provisions of the Law of the River during the course of the Study. In such 

cases, Reclamation and the Basin States developed and incorporated assumptions to further complete 

the Study. Where possible, a range of assumptions was typically used to identify the sensitivity of the 

results to those assumptions.

Nothing in the Study, however, is intended for use against any Basin State, any federally recognized 

tribe, the federal government or the Upper Colorado River Commission in administrative, judicial or 

other proceedings to evidence legal interpretations of the Law of the River. As such, assumptions 

contained in the Study or any reports generated during the Study do not, and shall not, represent a legal 

position or interpretation by the Basin States, any federally recognized tribe, federal government or 

Upper Colorado River Commission as it relates to the Law of the River. Furthermore, nothing in the 

Study is intended to, nor shall the Study be construed so as to, interpret, diminish or modify the rights 

of any Basin State, any federally recognized tribe, the federal government, or the Upper Colorado River 

Commission under federal or state law or administrative rule, regulation or guideline, including without 

limitation the Colorado River Compact (45 Stat. 1057), the Upper Colorado River Basin Compact 

(63 Stat. 31), the Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande, 

Treaty Between the United States of America and Mexico (Treaty Series 994, 59 Stat. 1219), the 

United States/Mexico agreement in Minute No. 242 of August 30, 1973 (Treaty Series 7708; 24 UST 

1968), or Minute No. 314 of November 26, 2008, or Minute No. 318 of December 17, 2010, or Minute 

No. 319 of November 20, 2012, the Consolidated Decree entered by the Supreme Court of the United 

States in Arizona v. California (547 U.S 150 (2006)), the Boulder Canyon Project Act (45 Stat. 1057), 

the Boulder Canyon Project Adjustment Act (54 Stat. 774; 43 U.S.C. 618a), the Colorado River 

Storage Project Act of 1956 (70 Stat. 105; 43 U.S.C. 620), the Colorado River Basin Project Act of 

1968 (82 Stat. 885; 43 U.S.C. 1501), the Colorado River Basin Salinity Control Act (88 Stat. 266; 

43 U.S.C. 1951) as amended, the Hoover Power Plant Act of 1984 (98 Stat. 1333), the Colorado River 

Floodway Protection Act (100 Stat. 1129; 43 U.S.C. 1600), the Grand Canyon Protection Act of 1992 

(Title XVIII of Public Law 102-575, 106 Stat. 4669), or the Hoover Power Allocation Act of 2011 

(Public Law 112-72). In addition, nothing in the Study is intended to, nor shall the Study be construed 

so as to, interpret, diminish or modify the rights of any federally recognized tribe, pursuant to 

federal court decrees, state court decrees, treaties, agreements, executive orders and federal trust 

responsibility. Reclamation and the Basin States continue to recognize the entitlement and right of 

each State and any federally recognized tribe under existing law, to use and develop the water of the 

Colorado River system.
Appendix C1

Water Demand Sub-Team Members

December 2012 C1-1

Appendix C1 — Water Demand Sub-Team 

Members

The information presented in Technical Report C – Water Demand Assessment is the outcome of 

a collaborative process involving representatives of numerous organizations. 

A list of Water Demand Sub-Team members and their affiliations is presented below. 

• Perri Benemelis, Arizona Department of Water Resources

• Jim Prairie, Bureau of Reclamation 

• Greg Gates, CH2M HILL

• Ted Kowalski, Colorado Water Conservation Board

• Jennifer Pitt, Environmental Defense Fund

• Jason John, Navajo Nation

• John Whipple, New Mexico Interstate Stream Commission

• Tom Maher, Southern Nevada Water Authority

• Bill Hasencamp, The Metropolitan Water District of Southern California

• Don Ostler, Upper Colorado River Commission

• Andrew Hautzinger, U.S. Fish and Wildlife Service

Alternate and/or contributing members who participated include:

• Don Gross, Arizona Department of Water Resources

• Brian Westfall, Keller-Bliesner Engineering (consultant for the Navajo Nation)

• Michael Foley, Navajo Nation

• Larry Tamashiro, Southern Nevada Water Authority

• Janet Bair, U.S. Fish and Wildlife Service

• Drew Beckwith, Western Resource Advocates

Members added in November-December 2010 include:

• Marc Waage, Denver Water

• Carole Klopatek, Fort McDowell Yavapai Nation

• Charles Vaughn, Hualapai Tribal Nation

• Darryl Vigil, Jicarilla Apache Nation
Appendix C2 

Colorado Water Demand

Scenario Quantification

December 2012 C2-1 

Appendix C2 ─ Colorado Water Demand

Scenario Quantification

1.0 Introduction

This appendix summarizes the data sources used in scenario quantification for Colorado River 

demandfor the state of Colorado and presents the results of quantification. As presented in 

figure C2-1, Colorado is divided into a number of planning areas that align with river basins 

including the Colorado River and its tributaries (Yampa, White, Gunnison, Dolores, and San 

Juan Rivers) as well as the South Platte and Arkansas basins that are served by Colorado River 

water. Data collection and development were completed at the planning area level.

The following sections present background information that summarizes the state’s planning 

areas as well as data sources used to quantify demand scenarios by category. Following the 

background section, results of demand scenario quantification are presented. The results section 

is broken out into a Colorado Study Area summary, followed by Colorado River demand by 

geography and finally by category. 

2.0 Background 

The Colorado Water Conservation Board (CWCB) is responsible for state-level water resource 

planning in Colorado. The CWCB has led numerous planning studies under the Statewide 

Water Supply Initiative (SWSI; CWCB, 2010a), leading to a number of available water supply 

planning reports. The SWSI process includes significant public and agency input for Colorado’s 

water resource planning. 

The CWCB coordinated Colorado’s efforts to provide information for scenario quantification. 

These efforts largely relied on information previously generated through the SWSI. However, 

new assumptions and/or data development were required where the assumptions of the Colorado 

River Basin Water Supply and Demand Study (Study) deviated from the SWSI process. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources include state, regional, and national agency reports. 

• Agricultural Demand: Irrigated acreage estimates were derived from SWSI table 4-10 

(CWCB, 2010a). The SWSI contemplated significant future transfers of agricultural lands 

and water rights to meet future demands. However, for the purposes of the Study, it was 

assumed that agricultural to municipal and industrial (M&I) transfers were only associated 

with physical land transfers due to urbanization, and not associated with additional dry-up 

outside urban corridors. This would allow increased M&I transfers to be considered as an 

option and strategy to meet supply and demand imbalances. 

 &RORUDGR5LYHUGHPDQGDVFRPSXWHGE\6WXG\$UHDGHPDQGPLQXVRWKHUVXSSOLHV
Colorado River Basin

Water Supply and Demand Study

C2-2 December 2012

FIGURE C2-1 

Colorado River Hydrologic Basin and Export Service Areas in Colorado
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-3 

• M&I: Population and per capita water use values were derived from the SWSI process. 

Population projection values for the Study scenarios were derived from the “low,” 

“medium,” and “high” values associated with the SWSI (table 4-1) and were interpolated or 

projected as necessary to reflect the dates reported in the Study (for example, SWSI data 

from 2035 and 2050 were interpolated to arrive at 2060 data for the Study). Per capita water 

use values were derived from “passive” and currently planned “active” conservation. 

Representatives from the Colorado River Water Conservation District and the Front Range 

Water Council reviewed the SWSI “passive” numbers in detail and concluded that the values 

include active measures. SWSI gallons per capita per day numbers were not used directly; 

the values used were provided through personal communication with the referenced entities 

and CWCB (CWCB, 2012). 

• Energy: Energy demands were derived from SWSI table 4-8, with additional demands from 

Appendix F of the CWCB report, 2050 M&I Water User Projections (CWCB, 2010b). 

• Minerals: Demand for mineral production was derived from Upper Colorado River 

Commission Schedule of Colorado River demands from 2007. Water demand for mineral 

production was inadvertently excluded from the 2010 SWSI process. 

• Fish, Wildlife, and Recreation: No water demands were noted for fish, wildlife, and 

recreation. 

• Tribal: For Colorado, at the request of Ute Mountain Ute and Southern Ute Indian Tribes, 

tribal demands were not considered separately from the demand categories noted above. As 

such, tribal agricultural acreage, tribal populations, etc., are included in the other category 

estimates. 

3.0 Results of Water Demand Scenario Quantification

This section summarizes Colorado’s Colorado River water demand trends by category across the 

scenarios. The purpose of this section is to describe changes in demands, both temporally and 

geographically, parameters that influence changes in demands, and how the parameters and 

demands differ among scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands); independent of the source of supply. However, for areas outside of the 

hydrologic basin, a portion of the Study Area demand is satisfied from other supplies, such as the 

Arkansas or South Platte rivers. To develop estimates of the Colorado River water demand, the 

Study Area demand was reduced by estimates of available supply from other sources. This 

appendix focuses on Colorado River demands, but includes discussion of the Study Area 

parameters that led to these demands.

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand in Colorado, the Colorado River demand 

for the state and individual planning areas across the six scenarios, and the Colorado River water 

demand by category across the six scenarios. Parameters and demands for all categories and all 

scenarios, along with references for data sources, are included. 
Colorado River Basin

Water Supply and Demand Study

C2-4 December 2012

3.1 Summary Results of Scenario Quantification

Values were developed for parameters and demands quantified for each of the scenarios. 

Table C2-1 presents summary results for the demand scenarios considered in the Study. The 

table presents agricultural and M&I demand parameters for Colorado’s Study Area, 

distinguishing the scenarios and the resulting Colorado River demands by category. 

Colorado estimates that slightly fewer than 6 million people will be in Colorado’s Study Area 

by 2015. This number is expected to increase to about 9 to 11 million by 2060. The greatest 

population growth is associated with the Rapid Growth (C1 and C2) scenarios and Enhanced 

Environment (D2). The Slow Growth (B) scenario has the lowest population growth of the 

scenarios (9.4 million by 2060), but still represents a growth of nearly 66 percent over 

2015 estimates. 

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, considering passive and active, or existing 

conservation levels, is expected to be 9 to 22 percent less in 2060 than in 2015. Although usage 

rates vary across Colorado’s planning areas, per capita reductions are assumed to be consistent 

across the planning areas. 

Irrigated acreage is projected to continue to decrease through 2060 under all scenarios. Under 

the Rapid Growth (C1 and C2) scenarios, projected irrigated acreage is reduced by about 

420,000 acres. Irrigated acreage is reduced by 150,000 acres in the Enhanced Environment (D1) 

scenario, with reductions of about 40,000 acres for the Current Projected (A), Slow Growth (B), 

and Enhanced Environment (D2) scenarios. These reductions in irrigated acreage are offset to 

some extent by increases in water delivery per acre as a result of more intense cultivation or full 

irrigation of remaining acreage, resulting in moderate decreases in demand for all scenarios but 

the Enhanced Environment (D2) scenario, in which demand increases by about 4 percent.

Water demands for energy and mineral categories are projected to increase under all scenarios. 

The growing need for energy sources (coal, solar, and oil shale) is projected to increase water 

demands. The largest increases in water demand for energy are anticipated in the Colorado River 

and White basins. Water needs for mineral extraction are projected to increase similarly in all 

planning areas except for the Front Range planning areas (South Platte and Arkansas), where 

water demands for mineral extraction are not identified, and the Dolores basin, where demands 

are small.

For Colorado, tribal demands are embedded in other categories and not represented under the 

tribal category.

Figure C2-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, 

and 3) change in Colorado River demand by demand category. 

 /RVVHVGXHWRUHVHUYRLUHYDSRUDWLRQDUHQRWSDUWRIWKLVWRWDO
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-5 

TABLE C2-1 

Summary Results of Colorado Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

2015 1 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 5.7 9.9 9.4 11.1 11.1 9.9 11.1

Change in per capita water usage (%), 

from 2015 — ‐9% ‐9% ‐9% ‐20% ‐22% ‐20%

Irrigated acreage (millions of acres) 2.17 2.13 2.13 1.75 1.75 2.02 2.13

Change in per acre water delivery (%), 

from 2015 — +0% +0% +2% +12% ‐1% +8%

Study Area Demand (thousand acre-feet [kaf])

2015 1 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 6,132 5,991 5,991 4,775 5,252 5,767 6,367

M&I demand 1,139 1,701 1,630 1,891 1,637 1,429 1,637

Energy demand 76 195 135 255 135 128 135

Minerals demand 32 60 60 66 54 54 54

FWR demand 0 0 0 0 0 0 0

Tribal demand2 0 0 0 0 0 0 0

Total Study Area Demand3 7,379 7,947 7,816 6,987 7,079 7,378 8,193

Colorado River Demand (kaf)

2015 1 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 1,875 1,875 1,875 1,728 1,867 1,711 2,029

M&I demand 455 732 661 1,007 931 711 890

Energy demand 30 118 58 178 58 58 58

Minerals demand 32 60 60 66 54 54 54

FWR demand 0 0 0 0 0 0 0

Tribal demand2 0 0 0 0 0 0 0

Total Colorado River Demand3 2,391 2,784 2,653 2,979 2,910 2,534 3,030

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 Tribal demands are included in other demand categories.

3 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to 

state.
Colorado River Basin

Water Supply and Demand Study

C2-6 December 2012

FIGURE C2-2 

Study Area Demand, Colorado River Demand, and Change in Colorado River Demand 

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

Thousand Acre-Feet per Year

Study Area Demand in Colorado

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white and 

colored border

2,300

2,400

2,500

2,600

2,700

2,800

2,900

3,000

3,100

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in Colorado

-300

-200

-100

0

100

200

300

400

500

600

700

800

Thousand Acre-Feet per Year

Change in Colorado River Demand in Colorado, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-7 

From panel one it can be seen that Study Area demand increases from about 7 million acre-feet 

(maf) in 2015 to up to 8.2 maf by 2060. The demand change across scenarios in 2060 is 

projected to be as low as a reduction of 0.4 maf or as high as an increase of 0.8 maf. The growth 

in Colorado River demand from 2015 to 2060 is projected to be as much as 0.6 maf with the 

Front Range, and in particular the South Platte planning area, growing by about 60 percent. 

About 60 percent of the Study Area demand is expected to be met by other supplies. 

Panel two provides a view of the range across scenarios of Colorado River demand. Colorado 

River demand increases from about 2.4 maf in 2015 to between 2.5 and 3.0 maf in 2060 (or 6 to 

27 percent) depending on the scenario. This difference results in a Colorado River demand range 

of about 0.5 maf across the scenarios in 2060, or about 20 percentage points. 

Panel three shows how specific categories affect the projected change in Colorado River demand 

by scenario. Although the single largest component of demand is agricultural (~70 percent), most 

of the growth in demand is driven by increases in M&I demand and more specifically by 

increases in population. Of the growing categories of Colorado River demand, between 70 and 

90 percent of the growth is contributed by the M&I demand category. Some portion of this 

increase is generally offset by decreases in agricultural demand, except under the Current 

Projected (A) and Slow Growth (B) scenarios, in which agricultural demand is constant, and 

under the Enhanced Environment (D2) scenario, in which agricultural demand increases 

significantly due to greater water delivery per acre. Water for energy and mineral demand make 

up the remaining increases in demand, with a significant increase in energy demand under the 

Rapid Growth (C1) scenario due to increased demand for oil shale production. 

Figure C2-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The 0.5 maf range across scenarios in 2060 is easily discernible, with a relatively even 

spread over the range across the scenarios. In addition, it appears that the quantified scenarios 

track well with the peaks in historical uses that likely represent the least supply-limited 

conditions or actual demand. 

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in figures 

C2-4, C2-5, and C2-6. These figures show two geographic levels: Study Area in Colorado, and 

individual planning areas. Demands at each geographic level are shown across the scenarios. The 

columns to the right show the Colorado River demand at a point in time (2015, 2035, or 2060) by 

relative contribution of the categories. 

The change in both magnitude and percentage of Colorado River demand varies considerably 

across the planning areas. The South Platte planning area shows the greatest magnitude and rate 

of overall growth in Colorado River demand from 2015 to 2060 across the scenarios, with 

between about 0.1 and 0.4 maf making up between 40 and 100 percent of the total growth in 

Colorado. This growth is primarily due to population growth, with between 70 and 90 percent 

of the increase in the growing sectors occurring in M&I demand. Demands for the Arkansas 

planning area are projected to grow by about 0.04 to about 0.14 maf, due to population growth. 

Demand in the Yampa planning area is projected to grow by between 0.02 and 0.04 maf, due 

 3RWHQWLDO&RORUDGR5LYHUGHPDQGLVEDVHGRQFKDQJHVLQSDUDPHWHUVVXFKDVSRSXODWLRQDQGIRUWKHSXUSRVHRIWKH6WXG\LV

QRWOLPLWHGE\DSSRUWLRQPHQW
Colorado River Basin

Water Supply and Demand Study

C2-8 December 2012

primarily to growth in water demand for energy. The other planning areas consistently make up 

the remaining growth, with greater relative contributions (more than 20 percent of total growth) 

from the Colorado River and White planning areas under the Current Projected (A) and Rapid 

Growth (C1) scenarios, respectively, due primarily to growth in demand for energy. 

When demands by category are examined in figure C2-5, the mix of demand categories varies 

between the hydrologic basin and adjacent areas, with agricultural demand dominating the 

hydrologic basin and M&I demand at 50 percent or greater in the two adjacent planning areas. 

Figure C2-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. The mix of demand categories across the planning areas varies considerably, with 

change in demand in the South Platte and Arkansas dominated by M&I and a range of increases 

and significant decreases in agricultural demand varying by basin and scenario. 

FIGURE C2-3 

Historical Use and Future Projected Demand Excluding Reservoir Evaporation1

1

Reservoir evaporation on the order of 430 thousand acre-feet is not included in this plot.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Apportionment
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-9 

FIGURE C2-4 

Colorado River Demand in Colorado

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and Recreation

Tribal

Legend Category Plot (Right)

0

1

2

3

4

5

6

2015 2035 2060

KAF

Legend Demand Plots

Current Projected (A) Slow Growth (B)

Rapid Growth (C1) Rapid Growth (C2)

Enhanced Environment (D1) Enhanced Environment (D2)

M&I

M&I

M&I

Agricultural

Agricultural

Agricultural

201520352060

0

250

500

750

1,000

2015 2035 2060

KAF

Gunnison

0

250

500

750

1,000

2015 2035 2060

KAF

Arkansas

0

250

500

750

1,000

2015 2035 2060

KAF

Yampa

0

250

500

750

1,000

2015 2035 2060

KAF

South Platte

0

250

500

750

1,000

2015 2035 2060

KAF

Colorado River

0

250

500

750

1,000

2015 2035 2060

KAF

San Juan

0

250

500

750

1,000

2015 2035 2060

KAF

Dolores

0

250

500

750

1,000

2015 2035 2060

KAF

White

2,300

2,400

2,500

2,600

2,700

2,800

2,900

3,000

3,100

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Colorado River Demand in Colorado
Colorado River Basin

Water Supply and Demand Study

C2-10 December 2012

FIGURE C2-5 

Colorado River Demand by Category 
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-11

FIGURE C2-6 

Change in Colorado River Demand in Colorado from 2015 by Category

-200

0

200

400

600

2015 2035 2060

KAF

San Juan

-200

0

200

400

600

2015 2035 2060

KAF

Yampa

-200

0

200

400

600

2015 2035 2060

KAF

White

-200

0

200

400

600

2015 2035 2060

KAF

Dolores

-200

0

200

400

600

2015 2035 2060

KAF

Arkansas

-200

0

200

400

600

2015 2035 2060

KAF

Gunnison

-200

0

200

400

600

2015 2035 2060

KAF

Colorado River

-200

0

200

400

600

2015 2035 2060

KAF

South Platte

-300

-200

-100

0

100

200

300

400

500

600

700

800

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Colorado, from 2015

2015 2035 2060

M&I

M&I

M&I

Agricultural

Agricultural

Agricultural

201520352060

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2
Colorado River Basin

Water Supply and Demand Study

C2-12 December 2012

3.3 Colorado River Demand by Category

3.3.1 Agriculture

Agricultural water demand is driven by irrigated acreage and water delivery per acre. Water 

delivery per acre is the amount of water diverted per irrigated acre. Components of this use 

include transmission and delivery losses (surface evaporation, riparian demand, and seepage), 

and on-farm losses that are made up of evaporation, crop irrigation requirements, and tail water 

(return). Each of these factors will vary by location (precipitation, growing season, etc.), 

irrigation method, and crop type. 

Colorado River Simulation System (CRSS) does not represent smaller tributaries in Colorado. 

Inflow nodes are only included for the Mainstem Colorado, Gunnison, Yampa, San Juan, and 

White Rivers. Demands upstream of these inflow nodes are aggregated and represented at those 

same locations. A significant portion of the aggregated irrigation demands divert from the 

smaller tributaries and are unable to receive a full water supply during the irrigation seasons, due 

to either physical flow limitations or the need to bypass water to satisfy downstream senior 

demands. Because of CRSS limitations, Colorado demands represent supply-limited conditions 

instead of full irrigation demands. 

Figure C2-7 presents the following by scenario in 2015, 2035, and 2060: 

• Agricultural demand for Colorado River water 

• Agricultural demand for Colorado River water by planning area 

• Agricultural demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C2-7, agricultural water demand is the largest component of 

Colorado River demand in Colorado, dropping from about 78 percent in 2015 to between 58 and 

71 percent of Colorado River demand in 2060, depending on which scenario is considered. This 

drop results from both a decrease in agricultural water demand and an increase in other 

categories of demand.

Colorado River demand for agricultural use decreases over time from 2015 to 2060 in the Rapid 

Growth (C1 and C2) and Enhanced Environment (D1) scenarios and increases in the Enhanced 

Environment (D2) scenario. The decreases are entirely due to a loss of irrigated acreage. The 

increase in demand in the Enhanced Environment (D2) scenario because decreases in irrigated 

acreage are overcome by increases in water delivery per acre due to more intensive agricultural 

production on these lands. 

In examining the planning areas, agricultural demand consistently decreases in the Rapid Growth 

(C1) and Enhanced Environment (D1) scenarios and increases in the Enhanced Environment 

(D2) scenario, with variability from planning area to planning area in Rapid Growth (C2) 

scenario. The largest decrease in demand occurs in the Colorado River planning area. 

A strong driver for loss of agricultural acreage is urbanization, leading to physical loss of acreage 

and market pressure for transfer of water rights. Increases in water delivery per acre are due to 

better delivery mechanisms or storage, allowing for more use of water on the same acreage in a 

given growing season. 
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-13

FIGURE C2-7 

Change in Colorado River Demand in Colorado from 2015 for Agriculture

-200

-100

0

100

2015 2035 2060

KAF

Gunnison

-200

-100

0

100

2015 2035 2060

KAF

Arkansas

-200

-100

0

100

2015 2035 2060

KAF

Yampa

201520352060

-200

-100

0

100

2015 2035 2060

KAF

South Platte

-200

-100

0

100

2015 2035 2060

KAF

Colorado River

-200

-100

0

100

2015 2035 2060

KAF

San Juan

-200

-100

0

100

2015 2035 2060

KAF

Dolores

-200

-100

0

100

2015 2035 2060

KAF

White

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

-200

-150

-100

-50

0

50

100

150

200

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Colorado, from 2015

Agricultural

Agriculture is 78.4% of Colorado River demand*

Agriculture is 71 - 74% of Colorado River demand*

Agriculture is 58 -

Six columns per time 

71% of Colorado River demand*

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin

Water Supply and Demand Study

C2-14 December 2012

Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita water use, with the 

addition of self-served industrial (SSI) demand. M&I per capita water use is a measure of the 

amount of water produced or diverted per person in a given municipality. Because this measure 

examines all water produced by a given municipality, it often includes industrial, commercial, 

and institutional demand as well as residential demand. A number of factors may influence the 

M&I per capita water use of a given community, including the amount of industrial demand, 

climate, number of institutional facilities, and number of visitors. 

SSI users are industries located in a given area that have their own water supply systems and are 

therefore not directly related to local measures of population and M&I per capita water use. 

Figure C2-8 presents the following by scenario in 2015, 2035, and 2060: 

• M&I demand for Colorado River water in the Study Area 

• M&I demand for Colorado River water in individual planning areas 

• M&I demand as a portion of Colorado River water demand (right hand side of graph)

As can be seen from figure C2-8, M&I water demand is the second largest component of 

Colorado River demand, increasing from about 19 percent in 2015 to between 25 and 34 percent 

of Colorado River demand in 2060, depending on which scenario is considered.

Colorado River demand for M&I use increases over time from 2015 to 2060 across all scenarios. 

The increase is primarily due to population increase, as M&I per capita water use decreases over 

time across all scenarios and SSI demand nominally increases or decreases. 

In examining the planning areas, between 60 and 75 percent of the increase in M&I demand for 

Colorado River water from 2015 to 2060 over time is due to population increase in the South 

Platte across all scenarios. The remaining increase in demand is primarily from M&I demand in 

the Arkansas, with some increase in the Colorado River planning area. 

Increases in population are somewhat tempered by decreases in M&I per capita water use. Per 

capita water use decreases in all scenarios, with reductions ranging from 9 to 22 percent by 2060. 

3.3.2 Energy

Water demand for energy can be estimated through known plans for new power plants or 

through applying a per capita energy water use factor. Power facilities often serve areas remote 

from their locations and therefore potentially represent exports or imports of energy and water 

from the Study Area to meet these distributed needs. 

Figure C2-9 presents the following by scenario in 2015, 2035, and 2060: 

• Energy demand for Colorado River water 

• Energy demand for Colorado River water by planning area 

• Energy demand as a portion of total Colorado River water demand (right hand side of graph) 

As can be seen from figure C2-9, energy water demand is a small fraction of Colorado River 

demand, increasing from about 1.3 percent of in 2015 to between 2 and 6 percent of Colorado 

River demand in 2060, depending on which scenario is considered. 
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-15

FIGURE C2-8 

Change in Colorado River Demand in Colorado from 2015 for M&I

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

100

200

300

400

500

600

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Colorado, from 2015

Municipal and Industrial

0

100

200

300

400

500

2015 2035 2060

KAF

Gunnison

0

100

200

300

400

500

2015 2035 2060

KAF

Arkansas

0

100

200

300

400

500

2015 2035 2060

KAF

Yampa

201520352060

0

100

200

300

400

500

2015 2035 2060

KAF

South Platte

0

100

200

300

400

500

2015 2035 2060

KAF

Colorado River

0

100

200

300

400

500

2015 2035 2060

KAF

San Juan

0

100

200

300

400

500

2015 2035 2060

KAF

Dolores

0

100

200

300

400

500

2015 2035 2060

KAF

White

M&I is 19% of Colorado River demand*

M&I is 22 - 25% of Colorado River demand*

M&I is 25 - 34% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin

Water Supply and Demand Study

C2-16 December 2012

FIGURE C2-9 

Change in Colorado River Demand in Colorado from 2015 for Energy

0

50

100

150

2015 2035 2060

KAF

Gunnison

0

50

100

150

2015 2035 2060

KAF

Arkansas

0

50

100

150

2015 2035 2060

KAF

Yampa

201520352060

0

50

100

150

2015 2035 2060

KAF

South Platte

0

50

100

150

2015 2035 2060

KAF

Colorado River

0

50

100

150

2015 2035 2060

KAF

San Juan

0

50

100

150

2015 2035 2060

KAF

Dolores

0

50

100

150

2015 2035 2060

KAF

White

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

20

40

60

80

100

120

140

160

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Colorado, from 2015

Energy

Energy is 1.3% of Colorado River demand*

Energy is 2 - 4% of Colorado River demand*

Energy is 2 - 6% of Colorado River demand*

N/A

N/A

N/A

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-17

Energy demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios, with notable increases for the Current Projected (A) and Rapid Growth (C1) scenarios 

primarily due to oil shale production. 

Energy demands are shown in the Yampa, White, San Juan, and Colorado River planning areas. 

Consistent increases occur in the Yampa planning area across all scenarios. The White planning 

area shows significant increases in energy demand in the Rapid Growth (C1) scenario, with 

nominal increases in the remaining scenarios. The San Juan planning area shows a consistent 

increase in energy demand across the scenarios. The Colorado River planning area shows 

significant increases in energy demand in the Current Projected (A) and Rapid Growth (C1) 

scenarios, with nominal increases in the remaining scenarios. 

3.3.3 Minerals Extraction

Water demand for mineral production can be estimated through existing uses and known plans 

for extraction in the Study Area. Water demand for mineral production can vary significantly 

based on market prices for a given product. 

Figure C2-10 presents the following by scenario in 2015, 2035, and 2060: 

• Mineral production demand for Colorado River water 

• Individual planning area mineral production demand for Colorado River water 

• Minerals demand as a portion of Colorado River demand (right hand side of graph) 

As can be seen from figure C2-10, minerals water demand is a small fraction of Colorado River 

demand, increasing from about 1.3 percent in 2015 to about 2 percent of Colorado River demand 

in 2060, depending on which scenario is considered. 

Minerals demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios. 

Demand for Colorado River water for minerals production is present in all of the planning areas 

in the hydrologic basin to varying degrees. The Yampa and Colorado River planning areas make 

up about 33 percent of the increase in demand each, with the Gunnison and San Juan planning 

areas making up about 16 percent of the increase each. Demand in the Dolores planning area is 

small and constant. 

3.3.4 Fish, Wildlife, and Recreation

There are no consumptive fish, wildlife, and recreation demands on Colorado River water in 

Colorado. 

3.3.5 Tribal

Tribal demands are represented as components of the other categories previously presented. The 

tribal reserved water rights are the senior rights in the San Juan basin in Colorado; therefore, in 

times when full basin demands cannot be met, the first water diverted in the basin is essentially 

for tribal water right diversions. The category totals in tables C2-2 to C2-5 include Southern Ute 

Indian Tribe and Ute Mountain Ute Indian Tribe demands. 

For additional information on tribal demands, see appendix C9. 
Colorado River Basin

Water Supply and Demand Study

C2-18 December 2012

FIGURE C2-10

Change in Colorado River Demand in Colorado from 2015 for Minerals

0

5

10

15

2015 2035 2060

KAF

Gunnison

0

5

10

15

2015 2035 2060

KAF

Arkansas

0

5

10

15

2015 2035 2060

KAF

Yampa

201520352060

0

5

10

15

2015 2035 2060

KAF

South Platte

0

5

10

15

2015 2035 2060

KAF

Colorado River

0

5

10

15

2015 2035 2060

KAF

San Juan

0

5

10

15

2015 2035 2060

KAF

Dolores

0

5

10

15

2015 2035 2060

KAF

White

A

A

B

B

C1

C1

C2

C2

D1D2

D1D2

0

5

10

15

20

25

30

35

40

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Colorado, from 2015

Minerals

Minerals is 1.3% of Colorado River demand*

Minerals is 2 - 3% of Colorado River demand*

Minerals is 2% of Colorado River demand*

No 

Change

N/A

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-19

3.4 Summary Tables of Parameters and Demands by Category

Tables C2-2 to C2-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 

4.0 References 

Colorado Water Conservation Board (CWCB). 2010a. Statewide Water Supply Initiative. 

Colorado Water Conservation Board (CWCB). 2010b. 2050 M&I Water User Projections. 

Appendix F. 

Colorado Water Conservation Board (CWCB). 2012. Personal communication with 

Reclamation.
Colorado River Basin 

Water Supply and Demand Study

C2-20 December 2012

TABLE C2-2 

Total Demand within Study Area under Current Projected (A) Scenario

LEGEND: 999 From States 999 From State Plans

Units are thousand acre-feet per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 270 270 270 269 269 269 93 93 93 27 27 27 220 220 220 40 40 40 918 918 918 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 6.89 6.89 6.89 4.44 4.44 4.44 10.25 10.25 10.25 3.52 3.52 3.52 3.70 3.70 3.70 5.79 5.79 5.79 2

Consumptive factor [%] 26% 26% 26% 26% 26% 26% 34% 34% 34% 15% 15% 15% 43% 43% 43% 37% 37% 37% 29% 29% 29% 3

Demand (Consumptive) 485 485 485 490 490 490 140 140 140 41 41 41 330 330 330 54 54 54 1,539 1,539 1,539

Municipal and Industrial (M&I) Population [thousands] 357 558 836 121 184 244 42 65 113 10 16 28 85 130 175 36 56 75 651 1,008 1,471 5

M&I Per Capita Use (Diversion) [gpcd] 181 173 164 173 166 157 228 219 208 228 219 208 182 174 165 182 174 165 183 176 167 6

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 7

M&I Demand (Consumptive) 25 38 54 8 12 15 4 6 9 1 1 2 6 9 11 3 4 5 47 69 96

Self Served Industrial Demand (Consumptive) 3 5 5 0 1 1 7 10 10 0 0 0 0.4 0.4 0.4 0 0 0 11 16 16 8

Demand (Consumptive) 29 43 58 9 13 16 11 16 19 1 1 2 6 9 12 3 4 5 58 85 112

Energy Demand (Consumptive) 2 30 65 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 30 78 118 9

Minerals Demand (Consumptive) 10 18 19 5 9 9 10 20 20 1 2 2 5 10 10 1 1 1 32 59 60 10

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11

Total Hydrologic Basin Demand (Consumptive) 525 575 626 503 512 515 186 215 221 44 48 51 343 352 356 58 59 60 0 0 0 0 0 0 1,659 1,762 1,829

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 828 810 789 428 427 426 1,255 1,237 1,215 12

Per-Acre Water Delivery (Diversion) [af/ac/yr] 3.50 3.50 3.50 3.97 3.97 3.97 3.66 3.66 3.66 2

Consumptive factor [%] 38% 38% 38% 32% 32% 32% 36% 36% 36% 3

Demand (Diversion) 2,893 2,832 2,758 1,700 1,697 1,693 4,593 4,529 4,451 4, 20

Demand (Consumptive) 1,112 1,089 1,061 543 542 541 1,656 1,631 1,602

Municipal and Industrial (M&I) Population [thousands] 3,945 5,244 6,581 1,079 1,451 1,846 5,024 6,695 8,427 13

M&I Per Capita Use (Diversion) [gpcd] 170 164 154 184 176 167 173 167 157 6

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 7

M&I Demand (Diversion) 751 963 1,135 222 286 345 973 1,249 1,481 8

Self Served Industrial Demand (Diversion) 59 59 59 49 49 49 108 108 108 14

Demand (Diversion) 810 1,022 1,194 271 335 395 1,081 1,358 1,589

Demand (Consumptive) 322 396 456 127 150 170 449 546 627

Energy Demand (Diversion) 36 47 59 10 15 18 46 62 78 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,739 3,901 4,012 1,982 2,047 2,106 5,720 5,949 6,118 17

Total Demand in the Study Area 525 575 626 503 512 515 186 215 221 44 48 51 343 352 356 58 59 60 3,739 3,901 4,012 1,982 2,047 2,106 7,379 7,710 7,947 18

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,204 3,268 3,315 1,784 1,813 1,848 4,988 5,082 5,163

Potential Colorado River Demand 525 575 626 503 512 515 186 215 221 44 48 51 343 352 356 58 59 60 534 633 697 198 234 258 2,391 2,629 2,784 19, 21

Agricultural Colorado River Demand 485 485 485 490 490 490 140 140 140 41 41 41 330 330 330 54 54 54 187 187 187 148 148 148 1,875 1,875 1,875 22

Municipal and Industrial Colorado River Demand 29 43 58 9 13 16 11 16 19 1 1 2 6 9 12 3 4 5 347 446 510 49 86 110 455 617 732

Energy Colorado River Demand 2 30 65 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 0 0 0 0 0 0 30 78 118

Minerals Colorado River Demand 10 18 19 5 9 9 10 20 20 1 2 2 5 10 10 1 1 1 0 0 0 0 0 0 32 59 60

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Colorado River Gunnison Yampa White San Juan Dolores South Platte Arkansas STATE TOTAL

Notes

FRONT RANGE FRONT RANGE
 Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-21

Notes:

1) Based on Colorado Decision Support System estimates, also used in SWSI. Irrigated acreage in the Colorado River basin-estimated to remain constant (SWSI table 4-10).

2) Calculated from SWSI as headgate diversion to irrigation divided by acreage. See supporting table below.

3) System efficiency = supply-limited consumptive use divided by headgate diversions. See supporting table below.

4) Diversions in the South Platte and Arkansas include both surface water and alluvial ground water sources.

5) Population for 2015 interpolated between SWSI 2008 and SWSI 2035 estimates. Population for 2035 from SWSI. Population for 2060 extrapolated based SWSI increases 

between 2035 and 2050 medium estimates (SWSI table 4-1). 

6) Per capita water withdrawal demands based on SWSI 2010 estimates, reduced by 10 percent in 2060 based on description in current trend analysis (table 4-3).

7) Consumptive use efficiency factor from CWCB CU&L Report.

8) Industrial based on SWSI table 4-8. Includes "Large Industry" and "Snowmaking" categories. Assumed to be 100 percent consumptive.

9) Energy demands based on SWSI table 4-8. Includes "Energy Development" and Thermoelectric" categories through 2050. An additional 60,000 acre-feet (af) is estimated to 

occur in the Colorado River basin based on the CWCB 2050 M&I Water User Projections July 2010 Report, Appendix F Medium projection. Assumed to be 100 percent 

consumptive.

10) Mineral uses were not included in SWSI. Uses are from the UCRS Schedule.

11) Tribal demands are included in the San Juan basin demands under the specific demand category. Their demands are estimated using the same parameters for Ag and M&I.

12) Per the Current Trend Storyline, agricultural use in the Arkansas and South Platte basins stay relatively constant. 2060 numbers reflect reduction based on table 4-11 low 

"decrease in acreage due to Urbanization". 2035 represents 1/2 of the low decrease in acreage due to urbanization value.

13) See 5) Population estimates for the entire Arkansas Basin; and the South Platte and Metro estimates combined from SWSI. Note that the entire South Platte and Arkansas 

basin cannot receive Colorado River basin water.

14) Industry demands based on SWSI Large Industry demands. Note that this is appropriate because there is no mining included in the South Platte and Arkansas estimates. 2008 

estimates are used for 2011. There is no change shown between 2035 and 2050, therefore 2050 estimates are used for 2060. (SWSI table 4-4). Assumed 100 percent 

consumptive.

15) Energy demands for the Arkansas and the South Platte represent SWSI Thermoelectric Power demands. 2008 values were used for 2011, 2050 medium level was used to 

estimate 2060. (SWSI table 4-6)

16) Based on SWSI estimates – no mineral, fish and wildlife, or tribal use in the Arkansas and South Platte.

17) Note that Arkansas and South Platte estimates do not include losses due to Reservoir Evaporation, estimated to be as high a as 500,000 af.

18) Calculated from the sum of Hydrologic Basin (Consumptive) Demand and Adjacent Areas (Diversion) Demand.

19) Current trans-Basin diversions based on recent averages and SWSI estimates split between basins based on average annual diversion over the 2000 to 2010 period. Future 

exports consider reuse of trans-Basin water. Note that essentially 100 percent of current trans-Basin water is reused within the service area – not necessarily by the original 

user (i.e., return flows from municipal exports may be reused by agricultural users). 

20) Agricultural transfers reduce the diversion demand only by the consumptive use portion—under Colorado Water Law, the return flows must be left in the river for the 

downstream diverters who have historically re-diverted them.

21) As new Colorado River water is brought to the front range for municipal use, it will move towards 100 percent consumptive by the importing entity (100 percent reuse).

22) Colorado River demand in adjacent areas is distributed amongst categories according to current estimated distribution of trans-Basin diversions. 
Colorado River Basin 

Water Supply and Demand Study

C2-22 December 2012

TABLE C2-3 

Total Demand within Study Area under Slow Growth (B) Scenario

COLORADO LEGEND: 999 From Current Projected Data She 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 270 270 270 269 269 269 93 93 93 27 27 27 220 220 220 40 40 40 918 918 918 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 6.89 6.89 6.89 4.44 4.44 4.44 10.25 10.25 10.25 3.52 3.52 3.52 3.70 3.70 3.70 5.79 5.79 5.79 2

Consumptive factor [%] 26% 26% 26% 26% 26% 26% 34% 34% 34% 15% 15% 15% 43% 43% 43% 37% 37% 37% 29% 29% 29%

Demand (Consumptive) 485 485 485 490 490 490 140 140 140 41 41 41 330 330 330 54 54 54 1,539 1,539 1,539

Municipal and Industrial (M&I) Population [thousands] 357 531 748 121 169 230 42 61 86 10 15 20 85 118 159 36 51 68 651 945 1,312 3

M&I Per Capita Use (Diversion) [gpcd] 181 173 164 173 166 157 228 219 208 228 219 208 182 174 165 182 174 165 183 176 166 4

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Consumptive) 25 36 48 8 11 14 4 5 7 0.9 1 2 6 8 10 3 3 4 47 65 86

Self Served Industrial Demand (Consumptive) 3 5 5 0.3 0.7 0.7 7 10 10 0 0 0 0.4 0.4 0.4 0 0 0 11 16 16 5

Demand (Consumptive) 29 41 53 9 12 15 11 15 17 0.9 1 2 6 8 11 3 3 4 58 81 102

Energy Demand (Consumptive) 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 30 51 58 6

Minerals Demand (Consumptive) 10 18 19 5 9 9 10 20 20 1 2 2 5 10 10 1 1 1 32 59 60 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 525 547 561 503 511 514 186 215 219 44 48 50 343 352 355 58 59 60 0 0 0 0 0 0 1,659 1,731 1,758

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 828 810 789 428 427 426 1,255 1,237 1,215 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 3.50 3.50 3.50 3.97 3.97 3.97 3.66 3.66 3.66 11

Consumptive factor [%] 38% 38% 38% 32% 32% 32% 36% 36% 36%

Demand (Diversion) 2,893 2,832 2,758 1,700 1,697 1,693 4,593 4,529 4,451

Demand (Consumptive) 1,112 1,089 1,061 543 542 541 1,656 1,631 1,602

Municipal and Industrial (M&I) Population [thousands] 3,945 5,020 6,364 1,079 1,366 1,724 5,024 6,386 8,088 12

M&I Per Capita Use (Diversion) [gpcd] 170 164 154 184 176 167 173 167 157 13

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Diversion) 751 922 1,098 222 269 323 974 1,191 1,420

Self Served Industrial Demand (Diversion) 59 59 59 49 49 49 108 108 108 14

Demand (Diversion) 810 981 1,157 272 319 372 1,082 1,300 1,529

Demand (Consumptive) 284 343 405 95 112 130 379 455 535

Energy Demand (Diversion) 36 47 59 10 15 18 46 62 78 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,739 3,860 3,974 1,982 2,030 2,083 5,721 5,891 6,058

Total Demand in the Study Area 525 547 561 503 511 514 186 215 219 44 48 50 343 352 355 58 59 60 3,739 3,860 3,974 1,982 2,030 2,083 7,380 7,621 7,816

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,204 3,268 3,315 1,784 1,813 1,848 4,988 5,082 5,163 19

Potential Colorado River Demand 525 547 561 503 511 514 186 215 219 44 48 50 343 352 355 58 59 60 534 592 660 198 217 235 2,391 2,540 2,653 20

Agricultural Colorado River Demand 485 485 485 490 490 490 140 140 140 41 41 41 330 330 330 54 54 54 187 187 187 148 148 148 1,875 1,875 1,875 21

Municipal and Industrial Colorado River Demand 29 41 53 9 12 15 11 15 17 0.9 1 2 6 8 11 3 3 4 347 405 473 50 69 87 455 555 661

Energy Colorado River Demand 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 0 0 0 0 0 0 30 51 58

Minerals Colorado River Demand 10 18 19 5 9 9 10 20 20 1 2 2 5 10 10 1 1 1 0 0 0 0 0 0 32 59 60

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

STATE TOTAL

Notes

Colorado River Gunnison Yampa White San Juan Dolores South Platte Arkansas
 Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-23

Notes:

1) No changes from Current Projected.

2) No changes from Current Projected.

3) Used low population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 low estimates.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Energy demands based on SWSI table 4-8. Includes Energy Development" and Thermoelectric categories through 2050. Assumed to be 100 percent

consumptive.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) Used low population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 low estimates.

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Set to Current Trend estimates based on same trends to increase use of existing projects and non-tributary groundwater.

20) Total Adjacent Area demand less Demand that may be met by Other Supplies.

21) Agricultural Use is estimated to be same as Current Projected for Adjacent Areas. Remaining Adjacent Area use is estimated to be M&I.
Colorado River Basin 

Water Supply and Demand Study

C2-24 December 2012

TABLE C2-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

COLORADO LEGEND: 999 From Current Projected Data She 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 270 240 217 269 259 251 93 91 89 27 26 26 220 216 213 40 39 39 918 871 835 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 6.89 6.89 6.89 4.44 4.44 4.44 10.25 10.25 10.25 3.52 3.52 3.52 3.70 3.70 3.70 5.79 5.75 5.71 2

Consumptive factor [%] 26% 26% 26% 26% 26% 26% 34% 34% 34% 15% 15% 15% 43% 43% 43% 37% 37% 37% 29% 29% 29%

Demand (Consumptive) 485 430 389 490 471 457 140 137 134 41 40 39 330 324 320 54 53 53 1,539 1,455 1,392

Municipal and Industrial (M&I) Population [thousands] 357 628 968 121 189 274 42 88 146 10 21 36 85 136 200 36 58 86 651 1,121 1,709 3

M&I Per Capita Use (Diversion) [gpcd] 181 173 164 173 166 157 228 219 208 228 219 208 182 174 165 182 174 165 183 176 168 4

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Consumptive) 25 43 62 8 12 17 4 8 12 0.9 2 3 6 9 13 3 4 6 47 78 112

Self Served Industrial Demand (Consumptive) 3 5 5 0.3 0.7 0.7 7 10 10 0 0 0 0.4 0.4 0.4 0 0 0 11 16 16 5

Demand (Consumptive) 29 47 67 9 13 18 11 18 22 0.9 2 3 6 10 13 3 4 6 58 93 128

Energy Demand (Consumptive) 2 41 95 0 0 0 25 40 42 1 15 36 2 4 5 0 0 0 30 101 178 6

Minerals Demand (Consumptive) 10 20 20 5 10 10 10 21 22 1 2 2 5 11 11 1 1 1 32 65 66 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 525 538 571 503 494 485 186 216 220 44 59 80 343 348 349 58 58 59 0 0 0 0 0 0 1,659 1,715 1,764

2 30 65

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 828 677 564 428 386 355 1,255 1,063 919 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 3.50 3.50 3.50 3.97 3.97 3.97 3.66 3.67 3.68 11

Consumptive factor [%] 38% 38% 38% 32% 32% 32% 36% 36% 36%

Demand (Diversion) 2,893 2,366 1,972 1,700 1,535 1,411 4,593 3,901 3,383

Demand (Consumptive) 1,112 910 758 543 490 451 1,656 1,400 1,209

Municipal and Industrial (M&I) Population [thousands] 3,945 5,461 7,357 1,079 1,515 2,059 5,024 6,976 9,416 12

M&I Per Capita Use (Diversion) [gpcd] 170 164 154 184 176 167 173 167 157 13

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Diversion) 751 1,003 1,269 222 299 385 974 1,302 1,654

Self Served Industrial Demand (Diversion) 59 59 59 49 49 49 108 108 108 14

Demand (Diversion) 810 1,062 1,328 272 348 434 1,082 1,410 1,763

Demand (Consumptive) 284 372 465 95 122 152 379 494 617

Energy Demand (Diversion) 36 47 59 10 15 18 46 62 78 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,739 3,476 3,359 1,982 1,898 1,864 5,721 5,374 5,223

Total Demand in the Study Area 525 538 571 503 494 485 186 216 220 44 59 80 343 348 349 58 58 59 3,739 3,476 3,359 1,982 1,898 1,864 7,380 7,088 6,987

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,204 2,848 2,403 1,784 1,705 1,605 4,988 4,553 4,009 19

Potential Colorado River Demand 525 538 571 503 494 485 186 216 220 44 59 80 343 348 349 58 58 59 534 628 956 198 193 258 2,391 2,535 2,979 20

Agricultural Colorado River Demand 485 430 389 490 471 457 140 137 134 41 40 39 330 324 320 54 53 53 187 187 187 148 148 148 1,875 1,791 1,728 21

Municipal and Industrial Colorado River Demand 29 47 67 9 13 18 11 18 22 0.9 2 3 6 10 13 3 4 6 347 441 769 50 45 110 455 579 1,007

Energy Colorado River Demand 2 41 95 0 0 0 25 40 42 1 15 36 2 4 5 0 0 0 0 0 0 0 0 0 30 101 178

Minerals Colorado River Demand 10 20 20 5 10 10 10 21 22 1 2 2 5 11 11 1 1 1 0 0 0 0 0 0 32 65 66

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

STATE TOTAL

Notes

Colorado River Gunnison Yampa White San Juan Dolores South Platte Arkansas
 Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-25

Notes:

1) Used estimated 2050 High irrigated acreage from SWSI table 4-11 for 2060, linearly interpolated to estimate 2035.

2) No changes from Current Projected.

3) Used high population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 high estimates.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Energy demands based on SWSI table 4-8. Includes Energy Development and Thermoelectric categories through 2050. An additional 120,000 af is 

estimated to occur in the Colorado River Basin (30,000) and the White River Basin (30,000) based on the CWCB 2050 M&I Water User Projections

July 2010 report, appendix F, table 13, High Projection. Assumed to be 100 percent consumptive.

7) Mineral use not included in SWSI, assume 10 percent decrease from Current Projected in 2035 and in 2060.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) Used estimated 2050 Low irrigated acreage from SWSI table 4-11 for 2060, linearly interpolated to estimate 2035.

11) No changes from Current Projected.

12) Used high population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 high estimates.

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Demand that may be met from Other Supplies decreases based on full development of current water rights, expanded reuse of both trans-Basin and 

in-Basin sources, and decreases yield from agricultural transfers estimated to decrease 25 percent from current levels by 2060 in the South Platte; and 

10 percent from current levels in the Arkansas.

20) Total Adjacent Area demand less Demand that may be met by Other Supplies.

21) Agricultural Use is estimated to be same as Current Projected for Adjacent Areas. Remaining Adjacent Area use is estimated to be M&I.
Colorado River Basin 

Water Supply and Demand Study

C2-26 December 2012

TABLE C2-5 

Total Demand within Study Area under Rapid Growth (C2) Scenario

COLORADO LEGEND: 999 From Current Projected Data She 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 270 240 217 269 259 251 93 91 89 27 26 26 220 216 213 40 39 39 918 871 835 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 7.26 7.53 6.89 7.31 7.58 4.44 4.71 4.89 10.25 10.86 11.27 3.52 3.73 3.87 3.70 3.92 4.07 5.79 6.09 6.28 2

Consumptive factor [%] 26% 26% 26% 26% 26% 26% 34% 34% 34% 15% 15% 15% 43% 43% 43% 37% 37% 37% 29% 29% 29%

Demand (Consumptive) 485 456 427 490 500 503 140 145 148 41 42 43 330 344 352 54 57 58 1,539 1,543 1,532

Municipal and Industrial (M&I) Population [thousands] 357 628 968 121 189 274 42 88 146 10 21 36 85 136 200 36 58 86 651 1,121 1,709 3

M&I Per Capita Use (Diversion) [gpcd] 181 165 145 173 158 138 228 208 182 228 208 182 182 166 146 182 166 146 183 168 148 4

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Consumptive) 25 41 55 8 12 15 4 7 10 0.9 2 3 6 9 11 3 4 5 47 74 99

Self Served Industrial Demand (Consumptive) 3 2 2 0.3 0.2 0.2 7 5 5 0 0 0 0.4 0.3 0.3 0 0 0 11 7 7 5

Demand (Consumptive) 29 43 57 9 12 15 11 12 15 0.9 2 3 6 9 12 3 4 5 58 81 106

Energy Demand (Consumptive) 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 30 51 58 6

Minerals Demand (Consumptive) 10 16 17 5 8 8 10 18 18 1 2 2 5 9 9 1 0.9 0.9 32 53 54 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 525 518 506 503 520 526 186 215 223 44 50 53 343 365 377 58 61 64 0 0 0 0 0 0 1,659 1,728 1,750

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 828 677 564 428 386 355 1,255 1,063 919 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 3.50 3.71 3.85 3.97 4.21 4.37 3.66 3.89 4.05 11

Consumptive factor [%] 38% 38% 38% 32% 32% 32% 36% 36% 36%

Demand (Diversion) 2,893 2,508 2,169 1,700 1,627 1,552 4,593 4,135 3,721

Demand (Consumptive) 1,112 964 834 543 520 496 1,656 1,484 1,330

Municipal and Industrial (M&I) Population [thousands] 3,945 5,461 7,357 1,079 1,515 2,059 5,024 6,976 9,416 12

M&I Per Capita Use (Diversion) [gpcd] 170 155 136 184 168 147 173 158 138 13

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Diversion) 751 948 1,121 222 285 339 974 1,233 1,460

Self Served Industrial Demand (Diversion) 59 38 38 49 32 32 108 70 70 14

Demand (Diversion) 810 987 1,159 272 317 371 1,082 1,304 1,530

Demand (Consumptive) 284 345 406 95 111 130 379 456 536

Energy Demand (Diversion) 36 47 59 10 15 18 46 62 78 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,739 3,542 3,387 1,982 1,959 1,941 5,721 5,501 5,329

Total Demand in the Study Area 525 518 506 503 520 526 186 215 223 44 50 53 343 365 377 58 61 64 3,739 3,542 3,387 1,982 1,959 1,941 7,380 7,229 7,079

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,204 2,920 2,563 1,784 1,705 1,605 4,988 4,624 4,169 19

Potential Colorado River Demand 525 518 506 503 520 526 186 215 223 44 50 53 343 365 377 58 61 64 534 623 824 198 254 336 2,391 2,605 2,910 20

Agricultural Colorado River Demand 485 456 427 490 500 503 140 145 148 41 42 43 330 344 352 54 57 58 187 187 187 148 148 148 1,875 1,878 1,867 21

Municipal and Industrial Colorado River Demand 29 43 57 9 12 15 11 12 15 0.9 2 3 6 9 12 3 4 5 347 436 637 50 106 188 455 623 931

Energy Colorado River Demand 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 0 0 0 0 0 0 30 51 58

Minerals Colorado River Demand 10 16 17 5 8 8 10 18 18 1 2 2 5 9 9 1 0.9 0.9 0 0 0 0 0 0 32 53 54

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

STATE TOTAL

Notes

Colorado River Gunnison Yampa White San Juan Dolores South Platte Arkansas
 Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-27

Notes:

1) Used estimated 2050 High irrigated acreage from SWSI table 4-11 for 2060, linearly interpolated to estimate 2035.

2) No estimates for increased in agricultural efficiency in SWSI – used 10 percent increase by 2060.

3) Used high population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 high estimates.

4) Per capita use decreases 25 percent by 2060 based on SWSI table 7-4 passive plus medium active conservation.

5) Assume 35 percent decrease from Current Projected based on technological efficiencies.

6) Energy demands based on SWSI table 4-8. Includes "Energy Development" and Thermoelectric" categories through 2050. Assumed to be 100 percent

consumptive.

7) Mineral use not included in SWSI, assume 10 percent decrease from Current Projected in 2035 and in 2060.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) Used estimated 2050 Low irrigated acreage from SWSI table 4-11 for 2060, linearly interpolated to estimate 2035.

11) No estimates for increased in agricultural efficiency in SWSI – used 10 percent increase by 2060.

12) Used high population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 high estimates.

13) Per capita use decreases 25 percent by 2060 based on SWSI table 7-4 passive plus medium active conservation.

14) Assume 35 percent decrease from Current Projected based on technological efficiencies.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Demand that may be met from Other Supplies decreases based on full development of current water rights, expanded reuse of both trans-Basin and 

in-Basin sources, and decreases yield from agricultural transfers estimated to decrease 20 percent from current levels by 2060 in the South Platte; and 

10 percent from current levels in the Arkansas.

20) Total Adjacent Area demand less Demand that may be met by Other Supplies.

21) Agricultural Use is estimated to be same as Current Projected for Adjacent Areas. Remaining Adjacent Area use is estimated to be M&I.
Colorado River Basin 

Water Supply and Demand Study

C2-28 December 2012

TABLE C2-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

COLORADO LEGEND: 999 From Current Projected Data She 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 270 224 212 269 246 243 93 92 91 27 27 26 220 216 215 40 39 39 918 843 826 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 6.89 6.89 6.89 4.44 4.44 4.44 10.25 10.25 10.25 3.52 3.52 3.52 3.70 3.70 3.70 5.79 5.71 5.69 2

Consumptive factor [%] 26% 26% 26% 26% 26% 26% 34% 34% 34% 15% 15% 15% 43% 43% 43% 37% 37% 37% 29% 29% 29%

Demand (Consumptive) 485 401 381 490 449 443 140 138 138 41 40 40 330 323 322 54 53 53 1,539 1,405 1,376

Municipal and Industrial (M&I) Population [thousands] 357 558 836 121 184 244 42 65 113 10 16 28 85 130 175 36 56 75 651 1,008 1,471 3

M&I Per Capita Use (Diversion) [gpcd] 181 163 140 173 156 134 228 205 177 228 205 177 182 164 141 182 164 141 183 165 143 4

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Consumptive) 25 36 46 8 11 13 4 5 8 0.9 1 2 6 8 10 3 4 4 47 65 82

Self Served Industrial Demand (Consumptive) 3 2 2 0.3 0.2 0.2 7 5 5 0 0 0 0.4 0.3 0.3 0 0 0 11 7 7 5

Demand (Consumptive) 29 38 48 9 11 13 11 10 12 0.9 1 2 6 9 10 3 4 4 58 73 90

Energy Demand (Consumptive) 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 30 51 58 6

Minerals Demand (Consumptive) 10 16 17 5 8 8 10 18 18 1 2 2 5 9 9 1 0.9 0.9 32 53 54 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 525 458 450 503 469 464 186 206 210 44 47 50 343 345 346 58 58 58 0 0 0 0 0 0 1,659 1,582 1,577

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 828 781 773 428 426 425 1,255 1,207 1,198 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 3.50 3.50 3.50 3.97 3.97 3.97 3.66 3.66 3.67 11

Consumptive factor [%] 38% 38% 38% 32% 32% 32% 36% 36% 36%

Demand (Diversion) 2,893 2,730 2,702 1,700 1,691 1,689 4,593 4,421 4,391

Demand (Consumptive) 1,112 1,050 1,039 543 541 540 1,656 1,590 1,579

Municipal and Industrial (M&I) Population [thousands] 3,945 5,244 6,581 1,079 1,451 1,846 5,024 6,695 8,427 12

M&I Per Capita Use (Diversion) [gpcd] 170 153 132 184 166 143 173 156 134 13

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Diversion) 751 899 973 222 270 296 974 1,169 1,269

Self Served Industrial Demand (Diversion) 59 38 38 49 32 32 108 70 70 14

Demand (Diversion) 810 937 1,011 272 302 328 1,082 1,239 1,339

Demand (Consumptive) 284 328 354 95 106 115 379 434 469

Energy Demand (Diversion) 36 45 53 10 14 17 46 59 70 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,739 3,712 3,767 1,982 2,007 2,033 5,721 5,719 5,801

Total Demand in the Study Area 525 458 450 503 469 464 186 206 210 44 47 50 343 345 346 58 58 58 3,739 3,712 3,767 1,982 2,007 2,033 7,380 7,301 7,378

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,204 3,084 3,081 1,784 1,772 1,764 4,988 4,855 4,844 19

Potential Colorado River Demand 525 458 450 503 469 464 186 206 210 44 47 50 343 345 346 58 58 58 534 628 686 198 236 270 2,391 2,446 2,534 20

Agricultural Colorado River Demand 485 401 381 490 449 443 140 138 138 41 40 40 330 323 322 54 53 53 187 187 187 148 148 148 1,875 1,740 1,711 21

Municipal and Industrial Colorado River Demand 29 38 48 9 11 13 11 10 12 0.9 1 2 6 9 10 3 4 4 347 441 499 50 87 122 455 601 711

Energy Colorado River Demand 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 0 0 0 0 0 0 30 51 58

Minerals Colorado River Demand 10 16 17 5 8 8 10 18 18 1 2 2 5 9 9 1 0.9 0.9 0 0 0 0 0 0 32 53 54

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

STATE TOTAL

Notes

Colorado River Gunnison Yampa White San Juan Dolores South Platte Arkansas
 Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-29

Notes

1) Calculated medium decrease in acreage due to urbanization using low and high acreage decreased from SWSI table 4-11 and low, high, and medium 

population projections from SWSI table 4-1. 

2) No changes from Current Projected.

3) No changes from Current Projected.

4) Per capita use decreases 0.5 percent per year per conservation organization recommendation.

5) Assume 35 percent decrease from Current Projected based on technological efficiencies.

6) Energy demands based on SWSI table 4-8. Includes "Energy Development" and Thermoelectric" categories through 2050. Assumed to be 100 percent

consumptive.

7) Mineral use not included in SWSI, assume 10 percent decrease from Current Projected in 2035 and in 2060.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) Calculated medium decrease in acreage due to urbanization using low and high acreage decreased from SWSI table 4-11 and low, high, and medium 

population projections from SWSI table 4-1. 

11) No changes from Current Projected.

12) Used medium population estimates from the SWSI table 4-1 for all basins.

13) Per capita use decreases 0.5 percent per year per conservation organization recommendation.

14) Assume 35 percent decrease from Current Projected based on technological efficiencies.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Demand that may be met from Other Supplies decreases based on expanded reuse of both trans-Basin and in-Basin sources, estimated to decrease 3

percent from current levels by 2060 in the South Platte; and 1 percent from current levels in the Arkansas.

20) Total Adjacent Area demand less Demand that may be met by Other Supplies.

21) Agricultural Use is estimated to be same as Current Projected for Adjacent Areas. Remaining Adjacent Area use is estimated to be M&I.
Colorado River Basin 

Water Supply and Demand Study

C2-30 December 2012

TABLE C2-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

COLORADO LEGEND: 999 From Current Projected Data She 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 270 270 270 269 269 269 93 93 93 27 27 27 220 220 220 40 40 40 918 918 918 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 7.26 7.53 6.89 7.31 7.58 4.44 4.71 4.89 10.25 10.86 11.27 3.52 3.73 3.87 3.70 3.92 4.07 5.79 6.13 6.36 2

Consumptive factor [%] 26% 26% 26% 26% 26% 26% 34% 34% 34% 15% 15% 15% 43% 43% 43% 37% 37% 37% 29% 29% 29%

Demand (Consumptive) 485 514 533 490 519 539 140 148 154 41 43 45 330 349 362 54 57 60 1,539 1,632 1,693

Municipal and Industrial (M&I) Population [thousands] 357 628 968 121 189 274 42 88 146 10 21 36 85 136 200 36 58 86 651 1,121 1,709 3

M&I Per Capita Use (Diversion) [gpcd] 181 165 145 173 158 138 228 208 182 228 208 182 182 166 146 182 166 146 183 168 148 4

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Consumptive) 25 41 55 8 12 15 4 7 10 0.9 2 3 6 9 11 3 4 5 47 74 99

Self Served Industrial Demand (Consumptive) 3 2 2 0.3 0.2 0.2 7 5 5 0 0 0 0.4 0.3 0.3 0 0 0 11 7 7 5

Demand (Consumptive) 29 43 57 9 12 15 11 12 15 0.9 2 3 6 9 12 3 4 5 58 81 106

Energy Demand (Consumptive) 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 30 51 58 6

Minerals Demand (Consumptive) 10 16 17 5 8 8 10 18 18 1.0 2 2 5 9 9 1 0.9 0.9 32 53 54 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 525 576 612 503 539 562 186 218 229 44 51 55 343 371 388 58 62 65 0 0 0 0 0 0 1,659 1,817 1,911

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 828 810 789 428 427 426 1,255 1,237 1,215 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 3.50 3.57 3.67 3.97 4.06 4.17 3.66 3.74 3.85 11

Consumptive factor [%] 38% 38% 38% 32% 32% 32% 36% 36% 36%

Demand (Diversion) 2,893 2,894 2,896 1,700 1,734 1,778 4,593 4,628 4,674

Demand (Consumptive) 1,112 1,113 1,114 543 554 568 1,656 1,667 1,682

Municipal and Industrial (M&I) Population [thousands] 3,945 5,461 7,357 1,079 1,515 2,059 5,024 6,976 9,416 12

M&I Per Capita Use (Diversion) [gpcd] 170 155 136 184 168 147 173 158 138 13

Consumptive factor [%] 35% 35% 35% 35% 35% 35% 35% 35% 35%

M&I Demand (Diversion) 751 948 1,121 222 285 339 974 1,233 1,460

Self Served Industrial Demand (Diversion) 59 38 38 49 32 32 108 70 70 14

Demand (Diversion) 810 987 1,159 272 317 371 1,082 1,304 1,530

Demand (Consumptive) 284 345 406 95 111 130 379 456 536

Energy Demand (Diversion) 36 47 59 10 15 18 46 62 78 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,739 3,928 4,115 1,982 2,066 2,167 5,721 5,994 6,282

Total Demand in the Study Area 525 576 612 503 539 562 186 218 229 44 51 55 343 371 388 58 62 65 3,739 3,928 4,115 1,982 2,066 2,167 7,380 7,811 8,193

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3,204 3,268 3,315 1,784 1,813 1,848 4,988 5,082 5,163 19

Potential Colorado River Demand 525 576 612 503 539 562 186 218 229 44 51 55 343 371 388 58 62 65 534 659 800 198 253 319 2,391 2,730 3,030 20

Agricultural Colorado River Demand 485 514 533 490 519 539 140 148 154 41 43 45 330 349 362 54 57 60 187 187 187 148 148 148 1,875 1,967 2,029 21

Municipal and Industrial Colorado River Demand 29 43 57 9 12 15 11 12 15 0.9 2 3 6 9 12 3 4 5 347 472 613 50 105 171 455 658 890

Energy Colorado River Demand 2 3 5 0 0 0 25 40 42 1 4 6 2 4 5 0 0 0 0 0 0 0 0 0 30 51 58

Minerals Colorado River Demand 10 16 17 5 8 8 10 18 18 1 2 2 5 9 9 1 0.9 0.9 0 0 0 0 0 0 32 53 54

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

STATE TOTAL

Notes

Colorado River Gunnison Yampa White San Juan Dolores South Platte Arkansas
 Appendix C2 — Colorado Water Demand 

 Scenario Quantification

December 2012 C2-31

Notes

1) No changes from Current Projected.

2) No reference. Assume 10 percent increase from Current Projected by 2060.

3) Used high population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 high estimates.

4) Per capita use decreases 25 percent by 2060 based on SWSI table 7-4 passive plus medium active conservation.

5) Assume 35 percent decrease from Current Projected based on technological efficiencies.

6) Energy demands based on SWSI table 4-8. Includes "Energy Development" and Thermoelectric" categories through 2050. Assumed to be 100 percent

consumptive.

7) Mineral use not included in SWSI, assume 10 percent decrease from Current Projected in 2035 and in 2060.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No reference. Assume 5 percent increase from Current Projected by 2060.

12) Used high population estimates from the SWSI table 4-1 for all basins. 2035 and 2060 interpolated from 2015 estimates and 2050 high estimates.

13) Per capita use decreases 25percent by 2060 based on SWSI table 7-4 passive plus medium active conservation.

14) Assume 35 percent decrease from Current Projected based on technological efficiencies.

15) No changes from Current Projected.

16) No reference. Assume 10 percent decrease from Current Projected in 2035 and in 2060.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) No changes from Current Projected.

20) Total Adjacent Area demand less Demand that may be met by Other Supplies.

21) Agricultural Use is estimated to be same as Current Projected for Adjacent Areas. Remaining Adjacent Area use is estimated to be M&I.
Appendix C3

New Mexico Water Demand

Scenario Quantification

December 2012 C3-1 

Appendix C3 — New Mexico Water Demand 

Scenario Quantification

1.0 Introduction 

This appendix summarizes the data sources used in scenario quantification for Colorado River 

demand1 for the state of New Mexico and presents the results of quantification. As presented in 

figure C3-1, New Mexico is divided into a number of planning areas that align with Colorado 

River Basin (Basin) tributaries (San Juan, Northwest [Little Colorado tributaries], and Southwest 

[Gila tributaries]), and Adjacent Areas that are served by Colorado River water. Data collection 

and development were completed at the planning area level.

The following sections present background information that summarizes the state’s planning 

areas, as well as data sources used to quantify demand scenarios by category. Following the 

background section, results of demand scenario quantification are presented. The results section 

is broken out into a New Mexico Study Area summary, followed by Colorado River demand by 

geography, and finally by category. 

2.0 Background 

The New Mexico Office of the State Engineer and the New Mexico Interstate Stream 

Commission (NMISC) are responsible for regional and state-level water resource planning in 

New Mexico. As part of New Mexico’s state water planning process, regional plans were 

developed by a number of regional planning entities. The NMISC coordinated these efforts, and 

once they were final, adopted the resulting regional plans. 

The NMISC also coordinated the efforts to provide information for scenario quantification. 

These efforts largely relied on information previously generated through regional plans and 

demographic studies. However, new assumptions and/or data development were required where 

the assumptions of the Colorado River Basin Water Supply and Demand Study (Study) required 

information not developed as part of the regional planning effort. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources include state, regional, and national agency reports. 

 1 Colorado River demand as computed by Study Area demand minus other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C3-2 December 2012

FIGURE C3-1 

Colorado River Hydrologic Basin and Export Service Areas in New Mexico
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-3 

• Agricultural Demand: Irrigated acreage, agricultural applied water use, and agricultural 

demand estimates were derived from the San Juan Regional Water Plan (San Juan Water 

Commission, 2003), the Southwest New Mexico Regional Water Plan (Daniel B. 

Stephens & Associates [DBSA], 2005), Taos Regional Water Plan (DBSA, 2008), 

Middle Rio Grande Water Supply Study (S.S. Papadopoulos and Associates, 2000), and 

additional information was provided by the NMISC. 

• Municipal and Industrial (M&I): Population and per capita water use values for the 

San Juan, Southwest, and Taos planning areas were derived from the same regional plans 

as agricultural parameters, and additional information was provided by the NMISC. 

Additional information for Adjacent Areas was derived based on the City of 

Albuquerque’s reported efficiency and Albuquerque population estimates prepared by the 

Bureau of Business and Economic Research. 

• Energy: Energy demands were derived from personal communication with the NMISC

(2011) for the San Juan planning area. Some additional energy use in the Taos and 

Southwest planning areas was derived from the regional plans. 

• Minerals: Minerals demands were derived from personal communication with the 

NMISC (2011) for the San Juan planning area. 

• Fish, Wildlife, and Recreation: Water demands for fish, wildlife, and recreation were 

derived from contracted amounts based on the San Juan Chama contract. 

• Tribal: Tribal demands were derived from personal communication with the NMISC

(2011), input from the Jicarilla Apache Nation and Navajo Nation, and San Juan Chama 

contract amounts. 

3.0 Results of Water Demand Scenario Quantification

This section summarizes New Mexico’s Colorado River water demand trends by category across 

the scenarios. The purpose of this section is to describe changes in demands, both temporally and 

geographically, parameters that influence changes in demands, and how the parameters and 

demands differ among scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands), independent of the source of supply. However, for areas outside of the 

hydrologic basin, a portion of the Study Area demand is satisfied from other supplies, such as the 

Rio Grande water and local groundwater. The communities within the Basin, including the 

Southwest and Northwest planning areas, also rely on non-tributary groundwater for a portion of 

their supply. To develop estimates of the Colorado River demand, the Study Area demand was 

reduced by estimates of available supply from other sources. This appendix focuses on Colorado 

River demands, but includes discussion of the Study Area parameters that led to these demands. 

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand, Colorado River demand for the state and 

individual planning areas across the six scenarios, and Colorado River water demand by category 

across the six scenarios. Parameters and demands for all categories and all scenarios, along with 

references for data sources, are included. 
Colorado River Basin 

Water Supply and Demand Study

C3-4 December 2012

3.1 Summary Results of Scenario Quantification

Values were developed for Study Area parameters to quantify Study Area demand for each of 

the scenarios. Colorado River demand was calculated as Study Area demand minus other 

supplies. Table C3-1 presents summary results for the demand scenarios considered in the Study. 

The table presents agricultural and M&I demand parameters for the entire Study Area that 

distinguish the scenarios, the resulting Study Area demands, and finally the Colorado River 

demands by category. Because other supplies may vary among scenarios, trends observed in the 

parameters and Study Area demands may not be reflected identically in Colorado River 

demand trends. 

New Mexico estimates that about 1.5 million people will be in New Mexico’s Study Area by 

2015. This number is expected to increase to about 2 to 3 million by 2060. The greatest 

population growth is associated with the Rapid Growth (C1 and C2) and Enhanced Environment 

(D2) scenarios. The Slow Growth (B) scenario has the lowest population growth of the scenarios 

(2 million by 2060) but still represents a growth of 37 percent over 2015 estimates. 

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, based solely on passive or existing conservation 

targets, is expected to be 11 to 24 percent less in 2060 than in 2015. While usage rates vary 

across New Mexico’s planning areas, per capita reductions are assumed to be consistent across 

the planning areas. 

Irrigated acreage is projected to decrease slightly (2 percent or 3,000 acres) through 2060 under 

all scenarios. Water delivery per acre does not change in the Current Projected (A), Rapid 

Growth (C1), and Enhanced Environment (D1) scenarios; increases slightly (4 percent) in the 

Slow Growth (B) scenario; and decreases by about 15 percent in the Rapid Growth (C2) and 

Enhanced Environment (D2) scenarios. 

Study Area demand for energy is projected to increase slightly under all scenarios due to the 

growing need for energy sources (coal and solar). The greatest increases in Study Area demand

for energy are anticipated in the San Juan planning area, with an increase of about 1,500 acrefeet per year (afy) (4 percent).

Study Area demand for minerals is projected to remain constant through time and across all 

scenarios. 

Study Area demand for tribal use is projected to increase across all scenarios between about 

20 and 75 percent. The larger increases occur in the Rapid Growth (C1 and C2) and Enhanced 

Environment (D2) scenarios. 

Figure C3-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, 

and 3) change in Colorado River demand by demand category. 

From panel one it can be seen that Study Area demand increases from about 1.3 million acre-feet 

(maf) in 2015 to between 1.5 and 1.8 maf in 2060. The Study Area demand growth across 

scenarios in 2060, however, is projected to be as low as 159 kaf or as high as 440 kaf. About half 

of the Study Area demand is expected to be met by other supplies. 
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-5 

TABLE C3-1 

Summary Results of New Mexico Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

 20151 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 1.5 2.6 2.0 3.0 3.0 2.6 3.0

Change in per capita water 

usage (%), from 2015 – -11% -11% -11% -15% -24% -22%

Irrigated acreage (millions of 

acres) 0.14 0.14 0.14 0.14 0.14 0.14 0.14

Change in per acre water 

delivery (%), from 2015 – +0% +4% +0% -15% +0% -15%

Study Area Demand (thousand acre-feet [kaf]) 

 20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 723 718 748 718 592 718 592

M&I demand 249–252 414 322 477 453 346 407

Energy demand 40.7 42.2 42.2 42.2 42.2 38.0 42.2

Minerals demand 6.2 6.2 6.2 6.2 6.2 6.2 6.2

FWR demand 5.0 5.0 5.0 5.0 5.0 5.0 5.0

Tribal demand 303–309 367 367 529 529 367 529

Total Study Area Demand2 1328–1337 1,551 1,490 1,777 1,627 1,480 1,581

Colorado River Demand (kaf) 

 20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 111 111 111 111 106 111 106

M&I demand 138–141 230 169 293 149 163 102

Energy demand 40.0 41.5 41.5 41.5 41.5 37.4 41.5

Minerals demand 0.0 0.0 0.0 0.0 0.0 0.0 0.0

FWR demand 5.0 5.0 5.0 5.0 5.0 5.0 5.0

Tribal demand 303–309 367 367 529 529 367 529

Total Colorado River Demand2 598–606 754 693 979 831 683 785

1 Range across scenarios. 2 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may 

 be charged to state. 
Colorado River Basin 

Water Supply and Demand Study

C3-6 December 2012

FIGURE C3-2 

Study Area, Colorado River, and Change in Colorado River Demand

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

Thousand Acre-Feet per Year

Study Area Demand in New Mexico 

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white and 

colored border

550

600

650

700

750

800

850

900

950

1,000

1,050

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in New Mexico

-100

-50

0

50

100

150

200

250

300

350

400

Thousand Acre-Feet per Year

Change in Colorado River Demand in New Mexico, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-7 

Panel two provides a view of the range across scenarios of Colorado River demand. This demand 

increases from about 600 kaf in 2015 to between 683 and 980 kaf in 2060 (or 14 to 62 percent), 

depending on the scenario. This difference results in a Colorado River demand range of 297 kaf 

across the scenarios in 2060, or about 40 percent. 

Panel three shows how specific categories affect the projected change in Colorado River 

demand by scenario. Growth in tribal demand across all scenarios results in the greatest increase 

in demand (between 41 and 100 percent), followed closely by M&I demand (between 3 and 

60 percent). 

Figure C3-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The nearly 300 kaf range across scenarios in 2060 is easily discernible, with a 

relatively even spread over the range across the scenarios.

FIGURE C3-3 

Historical Use and Future Projected Demand Excluding Reservoir Evaporation1

1

 Reservoir evaporation on the order of 70 kaf is not included in this plot.

0

200

400

600

800

1,000

1,200

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Apportionment
Colorado River Basin 

Water Supply and Demand Study

C3-8 December 2012

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in figures 

C3-4 and C3-5. These figures show two geographic levels: Study Area in New Mexico, and 

individual planning areas. Demands at each geographic level are shown across the scenarios. The 

columns to the right show the Colorado River demand at a point in time (2015, 2035, or 2060) by 

relative contribution of the categories. 

Colorado River demand2 in New Mexico is primarily in the San Juan and Adjacent Areas 

planning areas. The San Juan planning area has the greatest magnitude of Colorado River 

demand, with tribal demands making up the majority of those demands, along with some energy 

and agricultural demands. The primary demand category in the Adjacent Areas planning is M&I, 

with a small amount of agricultural demand. 

Figure C3-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. Change in Colorado River demand is roughly similar in magnitude on both the 

San Juan and Adjacent Areas planning areas, with tribal demand making up the vast majority of 

change in San Juan, and M&I making up all of the change in Adjacent Areas. 

3.3 Colorado River Demand by Category

3.3.1 Agricultural

Agricultural water demand is driven by irrigated acreage and water delivery per acre. Water 

delivery per acre is the amount of water diverted per irrigated acre. Components of this use 

include transmission and delivery losses (surface evaporation, riparian demand, and seepage) and 

on-farm losses that are made up of evaporation, crop irrigation requirements, and tail water 

(return). Each of these factors will vary by location (precipitation, growing season, etc.), 

irrigation method, and crop type. 

Figure C3-7 presents the following by scenario in 2015, 2035, and 2060: 

• Change in agricultural demand for Colorado River water 

• Change in agricultural demand for Colorado River water by planning area 

• Agricultural demand as a portion of Colorado River water demand (right hand side 

of graph) 

As can be seen from figure C3-7, agricultural water demand3 makes up 19 percent of Colorado 

River demand in New Mexico in 2015, and drops to between 11 and 16 percent of demand in 

2060. This drop results from both a decrease in agricultural water demand and an increase in 

other categories of demand. The majority of Colorado River demand for agriculture is located in 

the San Juan planning area. 

 2 Potential Colorado River demand is based on changes in parameters such as population and for the purpose of the Study is 

 not limited by apportionment. 

3 Tribal demand currently includes a significant quantity of agriculture demand that is included in the tribal category and not 

 represented here. Agricultural use in the tribal category continues to grow as settlements are implemented. 
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-9 

FIGURE C3-4 

Colorado River Demand in New Mexico 
Colorado River Basin 

Water Supply and Demand Study

C3-10 December 2012

FIGURE C3-5 

Colorado River Demand by Category
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-11

FIGURE C3-6 

Change in Colorado River Demand in New Mexico from 2015 by Category
Colorado River Basin 

Water Supply and Demand Study

C3-12 December 2012

FIGURE C3-7 

Change in Colorado River Demand in New Mexico from 2015 for Agriculture

-5

-4

-3

-2

-1

0

2015 2035 2060

KAF

Southwest -5

-4

-3

-2

-1

0

2015 2035 2060

KAF

Adjacent Areas

-5

-4

-3

-2

-1

0

2015 2035 2060

KAF

San Juan

-5

-4

-3

-2

-1

0

2015 2035 2060

KAF

Northwest

201520352060

A

B

C1

A

B

C1

C2

C2

D1

D1

D2

D2

-5

-4

-3

-2

-1

0

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in New Mexico, from 2015

Agricultural

Agriculture is 18 - 19% of Colorado River demand*Agriculture is 15 - 16% of Colorado River demand*Agriculture is 11 - 16% of Colorado River demand*

No 

Change

N/A

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-13

In the San Juan planning area, Colorado River demand for agriculture decreases in the Rapid 

Growth (C2) and Enhanced Environment (D2) scenarios, by about 4.5 kaf (5 percent of Colorado 

River demand). The decrease is due entirely to reduced water delivery per acre; irrigated acreage 

is forecast to remain constant in the San Juan planning area across all scenarios. Colorado River 

demand for agriculture in all other planning areas is forecast to remain constant through time 

across all scenarios.

3.3.2 Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita water use, with the 

addition of self-served industrial (SSI) demand. M&I per capita water use is a measure of the 

amount of water produced or diverted per person in a given municipality. Because this measure 

examines all water produced by a given municipality, it often includes industrial, commercial, 

and institutional demand as well as residential demand. A number of factors may influence the 

M&I per capita water use of a given community, including the amount of industrial demand, 

climate, number of institutional facilities, and number of visitors. 

SSI are industries located in a given area that have their own water supply systems and are 

therefore not directly related to local measures of population and M&I per capita water use. 

Figure C3-8 presents the following by scenario in 2015, 2035, and 2060: 

• Change in M&I demand for Colorado River water in the Study Area 

• Change in M&I demand for Colorado River water in individual planning areas 

• M&I demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C3-8, M&I water demand is the second-largest component of 

Colorado River demand, changing from 24 percent in 2015 to between 13 and 31 percent of 

Colorado River demand in 2060, depending on which scenario is considered. 

Colorado River demand for M&I use increases over time from 2015 to 2060 in the Current 

Projected (A), Slow Growth (B), Rapid Growth (C1), and Enhanced Environment (D1) 

scenarios. This increase is primarily due to population increase, as M&I per capita water use 

decreases over time across all scenarios and SSI demand nominally increases. Decrease in the 

M&I demand in the Rapid Growth (C2) and Enhanced Environment (D2) scenarios is due to 

decrease in per capita water use.

In examining the planning areas, nearly all of the increase in M&I demand for Colorado River 

water from 2015 to 2060 over time is due to population increase in the Adjacent Areas across all 

scenarios. The remaining increase in demand is primarily from M&I demand in the San Juan 

planning area. 

Increases in population are somewhat tempered by decreases in M&I per capita water use. 

Per capita water use decreases in all scenarios with reductions ranging from 11 to 24 percent 

by 2060. 
Colorado River Basin 

Water Supply and Demand Study

C3-14 December 2012

FIGURE C3-8 

Change in Colorado River Demand in New Mexico from 2015 for M&I 

-50

0

50

100

150

2015 2035 2060

KAF

San Juan

-50

0

50

100

150

2015 2035 2060

KAF

Adjacent Areas

-50

0

50

100

150

2015 2035 2060

KAF

Northwest

201520352060

A

A

B

B

C1

C1

C2

D1

C2

D1

D2

D2

-50

0

50

100

150

200

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in New Mexico, from 2015

Municipal and Industrial

M&I is 23 - 24% of Colorado River demand*M&I is 16 - 26% of Colorado River demand*M&I is 13 - 31% of Colorado River demand*

N/A

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-15

3.3.3 Energy

Water demand for energy can be estimated through known plans for new power plants or 

through applying a per capita energy water use factor. Power facilities often serve areas remote 

from their locations and therefore potentially represent exports or imports of water from the 

Study Area to meet these distributed needs. 

Figure C3-9 presents the following by scenario in 2015, 2035, and 2060: 

• Change in energy demand for Colorado River water 

• Change in energy demand for Colorado River water in individual planning areas

• Energy demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C3-9, energy water demand is a relatively small fraction of Colorado 

River demand, decreasing from 7 percent of in 2015 to between 4 and 6 percent of demand in 

2060, depending on which scenario is considered. The decreasing percentage is due to demands 

in other categories increasing at a faster rate than energy demands increase. 

Energy demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios, with notable increases for the Current Projected (A) and Rapid Growth (C1) scenarios. 

Energy demands are shown only in the San Juan planning areas. Consistent increases occur in 

the San Juan planning area across all scenarios, with an increase of 1.5 kaf to a total of 41.5 kaf. 

3.3.4 Minerals Extraction

Although there is some demand for minerals in the Southwest (about 900 afy in Current 

Projected [A] scenario) and the Adjacent Areas (about 5,300 afy in Current Projected [A] 

scenario), these demands are met by other supplies. There is no reported Colorado River demand 

for minerals extraction under the scenarios analyzed for the Study. 

3.3.5 Fish, Wildlife, and Recreation

There are no reported consumptive fish, wildlife, and recreation demands on Colorado River 

water in New Mexico.

3.3.6 Tribal

Tribal water demands were provided by the Jicarilla Apache Nation and the Navajo Nation in 

cooperation with the State of New Mexico. The projected Navajo Nation demands were provided 

by the Navajo Nation Department of Water Resources and modified to fit the storyline narratives 

regarding tribal use under each scenario. 

Figure C3-10 presents the following by scenario in 2015, 2035, and 2060: 

• Change in tribal demand for Colorado River water 

• Change in tribal demand for Colorado River water in individual planning area 

• Tribal demand as a portion of Colorado River demand (right hand side of graph) 
Colorado River Basin 

Water Supply and Demand Study

C3-16 December 2012

FIGURE C3-9 

Change in Colorado River Demand in New Mexico from 2015 for Energy

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

KAF

San Juan

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

KAF

Northwest

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

KAF

Adjacent Areas

201520352060

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

KAF

Southwest

A

B

C1C2

D2

A

B

C1C2

D2

0.0

0.5

1.0

1.5

2.0

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in New Mexico, from 2015

Energy

Energy is 7% of Colorado River demand*

Energy is 5 - 6% of Colorado River demand*

Energy is 4 - 6% of Colorado River demand*

N/A

N/A

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C3 — New Mexico Water Demand

Scenario Quantification

December 2012 C3-17

FIGURE C3-10

Change in Colorado River Demand in New Mexico from 2015 for Tribal

0

100

200

300

2015 2035 2060

KAF

San Juan

0

100

200

300

2015 2035 2060

KAF

Northwest

0

100

200

300

2015 2035 2060

KAF

Adjacent Areas

201520352060

0

100

200

300

2015 2035 2060

KAF

Southwest

A

B

A

B

C1

C1

C2

C2

D1

D1

D2

D2

0

50

100

150

200

250

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in New Mexico, from 2015

Tribal

Tribal is 50 - 51% of Colorado River demand*

Tribal is 52 - 61% of Colorado River demand*

Tribal is 49 - 67% of Colorado River demand*

No 

Change

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin 

Water Supply and Demand Study

C3-18 December 2012

As can be seen from figure C3-10, tribal water demand is the largest component of Colorado 

River demand in New Mexico, decreasing from about 50 percent in 2015 to between 49 and 67 

percent of Colorado River demand in 2060, depending on which scenario is considered. The 

decreasing percentage is due to demands in other categories increasing at a faster rate than tribal 

demands increase.

Colorado River tribal demand increases over time from 2015 to 2060 across all scenarios. These 

increases are primarily due to development of demands under water rights settlements. Increases 

occur mostly in the San Juan planning area, but there is also some increase in the Northwest 

planning area. The rate of increase is similar across all scenarios. 

For additional information on tribal water demands, see appendix C9. 

3.4 Summary Tables of Parameters and Demands by Category

Tables C3-2 to C3-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 

4.0 References

Bureau of Business and Economic Research (BBER). 1993. Population Growth Trends for the 

Upper Rio Grande and Albuquerque.

Bureau of Business and Economic Research (BBER). 2008. A Report on Historical and Future 

Population Dynamics in New Mexico Water Planning Regions.

Daniel B. Stephens & Associates (DBSA). 2005. Southwest New Mexico Regional Water Plan. 

Prepared for Southwest New Mexico Regional Water Plan Steering Committee, City of 

Deming, New Mexico, Fiscal Agent. Accepted by New Mexico Interstate Stream 

Commission, 2005. 

Daniel B. Stephens & Associates (DBSA). 2008. Taos Regional Water Plan. Prepared for Taos 

Regional Water Planning Steering Committee. Accepted by New Mexico Interstate 

Stream Commission, 2008. 

New Mexico Interstate Stream Commission (NMISC). 2011. Personal communication with 

Reclamation. 

San Juan Water Commission. 2003. San Juan Regional Water Plan. 

S.S. Papadopoulos and Associates (SSPA). 2000. Middle Rio Grande Water Supply Study. 

Colorado River Basin

Water Supply and Demand Study

C3-20 December 2012

TABLE C3-2 

Total Demand within Study Area under Current Projected (A) Scenario

NEW MEXICO LEGEND: 999 From States 999 From State Plans

Units are thousand acre-feet per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 34 34 34 17 15 14 0 0 0 51 50 48 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 5.08 5.08 5.08 5.89 5.89 5.89 0.00 0.00 0.00 5.34 5.33 5.31 1b

Consumptive factor [%] 51% 51% 51% 33% 33% 33% 0% 0% 0% 45% 45% 45% 2, 2b

Demand (Consumptive) 89 89 89 33 30 27 0 0 0 122 119 116 3, 3b

Municipal and Industrial (M&I) Population [thousands] 186 214 267 10 10 10 0 0 0 196 224 276 4, 4b

M&I Per Capita Use (Diversion) [gpcd] 200 181 146 193 192 193 0 0 0 200 181 148 5

Consumptive factor[%] 44% 50% 50% 50% 50% 50% 0% 0% 0% 45% 50% 50% 6

M&I Demand (Consumptive) 18 22 22 1 1 1 0 0 0 20 23 23 7, 7b

Self Served Industrial Demand (Consumptive) 0.10 0.10 0.10 0 0 0 0 0 0 0.10 0.10 0.10 8

Demand (Consumptive) 19 22 22 1 1 1 0 0 0 20 23 23

Energy Demand (Consumptive) 40 42 42 0.6 0.6 0.6 0 0 0 41 42 42 9, 9b

Minerals Demand (Consumptive) 0 0 0 0.9 0.9 0.9 0 0 0 0.9 0.9 0.9 10, 10b

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 11

Tribal Demand (Consumptive) 288 339 341 0 0 0 4 14 15 292 352 356 12, 12b

Total Hydrologic Basin Demand (Consumptive) 435 491 493 36 33 30 4 14 15 0 0 0 475 537 538

Adjacent Areas

Agricultural Irrigated Acreage [acres] 93 93 93 93 93 93 13

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.45 6.45 6.45 6.45 6.45 6.45 14

Consumptive factor [%] 33% 33% 33% 33% 33% 33%

Demand (Diversion) 601 601 601 601 601 601

Demand (Consumptive) 196 196 196 196 196 196 15

Municipal and Industrial (M&I) Population [thousands] 1,277 1,802 2,326 1,277 1,802 2,326 16

M&I Per Capita Use (Diversion)[gpcd] 163 150 150 163 150 150 17

Consumptive factor [%] 40% 40% 40% 40% 40% 40% 18

M&I Demand (Diversion) 233 303 391 233 303 391

Self Served Industrial Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 19

Demand (Diversion) 233 303 391 233 303 391

Demand (Consumptive) 93 121 156 93 121 156

Energy Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 20

Minerals Demand (Diversion) 5 5 5 5 5 5 21

Fish, Wildlife, and Recreation Demand (Diversion) 5 5 5 5 5 5 22

Tribal Demand (Diversion) 11 11 11 11 11 11 23

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 855 925 1,014 855 925 1,014

Total Demand in the Study Area 435 491 493 36 33 30 4 14 15 855 925 1,014 1,330 1,463 1,551 24

Demand that may be met by Other Supplies 0 0 0 36 33 30 0 0 0 694 727 767 730 760 797

Potential Colorado River Demand 435 491 493 0 0 0 4 14 15 161 199 246 600 703 754 25, 12b

Agricultural Colorado River Demand 89 89 89 0 0 0 0 0 0 22 22 22 111 111 111 26

Municipal and Industrial Colorado River Demand 19 22 22 0 0 0 0 0 0 123 161 208 141 183 230

Energy Colorado River Demand 40 42 42 0 0 0 0 0 0 0 0 0 40 42 42

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5

Tribal Colorado River Demand 288 339 341 0 0 0 4 14 15 11 11 11 303 363 367

STATE TOTAL

Notes

San Juan Southwest Northwest Adjacent Areas
 Appendix C3 — New Mexico Water Demand

 Scenario Quantification

December 2012 C3-21

Notes

1) San Juan: NMISC, personal communication, 2011.

1b) Southwest New Mexico Regional Water Plan, 2005, tables 6-8 through 6-12. Total diversion / total acres (for Catron, Grant, and 90 percent of Hidalgo Counties; Luna 

County excluded). Average of 1990, 1995, 2000. 

2) San Juan Regional Water Plan, 2003, consumptive factor of 51 percent based on agricultural diversion as twice the depletion plus 10 percent for incidental losses.

2b) Southwest New Mexico Regional Water Plan, 2005, tables 6-8 through 6-12. Weighted average (based on acreage for Catron, Grant, and 90 percent of Hidalgo Counties; 

Luna County excluded) of depletion/diversion, average of 1990, 1995, 2000.

3) San Juan: NMISC, personal communication, 2011. Current and forecast = 90,500 afy, minus 4,000 afy stockpond evaporation and use. 

3b) Southwest New Mexico Regional Water Plan, 2005. Based on appendix E5 (assume Catron, Grant, and 90 percent of Hidalgo Counties), average of low and high 

scenarios (diversion), multiplied by consumptive factor. Extrapolate to 2060. 

4) San Juan: San Juan Regional Water Plan, 2003.

4b) Southwest New Mexico Regional Water Plan, 2005, appendix E5; Sum of Catron and Hidalgo Counties. Average of low and high estimates; extrapolated to 2060.

5) San Juan Regional Water Plan, 2003 – weighted average of year 2000 calculated M&I efficiency by planning area for year 2011. 2015 based on 2011 to 2035 

interpolation. NMISC, personal communication, 2011 provided 2035 and 2060 values.

6) San Juan: Consumptive factor calculated from demand and M&I water use efficiency for 2015 (within reported range). This value moves to 50 percent by 2035 per 

NMISC, 2011.

7) San Juan: NMISC, personal communication, 2011; 100 afy moved to reservoir evaporation.

7b) Southwest New Mexico Regional Water Plan, 2005. Sum of Public (table 6-15), Commercial, Industrial, and Domestic (appendix E5) (Catron and Hidalgo Counties only), 

multiplied by consumptive use factor to get consumptive demand. Extrapolated for 2060.

8) San Juan: NMISC, personal communication, 2011.

9) San Juan: NMISC, personal communication, 2011.

9b) Southwest New Mexico Regional Water Plan, 2005, appendix E5, Grant, Hidalgo, and Catron Counties. Average of low and high scenario. Assume 2060 remains same 

as 2020–2040. 

10) San Juan: NMISC, personal communication, 2011.

10b) Southwest New Mexico Regional Water Plan, 2005, appendix E5 (Hidalgo and Catron Counties only). Average of low and high scenario. Assume 2060 remains same as 

2020–2040. 

11) San Juan: NMISC, personal communication, 2011; 100 afy moved to reservoir evaporation.

12) San Juan: NMISC, personal communication, 2011; 1,000 moved to reservoir evaporation.

12b) Northwest: Build-out of Navajo-Gallup pipeline.

13) 63,551 from Middle Rio Grande Regional Water Supply Study, S.S. Papadopulos & Associates (SSPA, 2000). + 29,750 from Taos Regional Water Plan (DBSA, 2008)

14) New Water Use by Categories 2005, Pg. 92. Applied water rate 7.8 estimated from Middle Rio Grande Conservancy District total diversion 39,403 divided by 5,004 acres, 

and applied to 63,551 acres. 3.55 afy/acre calculated for Taos based on 105,693 afy divided by 29,750 acres (Taos Regional Water Plan). Weighted average calculated.

15) Calculated based on consumptive water use of 2.10 af/ac/yr from NMISC, personal communication, 2011. 

16) Middle Rio Grande: BBER Regional Water Planning Areas, Middle Rio Grande Area, (SSPA, 2000) + Taos: Taos Regional Plan table 6-20 (DBSA, 2008) interpolated for 

2015/2035 and extrapolated past 2050 for 2060.

17) Taken from current Albuquerque reported M&I efficiency and planning. Assumed population of Albuquerque heavily influences overall average.

18) 40 percent assumed, based on Albuquerque's current use. Assumed population of Albuquerque heavily influences overall average.

19) Taos Regional Water Plan table 6-25 (DBSA, 2008) interpolated for 2015/2035 and extrapolated past 2050 for 2060.

20) Taos Regional Water Plan table 6-26 (DBSA, 2008) interpolated for 2015/2035 and extrapolated past 2050 for 2060.

21) Taos Regional Water Plan table 6-27 (DBSA, 2008) interpolated for 2015/2035 and extrapolated past 2050 for 2060.

22) Contracted amount from San Juan Chama contracts.

23) Contracted amount from San Juan Chama contracts for 2015. 

24) Calculated from the sum of Hydrologic Basin (Consumptive) Demand and Adjacent Areas (Diversion) Demand.

25) Adjacent areas: Potential Colorado River Demand is San Juan Chama Contract plus unsustainable portion of supply from Middle Rio Grande Regional Water Plan, 2004.

26) For Adjacent Area, 25,000 afy of Colorado River Demand is agricultural, per contracts. Assume full tribal is met by Colorado River. Remaining Colorado River demand is 

all M&I.
Colorado River Basin 

Water Supply and Demand Study

C3-22 December 2012

TABLE C3-3 

Total Demand within Study Area under Slow Growth (B) Scenario

NEW MEXICO LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 34 34 34 17 15 14 0 0 0 51 50 48 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 5.08 5.08 5.08 5.89 5.89 5.89 0.00 0.00 0.00 5.34 5.33 5.31 2

Consumptive factor [%] 51% 51% 51% 33% 33% 33% 0% 0% 0% 45% 45% 45%

Demand (Consumptive) 89 89 89 33 30 27 0 0 0 122 119 116

Municipal and Industrial (M&I) Population [thousands] 186 189 200 10 9 7 0 0 0 196 198 207 3

M&I Per Capita Use (Diversion) [gpcd] 200 181 146 193 192 193 0 0 0 200 181 148 4

Consumptive factor[%] 44% 50% 50% 50% 50% 50% 0% 0% 0% 45% 50% 50%

M&I Demand (Consumptive) 18 19 16 1 1 1 0 0 0 20 20 17

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0.1 0.1 0.1 5

Demand (Consumptive) 19 19 16 1 1 1 0 0 0 20 20 17

Energy Demand (Consumptive) 40 42 42 1 1 1 0 0 0 41 42 42 6

Minerals Demand (Consumptive) 0 0 0 1 1 1 0 0 0 1 1 1 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 288 339 341 0 0 0 4 14 15 292 352 356 9

Total Hydrologic Basin Demand (Consumptive) 435 488 487 36 33 30 4 14 15 0 0 0 475 535 532

Adjacent Areas

Agricultural Irrigated Acreage [acres] 93 93 93 93 93 93 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.45 6.59 6.77 6.45 6.59 6.77 11

Consumptive factor [%] 33% 33% 33% 33% 33% 33%

Demand (Diversion) 601 615 631 601 615 631

Demand (Consumptive) 196 200 206 196 200 206

Municipal and Industrial (M&I) Population [thousands] 1,277 1,562 1,814 1,277 1,562 1,814 12

M&I Per Capita Use (Diversion)[gpcd] 163 150 150 163 150 150 13

Consumptive factor [%] 40% 40% 40% 40% 40% 40%

M&I Demand (Diversion) 233 262 305 233 262 305

Self Served Industrial Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 14

Demand (Diversion) 233 262 305 233 262 305

Demand (Consumptive) 93 105 122 93 105 122

Energy Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 15

Minerals Demand (Diversion) 5 5 5 5 5 5 16

Fish, Wildlife, and Recreation Demand (Diversion) 5 5 5 5 5 5 17

Tribal Demand (Diversion) 11 11 11 11 11 11 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 855 898 957 855 898 957

Total Demand in the Study Area 435 488 487 36 33 30 4 14 15 855 898 957 1,330 1,433 1,490

Demand that may be met by Other Supplies 0 0 0 36 33 30 0 0 0 694 727 767 730 760 797 19

Potential Colorado River Demand 435 488 487 0 0 0 4 14 15 161 172 190 600 673 693

Agricultural Colorado River Demand 89 89 89 0 0 0 0 0 0 22 22 22 111 111 111 20

Municipal and Industrial Colorado River Demand 19 19 16 0 0 0 0 0 0 123 134 152 141 153 169

Energy Colorado River Demand 40 42 42 0 0 0 0 0 0 0 0 0 40 42 42

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5

Tribal Colorado River Demand 288 339 341 0 0 0 4 14 15 11 11 11 303 363 367

STATE TOTAL

Notes

San Juan Southwest Northwest Adjacent Areas
 Appendix C3 — New Mexico Water Demand

 Scenario Quantification

December 2012 C3-23

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) Based on regional trends, assume 2060 population is 25 percent less than that of Current Projected. 

4) No changes from Current Projected.

5) No changes from Current Projected.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Assumed 2035 demand from Current Projected is the new 2060 demand and interpolated for the 2035 demand.

10) No changes from Current Projected.

11) Used 5 percent increase from Current Projected in 2060, no changes from Current Projected in 2015, and interpolated for 2035.

12) Bureau of Business and Economic Research (BBER). 1993 (BBER, 2008).

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) San Juan Chama at full contract amount.

19) No changes from Current Projected.

20) For Adjacent Area, 25,000 afy of Colorado River Demand is agricultural, per contracts. Assume full tribal is met by Colorado River. Remaining 

Colorado River demand is all M&I. 
Colorado River Basin 

Water Supply and Demand Study

C3-24 December 2012

TABLE C3-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

NEW MEXICO LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 34 34 34 17 15 14 0 0 0 51 50 48 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 5.08 5.08 5.08 5.89 5.89 5.89 0.00 0.00 0.00 5.34 5.33 5.31 2

Consumptive factor [%] 51% 51% 51% 33% 33% 33% 0% 0% 0% 45% 45% 45%

Demand (Consumptive) 89 89 89 33 30 27 0 0 0 122 119 116

Municipal and Industrial (M&I) Population [thousands] 186 240 333 10 11 12 0 0 0 196 251 345 3

M&I Per Capita Use (Diversion) [gpcd] 200 181 146 193 192 193 0 0 0 200 181 148 4

Consumptive factor[%] 44% 50% 50% 50% 50% 50% 0% 0% 0% 45% 50% 50%

M&I Demand (Consumptive) 18 24 27 1 1 1 0 0 0 20 26 29

Self Served Industrial Demand (Consumptive) 0.10 0.10 0.10 0 0 0 0 0 0 0.10 0.10 0.10 5

Demand (Consumptive) 19 24 27 1 1 1 0 0 0 20 26 29

Energy Demand (Consumptive) 40 42 42 0.6 0.6 0.6 0 0 0 41 42 42 6

Minerals Demand (Consumptive) 0 0 0 0.9 0.9 0.9 0 0 0 0.9 0.9 0.9 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 294 387 503 0 0 0 4 15 15 298 402 518 9

Total Hydrologic Basin Demand (Consumptive) 441 542 661 36 33 30 4 15 15 0 0 0 481 590 706

Adjacent Areas

Agricultural Irrigated Acreage [acres] 93 93 93 93 93 93 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.45 6.45 6.45 6.45 6.45 6.45 11

Consumptive factor [%] 33% 33% 33% 33% 33% 33%

Demand (Diversion) 601 601 601 601 601 601

Demand (Consumptive) 196 196 196 196 196 196

Municipal and Industrial (M&I) Population [thousands] 1,277 1,816 2,666 1,277 1,816 2,666 12

M&I Per Capita Use (Diversion)[gpcd] 163 150 150 163 150 150 13

Consumptive factor [%] 40% 40% 40% 40% 40% 40%

M&I Demand (Diversion) 233 305 448 233 305 448

Self Served Industrial Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 14

Demand (Diversion) 233 305 448 233 305 448

Demand (Consumptive) 93 122 179 93 122 179

Energy Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 15

Minerals Demand (Diversion) 5 5 5 5 5 5 16

Fish, Wildlife, and Recreation Demand (Diversion) 5 5 5 5 5 5 17

Tribal Demand (Diversion) 11 11 11 11 11 11 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 855 928 1,071 855 928 1,071

Total Demand in the Study Area 441 542 661 36 33 30 4 15 15 855 928 1,071 1,337 1,518 1,777

Demand that may be met by Other Supplies 0 0 0 36 33 30 0 0 0 694 727 767 730 760 798 19

Potential Colorado River Demand 441 542 661 0 0 0 4 15 15 161 201 303 606 758 979

Agricultural Colorado River Demand 89 89 89 0 0 0 0 0 0 22 22 22 111 111 111 20

Municipal and Industrial Colorado River Demand 19 24 27 0 0 0 0 0 0 123 163 265 141 187 293

Energy Colorado River Demand 40 42 42 0 0 0 0 0 0 0 0 0 40 42 42

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5

Tribal Colorado River Demand 294 387 503 0 0 0 4 15 15 11 11 11 309 413 529

STATE TOTAL

Notes

San Juan Southwest Northwest Adjacent Areas
 Appendix C3 — New Mexico Water Demand

 Scenario Quantification

December 2012 C3-25

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) Based on regional trends, assume 2060 population is 25 percent greater than that of Current Projected. 

4) No changes from Current Projected.

5) No changes from Current Projected.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Northwest: Assumed 2060 demand from Current Projected would be reached in 2035 demand and that no new claims are filed (San Juan: Personal 

communication, Navajo Nation, April 16, 2012.) 

10) No changes from Current Projected.

11) No changes from Current Projected.

12) (BBER, 1993) (BBER, 2008).

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) San Juan Chama at full contract amount.

19) No changes from Current Projected.

20) For Adjacent Area, 25,000 afy of Colorado River Demand is agricultural, per contracts. Assume full tribal is met by Colorado River. Remaining Colorado 

River demand is all M&I. 
Colorado River Basin 

Water Supply and Demand Study

C3-26 December 2012

TABLE C3-5 

Total Demand Within Study Area Under Rapid Growth (C2) Scenario

NEW MEXICO LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 34 34 34 17 15 14 0 0 0 51 50 48 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 5.08 4.96 4.82 5.89 5.76 5.60 0.00 0.00 0.00 5.34 5.21 5.05 2

Consumptive factor [%] 51% 51% 51% 33% 33% 33% 0% 0% 0% 45% 45% 45%

Demand (Consumptive) 89 87 84 33 30 26 0 0 0 122 117 110

Municipal and Industrial (M&I) Population [thousands] 186 240 333 10 11 12 0 0 0 196 251 345 3

M&I Per Capita Use (Diversion) [gpcd] 199 176 139 192 187 183 0 0 0 199 177 140 4

Consumptive factor[%] 44% 50% 50% 50% 50% 50% 0% 0% 0% 45% 50% 50%

M&I Demand (Consumptive) 18 24 26 1 1 1 0 0 0 19 25 27

Self Served Industrial Demand (Consumptive) 0.10 0.10 0.10 0 0 0 0 0 0 0.10 0.10 0.10 5a, 5b

Demand (Consumptive) 18 24 26 1 1 1 0 0 0 20 25 27

Energy Demand (Consumptive) 40 42 42 0.6 0.6 0.6 0 0 0 41 42 42 6

Minerals Demand (Consumptive) 0 0 0 0.9 0.9 0.9 0 0 0 0.9 0.9 0.9 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 294 387 503 0 0 0 4 15 15 298 402 518 9

Total Hydrologic Basin Demand (Consumptive) 441 539 655 36 33 29 4 15 15 0 0 0 481 587 699

Adjacent Areas

Agricultural Irrigated Acreage [acres] 93 93 93 93 93 93 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.45 5.87 5.16 6.45 5.87 5.16 11

Consumptive factor [%] 33% 33% 33% 33% 33% 33%

Demand (Diversion) 601 548 481 601 548 481

Demand (Consumptive) 196 178 157 196 178 157

Municipal and Industrial (M&I) Population [thousands] 1,277 1,816 2,666 1,277 1,816 2,666 12

M&I Per Capita Use (Diversion)[gpcd] 162 146 143 162 146 143 13

Consumptive factor [%] 40% 40% 40% 40% 40% 40%

M&I Demand (Diversion) 231 298 426 231 298 426

Self Served Industrial Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 14

Demand (Diversion) 231 298 426 231 298 426

Demand (Consumptive) 93 119 170 93 119 170

Energy Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 15

Minerals Demand (Diversion) 5 5 5 5 5 5 16

Fish, Wildlife, and Recreation Demand (Diversion) 5 5 5 5 5 5 17

Tribal Demand (Diversion) 11 11 11 11 11 11 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 854 867 928 854 867 928

Total Demand in the Study Area 441 539 655 36 33 29 4 15 15 854 867 928 1,335 1,454 1,627

Demand that may be met by Other Supplies 0 0 0 36 33 29 0 0 0 694 727 767 730 759 796 19

Potential Colorado River Demand 441 539 655 0 0 0 4 15 15 160 140 161 605 694 831

Agricultural Colorado River Demand 89 87 84 0 0 0 0 0 0 22 22 22 111 109 106 20

Municipal and Industrial Colorado River Demand 18 24 26 0 0 0 0 0 0 122 102 123 140 126 149

Energy Colorado River Demand 40 42 42 0 0 0 0 0 0 0 0 0 40 42 42

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5

Tribal Colorado River Demand 294 387 503 0 0 0 4 15 15 11 11 11 309 413 529

STATE TOTAL

Notes

San Juan Southwest Northwest Adjacent Areas
 Appendix C3 — New Mexico Water Demand

 Scenario Quantification

December 2012 C3-27

Notes

1) No changes from Current Projected.

2) Used 5 percent growth from Current Projected in 2060, no change from Current Projected in 2015, and interpolated for 2035.

3) Based on regional trends, assume 2060 population is 25 percent greater than that of Current Projected. 

4) Assume 1 percent reduction per decade relative to Current Projected.

5a) Used same percentage change as GPCD section for San Juan Area.

5b) Assumed no increase from Current Projected in Southwest Area.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Northwest: Assumed 2060 demand from Current Projected would be reached in 2035 demand and that no new claims are filed (San Juan: Personal 

communication, Navajo Nation, April 16, 2012.) 

10) No changes from Current Projected.

11) Used 20 percent growth from Current Projected in 2060, no change from Current Projected in 2015, and interpolated for 2035.

12) (BBER, 1993) (BBER, 2008)

13) Assume 1 percent reduction per decade relative to Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) San Juan Chama at full contract amount.

19) No changes from Current Projected.

20) For Adjacent Area, 25,000 afy of Colorado River Demand is agricultural, per contracts. Assume full tribal is met by Colorado River. Remaining Colorado 

River demand is all M&I. 
Colorado River Basin 

Water Supply and Demand Study

C3-28 December 2012

TABLE C3-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

NEW MEXICO LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 34 34 34 17 15 14 0 0 0 51 50 48 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 5.08 5.08 5.08 5.89 5.89 5.89 0.00 0.00 0.00 5.34 5.33 5.31 2

Consumptive factor [%] 51% 51% 51% 33% 33% 33% 0% 0% 0% 45% 45% 45%

Demand (Consumptive) 89 89 89 33 30 27 0 0 0 122 119 116

Municipal and Industrial (M&I) Population [thousands] 186 214 267 10 10 10 0 0 0 196 224 276 3

M&I Per Capita Use (Diversion) [gpcd] 198 172 131 191 172 148 0 0 0 198 172 132 4

Consumptive factor[%] 44% 50% 50% 50% 50% 50% 0% 0% 0% 45% 50% 50%

M&I Demand (Consumptive) 18 21 20 1 1.0 0.8 0 0 0 19 22 20

Self Served Industrial Demand (Consumptive) 0.10 0.10 0.09 0.0 0.0 0.0 0 0 0 0.10 0.10 0.09 5a, 5b

Demand (Consumptive) 18 21 20 1 1.0 0.8 0 0 0 19 22 21

Energy Demand (Consumptive) 40 39 37 0.6 0.6 0.6 0 0 0 41 40 38 6

Minerals Demand (Consumptive) 0 0 0 0.9 0.9 0.9 0 0 0 0.9 0.9 0.9 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0.0 0 0 8

Tribal Demand (Consumptive) 288 339 341 0 0 0 4 14 15 292 352 356 9

Total Hydrologic Basin Demand (Consumptive) 435 487 486 36 33 30 4 14 15 0 0 0 475 534 531

Adjacent Areas

Agricultural Irrigated Acreage [acres] 93 93 93 93 93 93 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.45 6.45 6.45 6.45 6.45 6.45 11

Consumptive factor [%] 33% 33% 33% 33% 33% 33%

Demand (Diversion) 601 601 601 601 601 601

Demand (Consumptive) 196 196 196 196 196 196

Municipal and Industrial (M&I) Population [thousands] 1,277 1,802 2,326 1,277 1,802 2,326 12

M&I Per Capita Use (Diversion)[gpcd] 161 143 125 161 143 125 13

Consumptive factor [%] 40% 40% 40% 40% 40% 40%

M&I Demand (Diversion) 230 288 326 230 288 326

Self Served Industrial Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 14

Demand (Diversion) 230 288 326 230 288 326

Demand (Consumptive) 92 115 130 92 115 130

Energy Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 15

Minerals Demand (Diversion) 5 5 5 5 5 5 16

Fish, Wildlife, and Recreation Demand (Diversion) 5 5 5 5 5 5 17

Tribal Demand (Diversion) 11 11 11 11 11 11 18

Total Adjacent Areas Demand (Diversion) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 853 910 948 853 910 948

Total Demand in the Study Area 435 487 486 36 33 30 4 14 15 853 910 948 1,328 1,444 1,480

Demand that may be met by Other Supplies 0.0 0.0 0.0 36 33 30 0.0 0.0 0.0 694 727 767 730 760 797 19

Potential Colorado River Demand 435 487 486 0.0 0.0 0.0 4 14 15 158 184 181 598 684 683

Agricultural Colorado River Demand 89 89 89 0 0 0 0 0 0 22 22 22 111 111 111 20

Municipal and Industrial Colorado River Demand 18 21 20 0 0 0 0 0 0 120 146 143 139 166 163

Energy Colorado River Demand 40 39 37 0 0 0 0 0 0 0 0 0 40 39 37

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5

Tribal Colorado River Demand 288 339 341 0 0 0 4 14 15 11 11 11 303 363 367

STATE TOTAL

Notes

San Juan Southwest Northwest Adjacent Areas
 Appendix C3 — New Mexico Water Demand

 Scenario Quantification

December 2012 C3-29

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) Assume 2 percent reduction per decade relative to Current Projected.

5a) Used same percentage change as GPCD section for San Juan Area.

5b) Assumed no increase from Current Projected in Southwest Area.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) (BBER, 1993) (BBER, 2008)

13) Assume 2 percent reduction per decade relative to Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) No changes from Current Projected.

20) For Adjacent Area, 25,000 afy of Colorado River Demand is agricultural, per contracts. Assume full tribal is met by Colorado River. Remaining 

Colorado River demand is all M&I. 
Colorado River Basin 

Water Supply and Demand Study

C3-30 December 2012

TABLE C3-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

NEW MEXICO LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 34 34 34 17 15 14 0 0 0 51 50 48 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 5.08 4.96 4.82 5.89 5.76 5.60 0.00 0.00 0.00 5.34 5.21 5.05 2

Consumptive factor [%] 51% 51% 51% 33% 33% 33% 0% 0% 0% 45% 45% 45%

Demand (Consumptive) 89 87 84 33 30 26 0 0 0 122 117 110

Municipal and Industrial (M&I) Population [thousands] 186 240 333 10 11 12 0 0 0 196 251 345 3

M&I Per Capita Use (Diversion) [gpcd] 198 172 131 191 182 174 0 0 0 198 172 133 4

Consumptive factor[%] 44% 50% 50% 50% 50% 50% 0% 0% 0% 45% 50% 50%

M&I Demand (Consumptive) 18 23 25 1 1 1 0 0 0 19 24 26

Self Served Industrial Demand (Consumptive) 0.10 0.10 0.09 0 0 0 0 0 0 0.10 0.10 0.09 5a, 5b

Demand (Consumptive) 18 23 25 1 1 1 0 0 0 19 24 26

Energy Demand (Consumptive) 40 42 42 0.6 0.6 0.6 0 0 0 41 42 42 6

Minerals Demand (Consumptive) 0 0 0 0.9 0.9 0.9 0 0 0 0.9 0.9 0.9 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 294 387 503 0 0 0 4 15 15 298 402 518 9

Total Hydrologic Basin Demand (Consumptive) 441 539 654 36 33 29 4 15 15 0 0 0 481 586 698

Adjacent Areas

Agricultural Irrigated Acreage [acres] 93 93 93 93 93 93 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.45 5.87 5.16 6.45 5.87 5.16 11

Consumptive factor [%] 33% 33% 33% 33% 33% 33%

Demand (Diversion) 601 548 481 601 548 481

Demand (Consumptive) 196 178 157 196 178 157

Municipal and Industrial (M&I) Population [thousands] 1,277 1,816 2,666 1,277 1,816 2,666 12

M&I Per Capita Use (Diversion)[gpcd] 160 139 128 160 139 128 13

Consumptive factor [%] 40% 40% 40% 40% 40% 40%

M&I Demand (Diversion) 229 282 381 229 282 381

Self Served Industrial Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 14

Demand (Diversion) 229 282 381 229 282 381

Demand (Consumptive) 92 113 152 92 113 152

Energy Demand (Diversion) 0.02 0.02 0.03 0.02 0.02 0.03 15

Minerals Demand (Diversion) 5 5 5 5 5 5 16

Fish, Wildlife, and Recreation Demand (Diversion) 5 5 5 5 5 5 17

Tribal Demand (Diversion) 11 11 11 11 11 11 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 852 851 883 852 851 883

Total Demand in the Study Area 441 539 654 36 33 29 4 15 15 852 851 883 1,333 1,438 1,581

Demand that may be met by Other Supplies 0 0 0 36 33 29 0 0 0 694 727 767 730 759 796 19

Potential Colorado River Demand 441 539 654 0 0 0 4 15 15 157 125 116 603 678 785

Agricultural Colorado River Demand 89 87 84 0 0 0 0 0 0 22 22 22 111 109 106 20

Municipal and Industrial Colorado River Demand 18 23 25 0 0 0 0 0 0 119 87 78 138 110 102

Energy Colorado River Demand 40 42 42 0 0 0 0 0 0 0 0 0 40 42 42

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 5 5 5 5 5 5

Tribal Colorado River Demand 294 387 503 0 0 0 4 15 15 11 11 11 309 413 529

STATE TOTAL

Notes

San Juan Southwest Northwest Adjacent Areas
 Appendix C3 — New Mexico Water Demand

 Scenario Quantification

December 2012 C3-31

Notes

1) No changes from Current Projected.

2) Used 5 percent increase from Current Projected in 2060, no change from Current Projected in 2015, and interpolated for 2035.

3) Based on regional trends, assume 2060 population is 25 percent greater than that of Current Projected. 

4) Assume 3 percent reduction per decade relative to Current Projected.

5a) Used same percentage change as GPCD section for San Juan Area.

5b) Assumed no increase from Current Projected in Southwest Area.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Northwest: Assumed 2060 demand from Current Projected would be reached in 2035 demand and that no new claims are filed. (San Juan: Personal 

communication, Navajo Nation, April 16, 2012.) 

10) No changes from Current Projected.

11) Used 20 percent increase from Current Projected in 2060, no change from Current Projected in 2015, and interpolated for 2035.

12) (BBER, 1993) (BBER, 2008).

13) Assume 3 percent reduction per decade relative to Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) San Juan Chama at full contract amount.

19) No changes from Current Projected.

20) For Adjacent Area, 25,000 afy of Colorado River Demand is agricultural, per contracts. Assume full tribal is met by Colorado River. Remaining Colorado 

River demand is all M&I. 
Appendix C4 

Utah Water Demand 

Scenario Quantification

December 2012 C4-1 

Appendix C4 — Utah Water Demand 

Scenario Quantification

1.0 Introduction 

This appendix summarizes the data sources used in scenario quantification for Colorado River 

demand1 for the state of Utah and presents the results of quantification. As presented in figure 

C4-1, Utah is divided into a number of planning areas that align with Colorado River Basin 

(Basin) tributaries (Uintah, West Colorado River, Southeast Colorado River, and Kanab 

Creek/Virgin River) as well as adjacent areas that are served by Colorado River water. Data 

collection and development were completed at the planning area level.

The following sections present background information that summarizes the state’s planning 

areas as well as data sources used to quantify demand scenarios by category. Following the 

background section, results of demand scenario quantification are presented. The results section 

is broken out into a Utah Study Area summary, followed by Colorado River demand by 

geography, and finally by category. 

2.0 Background 

The Utah Division of Water Resources (DWR) is responsible for regional and state-level water 

resource planning in Utah. DWR has led numerous water resource planning studies that include 

individual river basins (planning areas) as well as state-wide efforts. Information presented in 

this summary was largely obtained from DWR’s planning studies. 

DWR coordinated Utah’s efforts to provide information for scenario quantification. These efforts 

largely relied on information previously generated through regional plans and demographic 

studies. However, new assumptions and/or data development were required where the 

assumptions of the Colorado River Basin Water Supply and Demand Study (Study) required 

information not developed as part of the regional planning effort. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources include state, regional, and national agency reports. 

• Agricultural Demand: Irrigated acreage and agricultural applied water use were derived 

from Utah’s Water Resources Planning for the Future (DWR, 2001a). Consumptive 

demand is derived from Colorado River Simulation System (CRSS). 

 

1 Colorado River demand as computed by Study Area demand minus other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C4-2 December 2012

FIGURE C4-1 

Colorado River Hydrologic Basin and Export Service Areas in Utah
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-3 

• Municipal and Industrial (M&I): Population estimates for all planning areas 

were derived from the Governor’s Office of Planning and Budget’s 2008 baseline 

projections. For all planning areas, per capita usage was derived from Colorado 

River demands, population, and consumptive use factors derived from State of 

Utah Municipal and Industrial Water Supply and Use Studies, Summary 2005

(DWR, 2009). 

Consumptive demands for hydrologic basin planning areas, except Kanab Creek/Virgin 

River, were derived from CRSS, whereas Kanab Creek/Virgin River consumptive 

demands were derived from the State Water Plan (DWR, 2001b.). For Wasatch Front, 

diversion demands are derived from Utah’s Water Resources Planning for the Future

(DWR, 2001a). 

• Energy: Energy demands were derived from the 2007 Upper Colorado River 

Commission demand schedule. 

• Minerals: Minerals demands were derived from the 2007 Upper Colorado River 

Commission demand schedule. 

• Fish, Wildlife, and Recreation: Fish, wildlife, and recreation demands were derived 

from the 2007 Upper Colorado River Commission demand schedule. 

• Tribal: Tribal demands were provided by the Ute Indian Tribe of the Uintah and 

Ouray Reservation and the Navajo Nation. 

3.0 Results of Water Demand Scenario Quantification

This section summarizes Utah’s Colorado River water demand trends by category across the 

initial scenarios. The purpose of this section is to describe changes in demands, both temporally 

and geographically, parameters that influence changes in demands, and how the parameters and 

demands differ among scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands), independent of the source of supply. However, for areas outside of the 

hydrologic basin, a portion of the Study Area demand is satisfied from other supplies such as 

local groundwater and imports from the Sevier River Basin. The communities within the 

Colorado River Basin also rely on non-tributary groundwater for a portion of their supply. To 

develop estimates of the Colorado River demand, the Study Area demand was reduced by 

estimates of available supply from other sources. This appendix focuses on Colorado River 

demands, but includes discussion of the Study Area parameters that led to these demands. 

Lower Colorado River Basin demands are not included; CRSS would need to be extended and 

natural flow data sets would need to be developed in order to include the Lower Basin tributaries 

in the analysis.

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand, Colorado River Demand for the state and 

individual planning areas across the six scenarios, and presenting Colorado River water demand 

by category across the six scenarios. Parameters and demands for all categories and all scenarios, 

along with references for data sources, are included. 
Colorado River Basin 

Water Supply and Demand Study

C4-4 December 2012

3.1 Summary Results of Scenario Quantification

Values were developed for Study Area parameters to quantify Study Area demand for each of 

the scenarios. Colorado River demand was calculated as Study Area demand minus other 

supplies. Table C4-1 presents summary results for the demand scenarios considered in the Study. 

The table presents agricultural and M&I demand parameters for the entire Study Area that 

distinguishes the scenarios, the resulting Study Area demands, and finally the Colorado River 

demands by category. Because other supplies may vary among scenarios, trends observed in the 

parameters and Study Area demands may not be reflected identically in Colorado River demand 

trends. 

Utah estimates that about 2.4 million people will be in Utah’s Study Area by 2015. This number 

is expected to increase to 3.7 to 6.2 million by 2060. The greatest population growth is 

associated with the Rapid Growth (C1 and C2) scenarios. The Slow Growth (B) scenario has the 

lowest population growth of the scenarios (3.7 million by 2060), but still represents a growth of 

about 55 percent over 2015 estimates. 

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, based solely on passive or existing conservation 

targets, is expected to be 14 to 25 percent less in 2060 than in 2015. Usage rates as well as per 

capita reductions vary across Utah’s planning areas. 

Irrigated acreage is projected to decrease through 2060 under all scenarios. Irrigated acreage 

decreases by between 66,000 acres (Current Projected [A], Slow Growth [B], and Enhanced 

Environment [D1 and D2] scenarios) and 113,000 acres (Rapid Growth [C1 and C2] scenarios), 

or 8 to 13 percent from 2015 irrigated acreage. Water delivery per acre decreases in all scenarios, 

with decreases ranging from less than 1 percent (Slow Growth [B] scenario) to 15 percent (Rapid 

Growth [C2] and Enhanced Environment [D2] scenarios). Water delivery per acre varies across 

planning areas, but reductions in water delivery per acre are consistent across most planning 

areas except the Wasatch Front, which has a greater reduction than the other planning areas. 

Study Area demand for energy is projected to increase under all scenarios due to the growing 

need for electricity generation. The greatest increases in Study Area demand for energy are 

anticipated in the Uintah and West Colorado River planning areas, with a combined increase of 

about 11,500 to 12,500 acre-feet per year (afy) (25 percent) for all scenarios except the Rapid 

Growth (C1) scenario, which has an increase of about 18,500 afy (40 percent). 

There is no reported projected Study Area demand for minerals under the scenarios considered in 

the Study. 

Study Area demand for tribal use is projected to remain constant in the Current Project (A) and 

Enhanced Environment (D1) scenarios and increases under the remaining scenarios. Under Slow 

Rapid Growth (C1 and C2) and Enhanced Environment (D2) scenarios, demand increases by 24 

percent. In the Slow Growth (B) scenario, tribal Study Area demand is projected to increase by 

52 percent. 

Figure C4-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, 

and 3) change in Colorado River demand by demand category. 
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-5 

TABLE C4-1 

Summary Results of Utah Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

20151 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 2.4 4.9 3.7 6.2 6.2 4.9 6.2

Change in per capita water usage (%), 

from 2015 — –14% –14% –14% –21% –23% –25%

Irrigated acreage (millions of acres) 0.86 0.80 0.80 0.75 0.75 0.80 0.80

Change in per acre water delivery (%), 

from 2015 — –3% –0% –3% –15% –3% –15%

Study Area Demand (thousand acre-feet [kaf])

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 2,040 1,760 1,822 1,654 1,396 1,760 1,486

M&I demand 790 1,382 1,036 1,727 1,514 1,154 1,405

Energy demand 47 60 60 66 59 54 59

Minerals demand 0 0 0 0 0 0 0

FWR demand 0 0 0 0 0 0 0

Tribal demand2 170–272 259 259 337 337 259 337

Total Study Area Demand3 3,136 3,460 3,176 3,784 3,307 3,226 3,287

Colorado River Demand (kaf)

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 457 493 492 466 442 492 469

M&I demand 236 342 274 409 384 304 347

Energy demand 47 60 60 66 59 54 59

Minerals demand 0 0 0 0 0 0 0

FWR demand 0 0 0 0 0 0 0

Tribal demand2 170–272 259 259 337 337 259 337

Total Colorado River Demand3 911–1012 1,154 1,084 1,277 1,222 1,109 1,212

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 The diversion and depletion associated with the demand for the Ute Indian Tribe of the Uintah and Ouray Reservation is

dependent upon the re-ratification of the Revised Ute Indian Compact of 1990 by the Tribe and the state of Utah. 3 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to 

state. 

From panel one it can be seen that Study Area demand increases from about 3.0 million acre-feet 

(maf) in 2015 to between 3.2 and 3.8 maf in 2060. The range in Study Area demand growth 

across scenarios in 2060, however, is projected to be as low as 129 kaf or as high as 634 kaf. 

About 63 to 67 percent of the Study Area demand is expected to be met by other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C4-6 December 2012

FIGURE C4-2 

Study Area, Colorado River, and Change in Colorado River Demand 

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

Thousand Acre-Feet per Year

Study Area Demand in Utah 

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white 

and colored border

800

900

1,000

1,100

1,200

1,300

1,400

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in Utah

-50

0

50

100

150

200

250

300

Thousand Acre-Feet per Year

Change in Colorado River Demand in Utah, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-7 

Panel two provides a view of the range across scenarios of Colorado River demand. Colorado 

River demand is calculated as Study Area demand minus other supplies. The Study and the 

results in this section focus on the resulting Colorado River demand. Colorado River demand2

increases from 911 kaf in 2015 to between 1,084 and 1,277 kaf in 2060 (or 19 to 26 percent), 

depending on the scenario. This difference results in a Colorado River demand range of about 

193 kaf across the scenarios in 2060 or about 18 percent. 

Panel three shows how specific categories affect the projected change in Colorado River demand 

by scenario. Growth in M&I and tribal demands results in the greatest increase in demand. 

Figure C4-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The 193 kaf range across scenarios in 2060 is easily discernible, with a relatively even 

spread over the range across the scenarios. In addition, it appears that the quantified scenarios 

track well with the peaks in historical uses that likely represent the least supply-limited 

conditions or actual demand. 

FIGURE C4-3 

Historical Use and Future Projected Demand Excluding Reservoir Evaporation1 

1

Reservoir evaporation on the order of 190 kaf is not included in this plot. 

 

2 Losses to reservoir evaporation are not part of this total. 

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Apportionment
Colorado River Basin 

Water Supply and Demand Study

C4-8 December 2012

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in figures C4-4 

and C4-5. These figures show two geographic levels: Study Area in Utah, and individual planning 

areas. Demands at each geographic level are shown across the scenarios. The columns to the right 

show the Colorado River demand at a point in time (2015, 2035, or 2060) by relative contribution 

of the categories. 

When demands by category are examined in figure C4-5, the mix of demand categories in the 

hydrologic basin and adjacent areas are different, with agricultural and tribal demand dominating 

the hydrologic basin and M&I demand dominating the adjacent areas.

Figure C4-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. The change in both magnitude and percentage change of Colorado River demand3 in 

Utah varies considerably across the planning area. The Uintah Basin shows the greatest magnitude,

rate, and variability of overall growth in Colorado River demand from 2015 to 2060 across the 

scenarios, with between 2 and 115 kaf making up between 1 and 66 percent of the total growth in 

Utah. This growth comes primarily from tribal demands, and is partially offset in some scenarios 

by a decrease in agricultural demands. Demands for the Kanab Creek/Virgin River planning area 

are projected to grow by 74 kaf across all scenarios, with the growth primarily coming from 

increased population. Demands for the Wasatch Front, which are primarily M&I, have variable 

changes through time, ranging from a decrease of about 33 kaf (Slow Growth [B] scenario) to an 

increase of about 90 kaf (Rapid Growth [C1] scenario), while Study Area M&I demand increases 

across all scenarios in the Wasatch Front (the portion that is Colorado River demand decreases in 

some scenarios due to changing assumptions of other supplies). 

3.3 Colorado River Demand by Category

3.3.1 Agricultural

Agricultural water demand is driven by irrigated acreage and water delivery per acre. Water 

delivery per acre is the amount of water diverted per irrigated acre. Components of this use 

include transmission and delivery losses (surface evaporation, riparian demand, and seepage), 

and on-farm losses that are made up of evaporation, crop irrigation requirements, and tail water 

(return). Each of these factors will vary by location (precipitation, growing season, etc.), 

irrigation method, and crop type. 

Figure C4-7 presents the following by scenario in 2015, 2035, and 2060: 

• Change in agricultural demand for Colorado River water 

• Change in agricultural demand for Colorado River water by planning area 

• Agricultural demand as a portion of Colorado River water demand (right hand side 

of graph) 

 

3 Potential Colorado River demand is based on changes in parameters such as population, and for the purpose of the Study, is not 

 limited by apportionment. 
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-9 

FIGURE C4-4 

Colorado River Demand in Utah
Colorado River Basin 

Water Supply and Demand Study

C4-10 December 2012

FIGURE C4-5 

Colorado River Demand by Category
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-11

FIGURE C4-6 

Change in Colorado River Demand in Utah from 2015 by Category
Colorado River Basin 

Water Supply and Demand Study

C4-12 December 2012

FIGURE C4-7 

Change in Colorado River Demand in Utah from 2015 for Agriculture

-40

-20

0

20

40

2015 2035 2060

KAF

Wasatch Front

-40

-20

0

20

40

2015 2035 2060

KAF

Kanab Creek / Virgin 

River

-40

-20

0

20

40

2015 2035 2060

KAF

West Colorado River

-40

-20

0

20

40

2015 2035 2060

KAF

Southeast Colorado 

River

-40

-20

0

20

40

2015 2035 2060

KAF

Uintah Basin

201520352060

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

-30

-20

-10

0

10

20

30

40

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Utah, from 2015

Agricultural

Agriculture is 45 - 50% of Colorado River demand*

Agriculture is 39 - 44% of Colorado River demand*

Agriculture is 36 - 45% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios

N/A
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-13

As can be seen from figure C4-7, agricultural water demand is the largest component of 

Colorado River demand in Utah, dropping from about 50 percent in 2015 to between 36 and 

45 percent of demand in 2060, depending on which scenario is considered. This drop results 

primarily from an increase in other categories of demand; agricultural demand increases or 

remains the same in all scenarios except the Rapid Growth (C2) scenario, in which it decreases. 

For all scenarios, agricultural demand generally increases through time in Uintah and Southeast 

Colorado River planning areas. Agricultural demand increases or decreases depending on the 

scenario in the Wasatch Front and West Colorado River planning areas. 

The drivers for change in agricultural demand vary across planning areas. Across all scenarios 

and all planning areas, irrigated acreage is forecast to decrease through time by varying amounts. 

In the Southeast Basin, the decrease in irrigated acreage is offset by an increase in applied water 

use, resulting in demand increasing through time across all scenarios. In the Uintah Basin, 

irrigated acreage increases by varying amounts across the scenarios. Increases in agricultural 

demand occur in the Current Projected (A), Slow Growth (B), Rapid Growth (C1), and Enhanced 

Environment (D1 and D2) scenarios due to increases in water delivery per acre. Decreased 

demand occurs in the Rapid Growth (C2) scenario where both irrigated acreage and water 

delivery per acre decrease. 

A strong driver for loss of agricultural acreage is urbanization, leading to physical loss of acreage 

and market pressure for transfer of water rights. Increases in water delivery per acre are due to 

better delivery mechanisms or storage, allowing for more use of water on the same acreage in a 

given growing season. 

3.3.2 Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita water use; there is no 

self-served industrial demand in Utah in the scenarios examined. M&I per capita water use is a 

measure of the amount of water produced or diverted per person in a given municipality. 

Because this measure examines all water produced by a given municipality, it often includes 

industrial, commercial, and institutional demand as well as residential demand. A number of 

factors may influence the M&I per capita water use of a given community, including the amount 

of industrial demand, climate, number of institutional facilities, and number of visitors. 

Figure C4-8 presents the following by scenario in 2015, 2035, and 2060: 

• Change in M&I demand for Colorado River water in the Study Area 

• Change in M&I demand for Colorado River water in individual planning areas 

• M&I demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C4-8, M&I water demand is the second largest component of 

Colorado River demand, changing from 26 percent in 2015 to between 25 and 32 percent of 

Colorado River demand in 2060, depending on which scenario is considered.

Colorado River demand for M&I use increases over time from 2015 to 2060 across all scenarios. 

The increase is primarily due to population increase as M&I per capita water use decreases over 

time across all scenarios. 
Colorado River Basin 

Water Supply and Demand Study

C4-14 December 2012

FIGURE C4-8 

Change in Colorado River Demand in Utah from 2015 for M&I 

-50

0

50

100

2015 2035 2060

KAF

Southeast Colorado 

River

-50

0

50

100

2015 2035 2060

KAF

West Colorado River

-50

0

50

100

2015 2035 2060

KAF

Uintah Basin

-50

0

50

100

2015 2035 2060

KAF

Kanab Creek / Virgin 

River

-50

0

50

100

2015 2035 2060

KAF

Wasatch Front

201520352060

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

20

40

60

80

100

120

140

160

180

200

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Utah, from 2015

Municipal and Industrial

M&I is 23 - 26% of Colorado River demand*

M&I is 27 - 30% of Colorado River demand*

M&I is 25 - 32% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-15

In examining the planning areas, the Kanab Creek/Virgin River and Wasatch Front planning 

areas make up the majority of increase in M&I demand for Colorado River water from 2015 to 

2060. In the Kanab Creek/Virgin River planning area, the increase is relatively consistent across 

scenarios, and is primarily the result of increasing population. In the Wasatch Front planning 

area, population increases across all scenarios, but changes in assumptions of other supplies 

results in variable increases, and in some scenarios a decrease, in Colorado River demand. 

Increases in population are somewhat tempered by decreases in M&I per capita water use in all 

scenarios, with reductions ranging from 14 to 25 percent by 2060. 

3.3.3 Energy

Water demand for energy can be estimated through known plans for new power plants or 

through applying a per capita energy water use factor. Power facilities often serve areas remote 

from their locations and therefore potentially represent exports or imports of water from the 

Study Area to meet these distributed needs. 

Figure C4-9 presents the following by scenario in 2015, 2035, and 2060: 

• Change in energy demand for Colorado River water 

• Change in energy demand for Colorado River water in individual planning areas 

• Energy demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C4-9, energy water demand is a relatively small fraction of Colorado 

River demand, making up about 5 percent of Colorado River demand through time, depending 

on which scenario is considered. 

Energy demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios, with the greatest increase in the Rapid Growth (C1) scenario. 

Energy demands are shown in the Uintah and West Colorado River planning areas. The Uintah 

Basin shows relatively consistent increases through time across scenarios of about 8 kaf. The 

West Colorado River planning area shows increases through time of 4 kaf for all scenarios 

except the Rapid Growth (C2) scenario, which shows an increase through time of 9 kaf. 

3.3.4 Minerals Extraction

Minerals extraction is included in Utah’s estimate of M&I demand discussed above. Utah’s State 

Water Plan (DWR, 2001b), suggests that about 1,000 afy of the M&I demand is for minerals 

extraction.

3.3.5 Fish, Wildlife, and Recreation

There are no reported consumptive fish, wildlife, and recreation demands on Colorado River 

water in Utah under the scenarios analyzed for the Study. 

3.3.6 Tribal

Tribal water demands were provided by the Ute Indian Tribe of the Uintah and Ouray 

Reservation and the Navajo Nation. The projected Navajo Nation demands were provided by the 

Navajo Nation Department of Water Resources and modified to fit the storyline narratives 

regarding tribal use under each scenario. 
Colorado River Basin 

Water Supply and Demand Study

C4-16 December 2012

FIGURE C4-9 

Change in Colorado River Demand in Utah from 2015 for Energy

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Uintah Basin

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

West Colorado River

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Wasatch Front

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Kanab Creek / Virgin 

River

201520352060

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Southeast Colorado 

River

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

2

4

6

8

10

12

14

16

18

20

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Utah, from 2015

Energy

Energy is 5% of Colorado River demand*

Energy is 5% of Colorado River demand*

Energy is 5% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

No 

Change N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Appendix C4 — Utah Water Demand

Scenario Quantification

December 2012 C4-17

Figure C4-10 presents the following by scenario in 2015, 2035, and 2060: 

• Change in tribal demand for Colorado River water 

• Change in tribal demand for Colorado River water in individual planning area 

• Tribal demand as a portion of Colorado River demand (right hand side of graph) 

As can be seen from figure C4-10, tribal water demand slightly decreases as a component 

of Colorado River demand in Utah, from 27 percent in 2015 to between 22 and 28 percent of 

Colorado River demand in 2060, depending on which scenario is considered. 

Colorado River tribal demand occurs in the Uintah Basin and Southeast Colorado River planning 

areas, and increases over time from 2015 to 2060 across all scenarios. 

For additional information on tribal demands, see appendix C9. 

3.4 Summary Tables of Parameters and Demands by Category

Tables C4-2 to C4-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 

4.0 References

Utah Department of Natural Resources, Division of Water Resources (DWR). 2001a. Utah’s 

Water Resources Planning for the Future. 

Utah Department of Natural Resources, Division of Water Resources (DWR). 2001b. State 

Water Plan. 

Utah Department of Natural Resources, Division of Water Resources (DWR). 2009. State of 

Utah Municipal and Industrial Water Supply and Use Studies, Summary 2005. 
Colorado River Basin 

Water Supply and Demand Study

C4-18 December 2012

FIGURE C4-10

Change in Colorado River Demand in Utah from 2015 for Tribal

0

50

100

150

2015 2035 2060

KAF

Uintah Basin

0

50

100

150

2015 2035 2060

KAF

West Colorado River

0

50

100

150

2015 2035 2060

KAF

Wasatch Front

0

50

100

150

2015 2035 2060

KAF

Kanab Creek / Virgin 

River

201520352060

0

50

100

150

2015 2035 2060

KAF

Southeast Colorado 

River

AA

B

B

C1

C1

C2

C2

D1D1

D2

D2

0

10

20

30

40

50

60

70

80

90

100

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Utah, from 2015

Tribal

Tribal is 19 - 27% of Colorado River demand*Tribal is 23 - 27% of Colorado River demand*Tribal is 22 - 28% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

N/A

*Percentages shown 

represent the range 

across scenarios

Colorado River Basin 

Water Supply and Demand Study

C4-20 December 2012

TABLE C4-2 

Total Demand within Study Area under Current Projected (A) Scenario

LEGEND: 999 From States 999 From State Plans

Units are thousand acre feed per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 198 197 197 19 18 18 83 83 83 19 18 15 319 317 312 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.90 2.82 3.12 2.93 3.61 4.20 3.27 3.41 3.42 4.56 4.36 4.55 3.10 3.10 3.33

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 2

Demand (Consumptive) 287 278 307 27 33 38 137 142 142 43 39 33 494 491 520 3

Municipal and Industrial (M&I) Population [thousands] 53 69 89 27 32 38 42 48 55 260 511 825 382 660 1,007 4

M&I Per Capita Use (Diversion) [gpcd] 308 265 220 337 315 284 250 229 201 284 240 223 287 246 224 5

Consumptive factor [%] 73% 73% 73% 56% 56% 56% 69% 69% 69% 44% 44% 44% 52% 50% 48% 6

M&I Demand (Consumptive) 13 15 16 6 6 7 8 8 9 36 60 91 64 90 122 7, 8

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Demand (Consumptive) 13 15 16 6 6 7 8 8 9 36 60 91 64 90 122 8

Energy Demand (Consumptive) 0 0.3 8 2 2 2 45 50 49 0 0 0 47 53 60 9

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11

Tribal Demand (Consumptive) 259 259 259 0 0 0 0 0 0 0 0 0 259 259 259 12

Total Hydrologic Basin Demand (Consumptive) 560 552 590 35 42 47 189 200 199 79 99 124 864 893 960

Adjacent Areas

Agricultural Irrigated Acreage [thousands] 543 514 484 543 514 484 13

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.85 2.62 2.56 2.85 2.62 2.56

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 2

Demand (Diversion) 1,547 1,349 1,240 1,547 1,349 1,240 14

Demand (Consumptive) 773 675 620 773 675 620

Municipal and Industrial (M&I) Population [thousands] 2,006 2,837 3,941 2,006 2,837 3,941 15

M&I Per Capita Use (Diversion) [gpcd] 323 303 285 323 303 285 16

Consumptive factor [%] 59% 59% 59% 59% 59% 59% 17

M&I Demand (Diversion) 726 963 1,260 726 963 1,260

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0

Demand (Diversion) 726 963 1,260 726 963 1,260

Demand (Consumptive) 428 568 743 428 568 743 18

Energy Demand (Diversion) 0 0 0 0 0 0

Minerals Demand (Diversion) 0 0 0 0 0 0

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0

Tribal Demand (Diversion) 0 0 0 0 0 0

Total Adjacent Areas Demand (Diversion) 2,273 2,312 2,499 2,273 2,312 2,499

Total Demand in the Study Area 560 552 590 35 42 47 189 200 199 79 99 124 2,273 2,312 2,499 3,136 3,206 3,460 19

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 79 42 50 2,058 2,082 2,257 2,137 2,124 2,306 20

Potential Colorado River Demand 560 552 590 35 42 47 189 200 199 0 57 74 215 230 243 999 1,082 1,154 21

Agricultural Colorado River Demand 287 278 307 27 33 38 137 142 142 0 0 0 6 6 6 457 459 493 22

Municipal and Industrial Colorado River Demand 13 15 16 6 6 7 8 8 9 0 57 74 209 224 237 236 311 342

Energy Colorado River Demand 0 0.3 8 2 2 2 45 50 49 0 0 0 0 0 0 47 53 60

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 259 259 259 0 0 0 0 0 0 0 0 0 0 0 0 259 259 259

Notes

Uintah Basin Southeast Colorado River West Colorado River Kanab Creek / Virgin River Wasatch Front STATE TOTAL
 Appendix C4 — Utah Water Demand 

 Scenario Quantification

December 2012 C4-21

Notes

1) No changes from Current Projected.

2) No changes from Current Projected per the regional trends matrix.

3) A 25 percent population decrease from Current Projected by 2060 was estimated based on regional trends (per census data).

4) No changes from Current Projected.

5) No changes from Current Projected.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) CRSS Demand Input Tool (DIT), 2011. Water users were delineated into UT basin planning areas based on location relative to CRSS nodes in DIT to 

obtain depletions. Demands based on Upper Colorado River Commission schedule dated 1/11/08. 

10) No changes from Current Projected.

11) A two percent increase in 2035 and a five percent increase in 2060 from Current Projected was used per the regional trends matrix.

12) A 25 percent population decrease from Current Projected by 2060 was estimated based on regional trends (per census data).

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Assume other sources are unchanged from Current Projected.

20) For Kanab/Virgin, all potential Colorado River demand is M&I (Lake Powell pipeline). For Wasatch Front, all Potential Colorado River Demand is M&I, 

except for one agricultural export. M&I is computed as total export minus agricultural user schedule.
Colorado River Basin 

Water Supply and Demand Study

C4-22 December 2012

TABLE C4-3 

Total Demand within Study Area under Slow Growth (B) Scenario

UTAH LEGEND: 999 Input Parameter 999 From Current Projected Data Sheet

Units are thousand acre-feet per year, unless otherwise noted 999 Computed

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 198 197 197 19 18 18 83 83 83 19 18 15 319 317 312 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.90 2.82 3.12 2.93 3.61 4.20 3.27 3.41 3.42 4.56 4.36 4.55 3.10 3.10 3.33 2

Consumptive Factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

Demand (Consumptive) 287 278 307 27 33 38 137 142 142 43 39 33 494 491 520

Municipal and Industrial (M&I) Population [thousands] 53 61 67 27 28 29 42 42 41 260 450 619 382 581 755 3

M&I Per Capita Use (Diversion) [gpcd] 308 265 220 337 315 284 250 229 201 284 240 223 287 246 224 4

Consumptive factor [%] 73% 73% 73% 56% 56% 56% 69% 69% 69% 44% 44% 44% 52% 50% 48%

M&I Demand (Consumptive) 13 13 12 6 6 5 8 7 6 36 53 68 64 79 91

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 13 13 12 6 6 5 8 7 6 36 53 68 64 79 91

Energy Demand (Consumptive) 0 0 8 2 2 2 45 50 49 0 0 0 47 53 60 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 170 241 259 0 0 0 0 0 0 0 0 0 170 241 259 9

Total Hydrologic Basin Demand (Consumptive) 471 533 586 35 41 45 189 199 197 79 92 101 0 0 0 775 865 930

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 543 514 484 543 514 484 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.85 2.68 2.69 2.85 2.68 2.69 11

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

Demand (Diversion) 1,547 1,376 1,302 1,547 1,376 1,302

Demand (Consumptive) 773 688 651 773 688 651

Municipal and Industrial (M&I) Population [thousands] 2,006 2,497 2,955 2,006 2,497 2,955 12

M&I Per Capita Use (Diversion) [gpcd] 323 303 285 323 303 285 13

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Diversion) 726 848 945 726 848 945

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 726 848 945 726 848 945

Demand (Consumptive) 428 500 557 428 500 557

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 2,273 2,224 2,246 2,273 2,224 2,246

Total Demand in the Study Area 471 533 586 35 41 45 189 199 197 79 92 101 2,273 2,224 2,246 3,048 3,089 3,176

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 79 35 27 2,058 2,021 2,065 2,137 2,056 2,092 19

Potential Colorado River Demand 471 533 586 35 41 45 189 199 197 0 57 74 215 203 181 911 1,033 1,084

Agricultural Colorado River Demand 287 278 307 27 33 38 137 142 142 0 0 0 6 6 5 457 458 492 20

Municipal and Industrial Colorado River Demand 13 13 12 6 6 5 8 7 6 0 57 74 209 197 177 236 280 274

Energy Colorado River Demand 0 0 8 2 2 2 45 50 49 0 0 0 0 0 0 47 53 60

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 170 241 259 0 0 0 0 0 0 0 0 0 0 0 0 170 241 259

Notes

Uintah Basin Southeast Colorado River West Colorado River Kanab Creek / Virgin River Wasatch Front STATE TOTAL
 Appendix C4 — Utah Water Demand 

 Scenario Quantification

December 2012 C4-23

Notes

1) No changes from Current Projected.

2) No changes from Current Projected per the regional trends matrix.

3) A 25 percent population decrease from Current Projected by 2060 was estimated based on regional trends (per census data).

4) No changes from Current Projected.

5) No changes from Current Projected.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) CRSS DIT, 2011. Water users were delineated into UT basin planning areas based on location relative to CRSS nodes in DIT to obtain depletions. 

Demands based on Upper Colorado River Commission schedule dated 1/11/08. 

10) No changes from Current Projected.

11) A 2 percent increase in 2035 and a 5 percent increase in 2060 from Current Projected was used per the regional trends matrix.

12) A 25 percent population decrease from Current Projected by 2060 was estimated based on regional trends (per census data).

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Assume other sources are unchanged from Current Projected.

20) For Kanab/Virgin, all potential Colorado River demand is M&I (Lake Powell pipeline). For Wasatch Front, all potential Colorado River demand is M&I, 

except for one agricultural export. M&I is computed as total export minus agricultural user schedule.
Colorado River Basin 

Water Supply and Demand Study

C4-24 December 2012

TABLE C4-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

UTAH LEGEND: 999 Input Parameter 999 From Current Projected Data Sheet

Units are thousand acre-feet per year, unless otherwise noted 999 Computed

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 198 191 185 19 18 17 83 81 78 19 17 14 319 307 293 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.90 2.82 3.12 2.93 3.61 4.20 3.27 3.41 3.42 4.56 4.36 4.55 3.10 3.10 3.33 2

Consumptive Factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

Demand (Consumptive) 287 270 289 27 32 36 137 137 133 43 37 31 494 477 489

Municipal and Industrial (M&I) Population [thousands] 53 77 111 27 36 48 42 53 68 260 572 1,031 382 739 1,258 3

M&I Per Capita Use (Diversion) [gpcd] 308 265 220 337 315 284 250 229 201 284 240 223 287 246 224 4

Consumptive factor [%] 73% 73% 73% 56% 56% 56% 69% 69% 69% 44% 44% 44% 52% 50% 48%

M&I Demand (Consumptive) 13 17 20 6 7 9 8 9 11 36 68 113 64 101 152

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 13 17 20 6 7 9 8 9 11 36 68 113 64 101 152

Energy Demand (Consumptive) 0 0 9 2 2 2 45 53 54 0 0 0 47 55 66 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 259 259 259 13 40 78 0 0 0 0 0 0 272 299 337 9

Total Hydrologic Basin Demand (Consumptive) 560 546 577 48 82 125 189 199 198 79 105 144 0 0 0 877 932 1,044

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 543 499 455 543 499 455 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.85 2.62 2.56 2.85 2.62 2.56 11

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

Demand (Diversion) 1,547 1,309 1,165 1,547 1,309 1,165

Demand (Consumptive) 773 654 583 773 654 583

Municipal and Industrial (M&I) Population [thousands] 2,006 3,178 4,926 2,006 3,178 4,926 12

M&I Per Capita Use (Diversion) [gpcd] 323 303 285 323 303 285 13

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Diversion) 726 1,079 1,575 726 1,079 1,575

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 726 1,079 1,575 726 1,079 1,575

Demand (Consumptive) 428 637 929 428 637 929

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 2,273 2,388 2,740 2,273 2,388 2,740

Total Demand in the Study Area 560 546 577 48 82 125 189 199 198 79 105 144 2,273 2,388 2,740 3,149 3,319 3,784

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 79 48 70 2,058 2,130 2,436 2,137 2,178 2,506 19

Potential Colorado River Demand 560 546 577 48 82 125 189 199 198 0 57 74 215 258 304 1,012 1,141 1,277

Agricultural Colorado River Demand 287 270 289 27 32 36 137 137 133 0 0 0 6 7 8 457 446 466 20

Municipal and Industrial Colorado River Demand 13 17 20 6 7 9 8 9 11 0 57 74 209 250 296 236 341 409

Energy Colorado River Demand 0 0 9 2 2 2 45 53 54 0 0 0 0 0 0 47 55 66

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 259 259 259 13 40 78 0 0 0 0 0 0 0 0 0 272 299 337

Notes

Uintah Basin Southeast Colorado River West Colorado River Kanab Creek / Virgin River Wasatch Front STATE TOTAL
 Appendix C4 — Utah Water Demand 

 Scenario Quantification

December 2012 C4-25

Notes

1) Estimates are within regional trends range, but less than twice the passive, Current Projected, rate.

2) No changes from Current Projected.

3) A 25 percent population increase from Current Projected by 2060 was estimated based on regional trends (per census data).

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Assume 10 percent increase relative to Current Projected by 2060. Increased demand is not offset by new technology.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Uintah: No changes from Current Projected; Southeast Colorado: personal communication, Navajo Nation, Apr. 16, 2012.

10) Estimates are within regional trends range, but less than twice the passive, Current Projected, rate.

11) No changes from Current Projected.

12) A 25 percent population increase from Current Projected by 2060 was estimated based on regional trends (per census data).

13) No changes from Current Projected.

14) No changes from Current Projected.

15) Assume 10 percent increased demand from Current Projected by 2060 is not offset by new technology.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Assume other sources are unchanged from Current Projected.

20) For Kanab/Virgin, all potential Colorado River demand is M&I (Lake Powell pipeline). For Wasatch Front, all potential Colorado River demand is M&I, 

except for one agricultural export. M&I is computed as total export minus agricultural user schedule.
Colorado River Basin 

Water Supply and Demand Study

C4-26 December 2012

TABLE C4-5 

Total Demand within Study Area under Rapid Growth (C2) Scenario

UTAH LEGEND: 999 Input Parameter 999 From Current Projected Data Sheet

Units are thousand acre-feet per year, unless otherwise noted 999 Computed

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 198 191 185 19 18 17 83 81 78 19 17 14 319 307 293 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.90 2.76 2.97 2.93 3.54 3.99 3.27 3.34 3.25 4.56 4.27 4.33 3.10 3.04 3.16 2

Consumptive Factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

Demand (Consumptive) 287 264 274 27 31 34 137 135 127 43 37 29 494 467 464

Municipal and Industrial (M&I) Population [thousands] 53 77 111 27 36 48 42 53 68 260 572 1,031 382 739 1,258 3

M&I Per Capita Use (Diversion) [gpcd] 301 263 220 325 284 258 234 204 186 284 240 223 284 242 222 4

Consumptive factor [%] 73% 73% 73% 56% 56% 56% 69% 69% 69% 44% 44% 44% 52% 50% 48%

M&I Demand (Consumptive) 13 17 20 6 6 8 8 8 10 36 68 113 63 99 151

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 13 17 20 6 6 8 8 8 10 36 68 113 63 99 151

Energy Demand (Consumptive) 0 0 8 2 2 2 45 50 49 0 0 0 47 53 59 6a, 6b

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 259 259 259 13 40 78 0 0 0 0 0 0 272 299 337 9

Total Hydrologic Basin Demand (Consumptive) 559 540 561 48 80 122 189 193 185 79 104 143 0 0 0 876 918 1,011

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 543 499 455 543 499 455 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.85 2.41 2.05 2.85 2.41 2.05 11

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

Demand (Diversion) 1,547 1,204 932 1,547 1,204 932

Demand (Consumptive) 773 602 466 773 602 466

Municipal and Industrial (M&I) Population [thousands] 2,006 3,178 4,926 2,006 3,178 4,926 12

M&I Per Capita Use (Diversion) [gpcd] 311 273 247 311 273 247 13

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Diversion) 699 972 1,364 699 972 1,364

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 699 972 1,364 699 972 1,364

Demand (Consumptive) 413 573 805 413 573 805

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 2,246 2,176 2,296 2,246 2,176 2,296

Total Demand in the Study Area 559 540 561 48 80 122 189 193 185 79 104 143 2,246 2,176 2,296 3,121 3,094 3,307

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 79 47 69 2,031 1,930 2,016 2,110 1,977 2,085 19

Potential Colorado River Demand 559 540 561 48 80 122 189 193 185 0 57 74 215 246 280 1,011 1,116 1,222

Agricultural Colorado River Demand 287 264 274 27 31 34 137 135 127 0 0 0 6 7 7 457 437 442 20

Municipal and Industrial Colorado River Demand 13 17 20 6 6 8 8 8 10 0 57 74 209 239 273 235 328 384

Energy Colorado River Demand 0 0.2 8 2 2 2 45 50 49 0 0 0 0 0 0 47 53 59

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 259 259 259 13 40 78 0 0 0 0 0 0 0 0 0 272 299 337

Notes

Uintah Basin Southeast Colorado River West Colorado River Kanab Creek / Virgin River Wasatch Front STATE TOTAL
 Appendix C4 — Utah Water Demand

 Scenario Quantification

December 2012 C4-27

Notes

1) Estimates are within regional trends range, but less than twice the passive, Current Projected rate.

2) Five percent decrease from Current Projected by 2060 based on regional trends matrix.

3) A 25 percent population increase from Current Projected by 2060 was estimated based on regional trends (per census data).

4) Assume 12.5 percent reduction in 2020 and 25 percent reduction by 2050 (relative to actual 2011 use) and stable trends after 2050.

5) No changes from Current Projected.

6a) Uintah Basin: Assume 10 percent decreased demand from Current Projected by 2060 due to new technology.

6b) Assume increased demand from Current Projected is offset by new technology in the Southeast Colorado River and West Colorado River planning 

areas.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Uintah: No changes from Current Projected; Southeast Colorado: personal communication, Navajo Nation, Apr. 16, 2012.

10) Estimates are within regional trends range, but less than twice the passive, Current Projected rate.

11) Twenty percent decrease from Current Projected by 2060 based on regional trends matrix.

12) A 25 percent population increase from Current Projected by 2060 was estimated based on regional trends (per census data).

13) Assume 12.5 percent reduction in 2020 and 25 percent reduction by 2050 (relative to actual 2011 use) and stable trends after 2050.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Assume other sources are unchanged from Current Projected.

20) For Kanab/Virgin, all potential Colorado River demand is M&I (Lake Powell pipeline). For Wasatch Front, all potential Colorado River demand is M&I, 

except for one agricultural export. M&I is computed as total export minus agricultural user schedule.
Colorado River Basin 

Water Supply and Demand Study

C4-28 December 2012

TABLE C4-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

UTAH LEGEND: 999 Input Parameter 999 From Current Projected Data Sheet

Units are thousand acre-feet per year, unless otherwise noted 999 Computed

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 198 197 197 19 18 18 83 83 83 19 18 15 319 317 312 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.90 2.82 3.12 2.93 3.61 4.20 3.27 3.41 3.42 4.56 4.36 4.55 3.10 3.10 3.33 2

Consumptive Factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

Demand (Consumptive) 287 278 307 27 33 38 137 142 142 43 39 33 494 491 520

Municipal and Industrial (M&I) Population [thousands] 53 69 89 27 32 38 42 48 55 260 511 825 382 660 1,007 3

M&I Per Capita Use (Diversion) [gpcd] 293 239 220 316 258 245 227 185 176 281 229 217 279 228 216 4

Consumptive factor [%] 73% 73% 73% 56% 56% 56% 69% 69% 69% 44% 44% 44% 51% 49% 48%

M&I Demand (Consumptive) 13 14 16 5 5 6 7 7 7 36 58 88 61 83 118

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 13 14 16 5 5 6 7 7 7 36 58 88 61 83 118

Energy Demand (Consumptive) 0 0 8 2 2 2 45 47 44 0 0 0 47 50 54 6a, 6b

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 259 259 259 0 0 0 0 0 0 0 0 0 259 259 259 9

Total Hydrologic Basin Demand (Consumptive) 559 551 590 35 40 46 189 196 193 79 96 121 0 0 0 861 883 950

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 543 514 484 543 514 484 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.85 2.62 2.56 2.85 2.62 2.56 11

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

Demand (Diversion) 1,547 1,349 1,240 1,547 1,349 1,240

Demand (Consumptive) 773 675 620 773 675 620

Municipal and Industrial (M&I) Population [thousands] 2,006 2,837 3,941 2,006 2,837 3,941 12

M&I Per Capita Use (Diversion) [gpcd] 303 247 235 303 247 235 13

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Diversion) 681 785 1,037 681 785 1,037

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 681 785 1,037 681 785 1,037

Demand (Consumptive) 402 463 612 402 463 612

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 2,228 2,134 2,276 2,228 2,134 2,276

Total Demand in the Study Area 559 551 590 35 40 46 189 196 193 79 96 121 2,228 2,134 2,276 3,089 3,017 3,226

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 79 39 47 2,013 1,919 2,070 2,092 1,958 2 19

Potential Colorado River Demand 559 551 590 35 40 46 189 196 193 0 57 74 215 215 206 997 1,059 1,109

Agricultural Colorado River Demand 287 278 307 27 33 38 137 142 142 0 0 0 6 6 5 457 459 492 20

Municipal and Industrial Colorado River Demand 13 14 16 5 5 6 7 7 7 0 57 74 209 209 201 234 292 304

Energy Colorado River Demand 0 0.2 8 2 2 2 45 47 44 0 0 0 0 0 0 47 50 54

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 259 259 259 0 0 0 0 0 0 0 0 0 0 0 0 259 259 259

Notes

Uintah Basin Southeast Colorado River West Colorado River Kanab Creek / Virgin River Wasatch Front STATE TOTAL
 Appendix C4 — Utah Water Demand

 Scenario Quantification

December 2012 C4-29

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) Assume 16 percent reduction in 2020 and 25 percent reduction by 2035 (relative to actual 2011 use) and two percent reduction per decade after 2035.

5) No changes from Current Projected.

6a) Uintah Basin: Assume 10 percent decreased demand from Current Projected by 2060 due to new technology.

6b) Assume increased demand from Current Projected is offset by new technology in the Southeast Colorado River and West Colorado River planning 

areas.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) Twenty percent decrease from Current Projected by 2060 based on regional trends matrix.

12) No changes from Current Projected.

13) Assume 16 percent reduction in 2020 and 25 percent reduction by 2035 (relative to actual 2011 use) and 2 percent reduction per decade after 2035.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Assume other sources are unchanged from Current Projected.

20) For Kanab/Virgin, all potential Colorado River demand is M&I (Lake Powell pipeline). For Wasatch Front, all potential Colorado River demand is M&I, 

except for one agricultural export. M&I is computed as total export minus agricultural user schedule.
Colorado River Basin 

Water Supply and Demand Study

C4-30 December 2012

TABLE C4-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

UTAH LEGEND: 999 Input Parameter 999 From Current Projected Data Sheet

Units are thousand acre-feet per year, unless otherwise noted 999 Computed

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 198 197 197 19 18 18 83 83 83 19 18 15 319 317 312 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.90 2.76 2.97 2.93 3.54 3.99 3.27 3.34 3.25 4.56 4.27 4.33 3.10 3.04 3.16 2

Consumptive Factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

Demand (Consumptive) 287 273 292 27 32 36 137 139 135 43 38 31 494 482 494

Municipal and Industrial (M&I) Population [thousands] 53 77 111 27 36 48 42 53 68 260 572 1,031 382 739 1,258 3

M&I Per Capita Use (Diversion) [gpcd] 293 239 220 316 258 238 227 185 171 281 229 212 279 228 211 4

Consumptive factor [%] 73% 73% 73% 56% 56% 56% 69% 69% 69% 44% 44% 44% 51% 49% 48%

M&I Demand (Consumptive) 13 15 20 5 6 7 7 8 9 36 65 108 61 93 144

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 13 15 20 5 6 7 7 8 9 36 65 108 61 93 144

Energy Demand (Consumptive) 0 0.2 8 2 2 2 45 50 49 0 0 0 47 53 59 6a, 6b

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Tribal Demand (Consumptive) 259 259 259 13 40 78 0 0 0 0 0 0 272 299 337 9 0

Total Hydrologic Basin Demand (Consumptive) 559 547 578 48 80 124 189 197 193 79 102 139 0 0 0 875 926 1,034

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 543 514 484 543 514 484 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.85 2.41 2.05 2.85 2.41 2.05 11

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

Demand (Diversion) 1,547 1,241 992 1,547 1,241 992

Demand (Consumptive) 773 621 496 773 621 496

Municipal and Industrial (M&I) Population [thousands] 2,006 3,178 4,926 2,006 3,178 4,926 12

M&I Per Capita Use (Diversion) [gpcd] 303 247 229 303 247 229 13

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Diversion) 681 879 1,261 681 879 1,261

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 681 879 1,261 681 879 1,261

Demand (Consumptive) 402 519 744 402 519 744

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 2,228 2,120 2,253 2,228 2,120 2,253

Total Demand in the Study Area 559 547 578 48 80 124 189 197 193 79 102 139 2,228 2,120 2,253 3,102 3,047 3,287

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 79 45 65 2,013 1,890 2,010 2,092 1,936 2,075 19

Potential Colorado River Demand 559 547 578 48 80 124 189 197 193 0 57 74 215 230 243 1,010 1,111 1,212

Agricultural Colorado River Demand 287 273 292 27 32 36 137 139 135 0 0 0 6 6 6 457 450 469 20

Municipal and Industrial Colorado River Demand 13 15 20 5 6 7 7 8 9 0 57 74 209 224 237 234 310 347

Energy Colorado River Demand 0 0.2 8 2 2 2 45 50 49 0 0 0 0 0 0 47 53 59

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tribal Colorado River Demand 259 259 259 13 40 78 0 0 0 0 0 0 0 0 0 272 299 337

Notes

Uintah Basin Southeast Colorado River West Colorado River Kanab Creek / Virgin River Wasatch Front STATE TOTAL
 Appendix C4 — Utah Water Demand 

 Scenario Quantification

December 2012 C4-31

Notes

1) No changes from Current Projected.

2) Five percent decrease from Current Projected by 2060 based on regional trends matrix.

3) A 25 percent population increase from Current Projected by 2060 was estimated based on regional trends (per census data).

4) Assume 16 percent reduction in 2020 and 25 percent reduction by 2035 (relative to actual 2011 use) and 3 percent reduction per decade after 2035.

5) No changes from Current Projected.

6a) Uintah Basin: Assume 10 percent decreased demand from Current Projected by 2060 due to new technology.

6b) Assume increased demand from Current Projected is offset by new technology in the Southeast Colorado River and West Colorado River planning 

areas.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) Uintah: No changes from Current Projected; Southeast Colorado: personal communication, Navajo Nation, Apr. 16, 2012.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) A 25 percent population increase from Current Projected by 2060 was estimated based on regional trends (per census data).

13) Assume 16 percent reduction in 2020 and 25 percent reduction by 2035 (relative to actual 2011 use) and 3 percent reduction per decade after 2035.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Assume other sources are unchanged from Current Projected.

20) For Kanab/Virgin, all potential Colorado River demand is M&I (Lake Powell pipeline). For Wasatch Front, all potential Colorado River demand is M&I, 

except for one agricultural export. M&I is computed as total export minus agricultural user schedule.
Appendix C5

Wyoming Water Demand 

Scenario Quantification

December 2012 C5-1 

Appendix C5 — Wyoming Water Demand 

Scenario Quantification

1.0 Introduction 

This appendix summarizes the data sources used in scenario quantification for Colorado River 

demand1 for the state of Wyoming and presents the results of quantification. As presented in 

figure C5-1, Wyoming is divided into a number of planning areas that align with Colorado River 

Basin (Basin) tributaries (Green River above Fontenelle, Fontenelle to Green River, Green River 

to Greendale, and Little Snake) as well as adjacent areas that are served by Colorado River 

water. Data collection and development were completed at the planning area level.

The following sections present background information that summarizes the state’s planning 

areas as well as data sources used to quantify demand scenarios by category. Following the 

background section, results of demand scenario quantification are presented. The results section 

is broken out into a Wyoming Study Area summary, followed by Colorado River demand by 

geography, and finally by category. 

2.0 Background 

The Wyoming State Engineer’s Office has primary responsibility for water resource planning in 

the state of Wyoming. Additionally, in 1979 the Wyoming legislature created the Wyoming 

Water Development Commission, which functions to develop the state’s water resources 

(including production of studies and water development projects that are funded during each 

legislative session). As directed by the legislature, the Commission has led numerous water 

resource planning studies. Information presented in this summary was largely obtained from 

Wyoming’s planning studies. 

The State Engineer’s Office coordinated Wyoming’s efforts to provide information for scenario 

quantification. These efforts largely relied on information previously generated through regional 

plans and demographic studies. However, new assumptions and/or data development were 

required where the assumptions of the Colorado River Basin Water Supply and Demand Study 

(Study) required information not developed as part of the regional planning effort. Information 

presented in this summary was obtained through consultation with the Wyoming State 

Engineer’s Office personnel. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources include state, regional, and national agency reports. 

 

1 Colorado River demand as computed by Study Area demand minus other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C5-2 December 2012

FIGURE C5-1 

Colorado River Hydrologic Basin and Export Service Areas in Wyoming
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-3 

• Agricultural Demand: Irrigated acreage and agricultural demands were derived from the 

Green River Basin Water Planning Process (States West Water Resources Corporation, 

2001) and Wyoming Framework Plan (WWC Engineering, 2007). Agricultural applied 

water use and consumptive factors were calculated. 

• Municipal and Industrial (M&I): Population estimates were derived from table 2 of the 

Green River Basin Plan (WWC Engineering, 2010) and from data obtained from the 

Wyoming Department of Administration and Information. 

• For the hydrologic basin, total consumptive demands were derived from the Green River 

Basin Water Planning Process (States West Water Resources Corporation, 2001). Per 

capita usage was calculated based on demand, population, and a consumptive use factor 

of 50 percent (Wyoming State Engineer’s Office, 2011). 

• For the North Platte, M&I per capita use was derived from Cheyenne population and 

demand in 2010. M&I per capita use was applied to population to get diversion demands, 

and a consumptive use factor of 50 percent (Wyoming State Engineer’s Office, 2011) 

was used to derive consumptive demands. 

• Energy: Energy demands were derived from the Green River Basin Water Planning 

Process (States West Water Resources Corporation, 2001). 

• Minerals: Minerals demands were derived from the Green River Basin Water Planning 

Process (States West Water Resources Corporation, 2001). 

• Fish, Wildlife, and Recreation: Fish, wildlife, and recreation demands were derived 

from the Green River Basin Water Planning Process (States West Water Resources 

Corporation, 2001). 

• Tribal: In Wyoming, there are no federally recognized tribes with rights to Colorado 

River water. 

3.0 Results of Water Demand Scenario Quantification

This section summarizes Wyoming’s Colorado River water demand trends by category across 

the initial scenarios. The purpose of this section is to describe changes in demands, both 

temporally and geographically, parameters that influence changes in demands, and how the 

parameters and demands differ amongst scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands), independent of the source of supply. However, for areas outside of the 

hydrologic basin, a portion of the Study Area demand is satisfied from other supplies. The 

communities within the Colorado River Basin also rely on non-tributary groundwater for a 

portion of their supply. To develop estimates of the Colorado River demand, the Study Area 

demand was reduced by estimates of available supply from other sources. This appendix focuses 

on Colorado River demands, but includes discussion of the Study Area parameters that led to 

these demands.

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand, Colorado River Demand for the state and 
Colorado River Basin 

Water Supply and Demand Study

C5-4 December 2012

individual planning areas across the six scenarios, and Colorado River water demand by category 

across the six scenarios. Parameters and demands for all categories and all scenarios, along with 

references for data sources, are included. 

3.1 Summary Results of Scenario Quantification

Values were developed for parameters to quantify Study Area demand for each of the scenarios. 

Colorado River demand was calculated as Study Area demand minus other supplies. Table C5-1 

presents summary results for the demand scenarios considered in this Study. The table presents 

agricultural and M&I demand parameters for the entire Study Area that distinguish the scenarios, 

the resulting Study Area demands, and finally the Colorado River demands by category. Because 

other supplies may vary among scenarios, trends observed in the parameters and Study Area 

demands may not be reflected identically in Colorado River demand trends. 

Wyoming estimates that about 310,000 people will be in Wyoming’s Study Area by 2015. This 

number is expected to increase to 370,000 to 440,000 by 2060. The greatest population growth is 

associated with the Rapid Growth (C1 and C2) scenarios. The Slow Growth (B) scenario has the 

lowest population of the scenarios in 2060 (370,000 people), but still represents a growth of about 

20 percent over 2015 estimates. 

The growing municipal population is forecast to be slightly less efficient in its per capita water 

use than today in all scenarios except Enhanced Environment (D1) scenario, in which per capita 

water use is expected to be 22 percent less in 2060 than in 2015. Per capita water use for the other 

Current Projected (A), Slow Growth (B), Rapid Growth (C1 and C2), and Enhanced Environment 

(D2) scenarios is expected to be 1 to 4 percent more in 2060 than in 2015. While usage rates vary 

across Wyoming’s planning areas, per capita changes are assumed to be consistent across the 

hydrologic basin planning areas. 

Irrigated acreage is projected to remain relatively constant (less than 1 percent decrease to 

3 percent increase) through 2060 under all scenarios. Water delivery per acre also remains 

relatively constant through 2060, with a 2 percent decrease in the Rapid Growth (C2) scenario 

and a range of no change to 3 percent increase in the other scenarios. 

Study Area demand for energy is projected to increase under all scenarios due to the growing 

need for electricity generation (coal and solar). The greatest increases in Study Area demand for 

energy are anticipated in the Fontenelle to Green River and Green River to Greendale areas, with 

combined increase of about 8,000 acre-feet per year (afy) (Rapid Growth [C2] and Enhanced 

Environment [D1 and D2] scenarios) to 105,000 afy (Rapid Growth [C1] scenario). 

Study Area demand for minerals is also projected to increase under all scenarios. Growth in 

minerals demand is entirely in the Fontenelle to Green River planning area, with a range of 

growth between 14,000 afy (Rapid Growth [C2] and Enhanced Environment [D1 and D2] 

scenarios) to 57,000 afy (Rapid Growth [C1] scenario). Growth primarily reflects increases in 

soda ash production. 

There are no projected Study Area demands for tribal use in any of the scenarios examined. 

Figure C5-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, and 

3) change in Colorado River demand by demand category. 
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-5 

TABLE C5-1 

Summary Results of Wyoming Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

20151 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 0.31 0.41 0.37 0.44 0.44 0.41 0.44

Change in per capita water usage (%), 

from 2015 — +3% +1% +4% +3% –22% +3%

Irrigated acreage (millions of acres) 0.95 0.94 0.94 0.97 0.97 0.94 0.94

Change in per acre water delivery (%), 

from 2015 — +1% +3% –0% –2% +1% +1%

Study Area Demand (thousand acre-feet [kaf])

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 1,951 1,959 1,976 1,976 1,959 1,959 1,959

M&I demand 74 95 89 100 100 73 100

Energy demand 42–52 65 65 171 50 50 50

Minerals demand 20–34 59 59 91 33 33 33

FWR demand 2 10 10 10 25 25 25

Tribal demand 0 0 0 0 0 0 0

Total Study Area Demand2 2,109 2,188 2,198 2,348 2,167 2,141 2,167

Colorado River Demand (kaf)

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 398 406 423 423 406 406 406

M&I demand 30 67 36 74 73 61 73

Energy demand 42–52 65 65 171 50 50 50

Minerals demand 20–34 59 59 91 33 33 33

FWR demand 2 10 10 10 25 25 25

Tribal demand 0 0 0 0 0 0 0

Total Colorado River Demand2 511 606 592 769 588 576 588

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to 

state. 

From panel one it can be seen that Study Area demand increases from about 2.11 million acrefeet (maf) in 2015 to between 2.14 and 2.35 maf in 2060. The range in Study Area demand 

growth across scenarios in 2060; however, is projected to be as low as 52 kaf or as high as 233 

kaf. About 70 to 75 percent of the Study Area demand is expected to be met by other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C5-6 December 2012

FIGURE C5-2 

Study Area, Colorado River, and Change in Colorado River Demand 

0

500

1,000

1,500

2,000

2,500

Thousand Acre-Feet per Year

Study Area Demand in Wyoming

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white and 

colored border

450

500

550

600

650

700

750

800

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in Wyoming

0

50

100

150

200

250

300

Thousand Acre-Feet per Year

Change in Colorado River Demand in Wyoming, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-7 

Panel two provides a view of the range across scenarios of Colorado River demand. This demand 

increases from 511 kaf in 2015 to between 576 and 769 kaf in 2060 (or 15 to 50 percent), 

depending on the scenario. This difference results in a Colorado River demand range of 193 kaf 

across the scenarios in 2060 or about 34 percent. 

Panel three shows how specific categories affect the projected change in Colorado River demand 

by scenario. Growth in Colorado River demand is influenced relatively proportionally by all 

categories of demand. The greatest growth, under the Rapid Growth (C1) scenario, is influenced 

strongly by growth in Energy and Minerals demand. 

Figure C5-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The 193 kaf range across scenarios in 2060 is easily discernible, with the greatest 

demand under Rapid Growth (C1) scenario and a narrower range of demand across the other 

scenarios. In addition, it appears that the quantified scenarios track well with the peaks in 

historical uses that likely represent the least supply-limited conditions or actual demand. 

FIGURE C5-3 

Historical Use and Future Projected Demand Excluding Reservoir Evaporation1

1

Reservoir evaporation on the order of 115 kaf is not included in this plot. 

0

200

400

600

800

1,000

1,200

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Apportionment
Colorado River Basin 

Water Supply and Demand Study

C5-8 December 2012

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in figures 

C5-4 and C5-5. These figures show two geographic levels: Study Area in Wyoming, and 

individual planning areas. Demands at each geographic level are shown across the scenarios. The 

columns to the right show the Colorado River demand at a point in time (2015, 2035, or 2060) by 

relative contribution of the categories. 

When demands by category are examined in figure C5-5, the mix of demand categories in the 

hydrologic basin and adjacent areas are different, with agricultural demand dominating the 

hydrologic basin and M&I demand dominating the adjacent areas. 

Figure C5-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. The change in both magnitude and percentage change of Colorado River demand2 in 

Utah varies considerably across the planning area. The Fontenelle to Green River planning area 

shows relatively large changes, primarily due to growth in minerals and energy demands. The 

North Platte also shows relatively significant changes, primarily due to growth in M&I demands. 

3.3 Colorado River Demand by Category

3.3.1 Agricultural

Agricultural water demand is driven by irrigated acreage and water delivery per acre. Water 

delivery per acre is the amount of water diverted per irrigated acre. Components of this use 

include transmission and delivery losses (surface evaporation, riparian demand, and seepage), 

and on-farm losses that are made up of evaporation, crop irrigation requirement, and tail water 

(return). Each of these factors will vary by location (precipitation, growing season, etc.), 

irrigation method, and crop type. 

Figure C5-7 presents the following by scenario in 2015, 2035, and 2060: 

• Change in agricultural demand for Colorado River water 

• Change in agricultural demand for Colorado River water by planning area 

• Agricultural demand as a portion of Colorado River water demand (right hand side 

of graph) 

As can be seen from figure C5-7, agricultural water demand is the largest component of 

Colorado River demand in Wyoming, dropping from about 80 percent in 2015 to between 55 and 

71 percent of Colorado River demand in 2060, depending on which scenario is considered. This 

drop results from other categories of demand increasing at a faster rate than agriculture; 

agricultural demand increases across all scenarios. 

 

2 Potential Colorado River demand is based on changes in parameters, such as population, and for the purpose of the study is not 

 limited by apportionment. 
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-9 

FIGURE C5-4 

Colorado River Demand in Wyoming
Colorado River Basin 

Water Supply and Demand Study

C5-10 December 2012

FIGURE C5-5 

Colorado River Demand by Category
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-11

FIGURE C5-6 

Change in Colorado River Demand in Wyoming from 2015 by Category
Colorado River Basin 

Water Supply and Demand Study

C5-12 December 2012

FIGURE C5-7 

Change in Colorado River Demand in Wyoming from 2015 for Agriculture

0

5

10

15

20

2015 2035 2060

KAF

Green River above 

Fontenelle

0

5

10

15

20

2015 2035 2060

KAF

Little Snake River

0

5

10

15

20

2015 2035 2060

KAF

Green River to 

Greendale 0

5

10

15

20

2015 2035 2060

KAF

North Platte

201520352060

0

5

10

15

20

2015 2035 2060

KAF

Fontenelle to Green 

River

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

5

10

15

20

25

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Wyoming, from 2015

Agricultural

Agriculture is 77 - 81% of Colorado River demand*Agriculture is 64 - 75% of Colorado River demand*Agriculture is 55 - 71% of Colorado River demand*

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-13

Agricultural demand consistently increases through time across all scenarios. The increase 

in agricultural demand is driven by both a change in irrigated acres and change in water delivery 

per acre. For Current Projected (A), Slow Growth (B), and Enhanced Environment (D1 and D2) 

scenarios, irrigated acreage decreases slightly (less than 1 percent), but that slight decrease is 

offset by an increase in applied water use. For the Rapid Growth (C1 and C2) scenarios, irrigated 

acreage is forecast to increase at a faster rate than a decrease in water delivery per acre. 

In examining the planning areas, the increase in agricultural demand is focused primarily in the 

Green River above Fontenelle and Green River to Greendale planning areas. 

3.3.2 Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita water use. M&I per

capita water use is a measure of the amount of water produced or diverted per person in a given 

municipality. Because this measure examines all water produced by a given municipality, it often 

includes industrial, commercial, and institutional demand as well as residential demand. A 

number of factors may influence the M&I per capita water use of a given community including 

the amount of industrial demand, climate, number of institutional facilities, and number of 

visitors. 

Figure C5-8 presents the following by scenario in 2015, 2035, and 2060: 

• Change in M&I demand for Colorado River water in the Study Area 

• Change in M&I demand for Colorado River water in individual planning areas

• M&I demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C5-8, M&I water demand increases from 6 percent in 2015 

to between 6 and 12 percent of Colorado River demand in 2060, depending on which scenario 

is considered. 

Colorado River demand for M&I use increases over time from 2015 to 2060 across all scenarios. 

The increase is primarily due to population increase (20 to 38 percent increase depending on the 

scenario), with a slight additional influence of changing per capita M&I water use (1 to 4 percent 

increase, depending on the Current Projected [A], Slow Growth [B], Rapid Growth [C1 and C2], 

and Enhanced Environment [D2] scenarios; 22 percent decrease in the Enhanced Environment 

[D1] scenario). 

In examining the planning areas, the majority of the increase in M&I demand for Colorado River 

water from 2015 to 2060 over time is due to population increase in the North Platte planning 

area. The three planning areas along the Green River also show increases in M&I demand. 
Colorado River Basin 

Water Supply and Demand Study

C5-14 December 2012

FIGURE C5-8 

Change in Colorado River Demand in Wyoming from 2015 for M&I

0

10

20

30

40

2015 2035 2060

KAF

Green River above 

Fontenelle

0

10

20

30

40

2015 2035 2060

KAF

Little Snake River

0

10

20

30

40

2015 2035 2060

KAF

Green River to 

Greendale 0

10

20

30

40

2015 2035 2060

KAF

North Platte

201520352060

0

10

20

30

40

2015 2035 2060

KAF

Fontenelle to Green 

River

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

5

10

15

20

25

30

35

40

45

50

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Wyoming, from 2015

Municipal and Industrial

M&I is 5.5 - 6% of Colorado River demand*

M&I is 5.7 - 10.4% of Colorado River demand*

M&I is 6.1 - 12.4% of Colorado River demand*

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-15

3.3.3 Energy

Water demand for energy can be estimated through known plans for new power plants or 

through applying a per capita energy water use factor. Power facilities often serve areas remote 

from their locations and therefore potentially represent exports or imports of water from the 

Study Area to meet these distributed needs. 

Figure C5-9 presents the following by scenario in 2015, 2035, and 2060: 

• Change in energy demand for Colorado River water 

• Change in energy demand for Colorado River water in individual planning areas 

• Energy demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C5-9, energy water demand increases from 9 percent of Colorado 

River demand in 2015 to between 9 and 22 percent of Colorado River demand in 2060, 

depending on which scenario is considered. 

Energy demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios. The most notable increase occurs in the Rapid Growth (C1) scenario, where energy 

demand is projected to increase by nearly 120 kaf due to an increase in electricity production. 

The other scenarios show an increase in energy demand of about 8 to 13 kaf. 

Increase in energy demand is focused primarily in the Fontenelle to Green River planning area, 

in which it increases across all scenarios. Some additional increase is forecast in some scenarios 

in the Green River to Greendale and Little Snake River planning areas.

3.3.4 Minerals Extraction

Water demand for mineral production can be estimated through existing uses and known plans 

for extraction in the Study Area. Water demand for mineral production can vary significantly 

based on market prices for a given product. 

Figure C5-10 presents the following by scenario in 2015, 2035, and 2060: 

• Change in mineral production demand for Colorado River water 

• Change in individual planning area mineral production demand for Colorado River water 

• Minerals demand as a portion of Colorado River demand (right hand side of graph) 

As can be seen from figure C5-10, minerals water demand is a relatively small fraction of 

Colorado River demand, increasing from 4 to 7 percent in 2015, to between 6 and 12 percent of 

Colorado River demand in 2060, depending on which scenario is considered. 

Minerals demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios. 

Demand for Colorado River water for minerals production is only found in the Fontenelle to 

Green River Planning Area. Increase in minerals demand ranges from about 14 kaf (Rapid 

Growth [C2] and Enhanced Environment [D1 and D2] scenarios) to about 57 kaf (Rapid Growth 

[C1] scenario), with Current Projected (A) and Slow Growth (B) scenarios showing an increase 

of about 30 kaf. 
Colorado River Basin 

Water Supply and Demand Study

C5-16 December 2012

FIGURE C5-9 

Change in Colorado River Demand in Wyoming from 2015 for Energy

0

20

40

60

80

2015 2035 2060

KAF

Green River above 

Fontenelle

0

20

40

60

80

2015 2035 2060

KAF

Little Snake River

0

20

40

60

80

2015 2035 2060

KAF

Green River to 

Greendale 0

20

40

60

80

2015 2035 2060

KAF

North Platte

201520352060

0

20

40

60

80

2015 2035 2060

KAF

Fontenelle to Green 

River

A

B

A

B

C1

C1

C2

D1D2

C2

D1

D2

0

20

40

60

80

100

120

140

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Wyoming, from 2015

Energy

Energy is 8.5 - 10.2% of Colorado River demand*

Energy is 8.4 - 16.2% of Colorado River demand*

Energy is 8.5 - 22.2% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-17

FIGURE C5-10

Change in Colorado River Demand in Wyoming from 2015 for Minerals

0

20

40

60

2015 2035 2060

KAF

Green River above 

Fontenelle

0

20

40

60

2015 2035 2060

KAF

Little Snake River

0

20

40

60

2015 2035 2060

KAF

Green River to 

Greendale 0

20

40

60

2015 2035 2060

KAF

North Platte

201520352060

0

20

40

60

2015 2035 2060

KAF

Fontenelle to Green 

River

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

10

20

30

40

50

60

70

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Wyoming, from 2015

Minerals

Minerals is 4 - 6.6% of Colorado River demand*

Minerals is 4.7 - 8.9% of Colorado River demand*

Minerals is 5.7 - 11.9% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin 

Water Supply and Demand Study

C5-18 December 2012

3.3.5 Fish, Wildlife, and Recreation

Water demand for fish, wildlife, and recreation is estimated from existing agreements or known 

consumptive use associated with this demand category. Non-consumptive demands associated 

with fish, wildlife and recreation, including in-stream flow requirements, are represented through 

the metrics portion of the Study presented in Technical Report D – System Reliability Metrics. 

Figure C5-11 presents the following by scenario in 2015, 2035, and 2060: 

• Change in fish, wildlife, and recreation demand for Colorado River water 

• Change in fish, wildlife, and recreation demand for Colorado River water in individual 

planning areas 

• Fish, wildlife, and recreation demand as a portion of Colorado River demand (right hand 

side of graph) 

As can be seen from figure C5-11, fish, wildlife, and recreation water demand is a small fraction 

of Colorado River demand, increasing from less than 1 percent in 2015 to between 1 and 4 

percent of Colorado River demand in 2060 across all scenarios. 

Total increase in fish, wildlife, and recreation demand ranges from about 8 kaf (Current 

Projected [A], Slow Growth [B], and Rapid Growth [C1] scenarios) to about 23 kaf (Rapid 

Growth [C2] and Enhanced Environment [D1 and D2] scenarios). These increases are relatively 

evenly split between the four hydrologic basin planning areas, with the upper two Green River 

planning areas exhibiting slightly greater increases. 

3.3.6 Tribal

In Wyoming, there are no federally recognized tribes with rights to Colorado River water. 

3.4 Summary Tables of Parameters and Demands by Category

Tables C5-2 to C5-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 

4.0 References

States West Water Resources Corporation. 2001. Green River Basin Water Planning Process. 

WWC Engineering. 2007. Wyoming Framework Plan. 

WWC Engineering. 2010. Green River Basin Plan.

Wyoming State Engineer’s Office. 2011. Personal communication with Reclamation.
Appendix C5 — Wyoming Water Demand 

Scenario Quantification

December 2012 C5-19

FIGURE C5-11

Change in Colorado River Demand in Wyoming from 2015 for Fish, Wildlife, and Recreation

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Green River above 

Fontenelle

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Little Snake River

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Green River to 

Greendale 0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

North Platte

201520352060

0.0

2.5

5.0

7.5

10.0

2015 2035 2060

KAF

Fontenelle to Green 

River

A

B

C1

A

B

C1

C2

C2

D1

D1

D2

D2

0

5

10

15

20

25

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Wyoming, from 2015

Fish, Wildlife, and Recreation

FWR is 0.4% of Colorado River demand*

FWR is 1.6 - 2.8% of Colorado River demand*FWR is 1.3 -

N/A

4.3% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin 

Water Supply and Demand Study

C5-20 December 2012

TABLE C5-2 

Total Demand within Study Area under Current Projected (A) Scenario

WYOMING LEGEND: 999 From States 999 From State Plans

Units are thousand acre-feet per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 193 195 191 19 19 18 106 107 105 18 18 17 336 339 332 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 2

Consumptive Factor [%] 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 3

Demand (Consumptive) 229 231 234 22 22 23 126 127 128 21 22 21 398 402 406

Municipal and Industrial (M&I) Population [thousands] 10 18 28 43 48 52 17 20 24 1 1 0.8 71 87 105 4

M&I Per Capita Use (Diversion) [gpcd] 287 297 306 287 297 306 287 297 306 287 296 306 287 297 306 5

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 6

M&I Demand (Consumptive) 2 3 5 7 8 9 3 3 4 0.2 0.2 0.1 11 14 18 7

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 8

Demand (Consumptive) 2 3 5 7 8 9 3 3 4 0.2 0.2 0.1 11 14 18

Energy Demand (Consumptive) 0 0 0 38 50 50 15 15 15 0 0 0 52 65 65 9

Minerals Demand (Consumptive) 0 0 0 29 42 59 0 0 0 0 0 0 29 42 59 10

Fish, Wildlife, and Recreation Demand (Consumptive) 0.9 3 3 0.6 5 5 0.3 1.0 1.0 0.3 2 2 2 10 10 11

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12

Total Hydrologic Basin Demand (Consumptive) 232 237 241 96 127 145 143 146 148 22 24 23 0 0 0 493 534 558

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 612 612 612 612 612 612 13

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.54 2.54 2.54 2.54 2.54 2.54

Consumptive factor [%] 43% 43% 43% 43% 43% 43%

Demand (Diversion) 1,553 1,553 1,553 1,553 1,553 1,553 14

Demand (Consumptive) 663 661 661 663 661 661 14

Municipal and Industrial (M&I) Population [thousands] 244 270 301 244 270 301 15

M&I Per Capita Use (Diversion)[gpcd] 229 229 229 229 229 229 16

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 17

M&I Demand (Diversion) 63 69 77 63 69 77 18

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0

Demand (Diversion) 63 69 77 63 69 77

Demand (Consumptive) 31 35 39 31 35 39

Energy Demand (Diversion) 0 0 0 0 0 0

Minerals Demand (Diversion) 0 0 0 0 0 0

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0

Tribal Demand (Diversion) 0 0 0 0 0 0

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 1,616 1,622 1,630 1,616 1,622 1,630

Total Demand in the Study Area 232 237 241 96 127 145 143 146 148 22 24 23 1,616 1,622 1,630 2,109 2,156 2,188 19

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 1,598 1,590 1,582 1,598 1,590 1,582 20

Potential Colorado River Demand 232 237 241 96 127 145 143 146 148 22 24 23 18 32 49 511 566 606 21

Agricultural Colorado River Demand 229 231 234 22 22 23 126 127 128 21 22 21 0 0 0 398 402 406 22

Municipal and Industrial Colorado River Demand 2 3 5 7 8 9 3 3 4 0.2 0.2 0.1 18 32 49 30 47 67

Energy Colorado River Demand 0 0 0 38 50 50 15 15 15 0 0 0 0 0 0 52 65 65

Minerals Colorado River Demand 0 0 0 29 42 59 0 0 0 0 0 0 0 0 0 29 42 59

Fish, Wildlife, and Recreation Colorado River Demand 0.9 3 3 0.6 5 5 0.3 1.0 1.0 0.3 2 2 0 0 0 2 10 10

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Notes

Green River above Fontenelle Fontenelle to Green River Green River to Greendale Little Snake River North Platte STATE TOTAL
 Appendix C5 — Wyoming Water Demand 

 Scenario Quantification

December 2012 C5-21

Notes:

1) Green River Basin Water Planning Process, 2001, Linear interpolation was used to project acreage in 2015.

2) Calculated - represents average unit water supply-limited diversion required per acre.

3) Calculated based on statewide diverted water use in 2011 of 4.22 acre-feet (af)/acre documented on pg. 5–7 of Wyoming Framework Plan, Volume 1.

4) Hydrologic Basin: Green River Basin Plan, table 2.

5) Calculated from total demand, consumptive use factor, and population.

6) Wyoming State Engineer’s Office, personal communication 2011.

7) Green River Basin Water Planning Process, 2001, Wyoming State Engineer’s Office, personal communication 2011, Linear interpolation used project 

demand for 2015.

8) Green River Basin Water Planning Process, 2001, Wyoming State Engineer’s Office, personal communication 2011, Linear interpolation used project 

demand for 2015.

9) Green River Basin Water Planning Process, 2001, Linear interpolation was used to project demand for 2015.

10) Green River Basin Water Planning Process, 2001, Linear interpolation was used to project demand for 2015.

11) Green River Basin Water Planning Process, 2001, Wyoming State Engineer’s Office, personal communication 2011, Linear interpolation used project 

demand for 2015.

12) Green River Basin Water Planning Process, 2001, Linear interpolation was used to project demand for 2015.

13) Wyoming Framework Water Plan, Volume I, October 2007.

14) Wyoming Framework Water Plan, Volume I, October 2007 for 2015 and 2035, 2036 demands assumed steady through 2060.

15) Wyoming Department of Administration and Information, Economic Analysis Division – WYOMING AND COUNTY POPULATION PROJECTIONS BY 

AGE: 2008 TO 2030, July, 2008, forecasts from 2009 of 2010 and 2030 data were used with 2010 census data to develop population. 2010 and 2030 

population were linearly interpolated to find population projections for 2035 and 2060.

16) M&I water use efficiency was calculated from Cheyenne population and demand in 2010. This value was then used for demand calculations from 

population estimates in future years.

17) Wyoming State Engineer’s Office, personal communication 2011.

18) Calculated from M&I efficiency, consumptive use factor, and population.

19) Calculated from the sum of Hydrologic Basin (Consumptive) Demand and Adjacent Areas (Diversion) Demand.

20) Calculated as the difference in Study Area demand and potential Colorado River demand.

21) Green River Basin Water Planning Process, 2001, Wyoming State Engineer’s Office, personal communication 2011, Linear interpolation used project 

demand for 2015. In 2011, 15,281 af represent represents Cheyenne's current contract and 2,920 af represents current agricultural contracts. In 2035 

and 2060, 22,700 afy represents Cheyenne's current contract and 2,920 af represents current agricultural contracts. The remaining projected growth is 

9,390 af in 2035 and 25,000 af in 2060.

22) For North Platte, all potential Colorado River demand is M&I. 
Colorado River Basin 

Water Supply and Demand Study

C5-22 December 2012

TABLE C5-3 

Total Demand within Study Area under Slow Growth (B) Scenario

WYOMING LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 193 195 191 19 19 18 106 107 105 18 18 17 336 339 332 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 4.24 4.24 4.40 4.24 4.29 4.50 4.24 4.45 4.81 4.24 4.21 4.44 4.24 4.31 4.53

Consumptive Factor [%] 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28%

Demand (Consumptive) 230 233 236 22 23 23 126 134 142 21 22 22 400 410 423 2

Municipal and Industrial (M&I) Population [thousands] 9 13 17 38 35 33 15 15 15 1.0 0.8 0.5 63 64 66 3

M&I Per Capita Use (Diversion) [gpcd] 287 297 306 287 297 306 287 297 306 287 296 306 287 297 306 4

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

M&I Demand (Consumptive) 1 2 3 6 6 6 2 2 3 0.2 0.1 0.09 10 11 11

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 1 2 3 6 6 6 2 2 3 0.2 0.1 0.09 10 11 11

Energy Demand (Consumptive) 0 0 0 38 50 50 15 15 15 0 0 0 52 65 65 6

Minerals Demand (Consumptive) 0 0 0 29 42 59 0 0 0 0 0 0 29 42 59 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0.9 3 3 0.6 5 5 0.3 1.0 1.0 0.3 2 2 2 10 10 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 233 237 242 96 125 142 143 152 160 22 23 24 0 0 0 494 538 568

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 612 612 612 612 612 612 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.54 2.54 2.54 2.54 2.54 2.54

Consumptive factor [%] 43% 43% 43% 43% 43% 43%

Demand (Diversion) 1,553 1,553 1,553 1,553 1,553 1,553 11

Demand (Consumptive) 663 661 661 663 661 661

Municipal and Industrial (M&I) Population [thousands] 244 270 301 244 270 301 12

M&I Per Capita Use (Diversion)[gpcd] 229 229 229 229 229 229 13

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

M&I Demand (Diversion) 63 69 77 63 69 77

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 63 69 77 63 69 77

Demand (Consumptive) 31 35 39 31 35 39

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 1,616 1,622 1,630 1,616 1,622 1,630

Total Demand in the Study Area 233 237 242 96 125 142 143 152 160 22 23 24 1,616 1,622 1,630 2,109 2,160 2,198

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 1,598 1,601 1,606 1,598 1,601 1,606 19

Potential Colorado River Demand 233 237 242 96 125 142 143 152 160 22 23 24 18 21 25 512 559 592 20

Agricultural Colorado River Demand 230 233 236 22 23 23 126 134 142 21 22 22 0 0 0 400 410 423 21

Municipal and Industrial Colorado River Demand 1 2 3 6 6 6 2 2 3 0.2 0.1 0.09 18 21 25 28 32 36

Energy Colorado River Demand 0 0 0 38 50 50 15 15 15 0 0 0 0 0 0 52 65 65

Minerals Colorado River Demand 0 0 0 29 42 59 0 0 0 0 0 0 0 0 0 29 42 59

Fish, Wildlife, and Recreation Colorado River Demand 0.9 3 3 0.6 5 5 0.3 1.0 1.0 0.3 2 2 0 0 0 2 10 10

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Notes

Green River above Fontenelle Fontenelle to Green River Green River to Greendale Little Snake River North Platte STATE TOTAL
 Appendix C5 — Wyoming Water Demand 

 Scenario Quantification

December 2012 C5-23

Notes

1) No changes from Current Projected.

2) High Growth scenario from Green River Basin Plan, 2010. 

3) Population estimates from Low Growth scenario of the Green River Basin Plan, 2010. 

4) Moderate Growth scenario from Green River Basin Plan, 2010; gallons per capita per day (gpcd) computed with Moderate Growth 

population and M&I demand.

5) No changes from Current Projected.

6) No changes from Current Projected.

7) Moderate Growth scenario from Green River Basin Plan, 2010; gpcd computed with Moderate Growth population and M&I demand.

8) Moderate Growth scenario from Green River Basin Plan, 2010; gpcd computed with Moderate Growth population and M&I demand.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) Population estimates from Low Growth scenario of the Green River Basin Plan, 2010. 

13) Moderate Growth scenario from Green River Basin Plan, 2010; gpcd computed with Moderate Growth population and M&I demand.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Low Growth scenario from Green River Basin Plan, 2010. 

20) Low Growth scenario exports to North Platte from Green River Basin Plan, 2010. 

21) For North Platte, all potential Colorado River demand is M&I. 
Colorado River Basin 

Water Supply and Demand Study

C5-24 December 2012

TABLE C5-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

WYOMING LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 193 198 203 19 19 20 106 114 121 18 18 19 336 349 363 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 4.24 4.18 4.15 4.24 4.18 4.15 4.24 4.18 4.15 4.24 4.18 4.15 4.24 4.18 4.15

Consumptive Factor [%] 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28%

Demand (Consumptive) 230 233 236 22 23 23 126 134 142 21 22 22 400 410 423 2

Municipal and Industrial (M&I) Population [thousands] 10 24 35 43 65 67 17 27 31 1 1 1 71 117 134 3

M&I Per Capita Use (Diversion) [gpcd] 287 297 306 287 297 306 287 297 306 287 296 306 287 297 306 4

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

M&I Demand (Consumptive) 2 4 6 7 11 12 3 5 5 0.2 0.2 0.2 11 19 23

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 2 4 6 7 11 12 3 5 5 0.2 0.2 0.2 11 19 23

Energy Demand (Consumptive) 0 0 0 38 74 115 15 29 43 0 0 14 52 103 171 6

Minerals Demand (Consumptive) 0 0 0 34 57 91 0 0 0 0 0 0 34 57 91 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0.9 3 3 0.6 5 5 0.3 1.0 1.0 0.3 2 2 2 10 10 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 233 239 245 102 169 245 144 168 190 22 24 38 0 0 0 500 599 718

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 612 612 612 612 612 612 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.54 2.54 2.54 2.54 2.54 2.54

Consumptive factor [%] 43% 43% 43% 43% 43% 43%

Demand (Diversion) 1,553 1,553 1,553 1,553 1,553 1,553 11

Demand (Consumptive) 663 661 661 663 661 661

Municipal and Industrial (M&I) Population [thousands] 244 270 301 244 270 301 12

M&I Per Capita Use (Diversion)[gpcd] 229 229 229 229 229 229 13

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

M&I Demand (Diversion) 63 69 77 63 69 77

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 63 69 77 63 69 77

Demand (Consumptive) 31 35 39 31 35 39

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 1,616 1,622 1,630 1,616 1,622 1,630

Total Demand in the Study Area 233 239 245 102 169 245 144 168 190 22 24 38 1,616 1,622 1,630 2,116 2,222 2,348

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 1,598 1,585 1,580 1,598 1,585 1,580 19

Potential Colorado River Demand 233 239 245 102 169 245 144 168 190 22 24 38 18 37 51 518 637 769 20

Agricultural Colorado River Demand 230 233 236 22 23 23 126 134 142 21 22 22 0 0 0 400 410 423 21

Municipal and Industrial Colorado River Demand 2 4 6 7 11 12 3 5 5 0.2 0.2 0.2 18 37 51 30 57 74

Energy Colorado River Demand 0 0 0 38 74 115 15 29 43 0 0 14 0 0 0 52 103 171

Minerals Colorado River Demand 0 0 0 34 57 91 0 0 0 0 0 0 0 0 0 34 57 91

Fish, Wildlife, and Recreation Colorado River Demand 0.9 3 3 0.6 5 5 0.3 1.0 1.0 0.3 2 2 0 0 0 2 10 10

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Notes

Green River above Fontenelle Fontenelle to Green River Green River to Greendale Little Snake River North Platte STATE TOTAL
 Appendix C5 — Wyoming Water Demand 

 Scenario Quantification

December 2012 C5-25

Notes

1) High Growth scenario from Green River Basin Plan, 2010. 

2) High Growth scenario from Green River Basin Plan, 2010. 

3) Population estimates from High Growth scenario of the Green River Basin Plan, 2010. 

4) Moderate Growth scenario from Green River Basin Plan, 2010; gpcd computed with Moderate Growth population and M&I demand.

5) No changes from Current Projected.

6) High Growth scenario from Green River Basin Plan, 2010. 

7) High Growth scenario from Green River Basin Plan, 2010. 

8) Moderate Growth scenario from Green River Basin Plan, 2010. 

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) Population estimates from High Growth scenario of the Green River Basin Plan, 2010. 

13) Moderate Growth scenario from Green River Basin Plan, 2010; gpcd computed with Moderate Growth population and M&I demand.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) High Growth scenario from Green River Basin Plan, 2010. 

20) High Growth scenario exports to North Platte from Green River Basin Plan, 2010. 

21) For North Platte, all potential Colorado River demand is M&I. 
Colorado River Basin 

Water Supply and Demand Study

C5-26 December 2012

TABLE C5-5 

Total Demand within Study Area under Rapid Growth (C2) Scenario

WYOMING LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 193 198 203 19 19 20 106 114 121 18 18 19 336 349 363 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 4.22 4.16 4.11 4.22 4.12 4.02 4.22 3.97 3.76 4.22 4.20 4.07 4.22 4.10 3.99

Consumptive Factor [%] 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28%

Demand (Consumptive) 229 231 234 22 22 23 126 127 128 21 22 21 398 402 406 2

Municipal and Industrial (M&I) Population [thousands] 10 24 35 43 65 67 17 27 31 1 1 1 71 117 134 3

M&I Per Capita Use (Diversion) [gpcd] 287 296 297 287 296 297 287 296 297 287 296 297 287 297 297 4

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

M&I Demand (Consumptive) 2 4 6 7 11 11 3 5 5 0.2 0.2 0.2 11 19 22

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 2 4 6 7 11 11 3 5 5 0.2 0.2 0.2 11 19 22

Energy Demand (Consumptive) 0 0 0 30 35 36 12 11 15 0 0 0 42 46 50 6

Minerals Demand (Consumptive) 0 0 0 20 25 33 0 0 0 0 0 0 20 25 33 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0.9 6 10 0.6 5 7 0.3 3 4 0.3 2 4 2 15 25 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 232 241 250 79 98 110 140 145 152 22 23 25 0 0 0 473 508 537

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 612 612 612 612 612 612 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.54 2.54 2.54 2.54 2.54 2.54

Consumptive factor [%] 43% 43% 43% 43% 43% 43%

Demand (Diversion) 1,553 1,553 1,553 1,553 1,553 1,553 11

Demand (Consumptive) 663 661 661 663 661 661

Municipal and Industrial (M&I) Population [thousands] 244 270 301 244 270 301 12

M&I Per Capita Use (Diversion)[gpcd] 229 229 229 229 229 229 13

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

M&I Demand (Diversion) 63 69 77 63 69 77

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 63 69 77 63 69 77

Demand (Consumptive) 31 35 39 31 35 39

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 1,616 1,622 1,630 1,616 1,622 1,630

Total Demand in the Study Area 79 98 110 140 145 152 22 23 25 1,616 1,622 1,630 2,088 2,130 2,167 2,088 2,130 2,167

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 1,598 1,585 1,580 1,598 1,585 1,580 19

Potential Colorado River Demand 232 241 250 79 98 110 140 145 152 22 23 25 18 37 51 491 545 588 20

Agricultural Colorado River Demand 229 231 234 22 22 23 126 127 128 21 22 21 0 0 0 398 402 406 21

Municipal and Industrial Colorado River Demand 2 4 6 7 11 11 3 5 5 0.2 0.2 0.2 18 37 51 30 57 73

Energy Colorado River Demand 0 0 0 30 35 36 12 11 15 0 0 0 0 0 0 42 46 50

Minerals Colorado River Demand 0 0 0 20 25 33 0 0 0 0 0 0 0 0 0 20 25 33

Fish, Wildlife, and Recreation Colorado River Demand 0.9 6 10 0.6 5 7 0.3 3 4 0.3 2 4 0 0 0 2 15 25

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Notes

Green River above Fontenelle Fontenelle to Green River Green River to Greendale Little Snake River North Platte STATE TOTAL
 Appendix C5 — Wyoming Water Demand 

 Scenario Quantification

December 2012 C5-27

Notes

1) High Growth scenario from Green River Basin Plan, 2010. 

2) Moderate Growth scenario from Green River Basin Plan, 2010. 

3) Population estimates from High Growth scenario of the Green River Basin Plan, 2010. 

4) High Growth scenario from Green River Basin Plan, 2010; gpcd computed with High Growth population and M&I demand.

5) No changes from Current Projected.

6) Low Growth scenario from Green River Basin Plan, 2010. 

7) Low Growth scenario from Green River Basin Plan, 2010. 

8) High Growth scenario from Green River Basin Plan, 2010. 

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) Population estimates from High Growth scenario of the Green River Basin Plan, 2010. 

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) High Growth scenario from Green River Basin Plan, 2010. 

20) High Growth scenario exports to North Platte from Green River Basin Plan, 2010. 

21) For North Platte, all potential Colorado River demand is M&I. 
Colorado River Basin 

Water Supply and Demand Study

C5-28 December 2012

TABLE C5-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

WYOMING LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 193 195 191 19 19 18 106 107 105 18 18 17 336 339 332 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36

Consumptive Factor [%] 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28%

Demand (Consumptive) 229 231 234 22 22 23 126 127 128 21 22 21 398 402 406 2

Municipal and Industrial (M&I) Population [thousands] 10 18 28 43 48 52 17 20 24 1 1 0.8 71 87 105 3

M&I Per Capita Use (Diversion) [gpcd] 287 258 222 287 258 222 287 258 222 287 258 222 287 258 222 4

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

M&I Demand (Consumptive) 2 3 3 7 7 6 3 3 3 0.2 0.2 0.1 11 13 13

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 2 3 3 7 7 6 3 3 3 0.2 0.2 0.1 11 13 13

Energy Demand (Consumptive) 0 0 0 30 35 36 12 11 15 0 0 0 42 46 50 6

Minerals Demand (Consumptive) 0 0 0 20 25 33 0 0 0 0 0 0 20 25 33 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0.9 6 10 0.6 5 7 0.3 3 4 0.3 2 4 2 15 25 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 232 240 247 79 95 105 140 143 150 22 23 25 0 0 0 473 501 528

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 612 612 612 612 612 612 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.54 2.54 2.54 2.54 2.54 2.54

Consumptive factor [%] 43% 43% 43% 43% 43% 43%

Demand (Diversion) 1,553 1,553 1,553 1,553 1,553 1,553 11

Demand (Consumptive) 663 661 661 663 661 661

Municipal and Industrial (M&I) Population [thousands] 244 270 301 244 270 301 12

M&I Per Capita Use (Diversion)[gpcd] 229 206 178 229 206 178 13

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

M&I Demand (Diversion) 63 62 60 63 62 60

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 63 62 60 63 62 60

Demand (Consumptive) 31 31 30 31 31 30

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 1,616 1,615 1,613 1,616 1,615 1,613

Total Demand in the Study Area 232 240 247 79 95 105 140 143 150 22 23 25 1,616 1,615 1,613 2,088 2,116 2,141

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 1,598 1,583 1,565 1,598 1,583 1,565 19

Potential Colorado River Demand 232 240 247 79 95 105 140 143 150 22 23 25 18 32 48 491 533 576 20

Agricultural Colorado River Demand 229 231 234 22 22 23 126 127 128 21 22 21 0 0 0 398 402 406 21

Municipal and Industrial Colorado River Demand 2 3 3 7 7 6 3 3 3 0.2 0.2 0.1 18 32 48 30 45 61

Energy Colorado River Demand 0 0 0 30 35 36 12 11 15 0 0 0 0 0 0 42 46 50

Minerals Colorado River Demand 0 0 0 20 25 33 0 0 0 0 0 0 0 0 0 20 25 33

Fish, Wildlife, and Recreation Colorado River Demand 0.9 6 10 0.6 5 7 0.3 3 4 0.3 2 4 0 0 0 2 15 25

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Notes

Green River above Fontenelle Fontenelle to Green River Green River to Greendale Little Snake River North Platte STATE TOTAL
 Appendix C5 — Wyoming Water Demand

 Scenario Quantification

December 2012 C5-29

Notes

1) No changes from Current Projected.

2) Moderate Growth scenario from Green River Basin Plan, 2010. 

3) Population estimates from Moderate Growth scenario of the Green River Basin Plan, 2010. 

4) High Growth scenario from Green River Basin Plan, 2010; gpcd computed with High Growth population and M&I demand.

5) No changes from Current Projected.

6) Low Growth scenario from Green River Basin Plan, 2010. 

7) Low Growth scenario from Green River Basin Plan, 2010. 

8) High Growth scenario from Green River Basin Plan, 2010. 

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) Population estimates from Moderate Growth scenario of the Green River Basin Plan, 2010. 

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) Moderate Growth scenario from Green River Basin Plan, 2010. 

20) Moderate Growth scenario exports to North Platte from Green River Basin Plan, 2010. 

21) For North Platte, all potential Colorado River Demand is M&I. 
Colorado River Basin 

Water Supply and Demand Study

C5-30 December 2012

TABLE C5-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

WYOMING LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agriculture Irrigated Acreage [thousands] 193 195 191 19 19 18 106 107 105 18 18 17 336 339 332 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36 4.22 4.22 4.36

Consumptive Factor [%] 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28% 28%

Demand (Consumptive) 229 231 234 22 22 23 126 127 128 21 22 21 398 402 406 2

Municipal and Industrial (M&I) Population [thousands] 10 24 35 43 65 67 17 27 31 1 1 1 71 117 134 3

M&I Per Capita Use (Diversion) [gpcd] 287 296 297 287 296 297 287 296 297 287 296 297 287 297 297 4

Consumptive factor [%] 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50% 50%

M&I Demand (Consumptive) 2 4 6 7 11 11 3 5 5 0.2 0.2 0.2 11 19 22

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 2 4 6 7 11 11 3 5 5 0.2 0.2 0.2 11 19 22

Energy Demand (Consumptive) 0 0 0 30 35 36 12 11 15 0 0 0 42 46 50 6

Minerals Demand (Consumptive) 0 0 0 20 25 33 0 0 0 0 0 0 20 25 33 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0.9 6 10 0.6 5 7 0.3 3 4 0.3 2 4 2 15 25 8

Tribal Demand (Consumptive) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

Total Hydrologic Basin Demand (Consumptive) 232 241 250 79 98 110 140 145 152 22 23 25 0 0 0 473 508 537

Adjacent Areas

Agriculture Irrigated Acreage [thousands] 612 612 612 612 612 612 10

Per-Acre Water Delivery (Diversion) [af/ac/yr] 2.54 2.54 2.54 2.54 2.54 2.54

Consumptive factor [%] 43% 43% 43% 43% 43% 43%

Demand (Diversion) 1,553 1,553 1,553 1,553 1,553 1,553 11

Demand (Consumptive) 663 661 661 663 661 661

Municipal and Industrial (M&I) Population [thousands] 244 270 301 244 270 301 12

M&I Per Capita Use (Diversion)[gpcd] 229 229 229 229 229 229 13

Consumptive factor [%] 50% 50% 50% 50% 50% 50%

M&I Demand (Diversion) 63 69 77 63 69 77

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 14

Demand (Diversion) 63 69 77 63 69 77

Demand (Consumptive) 31 35 39 31 35 39

Energy Demand (Diversion) 0 0 0 0 0 0 15

Minerals Demand (Diversion) 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 0 0 0 0 0 0 17

Tribal Demand (Diversion) 0 0 0 0 0 0 18

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 1,616 1,622 1,630 1,616 1,622 1,630

Total Demand in the Study Area 232 241 250 79 98 110 140 145 152 22 23 25 1,616 1,622 1,630 2,088 2,130 2,167

Demand that may be met by Other Supplies 0 0 0 0 0 0 0 0 0 0 0 0 1,598 1,585 1,580 1,598 1,585 1,580 19

Potential Colorado River Demand 232 241 250 79 98 110 140 145 152 22 23 25 18 37 51 491 545 588 20

Agricultural Colorado River Demand 229 231 234 22 22 23 126 127 128 21 22 21 0 0 0 398 402 406 21

Municipal and Industrial Colorado River Demand 2 4 6 7 11 11 3 5 5 0.2 0.2 0.2 18 37 51 30 57 73

Energy Colorado River Demand 0 0 0 30 35 36 12 11 15 0 0 0 0 0 0 42 46 50

Minerals Colorado River Demand 0 0 0 20 25 33 0 0 0 0 0 0 0 0 0 20 25 33

Fish, Wildlife, and Recreation Colorado River Demand 0.9 6 10 0.6 5 7 0.3 3 4 0.3 2 4 0 0 0 2 15 25

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Notes

Green River above Fontenelle Fontenelle to Green River Green River to Greendale Little Snake River North Platte STATE TOTAL
 Appendix C5 — Wyoming Water Demand 

 Scenario Quantification

December 2012 C5-31

Notes

1) No changes from Current Projected.

2) Moderate Growth scenario from Green River Basin Plan, 2010. 

3) Population estimates from High Growth scenario of the Green River Basin Plan, 2010. 

4) High Growth scenario from Green River Basin Plan, 2010; gpcd computed with High Growth population and M&I demand.

5) No changes from Current Projected.

6) Low Growth scenario from Green River Basin Plan, 2010. 

7) Low Growth scenario from Green River Basin Plan, 2010. 

8) High Growth scenario from Green River Basin Plan, 2010. 

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12) Population estimates from High Growth scenario of the Green River Basin Plan, 2010. 

13) No changes from Current Projected.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) High Growth scenario from Green River Basin Plan, 2010. 

20) High Growth scenario exports to North Platte from Green River Basin Plan, 2010. 

21) For North Platte, all potential Colorado River Demand is M&I. 
Appendix C6

Arizona Water Demand

Scenario Quantification

December 2012 C6-1 

Appendix C6 ─ Arizona Water Demand 

Scenario Quantification 

1.0 Introduction

This appendix summarizes the data sources used in scenario quantification for Colorado River

demand1 for the state of Arizona and presents the results of quantification. As presented in 

figure C6-1, Arizona is divided into six planning areas, all of which are in the Colorado River 

hydrologic basin: Mainstem, Central Arizona, North Central, Central Yavapai Highlands, 

Upper San Pedro, and San Juan. Data collection and development were completed at the 

planning-area level.

The following sections present background information that summarizes the state’s planning 

areas as well as data sources used to quantify demand scenarios by category. Following the 

background section, results of demand scenario quantification are presented. The results section 

is broken out into an Arizona Study Area summary, followed by Colorado River demand by 

geography, and finally by category. 

2.0 Background 

The Arizona Department of Water Resources (ADWR) is the agency given authority to protect 

the interests and rights of the State and its citizens in matters pertaining to interstate waters. 

ADWR developed information intended to capture Arizona’s demands on the Colorado River for 

use in the Colorado River Basin Water Supply and Demand Study (Study). In order to develop 

demands for the Study, ADWR used data from the Arizona Water Atlas (ADWR, 2010a), 

groundwater active management area assessments, the Water Resources Development 

Commission, Arizona Department of Commerce population projections, Reclamation's 

Mainstem Water Use Accounting Reports, and Bureau of Reclamation’s (Reclamation) planning 

studies for the North Central, Central Yavapai Highlands, and Upper San Pedro areas. In 

addition, for the purpose of this study, ADWR developed a Central Arizona model to project 

demands for Phoenix, Pinal, and Tucson. New demand data were also developed for Upper San 

Pedro River area, the Central Yavapai Highlands area, and the North Central Arizona area.

Quantification of the Basin Study scenarios used these base data. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources included state, regional, and national agency 

reports.

 1 Colorado River demand as computed by Study Area demand minus other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C6-2 December 2012

FIGURE C6-1 

Colorado River Hydrologic Basin and Export Service Areas in Arizona
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-3 

• Agricultural Demand: Irrigated acreage, consumptive factors, and agricultural demands 

were derived by ADWR using various studies and reports shown in the references section 

(ADWR, 2005, 2010b, 2010c, 2011b; Reclamation, 1964–2002, 1996–2008, 2003–2009, 

2006, 2007a, 2009; USGS, 2007, 2009). Agricultural applied water use was calculated based 

on irrigated acreage, consumptive factors, and consumptive demands. 

• Municipal and Industrial (M&I): Population estimates were disaggregated from

Arizona state population (ADWR, 2011a). Demand and consumptive factors were derived by 

ADWR using various studies and reports (ADWR, 2005, 2010b, 2010c, 2011b; Reclamation, 

1964–2002, 1996–2008, 2003–2009, 2006, 2007a, 2009; USGS, 2007, 2009), and per capita 

usage was calculated based on population estimates, demand, and consumptive factors. 

• Energy: Energy demands were derived by ADWR using various studies and reports (Water 

Resources Development Commission, Arizona, 2011). 

• Minerals: Minerals demands were derived by ADWR using various studies and reports

(ADWR, 2010b, 2010c, 2011b). 

• Fish, Wildlife, and Recreation: Fish, wildlife, and recreation demands were derived by 

ADWR using various studies and reports (ADWR, 2005; Reclamation, 1964–2002, 2003–

2009, 2006; USGS, 2007, 2009). 

• Tribal: Tribal demands were derived with input from the tribes and ADWR (ADWR, 2010b, 

2010c, 2011b; Reclamation, 1964–2002, 1996–2008; Reclamation, 2003–2009, 2006). 

3.0 Results of Water Demand Scenario Quantification

This section summarizes Arizona’s Colorado River water demand trends by category across the 

scenarios. The purpose of this section is to describe changes in demands, both temporally and 

geographically, parameters that influence changes in demands, and how the parameters and 

demands differ amongst scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands), independent of the source of supply. However, a portion of the Study 

Area demand, particularly in the Central Arizona planning area, is satisfied from other supplies 

such as surface water, groundwater, and reclaimed water/effluent. To develop estimates of the 

Colorado River demand, the Study Area demand was reduced by estimates of available supply 

from other sources. This appendix focuses on Colorado River demands, but includes discussion 

of the Study Area parameters that led to these demands. Gila River Basin demands are not 

included. The Colorado River Simulation System model would need to be extended, and natural 

flow data sets would need to be developed in order to include the Gila River Basin tributaries in 

the analysis.

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand, Colorado River Demand for the state and 

individual planning areas across the six scenarios, and Colorado River water demand by category 

across the six scenarios. Parameters and demands for all categories and all scenarios, along with 

references for data sources, are included. 
Colorado River Basin 

Water Supply and Demand Study

C6-4 December 2012

3.1 Summary Results of Scenario Quantification

Values were developed for Study Area parameters to quantify Study Area demand for each of 

the scenarios. Colorado River demand was calculated as Study Area demand minus other 

supplies. Tables C6-1A, B, and C present summary results for the demand scenarios considered 

in the Study for Arizona’s Study Area, the Upper Basin, and Lower Basin in Arizona, 

respectively. The tables present agricultural and M&I demand parameters for the entire Study 

Area that distinguish the scenarios, the resulting Study Area demands, and finally the Colorado 

River demands by category. Because other supplies may vary among scenarios, trends observed 

in the parameters and Study Area demands may not be reflected identically in Colorado River 

demand trends. 

Arizona estimates that about 7 million people will be in Arizona’s Study Area by 2015. 

This number is expected to increase to 9.8 to 16.0 million by 2060. The greatest population 

growth is associated with the Rapid Growth (C1 and C2) scenarios and the Enhanced 

Environment (D2) scenario. The Slow Growth (B) scenario has the lowest population growth 

of the scenarios (9.8 million by 2060), but still represents a growth of about 45 percent over 

2015 estimates. 

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, based solely on passive or existing conservation 

targets, is expected to be 4 to 23 percent less in 2060 than in 2015 in all scenarios except for 

Slow Growth (B) scenario, where it is expected to increase by about 1 percent. Usage rates and 

per capita reductions vary across Arizona’s planning areas. 

Irrigated acreage is projected to decrease through 2060 under all scenarios. Decrease in irrigated 

acreage varies by scenario, and ranges from a 30 percent decrease in the Slow Growth (B) 

scenario to a 48 percent decrease in the Rapid Growth (C1 and C2) and Enhanced Environment 

(D2) scenarios. In each case, the bulk of the decrease comes from Central Arizona. The effect of 

decreased irrigated acreage is offset by an increase in water delivery per acre across all scenarios. 

The increase in water delivery per acre ranges from 14 percent Slow Growth (B) scenario to 25 

percent Rapid Growth (C2) scenario. 

Study Area demand for energy is projected to increase under all scenarios due to the growing 

need for electricity generation, including solar. Most of the energy demands are met by local 

supplies. The portion of Study Area demand for energy met by the Colorado River is forecast 

to increase modestly, from about 1,100 acre-feet per year (afy) in 2015 to between 1,400 and 

1,900 afy in 2060. 

Study Area demand for minerals is projected to increase across all scenarios, from 42,000 afy

in 2015 to between 53,000 and 60,000 afy in 2060. 

Study Area demand for tribal use is projected to increase across all scenarios, with demand 

increasing between 21 and 34 percent by 2060. 

Figure C6-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, 

and 3) change in Colorado River demand by demand category. 
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-5 

TABLE C6-1A 

Summary Results of Arizona Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

2015 1 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 6.7–7.5 12.5 9.8 16.0 16.0 12.5 16.0

Change in per capita water usage 

(%), from 2015 — -4% +1% -5% -22% -23% -23%

Irrigated acreage (millions of acres) 0.62 0.36 0.45 0.31 0.31 0.36 0.31

Change in per acre water delivery 

(%), from 2015 — +16% +14% +21% +25% +16% +19%

Study Area Demand (thousand acre-feet [kaf])

2015 1 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 2,056–2,342 1,314 1,759 1,161 1,196 1,314 1,101

M&I demand 1,855 3,099 2,587 3,857 3,158 2,475 3,110

Energy demand 78–87 137 109 188 133 106 133

Minerals demand 42 58 60 58 58 58 58

FWR demand 27–91 27.0 27.7 27.0 30.2 89.7 90.9

Tribal demand 1,015–1,141 1,311 1,224 1,453 1,422 1,287 1,450

Total Study Area Demand2 5,315 5,945 5,766 6,744 5,997 5,330 5,943

Colorado River Demand (kaf)

2015 1 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 1,007–1,145 703 724 703 763 703 668

M&I demand 762 1,460 1,164 2,060 1,357 1,337 1,609

Energy demand 1.1 1.6 1.6 1.9 1.6 1.4 1.6

Minerals demand 42 55 60 54 53 53 54

FWR demand 16–80 15.9 16.6 15.9 19.1 78.6 79.8

Tribal demand2 924–1,051 1,258 1,143 1,408 1,406 1,257 1,408

Total Colorado River Demand2 2,985 3,493 3,109 4,243 3,600 3,431 3,821

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to 

state.
Colorado River Basin 

Water Supply and Demand Study

C6-6 December 2012

TABLE C6-1B 

Summary Results of Arizona Water Demand Scenario Quantification by 2060 for the Upper Basin

Key Study Area Demand Scenario Parameters

2015 1 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 0.012 0.020 0.020 0.020 0.020 0.020 0.020

Change in per capita water usage 

(%), from 2015 — –30% –30% –30% –30% –30% –30%

Irrigated acreage (millions of acres) 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Change in per acre water delivery 

(%), from 2015 — — — — — — — 

Study Area Demand (thousand acre-feet [kaf])

2015 1 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 0 0 0 0 0 0 0

M&I demand 1.68 1.96 1.96 1.96 1.96 1.96 1.96

Energy demand 0 0 0 0 0 0 0

Minerals demand 0 0 0 0 0 0 0

FWR demand 0.34 0.34 0.34 0.34 0.34 0.34 0.34

Tribal demand 38–44 43.3 43.3 70.9 70.9 43.3 70.9

Total Study Area Demand2 40–46 46 46 73 73 46 73

Colorado River Demand (kaf)

2015 1 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 0 0 0 0 0 0 0

M&I demand 1.68 1.96 1.96 1.96 1.96 1.96 1.96

Energy demand 0 0 0 0 0 0 0

Minerals demand 0 0 0 0 0 0 0

FWR demand 0.34 0.34 0.34 0.34 0.34 0.34 0.34

Tribal demand2 38–44 43.3 43.3 70.9 70.9 43.3 70.9

Total Colorado River Demand2 40–46 46 46 73 73 46 73

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to 

state.
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-7 

TABLE C6-1C 

Summary Results of Arizona Water Demand Scenario Quantification by 2060 for the Lower Basin

Key Study Area Demand Scenario Parameters

20151 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 6.7–7.5 12.5 9.8 16.0 16.0 12.5 16.0

Change in per capita water usage 

(%), from 2015 — –4% +1% –5% –22% –23% –23%

Irrigated acreage (millions of acres) 0.62 0.36 0.45 0.31 0.31 0.36 0.31

Change in per acre water delivery 

(%), from 2015 — +16% +14% +21% +25% +16% +19%

Study Area Demand (thousand acre-feet [kaf])

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 2,056–2,342 1,314 1,759 1,161 1,196 1,314 1,101

M&I demand 1,854 3,097 2,585 3,855 3,156 2,473 3,108

Energy demand 78–87 137 109 188 133 106 133

Minerals demand 42 58 60 58 58 58 58

FWR demand 27–91 26.7 27.4 26.7 29.9 89.4 90.6

Tribal demand 971–1,103 1,267 1,180 1,382 1,351 1,244 1,379

Total Study Area Demand2 5,270 5,900 5,720 6,671 5,924 5,284 5,870

Colorado River Demand (kaf)

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 1007–1145 703 724 703 763 703 668

M&I demand 760 1,458 1,162 2,058 1,355 1,335 1,607

Energy demand 1.1 1.6 1.6 1.9 1.6 1.4 1.6

Minerals demand 42 55 60 54 53 53 54

FWR demand 16–79 15.5 16.3 15.5 18.8 78.3 79.5

Tribal demand2 881–1013 1,215 1,100 1,337 1,335 1,213 1,337

Total Colorado River Demand2 2,940 3,447 3,064 4,170 3,527 3,385 3,747

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to 

state.
Colorado River Basin 

Water Supply and Demand Study

C6-8 December 2012

FIGURE C6-2 

Study Area, Colorado River, and Change in Colorado River Demand 

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

Thousand Acre-Feet per Year

Study Area Demand in Arizona

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white and 

colored border

2,000

2,500

3,000

3,500

4,000

4,500

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in Arizona

-1,000

-500

0

500

1,000

1,500

2,000

Thousand Acre-Feet per Year

Change in Colorado River Demand in Arizona, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

All plots include Upper Basin demand of 40 to 73 thousand acre-feet per year 
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-9 

From panel one it can be seen that Study Area demand increases from about 5.3 million acre-feet 

(maf) in 2015 to between 5.3 and 6.7 maf in 2060. The range in Study Area demand growth 

across scenarios in 2060, however, is projected to be as low as 14 kaf or as high as 1,429 kaf. 

About 36 to 46 percent of the Study Area demand is expected to be met by other supplies. 

Panel two provides a view of the range across scenarios of Colorado River demand. This 

demand changes from about 3.0 maf in 2015 to between 3.1 and 4.2 maf in 2060 (or 5 to 

41 percent) depending on the scenario. This difference results in a Colorado River demand range 

of about 1.1 maf across the scenarios in 2060, or 36 percent.

Panel three shows how specific categories affect the projected change in Colorado River demand 

by scenario. Growth in M&I demand across all scenarios results in the greatest increase in 

demand, followed by tribal demand and minerals demand. Agricultural demand decreases across 

all scenarios.

Figure C6-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The 1.1 maf range across scenarios in 2060 is easily discernible, with a relatively even 

spread over the range across the scenarios. 

FIGURE C6-3 

Historical Use and Future Projected Demand 

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Apportionment

Note: Includes Upper and Lower Basin demands
Colorado River Basin 

Water Supply and Demand Study

C6-10 December 2012

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in figures 

C6-4 and C6-5. These figures show two geographic levels: Study Area in Arizona, and 

individual planning areas. Demands at each geographic level are shown across the scenarios. 

The columns to the right show Colorado River demand at a point in time (2015, 2035, or 2060) 

by relative contribution of the categories. 

Colorado River demand2 in Arizona is primarily in the Mainstem and Central Arizona planning 

areas. Demands in the Mainstem are primarily agricultural and tribal, whereas demands in 

Central Arizona are primarily M&I, with some tribal and agricultural. 

Figure C6-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. Change in Colorado River demand is dominated by the Central Arizona planning area, 

with a large increase in M&I demands and a smaller increase in tribal demands, offset by a 

decrease in agricultural demands. 

3.3 Colorado River Demand by Category

3.3.1 Agricultural

Agricultural water demand is driven by irrigated acreage and water delivery per acre. Water 

delivery per acre is the amount of water diverted per irrigated acre. Components of this use 

include transmission and delivery losses (surface evaporation, riparian demand, and seepage), 

and on-farm losses that are made up of evaporation, crop irrigation requirements, and tail water 

(return). Each of these factors will vary by location (precipitation, growing season, etc.), 

irrigation method, and crop type. 

Figure C6-7 presents the following by scenario in 2015, 2035, and 2060: 

• Change in agricultural demand for Colorado River water 

• Change in agricultural demand for Colorado River water by planning area 

• Agricultural demand as a portion of Colorado River water demand (right hand side 

of graph) 

As can be seen from figure C6-7, agricultural water demand makes up 34 to 39 percent of 

Colorado River demand in Arizona in 2015, and drops to 17 to 23 percent of Colorado River 

demand in 2060. This drop results from both a decrease in agricultural water demand and an 

increase in other categories of demand. 

There are two Arizona planning areas with significant agricultural water use: the Mainstem and 

the Central Arizona planning areas. Mainstem users hold senior water rights and have the 

greatest demand. Lower priority water rights supply the Central Arizona planning area. 

Agricultural demand is forecast to decrease over the Study period by varying amounts in the 

Central Arizona planning area, ranging from about 330 kaf to 420 kaf, depending on the 

efficiency and acreage assumptions in each scenario. Some decreases are assumed to result from 

the conversion of agricultural lands to urban development as the Central Arizona Project

agricultural pool decreases over time until it is eliminated in 2030. 

 2 Potential Colorado River demand is based on changes in parameters such as population and for the purpose of the Study is

 not limited by apportionment.
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-11

FIGURE C6-4 

Colorado River Demand in Arizona

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and Recreation

Tribal

Legend Category Plot (Right)

0

1

2

3

4

5

6

2015 2035 2060

KAF

Legend Demand Plots

Current Projected (A) Slow Growth (B)

Rapid Growth (C1) Rapid Growth (C2)

Enhanced Environment (D1) Enhanced Environment (D2)

Tribal

Tribal

Tribal

Municipal and Industrial

Municipal and Industrial

Municipal and Industrial

Agricultural

Agricultural

Agricultural

2015

2035

2060

0

1,000

2,000

3,000

2015 2035 2060

KAF

Mainstem

0

1,000

2,000

3,000

2015 2035 2060

KAF

Upper San Pedro River

0

1,000

2,000

3,000

2015 2035 2060

KAF

North Central and 

Navajo Nation

0

1,000

2,000

3,000

2015 2035 2060

KAF

Central Arizona

0

1,000

2,000

3,000

2015 2035 2060

KAF

San Juan

0

1,000

2,000

3,000

2015 2035 2060

KAF

Central Yavapai 

Highlands

2,000

2,500

3,000

3,500

4,000

4,500

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Colorado River Demand in Arizona

Includes Upper Basin demand as shown in San Juan plot below
Colorado River Basin 

Water Supply and Demand Study

C6-12 December 2012

FIGURE C6-5 

Colorado River Demand by Category

0

1,000

2,000

3,000

2015 2035 2060

KAF

Central Arizona

0

1,000

2,000

3,000

2015 2035 2060

KAF

Upper San Pedro River

0

1,000

2,000

3,000

2015 2035 2060

KAF

Mainstem

0

1,000

2,000

3,000

2015 2035 2060

KAF

San Juan

0

1,000

2,000

3,000

2015 2035 2060

KAF

North Central and 

Navajo Nation

0

1,000

2,000

3,000

2015 2035 2060

KAF

Central Yavapai 

Highlands

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

Thousand Acre-Feet per Year (KAF)

Colorado River Demand in Arizona

2015 2035 2060

Includes Upper Basin demand as shown in San Juan plot below

Tribal

Tribal

Tribal

Municipal and Industrial

Municipal and Industrial

Municipal and Industrial

Agricultural

Agricultural

Agricultural

201520352060

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-13

FIGURE C6-6 

Change in Colorado River Demand in Arizona from 2015 by Category

-500

0

500

1,000

1,500

2015 2035 2060

KAF

Central Yavapai 

Highlands

-500

0

500

1,000

1,500

2015 2035 2060

KAF

Mainstem

-500

0

500

1,000

1,500

2015 2035 2060

KAF

Upper San Pedro River

-500

0

500

1,000

1,500

2015 2035 2060

KAF

Central Arizona

-500

0

500

1,000

1,500

2015 2035 2060

KAF

North Central and 

Navajo Nation

-1,000

-500

0

500

1,000

1,500

2,000

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Arizona, from 2015

2015 2035 2060

Includes Upper Basin change in demand as shown in San Juan plot below

Tribal

Tribal

Tribal

Municipal and Industrial

Municipal and Industrial

Municipal and Industrial

Agricultural

Agricultural

Agricultural

201520352060

-500

0

500

1,000

1,500

2015 2035 2060

KAF

San Juan

Agricultural Municipal and Industrial

Energy Minerals

Fish and Wildlife and Recreation Tribal

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2
Colorado River Basin 

Water Supply and Demand Study

C6-14 December 2012

FIGURE C6-7 

Change in Colorado River Demand in Arizona from 2015 for Agriculture

-450

-350

-250

-150

-50

2015 2035 2060

KAF

Mainstem

-450

-350

-250

-150

-50

2015 2035 2060

KAF

North Central and 

Navajo Nation

-450

-350

-250

-150

-50

2015 2035 2060

KAF

Central Arizona

-450

-350

-250

-150

-50

2015 2035 2060

KAF

Upper San Pedro River

-450

-350

-250

-150

-50

2015 2035 2060

KAF

Central Yavapai 

Highlands

201520352060

-450

-350

-250

-150

-50

2015 2035 2060

KAF

San Juan

N/A

A

B

A

B

C1C1

C2C2

D1

D2

D1

D2

-450

-400

-350

-300

-250

-200

-150

-100

-50

0

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Arizona, from 2015

Agricultural

Agriculture is 33.5 - 38.8% of Colorado River demand*

Agriculture is 19.9 - 24% of Colorado River demand*

Agriculture is 16.6 - 23.3% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-15

3.3.2 Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita water use, with 

the addition of self-served industrial (SSI) demand. Municipal per capita water demand 

calculations include industrial, commercial, institutional, and residential water demand. 

A number of factors may influence the M&I per capita water use of a given community, 

including the amount of industrial demand, climate, number of institutional facilities, and 

number of visitors. 

SSI users are industries located in a given area that have their own water supply systems and 

are therefore not directly related to local measures of population and M&I per capita water use. 

Figure C6-8 presents the following by scenario in 2015, 2035, and 2060: 

• Change in M&I demand for Colorado River water 

• Change in M&I demand for Colorado River water in individual planning areas 

• M&I demand as a portion of Colorado River water demand (right hand side of graph)

As can be seen from figure C6-8, M&I water demand is the one of the largest components of 

Colorado River demand, changing from 26 to 28 percent in 2015 to between 37 and 49 percent 

of Colorado River demand in 2060, depending on which scenario is considered. 

Colorado River demand for M&I use increases over time from 2015 to 2060 across all scenarios. 

The increase is primarily due to population increase as M&I per capita water use decreases over 

time across all scenarios; SSI demand also increases across all scenarios. 

In examining the planning areas, population growth from 2015 to 2060 drives the increase in 

M&I demand for Colorado River water in the Central Arizona planning area and to a lesser 

extent in the Mainstem planning area. Colorado River water allocations and the availability of 

other supplies also affect M&I Colorado River water demand. 

Increases in population are somewhat tempered by decreases in M&I per capita water use. Per 

capita water use is expected to be 4 to 23 percent less in 2060 than in 2015 in all scenarios except 

for Slow Growth (B) scenario, where it is expected to increase by about 1 percent.

3.3.3 Energy

Water demand for energy can be estimated through known plans for new power plants or 

through applying a per capita energy water use factor. Power facilities often serve areas remote 

from their locations and therefore potentially represent exports or imports of water from the 

Study Area to meet these distributed needs. 

Figure C6-9 presents the following by scenario in 2015, 2035, and 2060: 

• Change in energy demand for Colorado River water 

• Change in energy demand for Colorado River water in individual planning areas 

• Energy demand as a portion of Colorado River water demand (right hand side of graph)

As can be seen from figure C6-9, energy water demand is a small fraction of Colorado River 

demand, making up less than 0.1 percent of Colorado River demand in 2060. 
Colorado River Basin 

Water Supply and Demand Study

C6-16 December 2012

FIGURE C6-8 

Change in Colorado River Demand in Arizona from 2015 for M&I 

0

500

1,000

1,500

2015 2035 2060

KAF

Central Yavapai 

Highlands

0

500

1,000

1,500

2015 2035 2060

KAF

Upper San Pedro River

0

500

1,000

1,500

2015 2035 2060

KAF

Mainstem

0

500

1,000

1,500

2015 2035 2060

KAF

Central Arizona

0

500

1,000

1,500

2015 2035 2060

KAF

North Central and 

Navajo Nation

201520352060

0

500

1,000

1,500

2015 2035 2060

KAF

San Juan

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

200

400

600

800

1,000

1,200

1,400

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Arizona, from 2015

Municipal and Industrial

Includes Upper Basin change in demand as shown in San Juan plot below

M&I is 25.5 - 27.9% of Colorado River demand*

M&I is 32.6 - 38.1% of Colorado River demand*

M&I is 37.4 - 48.5% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-17

FIGURE C6-9 

Change in Colorado River Demand in Arizona from 2015 for Energy

0.0

0.2

0.4

0.6

2015 2035 2060

KAF

Mainstem

0.0

0.2

0.4

0.6

2015 2035 2060

KAF

Upper San Pedro River

0.0

0.2

0.4

0.6

2015 2035 2060

KAF

North Central and 

Navajo Nation

0.0

0.2

0.4

0.6

2015 2035 2060

KAF

Central Arizona

201520352060

0.0

0.2

0.4

0.6

2015 2035 2060

KAF

San Juan

0.0

0.2

0.4

0.6

2015 2035 2060

KAF

Central Yavapai 

Highlands

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Arizona, from 2015

Energy

Energy is 0.04% of Colorado River demand*

Energy is 0.04 - 0.05% of Colorado River demand*

Energy is 0.04 - 0.05% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

N/A

*Percentages shown 

represent the range 

across scenarios

N/A
Colorado River Basin 

Water Supply and Demand Study

C6-18 December 2012

Energy demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios, with the increase ranging from about 0.3 to 0.7 kaf. 

Water use associated with energy demand is estimated on a per capita basis for the Mainstem and 

Central Arizona planning areas, and is estimated to increase as the population increases over 

time. Other planning area water use related to energy demand is estimated based on existing 

power generation facilities use.

3.3.4 Minerals Extraction

Water demand for mineral production can be estimated through existing uses and known plans 

for extraction in the Study Area. Water demand for mineral production can vary significantly, 

based on market prices for a given product. 

Figure C6-10 presents the following by scenario in 2015, 2035, and 2060: 

• Change in mineral production demand for Colorado River water 

• Change in mineral production demand for Colorado River water in individual planning 

areas

• Minerals production demand as a portion of Colorado River demand (right hand side of 

graph) 

As can be seen from figure C6-10, minerals water demand is a small fraction of Colorado River 

demand, changing from 1.4 percent in 2015 to between 1.3 and 1.9 percent of Colorado River 

demand in 2060, depending on which scenario is considered. 

Minerals demand for Colorado River water increases through time by about 13 kaf from 2015 to 

2060 across all scenarios. 

Demand for Colorado River water for minerals extraction is present only in the Central Arizona 

planning area; accordingly, all of the increase occurs in the Central Arizona planning area.

3.3.5 Fish, Wildlife, and Recreation

Water demand for fish, wildlife, and recreation is estimated from existing agreements or known 

consumptive use associated with this demand category. Non-consumptive demands associated 

with fish, wildlife, and recreation, including in-stream flow requirements, are represented 

through the metrics portion of the Study presented in Technical Report D – System Reliability 

Metrics. 

Fish, wildlife, and recreation demands are forecast to remain constant through time, although the 

demands are variable among different scenarios. All scenarios have fish, wildlife, and recreation 

demands between about 16 and 19 kaf, except the Enhanced Environment (D1 and D2) scenarios 

which have demands at about 80 kaf. All fish, wildlife, and recreation demands are in the 

Mainstem planning area. 
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-19

FIGURE C6-10

Change in Colorado River Demand in Arizona from 2015 for Minerals

0

5

10

15

20

2015 2035 2060

KAF

Mainstem

0

5

10

15

20

2015 2035 2060

KAF

Upper San Pedro River

0

5

10

15

20

2015 2035 2060

KAF

North Central and 

Navajo Nation

0

5

10

15

20

2015 2035 2060

KAF

Central Arizona

201520352060

0

5

10

15

20

2015 2035 2060

KAF

San Juan

0

5

10

15

20

2015 2035 2060

KAF

Central Yavapai 

Highlands

A

A

B

B

C1

C1

C2

D1

C2

D1

D2

D2

0

2

4

6

8

10

12

14

16

18

20

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Arizona, from 2015

Minerals

Minerals is 1.4% of Colorado River demand

Minerals is 1.6 - 2% of Colorado River demand*

Minerals is 1.3 - 1.9% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

N/A

N/A

*Percentages shown 

represent the range 

across scenarios

N/A
Colorado River Basin 

Water Supply and Demand Study

C6-20 December 2012

3.3.6 Tribal

Water demand for federally recognized tribes in Arizona with rights to Colorado River water 

relied on information submitted by the Ten Tribes Partnership for use in the Colorado River 

Interim Surplus Criteria Final Environmental Impacts Statement (Reclamation, 2000) and used 

in the more recent Colorado River Interim Guidelines for Lower Basin Shortages and 

Coordinated Operations of Lake Powell and Lake Mead Final Environmental Impact Statement

(Reclamation, 2007b), information from ADWR, input from the individual tribes, and 

Reclamation’s 2005 to 2009 Decree Accounting Report (Reclamation, 2007 and 2010). The 

projected Navajo Nation demands were provided by the Navajo Nation Department of Water 

Resources and modified to fit the storyline narratives regarding tribal use under each scenario. 

Figure C6-11 presents the following by scenario in 2015, 2035, and 2060: 

• Change in tribal demand for Colorado River water 

• Change in tribal demand for Colorado River water in individual planning area 

• Tribal demand as a portion of Colorado River demand (right hand side of graph) 

As can be seen from figure C6-11, tribal water demand is one of the larger components of 

Colorado River demand in Arizona, increasing slightly from 31 to 35 percent in 2015 to between 

33 and 39 percent of Colorado River demand in 2060, depending on which scenario is 

considered. 

Colorado River tribal demand increases over time by 217 to 357 kaf (about 21 to 34 percent) 

from 2015 to 2060 across all scenarios. These increases are primarily due to development of 

demands under existing water rights and the realization of new tribal claims and settlements. 

Increases occur mostly in the Central Arizona planning area, but there is also some increase in 

the Mainstem planning area. The rate of increase is greatest in Rapid Growth (C1 and C2) and 

Enhanced Environment (D2) scenarios. 

For additional information on tribal demands, see appendix C9. 

3.4 Summary Tables of Parameters and Demands by Category

Tables C6-2 to C6-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 
Appendix C6 — Arizona Water Demand

Scenario Quantification

December 2012 C6-21

FIGURE C6-11

Change in Colorado River Demand in Arizona from 2015 for Tribal

0

100

200

300

2015 2035 2060

KAF

Mainstem

0

100

200

300

2015 2035 2060

KAF

Upper San Pedro River

0

100

200

300

2015 2035 2060

KAF

North Central and 

Navajo Nation

0

100

200

300

2015 2035 2060

KAF

Central Arizona

201520352060

0

100

200

300

2015 2035 2060

KAF

San Juan

0

100

200

300

2015 2035 2060

KAF

Central Yavapai 

Highlands

A

B

A

B

C1

C1

C2

C2

D1

D1

D2

D2

0

50

100

150

200

250

300

350

400

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Arizona, from 2015

Tribal

Includes Upper Basin change in demand as shown in San Juan plot below

Tribal is 31.3 - 35.1% of Colorado River demand*Tribal is 37.9 - 41.6% of Colorado River demand*

Tribal is 33.2 - 39.1% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

N/A

N/A

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin 

Water Supply And Demand Study

C6-22 December 2012

TABLE C6-2 

Total Demand within Study Area under Current Projected (A) Scenario

ARIZONA LEGEND: 999 From States 999 From State Plans

Units are thousand acre-feet per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 168 168 168 447 288 189 0 0 0 7 6 4 0.1 0.1 0.1 623 462 361 0 0 0 0 0 0 623 462 361 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 3.2 3.2 3.2 3.6 3.6 3.6 2.9 2.9 2.9 4.22 4.54 4.88 4.22 4.54 4.88

Consumptive factor [%] 61% 61% 61% 100% 100% 100% 100% 100% 100% 100% 100% 100% 83% 79% 75% 83% 79% 75% 2

Demand (Consumptive) 703 703 703 1,449 924 596 0 0 0 27 22 15 0.4 0.4 0.4 2,179 1,649 1,314 0 0 0 0 0 0 2,179 1,649 1,314 3

Municipal and Industrial (M&I) Population [thousands] 298 434 528 6,348 9,086 11,305 101 116 125 250 340 402 94 116 134 7,091 10,091 12,493 12 16 20 12 16 20 7,103 10,107 12,513 4

M&I Per Capita Use (Diversion) [gpcd] 271 271 277 215 209 207 126 127 127 151 138 121 187 187 187 214 208 206 123 111 86 123 111 86 214 208 206 5, 6

Consumptive factor [%] 66% 68% 70% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 98% 98% 98% 100% 100% 100% 100% 100% 100% 98% 98% 98% 2

M&I Demand (Consumptive) 59 90 115 1,532 2,131 2,622 14 16 18 42 53 55 20 24 28 1,668 2,314 2,838 2 2 2 2 2 2 1,670 2,316 2,840

Self Served Industrial Demand (Consumptive) 5 6 6 170 220 233 0 0 0 9 13 18 1 2 2 186 242 259 0 0 0 0 0 0 186 242 259 3

Demand (Consumptive) 65 96 121 1,702 2,351 2,855 14 16 18 51 66 72 21 27 30 1,854 2,555 3,097 2 2 2 2 2 2 1,855 2,557 3,099

Energy Demand (Consumptive) 0.4 0.6 0.7 81 112 136 0 0 0 0 0 0 0 0 0 81 113 137 0 0 0 0 0 0 81 113 137 7

Minerals Demand (Consumptive) 0 0 0 42 58 58 0 0 0 0 0 0 0 0 0 42 58 58 0 0 0 0 0 0 42 58 58 8

Fish, Wildlife, and Recreation Demand (Consumptive) 16 16 16 0 0 0 0.3 0.3 0.3 0 0 0 11 11 11 27 27 27 0.3 0.3 0.3 0.3 0.3 0.3 27 27 27 9

Tribal Demand (Consumptive) 552 556 556 535 735 711 0.7 0.8 0.8 0 0 0 0 0 0 1,087 1,291 1,267 44 43 43 44 43 43 1,131 1,334 1,311 10

Total Hydrologic Basin Demand (Consumptive) 1,336 1,370 1,396 3,808 4,180 4,356 15 17 19 79 87 87 32 38 42 5,270 5,692 5,900 46 46 46 46 46 46 5,315 5,738 5,945

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population [thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 1,336 1,370 1,396 3,808 4,180 4,356 15 17 19 79 87 87 32 38 42 5,270 5,692 5,900 46 46 46 46 46 46 5,315 5,738 5,945 11

Demand that may be met by Other Supplies 0 0 0 2,233 2,508 2,359 11 10 8 72 72 72 14 14 14 2,330 2,604 2,453 0 0 0 0 0 0 2,330 2,604 2,453 12

Potential Colorado River Demand 1,336 1,370 1,396 1,575 1,671 1,997 4 8 11 6 15 15 18 24 28 2,940 3,088 3,447 46 46 46 46 46 46 2,985 3,134 3,493 13

Agricultural Colorado River Demand 703 703 703 421 0 0 0 0 0 0 0 0 0 0 0 1,124 703 703 0 0 0 0 0 0 1,124 703 703

Municipal and Industrial Colorado River Demand 65 96 121 667 957 1,283 4 8 11 6 15 15 18 24 28 760 1,099 1,458 2 2 2 2 2 2 762 1,101 1,460

Energy Colorado River Demand 0.4 0.6 0.7 0.7 0.9 0.9 0 0 0 0 0 0 0 0 0 1 1 2 0 0 0 0 0 0 1 1 2

Minerals Colorado River Demand 0 0 0 42 54 55 0 0 0 0 0 0 0 0 0 42 54 55 0 0 0 0 0 0 42 54 55

Fish, Wildlife, and Recreation Colorado River Demand 16 16 16 0 0 0 0 0 0 0 0 0 0 0 0 16 16 16 0.3 0.3 0.3 0.3 0.3 0.3 16 16 16

Tribal Colorado River Demand 552 556 556 445 660 659 0 0 0 0 0 0 0 0 0 997 1,216 1,215 44 43 43 44 43 43 1,041 1,259 1,258

STATE TOTAL

Notes

Mainstem Central Arizona

North Central and 

Navajo Nation

Central Yavapai 

Highlands Upper San Pedro River

LOWER BASIN 

SUBTOTAL San Juan

UPPER BASIN 

SUBTOTAL
 Appendix C6 — Arizona Water Demand 

 Scenario Quantification

December 2012 C6-23

Notes

1) Personal communication, ADWR, Aug. 26, 2011 (ADWR, 2011c).

2) Mainstem: 61 percent based Personal communication, ADWR, Oct. 21, 2011 (ADWR, 2011c); Non-mainstem: 100 percent based on 

consumptive need equaling diversion from mainstem.

3) Personal communication, ADWR, Aug. 26, 2011; non-mainstem areas.

4) Personal communication, ADWR, Aug. 26, 2011. Population figures for each planning area are disaggregated from total Arizona state 

population. See Draft Arizona Demand Narrative, Aug. 2011. 

5) In mainstem, gallons per capital per day (gpcd) increase due to the addition of Arizona's unallocated Priority 4 entitlement, which is 

assumed to be allocated after 2020; no population has been associated with this allocation. 

6) In North Central, municipal gpcds based on non-tribal population estimates; 2015–100,580; 2035–118,010; and 2060–131,450. Tribal 

population estimates are: 2015–17,890; 2035–20,990; and 2060–23,380.

7) Personal communication, ADWR, Aug. 26, 2011. Mainstem and Central based on per capita energy factor of 18.4 megawatt hours per 

person per year, and 650 gallons per megawatt hour. 

8) Personal communication, ADWR, Aug. 26, 2011.

9) Personal communication, ADWR, Aug. 26, 2011. Mainstem: 2005–2009 average. Upper San Pedro: Use based on Water Management 

of the Regional Aquifer in the Sierra Vista Subwatershed, Arizona–2007 report to Congress.

10) Personal communication, ADWR, Oct. 21, 2011. Tribal demands include agricultural, M&I, and other uses. There are approximately 

82,000 acres of tribal agricultural lands in the mainstem and 180 acres in North Central.

11) Calculated from the sum of Hydrologic Basin (Consumptive) Demand and Adjacent Areas (Diversion) Demand.

12) Personal communication, ADWR, Oct. 21, 2011. Other local supplies include surface water, groundwater, groundwater mining, and 

effluent re-use.

13) For planning areas other than Central AZ, all Colorado River demand is municipal. For Central AZ, based on recent distribution of Central 

Arizona Project (CAP) water (20110510 Basin Study AZCAPBreakout.xlsx). Approach was to start with recent distribution, and then 

make the change in distribution the same as the change in overall demands. This was done for current trends only. The values for all 

categories but M&I were then applied to all other scenarios, with M&I used as the makeup term. The formulas also were checked to 

make sure Colorado River demand was not greater than total demand for each category–if so, M&I makes up the difference.
Colorado River Basin 

Water Supply And Demand Study

C6-24 December 2012

TABLE C6-3 

Total Demand within Study Area under Slow Growth (B) Scenario

ARIZONA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 168 168 168 464 346 273 0 0 0 7 6 4 0.1 0.1 0.1 640 520 446 0 0 0 0 0 0 640 520 446 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 7.18 7.18 7.18 3.41 3.73 3.72 0.00 0.00 0.00 4.37 4.37 4.37 3.57 3.57 3.57 4.41 4.86 5.03 0.00 0.00 0.00 0.00 0.00 0.00 4.41 4.86 5.03 2

Consumptive factor [%] 60% 60% 60% 100% 100% 100% 0% 0% 0% 100% 100% 100% 100% 100% 100% 83% 81% 78% 0% 0% 0% 0% 0% 0% 83% 81% 78%

Demand (Consumptive) 724 724 724 1,585 1,291 1,017 0 0 0 33 26 18 0.5 0.5 0.5 2,342 2,041 1,759 0 0 0 0 0 0 2,342 2,041 1,759

Municipal and Industrial (M&I) Population [thousands] 283 367 412 6,026 7,679 8,831 96 98 105 237 288 314 89 98 104 6,731 8,529 9,766 12 16 20 12 16 20 6,743 8,545 9,787 3

M&I Per Capita Use (Diversion) [gpcd] 274 282 302 219 220 218 128 133 139 156 162 171 189 196 207 218 219 219 123 111 86 123 111 86 217 219 219 4

Consumptive factor [%] 66% 67% 69% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 98% 98% 98% 100% 100% 100% 100% 100% 100% 98% 98% 98%

M&I Demand (Consumptive) 57 78 96 1,480 1,890 2,156 14 15 16 41 52 60 19 22 24 1,611 2,056 2,353 2 2 2 2 2 2 1,613 2,058 2,355

Self Served Industrial Demand (Consumptive) 5 6 6 165 203 206 0 0 0 9 13 18 1 2 2 182 224 232 0 0 0 0 0 0 182 224 232 5

Demand (Consumptive) 62 84 103 1,645 2,093 2,362 14 15 16 51 65 78 20 24 26 1,792 2,280 2,585 2 2 2 2 2 2 1,794 2,282 2,587

Energy Demand (Consumptive) 0.4 0.5 0.5 77 96 108 0 0 0 0 0 0 0 0 0 78 97 109 0 0 0 0 0 0 78 97 109 6

Minerals Demand (Consumptive) 0 0 0 42 60 60 0 0 0 0 0 0 0 0 0 42 60 60 0 0 0 0 0 0 42 60 60 7

Fish, Wildlife, and Recreation Demand (Consumptive) 16 16 16 0 0 0 0.3 0.3 0.3 0 0 0 11 11 11 27 27 27 0.3 0.3 0.3 0.3 0.3 0.3 28 28 28 8

Tribal Demand (Consumptive) 436 439 439 535 740 740 0.7 0.8 0.8 0 0 0 0 0 0 971 1,180 1,180 44 43 43 44 43 43 1,015 1,224 1,224 9

Total Hydrologic Basin Demand (Consumptive) 1,239 1,264 1,283 3,884 4,280 4,287 15 16 18 83 91 95 32 35 38 5,252 5,686 5,720 46 46 46 46 46 46 5,298 5,731 5,766

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population [thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 1,239 1,264 1,283 3,884 4,280 4,287 15 16 18 83 91 95 32 35 38 5,252 5,686 5,720 46 46 46 46 46 46 5,298 5,731 5,766

Demand that may be met by Other Supplies 0 0 0 2,250 2,616 2,563 11 9 8 72 72 72 14 14 14 2,346 2,711 2,657 0 0 0 0 0 0 2,346 2,711 2,657 10

Potential Colorado River Demand 1,239 1,264 1,283 1,634 1,664 1,725 4 7 9 11 19 23 18 21 24 2,906 2,975 3,064 46 46 46 46 46 46 2,952 3,020 3,109

Agricultural Colorado River Demand 724 724 724 421 0 0 0 0 0 0 0 0 0 0 0 1,145 724 724 0 0 0 0 0 0 1,145 724 724 11

Municipal and Industrial Colorado River Demand 62 84 103 726 942 1,003 4 7 9 11 19 23 18 21 24 821 1,073 1,162 2 2 2 2 2 2 823 1,075 1,164

Energy Colorado River Demand 0.4 0.5 0.5 0.8 1 1 0 0 0 0 0 0 0 0 0 1 1 2 0 0 0 0 0 0 1 1 2

Minerals Colorado River Demand 0 0 0 42 60 60 0 0 0 0 0 0 0 0 0 42 60 60 0 0 0 0 0 0 42 60 60

Fish, Wildlife, and Recreation Colorado River Demand 16 16 16 0 0 0 0 0 0 0 0 0 0 0 0 16 16 16 0.3 0.3 0.3 0.3 0.3 0.3 17 17 17

Tribal Colorado River Demand 436 439 439 445 661 661 0 0 0 0 0 0 0 0 0 881 1,100 1,100 44 43 43 44 43 43 924 1,143 1,143

STATE TOTAL

Notes

Mainstem Central Arizona

North Central and 

Navajo Nation

Central Yavapai 

Highlands Upper San Pedro River

LOWER BASIN 

SUBTOTAL San Juan

UPPER BASIN 

SUBTOTAL
 Appendix C6 — Arizona Water Demand 

 Scenario Quantification

December 2012 C6-25

Notes

1) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona: higher utilization rate (up < 10 percent), slower land 

conversion (driven by population); Other areas: no change from Current Projected.

2) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona and mainstem: 5 percent increase relative to Current 

Projected. Note that 5 percent is applied to each of 3 different Active Management Areas (AMAs) in Central Arizona, which, combined 

with changes in acreage, results in an average difference from Current Projected that does not equal 5 percent. Other areas: 20 percent

increase from Current Projected.

3) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Annual population change is reduced by 35 percent relative to Current 

Projected. 

4) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona: increase system loss to 10 percent (cannot exceed 

10 percent in AMAs); All other areas: increase gpcd by 10 percent to 2060 due to increased system loss.

5) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. SSI is a function of population.

6) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. No change in per-capita energy water use values from Current 

Projected (Water Resources Development Commission "moderate"). However, total energy use is reduced due to population reduction. 

7) No change from Current Projected.

8) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem: National Wildlife Refuges increased use of 5 percent

relative to Current Projected; Other areas: no change from Current Projected.

9) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem: use ADWR tribal projection, which is less than the "Ten 

Tribes Partnership" assumption used in Current Projected; Central Arizona: no change from Current Projected; North Central and Navajo 

Nation: based on population estimates for the portions of the Navajo and Hopi Reservations located within the North Central portion of the 

Study Area.

10) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. North Central: local supplies were calculated as the difference between 

the total demand and unmet demand; Central Yavapai Highlands and Upper San Pedro Study: based on information from Reclamation

appraisal reports. Central AZ: AZ used internal models to estimate its demands met by Other Supplies and CAP deliveries. The remaining 

or unmet demands are represented as Potential Colorado River Basin demands, where CAP deliveries are a portion of potential Colorado 

River Demands in the Central AZ planning area.

11) For planning areas other than Central AZ, all Colorado River demand is municipal. For Central AZ, based on recent distribution of CAP 

water (20110510 Basin Study AZCAPBreakout.xlsx). Approach was to start with recent distribution, and then make the change in 

distribution the same as the change in overall demands. This was done for Current Projected only. The values for all categories but M&I 

were then applied to all other scenarios, with M&I used as the makeup term. The formulas also were checked to make sure Colorado 

River demand was not greater than total demand for each category–if so, M&I makes up the difference.
Colorado River Basin 

Water Supply And Demand Study

C6-26 December 2012

TABLE C6-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

ARIZONA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 168 168 168 429 231 141 0 0 0 7 6 4 0.1 0.1 0.1 605 405 314 0 0 0 0 0 0 605 405 314 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 3.24 3.17 3.14 0.00 0.00 0.00 3.64 3.64 3.64 2.95 2.95 2.95 4.25 4.70 5.14 0.00 0.00 0.00 0.00 0.00 0.00 4.25 4.70 5.14 2

Consumptive factor [%] 61% 61% 61% 100% 100% 100% 0% 0% 0% 100% 100% 100% 100% 100% 100% 83% 76% 72% 0% 0% 0% 0% 0% 0% 83% 76% 72%

Demand (Consumptive) 703 703 703 1,389 731 443 0 0 0 27 22 15 0.4 0.4 0.4 2,120 1,456 1,161 0 0 0 0 0 0 2,120 1,456 1,161

Municipal and Industrial (M&I) Population [thousands] 313 513 675 6,685 10,738 14,452 106 137 159 263 402 514 99 137 171 7,467 11,926 15,971 12 16 20 12 16 20 7,479 11,942 15,991 3

M&I Per Capita Use (Diversion) [gpcd] 271 269 272 214 206 203 126 127 127 151 138 121 187 187 187 213 206 203 123 111 86 123 111 86 213 205 202 4

Consumptive factor [%] 66% 70% 72% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 98% 98% 98% 100% 100% 100% 100% 100% 100% 98% 98% 98%

M&I Demand (Consumptive) 63 108 149 1,603 2,481 3,290 15 19 23 45 62 70 21 29 36 1,746 2,699 3,567 2 2 2 2 2 2 1,748 2,701 3,569

Self Served Industrial Demand (Consumptive) 5 6 7 174 237 261 0 0 0 9 13 18 1 2 2 190 259 288 0 0 0 0 0 0 190 259 288 5

Demand (Consumptive) 68 114 156 1,777 2,718 3,551 15 19 23 54 75 88 22 31 38 1,936 2,957 3,855 2 2 2 2 2 2 1,938 2,959 3,857

Energy Demand (Consumptive) 0.4 0.7 1.0 86 143 187 0 0 0 0 0 0 0 0 0 87 144 188 0 0 0 0 0 0 87 144 188 6

Minerals Demand (Consumptive) 0 0 0 42 58 58 0 0 0 0 0 0 0 0 0 42 58 58 0 0 0 0 0 0 42 58 58 7

Fish, Wildlife, and Recreation Demand (Consumptive) 16 16 16 0 0 0 0.3 0.3 0.3 0 0 0 11 11 11 27 27 27 0.3 0.3 0.3 0.3 0.3 0.3 27 27 27 8

Tribal Demand (Consumptive) 552 556 556 535 732 703 17 73 124 0 0 0 0 0 0 1,103 1,360 1,382 38 55 71 38 55 71 1,141 1,415 1,453 9

Total Hydrologic Basin Demand (Consumptive) 1,339 1,389 1,431 3,829 4,382 4,942 32 92 147 81 97 102 33 42 49 5,315 6,002 6,671 40 57 73 40 57 73 5,355 6,059 6,744

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population [thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 1,339 1,389 1,431 3,829 4,382 4,942 32 92 147 81 97 102 33 42 49 5,315 6,002 6,671 40 57 73 40 57 73 5,355 6,059 6,744

Demand that may be met by Other Supplies 0 0 0 2,250 2,541 2,405 12 12 10 72 72 72 14 14 14 2,347 2,638 2,501 0 0 0 0 0 0 2,347 2,638 2,501 10

Potential Colorado River Demand 1,339 1,389 1,431 1,579 1,841 2,536 21 81 137 9 25 30 20 28 35 2,967 3,364 4,170 40 57 73 40 57 73 3,007 3,421 4,243

Agricultural Colorado River Demand 703 703 703 379 0 0 0 0 0 0 0 0 0 0 0 1,082 703 703 0 0 0 0 0 0 1,082 703 703 11

Municipal and Industrial Colorado River Demand 68 114 156 713 1,127 1,823 4 9 14 9 25 30 20 28 35 814 1,303 2,058 2 2 2 2 2 2 816 1,305 2,060

Energy Colorado River Demand 0.4 0.7 1.0 0.7 0.9 0.9 0 0 0 0 0 0 0 0 0 1 2 2 0 0 0 0 0 0 1 2 2

Minerals Colorado River Demand 0 0 0 42 53 54 0 0 0 0 0 0 0 0 0 42 53 54 0 0 0 0 0 0 42 53 54

Fish, Wildlife, and Recreation Colorado River Demand 16 16 16 0 0 0 0 0 0 0 0 0 0 0 0 16 16 16 0.3 0.3 0.3 0.3 0.3 0.3 16 16 16

Tribal Colorado River Demand 552 556 556 445 660 659 16 72 123 0 0 0 0 0 0 1,013 1,288 1,337 38 55 71 38 55 71 1,051 1,342 1,408

STATE TOTAL

Notes

Mainstem Central Arizona

North Central and 

Navajo Nation

Central Yavapai 

Highlands Upper San Pedro River

LOWER BASIN 

SUBTOTAL San Juan

UPPER BASIN 

SUBTOTAL
 Appendix C6 — Arizona Water Demand 

 Scenario Quantification

December 2012 C6-27

Notes

1) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona: faster land conversion (driven by population); Other 

areas: no change from Current Projected.

2) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. No change from Current Projected (note that this is applied to each of 

3 different AMAs in Central Arizona, which, combined with changes in acreage, results in an average applied water rate that is slightly 

different from Current Projected).

3) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Annual population change is increased by 35 percent relative to 

Current Projected. 

4) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. All areas: no change relative to Current Projected. Note that this is 

applied to each of 3 different AMAs in Central Arizona, which, combined with changes in population, results in an average gpcd that is 

slightly different from Current Projected; similarly, in Mainstem it is applied to individual contractors, so changes in population of 

individual contractors results in a slight change from Current Projected.

5) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. SSI is a function of population.

6) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Water Resources Development Commission "high" energy use value 

used–increased energy water use values from Current Projected. Note that these are per capita, so energy use is also affected by 

population.

7) No change from Current Projected.

8) No change from Current Projected.

9) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem and Central Arizona: no change from Current Projected; 

Personal communication, Navajo Nation, Apr 16, 2012. North Central and Navajo Nation and San Juan: Nation provided demand 

schedules.

10) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. North Central: local supplies were calculated as the difference 

between the total demand and unmet demand; Central Yavapai Highlands and Upper San Pedro Study: based on information from 

Reclamation appraisal reports. Central AZ: AZ used internal models to estimate its demands met by Other Supplies and CAP deliveries. 

The remaining or unmet demands are represented as Potential Colorado River Basin demands, where CAP deliveries are a portion of 

potential Colorado River Demands in the Central AZ planning area.

11) For planning areas other than Central AZ, all Colorado River demand is municipal. For Central AZ, based on recent distribution of CAP 

water (20110510 Basin Study AZCAPBreakout.xlsx). Approach was to start with recent distribution, and then make the change in 

distribution the same as the change in overall demands. This was done for Current Projected only. The values for all categories but M&I 

were then applied to all other scenarios, with M&I used as the makeup term. The formulas also were checked to make sure Colorado 

River demand was not greater than total demand for each category–if so, M&I makes up the difference.
Colorado River Basin 

Water Supply And Demand Study

C6-28 December 2012

TABLE C6-5 

Total Demand within Study Area under Rapid Growth (C2) Scenario

ARIZONA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 168 168 168 429 231 141 0 0 0 7 6 4 0.1 0.1 0.1 605 405 314 0 0 0 0 0 0 605 405 314 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 7.92 7.92 7.92 3.19 3.01 2.98 0.00 0.00 0.00 2.91 2.91 2.92 2.33 2.33 2.33 4.50 5.05 5.63 0.00 0.00 0.00 0.00 0.00 0.00 4.50 5.05 5.63 2

Consumptive factor [%] 57% 57% 57% 100% 100% 100% 0% 0% 0% 100% 100% 100% 100% 100% 100% 79% 72% 68% 0% 0% 0% 0% 0% 0% 79% 72% 68%

Demand (Consumptive) 763 763 763 1,366 695 421 0 0 0 22 17 12 0.3 0.3 0.3 2,152 1,476 1,196 0 0 0 0 0 0 2,152 1,476 1,196

Municipal and Industrial (M&I) Population [thousands] 313 513 675 6,685 10,738 14,452 106 137 159 263 402 514 99 137 171 7,467 11,926 15,971 12 16 20 12 16 20 7,479 11,942 15,991 3

M&I Per Capita Use (Diversion) [gpcd] 280 251 228 209 177 162 123 113 101 151 138 124 183 167 150 208 178 163 123 111 86 123 111 86 208 178 163 4

Consumptive factor [%] 66% 69% 71% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 98% 98% 98% 100% 100% 100% 100% 100% 100% 98% 98% 98%

M&I Demand (Consumptive) 65 100 122 1,563 2,124 2,628 15 17 18 44 62 71 20 26 29 1,708 2,329 2,868 2 2 2 2 2 2 1,709 2,331 2,870

Self Served Industrial Demand (Consumptive) 5 6 7 174 237 261 0 0 0 9 13 18 1 2 2 190 258 287 0 0 0 0 0 0 190 258 287 5a, 5b

Demand (Consumptive) 70 106 129 1,737 2,361 2,889 15 17 18 54 75 89 22 28 31 1,897 2,588 3,156 2 2 2 2 2 2 1,899 2,590 3,158

Energy Demand (Consumptive) 0.4 0.5 0.7 82 107 132 0 0 0 0 0 0 0 0 0 82 107 133 0 0 0 0 0 0 82 107 133 6

Minerals Demand (Consumptive) 0 0 0 42 58 58 0 0 0 0 0 0 0 0 0 42 58 58 0 0 0 0 0 0 42 58 58 7

Fish, Wildlife, and Recreation Demand (Consumptive) 19 19 19 0 0 0 0.3 0.3 0.3 0 0 0 11 11 11 30 30 30 0.3 0.3 0.3 0.3 0.3 0.3 30 30 30 8

Tribal Demand (Consumptive) 552 555 555 535 712 672 17 73 124 0 0 0 0 0 0 1,103 1,340 1,351 38 55 71 38 55 71 1,141 1,395 1,422 9

Total Hydrologic Basin Demand (Consumptive) 1,405 1,444 1,467 3,761 3,932 4,172 32 90 142 75 93 101 33 39 42 5,306 5,598 5,924 40 57 73 40 57 73 5,346 5,655 5,997

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population [thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 1,405 1,444 1,467 3,761 3,932 4,172 32 90 142 75 93 101 33 39 42 5,306 5,598 5,924 40 57 73 40 57 73 5,346 5,655 5,997

Demand that may be met by Other Supplies 0 0 0 2,254 2,332 2,303 11 10 8 72 72 72 14 14 14 2,351 2,428 2,397 0 0 0 0 0 0 2,351 2,428 2,397 10

Potential Colorado River Demand 1,405 1,444 1,467 1,507 1,601 1,869 20 80 134 3 20 29 19 25 28 2,955 3,170 3,527 40 57 73 40 57 73 2,995 3,227 3,600

Agricultural Colorado River Demand 763 763 763 349 0 0 0 0 0 0 0 0 0 0 0 1,112 763 763 0 0 0 0 0 0 1,112 763 763 11

Municipal and Industrial Colorado River Demand 70 106 129 671 890 1,158 4 8 11 3 20 29 19 25 28 768 1,050 1,355 2 2 2 2 2 2 769 1,052 1,357

Energy Colorado River Demand 0.4 0.5 0.7 0.7 0.9 0.9 0 0 0 0 0 0 0 0 0 1 1 2 0 0 0 0 0 0 1 1 2

Minerals Colorado River Demand 0 0 0 42 51 53 0 0 0 0 0 0 0 0 0 42 51 53 0 0 0 0 0 0 42 51 53

Fish, Wildlife, and Recreation Colorado River Demand 19 19 19 0 0 0 0 0 0 0 0 0 0 0 0 19 19 19 0.3 0.3 0.3 0.3 0.3 0.3 19 19 19

Tribal Colorado River Demand 552 555 555 445 659 657 16 72 123 0 0 0 0 0 0 1,013 1,286 1,335 38 55 71 38 55 71 1,051 1,341 1,406

STATE TOTAL

Notes

Mainstem Central Arizona

North Central and 

Navajo Nation

Central Yavapai 

Highlands Upper San Pedro River

LOWER BASIN 

SUBTOTAL San Juan

UPPER BASIN 

SUBTOTAL
 Appendix C6 — Arizona Water Demand 

 Scenario Quantification

December 2012 C6-29

Notes

1) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona: faster land conversion (driven by population); Other 

areas: no change from Current Projected.

2) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem: 5 percent decrease in water duties, but overall higher water 

duties result from consumptive use being higher for the same acreage. Central Arizona: 5 percent decrease relative to Current Projected 

(note that 5 percent is applied to each of 3 different AMAs in Central Arizona, which, combined with changes in acreage, results in an 

average difference from Current Projected that does not equal 5 percent). Other areas: 20 percent decrease from Current Projected.

3) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Annual population change is increased by 35 percent relative to 

Current Projected. 

4) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. All areas: gpcd reduced annually by 0.44 percent. Note that this is 

applied to each of 3 different AMAs in Central Arizona, which, combined with changes in population, results in an average gpcd that 

changes at a slightly different rate than 0.44 percent; similarly, in Mainstem it is applied to individual contractors, so changes in population 

of individual contractors results in a slightly different rate than 0.44 percent.

5) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. SSI is a function of population.

6) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Water Resources Development Commission "low" energy use value 

used–decreased energy water use values from Current Projected. Note that these are per capita, so energy use is also affected by 

population.

7) No change from Current Projected.

8) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem: recreation contractors use full entitlement, no change to 

National Wildlife Refuges; Other areas: no change from Current Projected.

9) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem and Central Arizona: no change from Current Projected; 

Personal communication, Navajo Nation, Apr 16, 2012. North Central and Navajo Nation and San Juan: Nation provided demand 

schedules.

10) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. North Central: local supplies were calculated as the difference between 

the total demand and unmet demand; Central Yavapai Highlands and Upper San Pedro Study: based on information from Reclamation 

appraisal reports. Central AZ: AZ used internal models to estimate its demands met by Other Supplies and CAP deliveries. The remaining 

or unmet demands are represented as Potential Colorado River Basin demands, where CAP deliveries are a portion of potential Colorado 

River Demands in the Central AZ planning area.

11) For planning areas other than Central AZ, all Colorado River demand is municipal. For Central AZ, based on recent distribution of CAP 

water (20110510 Basin Study AZCAPBreakout.xlsx). Approach was to start with recent distribution, and then make the change in 

distribution the same as the change in overall demands. This was done for Current Projected only. The values for all categories but M&I 

were then applied to all other scenarios, with M&I used as the makeup term. The formulas also were checked to make sure Colorado 

River demand was not greater than total demand for each category–if so, M&I makes up the difference.
Colorado River Basin 

Water Supply And Demand Study

C6-30 December 2012

TABLE C6-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

ARIZONA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 168 168 168 447 288 189 0 0 0 7 6 4 0.1 0.1 0.1 623 462 361 0 0 0 0 0 0 623 462 361 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.85 6.85 6.85 3.24 3.21 3.16 0.00 0.00 0.00 3.64 3.64 3.64 2.95 2.95 2.95 4.22 4.54 4.88 0.00 0.00 0.00 0.00 0.00 0.00 4.22 4.54 4.88 2

Consumptive factor [%] 61% 61% 61% 100% 100% 100% 0% 0% 0% 100% 100% 100% 100% 100% 100% 83% 79% 75% 0% 0% 0% 0% 0% 0% 83% 79% 75%

Demand (Consumptive) 703 703 703 1,449 924 596 0 0 0 27 22 15 0.4 0.4 0.4 2,179 1,649 1,314 0 0 0 0 0 0 2,179 1,649 1,314

Municipal and Industrial (M&I) Population [thousands] 298 434 528 6,348 9,086 11,305 101 116 125 250 340 402 94 116 134 7,091 10,091 12,493 12 16 20 12 16 20 7,103 10,107 12,513 3

M&I Per Capita Use (Diversion) [gpcd] 260 221 186 210 181 163 121 101 94 148 124 100 179 150 120 209 180 161 123 111 86 123 111 86 208 179 161 4

Consumptive factor [%] 66% 67% 67% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 98% 98% 98% 100% 100% 100% 100% 100% 100% 98% 98% 98%

M&I Demand (Consumptive) 57 72 74 1,497 1,843 2,064 14 13 13 41 47 45 19 19 18 1,627 1,995 2,214 2 2 2 2 2 2 1,629 1,997 2,216

Self Served Industrial Demand (Consumptive) 5 6 6 170 220 233 0 0 0 9 13 18 1 2 2 186 242 259 0 0 0 0 0 0 186 242 259 5a, 5b

Demand (Consumptive) 62 78 80 1,666 2,063 2,297 14 13 13 51 60 63 20 22 20 1,813 2,236 2,473 2 2 2 2 2 2 1,814 2,238 2,475

Energy Demand (Consumptive) 0.4 0.5 0.5 78 91 105 0 0 0 0 0 0 0 0 0 78 92 106 0 0 0 0 0 0 78 92 106 6

Minerals Demand (Consumptive) 0 0 0 42 58 58 0 0 0 0 0 0 0 0 0 42 58 58 0 0 0 0 0 0 42 58 58 7

Fish, Wildlife, and Recreation Demand (Consumptive) 78 78 78 0 0 0 0.3 0.3 0.3 0 0 0 11 11 11 89 89 89 0.3 0.3 0.3 0.3 0.3 0.3 90 90 90 8

Tribal Demand (Consumptive) 552 556 556 535 694 688 0.7 0.8 0.8 0 0 0 0 0 0 1,087 1,251 1,244 44 43 43 44 43 43 1,131 1,294 1,287 9

Total Hydrologic Basin Demand (Consumptive) 1,396 1,415 1,418 3,769 3,831 3,743 15 14 14 78 82 77 31 33 31 5,289 5,375 5,284 46 46 46 46 46 46 5,334 5,421 5,330

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population [thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 1,396 1,415 1,418 3,769 3,831 3,743 15 14 14 78 82 77 31 33 31 5,289 5,375 5,284 46 46 46 46 46 46 5,334 5,421 5,330

Demand that may be met by Other Supplies 0 0 0 2,248 2,074 1,807 11 8 6 72 72 72 14 14 14 2,344 2,168 1,899 0 0 0 0 0 0 2,344 2,168 1,899 10

Potential Colorado River Demand 1,396 1,415 1,418 1,521 1,757 1,936 4 6 8 6 10 5 18 19 18 2,945 3,208 3,385 46 46 46 46 46 46 2,990 3,253 3,431

Agricultural Colorado River Demand 703 703 703 333 0 0 0 0 0 0 0 0 0 0 0 1,036 703 703 0 0 0 0 0 0 1,036 703 703 11

Municipal and Industrial Colorado River Demand 62 78 80 701 1,045 1,224 4 6 8 6 10 5 18 19 18 791 1,158 1,335 2 2 2 2 2 2 792 1,160 1,337

Energy Colorado River Demand 0.4 0.5 0.5 0.7 0.9 0.9 0 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 1 1 1

Minerals Colorado River Demand 0 0 0 42 53 53 0 0 0 0 0 0 0 0 0 42 53 53 0 0 0 0 0 0 42 53 53

Fish, Wildlife, and Recreation Colorado River Demand 78 78 78 0 0 0 0 0 0 0 0 0 0 0 0 78 78 78 0.3 0.3 0.3 0.3 0.3 0.3 79 79 79

Tribal Colorado River Demand 552 556 556 445 658 658 0 0 0 0 0 0 0 0 0 997 1,214 1,213 44 43 43 44 43 43 1,041 1,257 1,257

STATE TOTAL

Notes

Mainstem Central Arizona

North Central and 

Navajo Nation

Central Yavapai 

Highlands Upper San Pedro River

LOWER BASIN 

SUBTOTAL San Juan

UPPER BASIN 

SUBTOTAL
 Appendix C6 — Arizona Water Demand 

 Scenario Quantification

December 2012 C6-31

Notes

1) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. All areas: no change from Current Projected.

2) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. No change from Current Projected. Note that this is applied to each of 

3 different AMAs in Central Arizona, which, combined with changes in acreage. Results in an average applied water rate that is slightly 

different from Current Projected.

3) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. No change from Current Projected. 

4) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. All areas: gpcd reduced annually by 0.88 percent, with lower limit of 

100 gpcd. Note that this is applied to each of 3 different AMAs in Central Arizona, which, combined with changes in population, results in 

an average gpcd that changes at a slightly different rate than 0.44 percent; similarly, in Mainstem it is applied to individual contractors, so 

changes in population of individual contractors results in a slightly different rate than 0.44 percent. There is an exception for Central 

Arizona and North Central and Navajo Nation in 2060, where gpcd was calculated as a 22.5 percent reduction from 2015 levels.

5) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. SSI is a function of population.

6) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Water Resources Development Commission "low" energy use value 

used–decreased energy water use values from Current Projected. Note that these are per capita, so energy use is also affected by 

population. There is an exception for Central Arizona, where a 5.6 percent reduction from the Scenario A is realized in 2035 and a 10

percent reduction in 2060.

7) No change from Current Projected.

8) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem: National Wildlife Refuges use full entitlement; Other areas: 

no change from Current Projected.

9) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. No change from Current Projected.

10) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. North Central: local supplies were calculated as the difference 

between the total demand and unmet demand; Central Yavapai Highlands and Upper San Pedro Study: based on information from 

Reclamation appraisal reports. Central AZ: AZ used internal models to estimate its demands met by Other Supplies and CAP deliveries. 

The remaining or unmet demands are represented as Potential Colorado River Basin demands, where CAP deliveries are a portion of 

potential Colorado River Demands in the Central AZ planning area.

11) For planning areas other than Central AZ, all Colorado River demand is municipal. For Central AZ, based on recent distribution of CAP 

water (20110510 Basin Study AZCAPBreakout.xlsx). Approach was to start with recent distribution, and then make the change in 

distribution the same as the change in overall demands. This was done for Current Projected only. The values for all categories but M&I 

were then applied to all other scenarios, with M&I used as the makeup term. The formulas also were checked to make sure Colorado 

River demand was not greater than total demand for each category–if so, M&I makes up the difference.
Colorado River Basin 

Water Supply And Demand Study

C6-32 December 2012

TABLE C6-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

ARIZONA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 168 168 168 429 231 141 0 0 0 7 6 4 0.1 0.1 0.1 605 405 314 0 0 0 0 0 0 605 405 314 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 6.51 6.51 6.51 3.19 3.01 2.98 0.00 0.00 0.00 2.91 2.91 2.92 2.33 2.33 2.33 4.11 4.46 4.87 0.00 0.00 0.00 0.00 0.00 0.00 4.11 4.46 4.87 2

Consumptive factor [%] 61% 61% 61% 100% 100% 100% 0% 0% 0% 100% 100% 100% 100% 100% 100% 83% 76% 72% 0% 0% 0% 0% 0% 0% 83% 76% 72%

Demand (Consumptive) 668 668 668 1,366 695 421 0 0 0 22 17 12 0.3 0.3 0.3 2,056 1,380 1,101 0 0 0 0 0 0 2,056 1,380 1,101

Municipal and Industrial (M&I) Population [thousands] 313 513 675 6,685 10,738 14,452 106 137 159 263 402 514 99 137 171 7,467 11,926 15,971 12 16 20 12 16 20 7,479 11,942 15,991 3

M&I Per Capita Use (Diversion) [gpcd] 261 220 182 209 177 162 121 101 100 148 124 100 179 150 120 207 176 160 123 111 86 123 111 86 207 175 160 4

Consumptive factor [%] 66% 68% 69% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 98% 98% 98% 100% 100% 100% 100% 100% 100% 98% 98% 98%

M&I Demand (Consumptive) 60 85 94 1,563 2,124 2,628 14 15 18 44 56 58 20 23 23 1,701 2,304 2,821 2 2 2 2 2 2 1,703 2,306 2,823

Self Served Industrial Demand (Consumptive) 5 6 7 174 237 261 0 0 0 9 13 18 1 2 2 190 258 287 0 0 0 0 0 0 190 258 287 5a, 5b

Demand (Consumptive) 65 91 101 1,737 2,361 2,889 14 15 18 53 69 75 21 25 25 1,891 2,562 3,108 2 2 2 2 2 2 1,892 2,564 3,110

Energy Demand (Consumptive) 0.4 0.5 0.7 82 107 132 0 0 0 0 0 0 0 0 0 82 107 133 0 0 0 0 0 0 82 107 133 6

Minerals Demand (Consumptive) 0 0 0 42 58 58 0 0 0 0 0 0 0 0 0 42 58 58 0 0 0 0 0 0 42 58 58 7

Fish, Wildlife, and Recreation Demand (Consumptive) 79 79 79 0 0 0 0.3 0.3 0.3 0 0 0 11 11 11 91 91 91 0.3 0.3 0.3 0.3 0.3 0.3 91 91 91 8

Tribal Demand (Consumptive) 552 555 555 535 702 700 17 73 124 0 0 0 0 0 0 1,103 1,330 1,379 38 55 71 38 55 71 1,141 1,385 1,450 9

Total Hydrologic Basin Demand (Consumptive) 1,365 1,395 1,405 3,761 3,923 4,200 31 88 142 74 86 87 32 36 36 5,264 5,529 5,870 40 57 73 40 57 73 5,305 5,586 5,943

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population [thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 1,365 1,395 1,405 3,761 3,923 4,200 31 88 142 74 86 87 32 36 36 5,264 5,529 5,870 40 57 73 40 57 73 5,305 5,586 5,943

Demand that may be met by Other Supplies 0 0 0 2,204 2,138 2,029 11 9 7 72 72 72 14 14 14 2,301 2,233 2,122 0 0 0 0 0 0 2,301 2,233 2,122 10

Potential Colorado River Demand 1,365 1,395 1,405 1,557 1,785 2,171 20 79 134 2 14 15 19 23 23 2,963 3,296 3,747 40 57 73 40 57 73 3,003 3,353 3,821

Agricultural Colorado River Demand 668 668 668 339 0 0 0 0 0 0 0 0 0 0 0 1,007 668 668 0 0 0 0 0 0 1,007 668 668 11

Municipal and Industrial Colorado River Demand 65 91 101 731 1,071 1,457 4 7 12 2 14 15 19 23 23 821 1,206 1,607 2 2 2 2 2 2 823 1,208 1,609

Energy Colorado River Demand 0.4 0.5 0.7 0.8 0.9 0.9 0 0 0 0 0 0 0 0 0 1 1 2 0 0 0 0 0 0 1 1 2

Minerals Colorado River Demand 0 0 0 42 54 54 0 0 0 0 0 0 0 0 0 42 54 54 0 0 0 0 0 0 42 54 54

Fish, Wildlife, and Recreation Colorado River Demand 79 79 79 0 0 0 0 0 0 0 0 0 0 0 0 79 79 79 0.3 0.3 0.3 0.3 0.3 0.3 80 80 80

Tribal Colorado River Demand 552 555 555 445 659 658 16 72 123 0 0 0 0 0 0 1,013 1,286 1,337 38 55 71 38 55 71 1,051 1,341 1,408

STATE TOTAL

Notes

Mainstem Central Arizona

North Central and 

Navajo Nation

Central Yavapai 

Highlands Upper San Pedro River

LOWER BASIN 

SUBTOTAL San Juan

UPPER BASIN 

SUBTOTAL
 Appendix C6 — Arizona Water Demand 

 Scenario Quantification

December 2012 C6-33

Notes

1) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona: faster land conversion (driven by population); Other 

areas: no change from Current Projected.

2) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Central Arizona and Mainstem: 5 percent decrease relative to Current 

Projected. Note that 5 percent is applied to each of 3 different AMAs in Central Arizona, which, combined with changes in acreage, 

results in an average difference from Current Projected that does not equal 5 percent. Other areas: 20 percent decrease from Current 

Projected.

3) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Annual population change is increased by 35 percent relative to 

Current Projected. 

4) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. All areas: gpcd reduced annually by 0.88 percent, with lower limit of 

100 gpcd. Note that this is applied to each of 3 different AMAs in Central Arizona, which, combined with changes in population, results in 

an average gpcd that changes at a slightly different rate than 0.44 percent; similarly, in Mainstem it is applied to individual contractors, so 

changes in population of individual contractors results in a slightly different rate than 0.44 percent.

5) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. SSI is a function of population.

6) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Water Resources Development Commission "low" energy use value 

used–decreased energy water use values from Current Projected. Note that these are per capita, so energy use is also affected by 

population.

7) No change from Current Projected.

8) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem: National Wildlife Refuges use full entitlement; Other areas: 

no change from Current Projected.

9) Personal communication, ADWR, Dec 3, 2011, and Feb 22, 2012. Mainstem and Central Arizona: no change from Current Project; 

Personal communication, Navajo Nation, Apr 16, 2012. North Central and Navajo Nation and San Juan: Nation provided demand 

schedules.

10) Personal communication, ADWR Dec 3, 2011, and Feb 22, 2012. North Central: local supplies were calculated as the difference 

between the total demand and unmet demand; Central Yavapai Highlands and Upper San Pedro Study: based on information from 

Reclamation appraisal reports. Central AZ: AZ used internal models to estimate its demands met by Other Supplies and CAP deliveries. 

The remaining or unmet demands are represented as Potential Colorado River Basin demands, where CAP deliveries are a portion of 

potential Colorado River Demands in the Central AZ planning area.

11) For planning areas other than Central AZ, all Colorado River demand is municipal. For Central AZ, based on recent distribution of CAP 

water (20110510 Basin Study AZCAPBreakout.xlsx). Approach was to start with recent distribution, and then make the change in 

distribution the same as the change in overall demands. This was done for Current Projected only. The values for all categories but M&I 

were then applied to all other scenarios, with M&I used as the makeup term. The formulas also were checked to make sure Colorado 

River demand was not greater than total demand for each category–if so, M&I makes up the difference.
Colorado River Basin 

Water Supply and Demand Study

C6-34 December 2012

4.0 References 

Arizona Department of Water Resources (ADWR). 2005. Upper San Pedro Basin, Active 

Management Area Review Report. 

Arizona Department of Water Resources (ADWR). 2010a. Arizona Water Atlas. 

Arizona Department of Water Resources (ADWR). 2010b. Draft Demand and Supply 

Assessment, Tucson Active Management Area. 

Arizona Department of Water Resources (ADWR). 2010c. Draft Demand and Supply 

Assessment, Phoenix Active Management Area. 

Arizona Department of Water Resources (ADWR). 2011a. Draft Arizona Demand 

Narrative, August. 

Arizona Department of Water Resources (ADWR). 2011b. Draft Demand and Supply 

Assessment, Pinal Active Management Area. 

Arizona Department of Water Resources (ADWR). 2011c. Personal communication with 

Reclamation. 

Bureau of Reclamation (Reclamation). 1964–2002. Compilation of Records in Accordance with 

Article V of the Decree of the Supreme Court of the United States in Arizona v. 

California Et. Al., Dated March 9, 1964. 

Bureau of Reclamation (Reclamation). 1996–2008. Lower Colorado River Accounting System 

Evapotranspiration and Evaporation Calculations. 

Bureau of Reclamation (Reclamation). 2000. Colorado River Interim Surplus Criteria Final 

Environmental Impacts Statement. 

Bureau of Reclamation (Reclamation). 2003–2009. Colorado River Accounting and Water Use 

Report, Arizona, California, and Nevada. 

Bureau of Reclamation (Reclamation). 2006. North Central Water Supply Study, Report of 

Findings. 

Bureau of Reclamation (Reclamation). 2007a. Appraisal Report, Augmentation Alternatives for 

the Sierra Vista Sub-watershed, Arizona. 

Bureau of Reclamation (Reclamation). 2007b. Colorado River Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2007 and 2010. 5 year reports. Provisional Upper 

Colorado River Basin Consumptive Uses and Losses Report 2001–2008. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2009. Central Yavapai Highlands Water Resources 

Management Study, Appraisal Level Phase I. 
Appendix C6 — Arizona Water Demand 

Scenario Quantification

December 2012 C6-35

U.S. Geological Survey (USGS). 2007. Water Management of the Regional Aquifer in the Sierra 

Vista Subwatershed, Arizona – 2009 Report to Congress, prepared in response to Public 

108-136, Section 321. 

U.S. Geological Survey (USGS). 2009. Water Management of the Regional Aquifer in the Sierra 

Vista Subwatershed, Arizona – 2009 Report to Congress, prepared in response to Public 

108-136, Section 321. 

Water Resources Development Commission, Arizona. 2011. Water Supply and Demand Working 

Group Report. 
 Appendix C7

 California Water Demand 

 Scenario Quantification

December 2012 C7-1 

Appendix C7 ─ California Water Demand 

Scenario Quantification

1.0 Introduction

This appendix summarizes the data sources used in scenario quantification for Colorado River 

demandfor the state of California and presents the results of quantification. As presented in 

figure C7-1, California is divided into two planning areas in the hydrologic basin (Mainstem and 

Palo Verde Irrigation District [PVID]), and three planning areas in the adjacent area that are 

served by Colorado River water (Metropolitan Water District of Southern California [MWD], 

Coachella Valley Water District [CVWD], and Imperial Irrigation District [IID]). Data collection 

and development were completed at the planning area level.

The following sections present background information that summarizes the planning areas as 

well as data sources used to quantify demand scenarios by category. Following the background 

section, results of demand scenario quantification are presented. The results section is broken out 

into a California Study Area summary, followed by Colorado River demand by geography, and 

finally by category.

2.0 Background 

The Colorado River Board (CRB) of California was established in 1937 and coordinates efforts 

among its members in planning for future Colorado River water demands. CRB has developed 

plans such as the draft California’s Colorado River Water Use Plan (CRB, 2000). 

CRB and member agencies coordinated California’s efforts to provide information for scenario 

quantification. These efforts largely relied on information previously generated through regional 

plans and demographic studies. However, new assumptions and/or data development were 

required where the assumptions of the Colorado River Basin Water Demand and Supply Study 

(Study) required information not developed as part of the regional planning effort. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources include state, regional, and national agency reports. 

• Agricultural Demand: Agricultural parameters and demand were derived differently for 

each planning area. For PVID, irrigated acreage and demand were derived from personal 

communication (PVID, 2011), and water delivery per acre was calculated based on 

acreage, consumptive demand, and a consumptive factor. 

 

&RORUDGR5LYHUGHPDQGDVFRPSXWHGE\6WXG\$UHDGHPDQGPLQXVRWKHUVXSSOLHV
Colorado River Basin 

Water Supply and Demand Study

C7-2 December 2012

FIGURE C7-1 

Colorado River Hydrologic Basin and Export Service Areas in California
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-3 

For Mainstem, agricultural demand was provided by personal communication with CRB

(CRB, 2011), water delivery per acre was assumed to be the same as PVID, and acreage 

was calculated based on demand, water delivery per acre, and a consumptive factor. 

For IID, irrigated acres were derived from IID Crop Report (IID, 2011a), demand was 

derived from exhibit B of the Colorado River Water Delivery Agreement (Secretary of 

the Interior, 2003), and water delivery per acre was calculated. 

For MWD, agricultural demand was derived from MWD’s The Regional Urban Water 

Management Plan (MWD, 2010), and water delivery per acre was based on an irrigated 

acreage estimate from Southern California Association of Governments (2005) and 

San Diego Association of Governments (2007) data. Demands in 2060 are assumed to 

be the same as 2010. 

For CVWD, demand was derived from the Coachella Valley Water Management Plan

(CVWMP) (CVWD, 2010a), water delivery per acre was calculated based on 2010 

acreage reported in 2010 Crop and Water Report (CVWD, 2010b) and assumed to be 

constant through time, and acreage was then calculated based on demand and water 

delivery per acre. 

• Municipal and Industrial (M&I): M&I parameters and demand were derived 

differently for each planning area. For PVID there is no M&I demand. 

For Mainstem, population was derived from 2010 census data. Consumptive demand was 

derived from the Colorado River Simulation System (CRSS), and per capita usage was 

calculated based on an assumed consumptive factor.

For IID, population was derived from IID Integrated Regional Water Planning 

(preliminary data); per capita use was based on 2011 population and demand; and 

demand was calculated as population times per capita use. 

For MWD, population and demands were derived from The Regional Urban Water 

Management Plan (MWD, 2010), for 2015 and 2035 and from the Report of the Blue 

Ribbon Committee for 2060 (Blue Ribbon Committee, 2011), and per capita usage was

calculated. 

For CVWD, population, M&I demands, and self-served industrial (SSI) demands were 

derived from CVWMP (CVWD, 2010a), and per capita usage was calculated. 

• Energy: IID energy demands were derived from IID Integrated Regional Water 

Management Planning (preliminary data; IID, 2011b). 

• Minerals: There are no reported Colorado River minerals demands in California. 

• Fish, Wildlife, and Recreation: Fish, wildlife, and recreation demands were derived 

from personal communication with IID (2011b), the Bureau of Land Management 

(2012), and from the CVWMP table 3-2 (CVWD, 2010a). 

• Tribal: Tribal demands for the Mainstem area were derived from discussions with 

federally recognized tribes and Bureau of Reclamation’s (Reclamation) 2005 to 2009 

Decree Accounting Report (Reclamation, 2007 and 2010). 
Colorado River Basin 

Water Supply and Demand Study

C7-4 December 2012

3.0 Results of Water Demand Scenario Quantification

This section summarizes California’s Colorado River water demand trends by category across 

the initial scenarios. The purpose of this section is to describe changes in demands, both 

temporally and geographically, parameters that influence changes in demands, and how the 

parameters and demands differ among scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands), independent of the source of supply. However, for areas outside of the 

hydrologic basin, a portion of the Study Area demand is satisfied from other supplies such as the 

California State Water Project (MWD and CVWD) and local groundwater (MWD and CVWD). 

To develop estimates of the Colorado River demand, the Study Area demand was reduced by 

estimates of the demand that may be met by supplies from other sources. This appendix focuses 

on Colorado River demands, but includes discussion of the Study Area parameters that led to 

these demands.

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand, Colorado River Demand for the state and 

individual planning areas across the six scenarios, and Colorado River water demand by category 

across the six scenarios. Parameters and demands for all categories and all scenarios, along with 

references for data sources, are included. 

3.1 Summary Results of Scenario Quantification

Values were developed for Study Area parameters to quantify Study Area demand for each of 

the scenarios. Colorado River demand was calculated as Study Area demand minus the demand 

that may be met by supplies from other sources. Table C7-1 presents summary results for the 

demand scenarios considered in the Study. The table presents agricultural and M&I demand 

parameters for the entire Study Area that distinguish the scenarios, the resulting Study Area 

demands, and finally the Colorado River demands by category. Because demands that may be 

met by supplies from other sources may vary among scenarios, trends observed in the parameters 

and Study Area demands may not be reflected identically in Colorado River demand trends. 

The California agencies estimate that about 20.4 million people will reside in California’s Study 

Area by 2015. This number is expected to change to 19.8 to 34.6 million by 2060. The greatest 

population growth is associated with the Rapid Growth (C1 and C2) Scenarios. The Slow 

Growth (B) scenario has the lowest population growth of the scenarios in 2035 and an overall 

population decline to 19.8 million by 2060, reflecting a shift of population from the Study Area 

to other areas of the state. 

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, based on passive or existing conservation targets or 

continuing implementation of utility-funded conservation, is expected to be 9 to 18 percent less 

in 2060 than in 2015. Usage rates and per capita reductions vary across California’s 

planning areas. 

Under all scenarios, irrigated acreage is projected to decrease by about 16,000 acres through 

2060, representing a 2 percent decrease. Water delivery per acre is projected to decline slightly 

across all scenarios. Due to variability across the planning area, these changes result in a 3 

percent decline in agricultural demand in the Study Area. 
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-5 

TABLE C7-1 

Summary Results of California Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

20151 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 20.4 27.6 19.8 34.6 34.6 27.6 34.6

Change in per capita water usage (%), 

from 2015 — –12% –9% –13% –13% –18% –13%

Irrigated acreage (millions of acres) 0.71 0.69 0.69 0.69 0.69 0.69 0.69

Change in per acre water delivery (%), 

from 2015 — –1% –1% –1% –1% –1% –1%

Study Area Demand (thousand acre-feet [kaf])

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 3,519 3,414 3,414 3,414 3,414 3,414 3,414

M&I demand2 4,117 5,312 4,035 6,435 6,426 4,961 6,426

Energy demand 52–61 157 157 285 160 139 139

Minerals demand 0 0 0 0 0 0 0

FWR demand 126 36.1 36.1 36.1 37.9 39.1 39.1

Tribal demand 92 92 92 92 92 92 92

Total Study Area Demand 7,908 9,011 7,734 10,261 10,129 8,645 10,110

Colorado River Demand (kaf)

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 3,230 3,159 3,158 3,159 3,159 3,158 3,158

M&I demand2 1,481 1,765 1,744 1,770 1,760 1,744 1,760

Energy demand 52–61 156 156 284 159 138 139

Minerals demand 0 0 0 0 0 0 0

FWR demand 124 31.7 31.7 31.7 33.5 34.7 34.7

Tribal demand 92 92 92 92 92 92 92

Total Colorado River Demand 4,979 5,203 5,182 5,336 5,203 5,168 5,184

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 M&I totals equal sum of M&I (parameter-based) and "other" categories.
Colorado River Basin 

Water Supply and Demand Study

C7-6 December 2012

Study Area demand for energy is projected to increase under all scenarios due to the growing 

need for energy sources (solar and geothermal). The greatest increases in Study Area demand 

for energy are anticipated in the IID planning area, ranging from 95 thousand acre-feet (kaf) to 

139 kaf. A notable increase of 85 kaf also occurs in the Mainstem planning area under the Rapid 

Growth (C1) scenario. 

There is no reported Study Area demand for minerals extraction under the scenarios analyzed for 

the Study. 

Study Area demands for tribal use are projected to remain constant through time across all 

scenarios. For additional information on tribal demands, see appendix C9.

Figure C7-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, 

and 3) change in Colorado River demand by demand category. 

From panel one it can be seen that Study Area demand changes from about 7.9 million acre-feet 

(maf) in 2015 to between 7.7 and 10.3 maf in 2060. Between 33 and 49 percent of the 2060 

Study Area demand may be met by supplies from other sources. 

Panel two provides a view of the range across scenarios of Colorado River demand. This demand 

increases from about 5.0 maf in 2015 to between 5.2 and 5.3 maf in 2060 (or 4 to 7 percent), 

depending on the scenario. This difference results in a Colorado River demand range of about 

168 kaf across the scenarios in 2060, or 3 percent. 

Panel three shows how specific categories affect the projected change in Colorado River demand 

by scenario. Growth in M&I and energy demand across all scenarios are offset by decreases in 

agricultural demand and demand for fish, wildlife, and recreation. 

Figure C7-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The 168 kaf range across scenarios in 2060 is easily discernible, with a relatively even 

spread over the range across the scenarios. In addition, it appears that the quantified scenarios 

track well with the peaks in historical uses that likely represent the least supply limited 

conditions or actual demand. 

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in 

figures C7-4 and C7-5. These figures show two geographic levels: Study Area in California, and 

individual planning areas. Demands at each geographic level are shown across the scenarios. The 

columns to the right show the Colorado River demand at a point in time (2015, 2035, or 2060) by 

relative contribution of the categories. 

The greatest Colorado River demand in California is in the IID planning area, followed by 

MWD. Lesser demands exist in CVWD, PVID, and Mainstem planning areas. Demand 

categories vary across planning areas, with IID and PVID being primarily agricultural and MWD 

being primarily M&I. Demands in the Mainstem area are primarily tribal, and demands in 

CVWD are a mix of agricultural and M&I. 

 

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Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-7 

FIGURE C7-2 

Study Area, Colorado River, and Change in Colorado River Demand

 

0

2,000

4,000

6,000

8,000

10,000

12,000

Thousand Acre-Feet per Year

Study Area Demand in California

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white and 

colored border

4,900

4,950

5,000

5,050

5,100

5,150

5,200

5,250

5,300

5,350

5,400

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in California

-300

-200

-100

0

100

200

300

400

500

600

Thousand Acre-Feet per Year

Change in Colorado River Demand in California, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Colorado River Basin 

Water Supply and Demand Study

C7-8 December 2012

FIGURE C7-3 

Historical Use and Future Projected Demand

0

1,000

2,000

3,000

4,000

5,000

6,000

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Normal Year 

Apportionment
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-9 

FIGURE C7-4 

Colorado River Demand in California
Colorado River Basin 

Water Supply and Demand Study

C7-10 December 2012

FIGURE C7-5 

Colorado River Demand by Category
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-11

Figure C7-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. Increase in Colorado River demand is driven by increases in M&I demands (primarily 

in CVWD) and energy demands (primarily in IID). These are partially offset by decreases in 

agricultural (primarily in CVWD) and fish, wildlife, and recreation (primarily in IID) demands. 

3.3 Colorado River Demand by Category

3.3.1 Agriculture

Agricultural water demand is driven by irrigated acreage and water delivery per acre. Water 

delivery per acre is the amount of water diverted per irrigated acre. Components of this use 

include transmission and delivery losses (surface evaporation, riparian demand, seepage, and 

canal spills), and on-farm losses that are made up of evaporation, crop irrigation requirements, 

and tail and tile water (return). Each of these factors will vary by location (precipitation, growing 

season, etc.), irrigation method, and crop type. 

Figure C7-7 presents the following by scenario in 2015, 2035, and 2060: 

• Agricultural demand for Colorado River water 

• Agricultural demand for Colorado River water by planning area 

• Agricultural demand as a portion of Colorado River water demand (right hand side 

of graph) 

As can be seen from figure C7-7, agricultural water demand is the largest component of 

Colorado River demand in California, dropping from about 65 percent in 2015 to between 59 and 

61 percent in 2060, depending on which scenario is considered. This drop results from both a 

decrease in agricultural water demand and an increase in other categories of demand, principally 

M&I.

Colorado River demand for agricultural use decreases over time from 2015 to 2060 in all 

scenarios. The decreases are primarily due to a loss of irrigated acreage as water delivery 

per acre decreases slightly across all scenarios. 

In examining the planning areas, agricultural demand consistently decreases in all scenarios in 

the CVWD and IID and increases in all scenarios in PVID, with variability in planning area to 

planning area in the remaining scenarios. Agricultural demand for the Mainstem area is constant 

across all scenarios. More than 2.5 maf, or 80 percent, of California’s agricultural demand is 

projected to occur in IID in 2060. 

A strong driver for loss of agricultural acreage is urbanization, leading to physical loss of 

acreage. 
Colorado River Basin 

Water Supply and Demand Study

C7-12 December 2012

FIGURE C7-6 

Change in Colorado River Demand in California from 2015 by Category
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-13

FIGURE C7-7 

Change in Colorado River Demand in California from 2015 for Agriculture

-150

-100

-50

0

50

100

2015 2035 2060

KAF

MWD

-150

-100

-50

0

50

100

2015 2035 2060

KAF

CVWD

-150

-100

-50

0

50

100

2015 2035 2060

KAF

PVID 

-150

-100

-50

0

50

100

2015 2035 2060

KAF

IID

-150

-100

-50

0

50

100

2015 2035 2060

KAF

Mainstem

201520352060

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

-140

-120

-100

-80

-60

-40

-20

0

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in California, from 2015

Agricultural

Agriculture is 64.8 - 64.9% of Colorado River demand*

Agriculture is 61.6 - 62.6% of Colorado River demand*

Agriculture is 59.2 - 61.1% of Colorado River demand*

No 

Change

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Colorado River Basin 

Water Supply and Demand Study

C7-14 December 2012

3.3.2 Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita use, with the addition 

of SSI demand. M&I per capita use is a measure of the amount of water produced or diverted per 

person in a given municipality. Because this measure examines all water produced by a given 

municipality, it often includes industrial, commercial, and institutional demand as well as 

residential demand. A number of factors may influence the M&I per capita use of a given 

community, including the amount of industrial demand, climate, number of institutional 

facilities, and number of visitors. 

SSI are industries located in a given area that have their own water supply systems and are 

therefore not directly related to local measures of population and M&I per capita water use. 

Figure C7-8 presents the following by scenario in 2015, 2035, and 2060: 

• M&I demand for Colorado River water in the Study Area 

• M&I demand for Colorado River water in individual planning areas 

• M&I demand as a portion of Colorado River water demand (right hand side of graph)

As can be seen from figure C7-8, M&I water demand is the second largest component of 

Colorado River demand, increasing from about 30 percent in 2015 to between 33 and 34 percent 

of Colorado River demand in 2060, depending on which scenario is considered. 

Colorado River demand for M&I use increases over time from 2015 to 2060 across all scenarios. 

The increase is primarily due to population increase as Study Area M&I per capita use decreases 

over time across all scenarios and SSI demand is less than 10 percent of M&I demand. 

In examining the planning areas, about 75 percent of the increase in M&I demand for Colorado 

River water from 2015 to 2060 over time is due to population increase in CVWD. The remaining 

increase in demand is primarily from M&I demand in the IID service area, with a small increase 

in the Mainstem planning area. While these planning areas show the greatest increase, MWD 

represents 71 percent of the total M&I demand. Population growth occurs in the MWD planning 

area, but growth in Colorado River demand is limited by existing infrastructure and remaining 

demands will be met by supplies from other sources. 

Increases in population are somewhat tempered by decreases in M&I per capita use. Per capita 

water use decreases in all scenarios with reductions ranging from 9 to 18 percent by 2060. 

3.3.3 Energy

Water demand for energy can be estimated through known plans for new power plants or 

through applying a per capita energy water use factor. Power facilities often serve areas remote 

from their locations. 

Figure C7-9 presents the following by scenario in 2015, 2035, and 2060: 

• Energy demand for Colorado River water 

• Individual planning area energy demand for Colorado River water 

• Energy demand as a portion of Colorado River water demand (right hand side of graph)
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-15

FIGURE C7-8 

Change in Colorado River Demand in California from 2015 for M&I 

0

50

100

150

200

250

2015 2035 2060

KAF

IID

0

50

100

150

200

250

2015 2035 2060

KAF

PVID 

0

50

100

150

200

250

2015 2035 2060

KAF

Mainstem

0

50

100

150

200

250

2015 2035 2060

KAF

CVWD

0

50

100

150

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250

2015 2035 2060

KAF

MWD

201520352060

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

50

100

150

200

250

300

350

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in California, from 2015

Municipal and Industrial

M&I is 29.7% of Colorado River demand*

M&I is 32.7 - 33.1% of Colorado River demand*

M&I is 33.2 - 34% of Colorado River demand*

No 

Change

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios

M&I totals equal sum of 

M&I (parameter-based) 

and "other" categories.

N/A
Colorado River Basin 

Water Supply and Demand Study

C7-16 December 2012

FIGURE C7-9 

Change in Colorado River Demand in California from 2015 for Energy

-50

0

50

100

150

2015 2035 2060

KAF

Mainstem

-50

0

50

100

150

2015 2035 2060

KAF

PVID 

-50

0

50

100

150

2015 2035 2060

KAF

MWD

-50

0

50

100

150

2015 2035 2060

KAF

CVWD

201520352060

-50

0

50

100

150

2015 2035 2060

KAF

IID

A

A

B

C1

B

C1

C2

C2

D1

D1

D2

D2

0

50

100

150

200

250

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in California, from 2015

Energy

Energy is 1 - 1.2% of Colorado River demand*

Energy is 2 - 3.4% of Colorado River demand*

Energy is 2.7 - 5.3% of Colorado River demand*

No 

Change

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios

N/A
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-17

As can be seen from figure C7-9, energy water demand is a small fraction of Colorado River 

demand, increasing from 1 percent in 2015 to between 2.7 and 5 percent of demand in 2060, 

depending on which scenario is considered. 

Energy demand for Colorado River water increases over time from 2015 to 2060 across all 

scenarios with notable increases for the Rapid Growth (C1) scenario. 

Energy demands are shown only in the IID and Mainstem planning areas. Consistent increases 

occur in the IID planning area across all scenarios. The Mainstem planning area shows 

significant increases in energy demand in the Rapid Growth (C1) scenario and nominal decreases 

in the remaining scenarios. Growth in the IID planning area represents all of the increase in 

energy demand for water in all scenarios but the Rapid Growth (C1) scenario, where growth in 

the IID planning area is about 60 percent of the total growth. The water demand increases for 

energy are primarily due to expansion of geothermal and solar energy. 

3.3.4 Minerals Extraction

California does not report use of Colorado River water for minerals extraction.

3.3.5 Fish, Wildlife, and Recreation

Water demand for fish, wildlife, and recreation is estimated from existing agreements or known 

consumptive use associated with this demand category. Non-consumptive demands associated 

with fish, wildlife, and recreation are represented through the metrics portion of the Study 

presented in Technical Report D – System Reliability Metrics. 

Figure C7-10 presents the following by scenario in 2015, 2035, and 2060: 

• Change in fish, wildlife, and recreation demand for Colorado River water 

• Change in fish, wildlife, and recreation demand for Colorado River water in individual 

planning areas 

• Fish, wildlife, and recreation demand as a portion of Colorado River demand (right hand 

side of graph) 

As can be seen from figure C7-10, fish, wildlife, and recreation water demand is a small fraction 

of Colorado River demand, decreasing from 2.5 percent in 2015 to between 0.6 and 0.7 percent 

of Colorado River demand in 2060 across all scenarios. 

Total decrease in fish, wildlife, and recreation demands is about 90 kaf. These decreases are 

dominated by decreases in the IID planning area associated with the Salton Sea mitigation. Total 

demand decreases from about 124 kaf in 2015 to between 32 and 35 kaf in 2060. 
Colorado River Basin 

Water Supply and Demand Study

C7-18 December 2012

FIGURE C7-10

Change in Colorado River Demand in California from 2015 for Fish, Wildlife, and Recreation

-125

-100

-75

-50

-25

0

2015 2035 2060

KAF

Mainstem

-125

-100

-75

-50

-25

0

2015 2035 2060

KAF

PVID 

-125

-100

-75

-50

-25

0

2015 2035 2060

KAF

MWD

-125

-100

-75

-50

-25

0

2015 2035 2060

KAF

CVWD

201520352060

-125

-100

-75

-50

-25

0

2015 2035 2060

KAF

IID

A A B

B

C1

C1

C2

C2

D1

D1

D2

D2

-125

-100

-75

-50

-25

0

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in California, from 2015

Fish, Wildlife, and Recreation

FWR is 2.5% of Colorado River demand*

FWR is 0.5% of Colorado River demand*

FWR is 0.6 - 0.7% of Colorado River demand*

No 

Change

N/A

N/A

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C7 — California Water Demand

Scenario Quantification

December 2012 C7-19

3.3.6 Tribal

The following federally recognized tribes divert Colorado River water under water rights 

assigned to reservations in California: 

• Fort Mojave Indian Tribe 

• Chemehuevi Tribe 

• Colorado River Indian Tribes 

• Quechan Indian Tribe 

Tribal water demands relied on information submitted by the Ten Tribes Partnership for use in 

the Colorado River Interim Surplus Criteria Final Environmental Impacts Statement

(Reclamation, 2000) and used in the more recent Colorado River Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead Final 

Environmental Impact Statement (Reclamation, 2007) and Reclamation’s 2005 to 2009 Decree 

Accounting Report (Reclamation, 2007 and 2010). 

Tribal demands are forecast to remain constant through time and across scenarios, at about 

92,000 acre-feet (af) per year. 

For additional information on tribal demands, see appendix C9. 

3.4 Summary Tables of Parameters and Demands by Category

Tables C7-2 to C7-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 
Colorado River Basin 

Water Supply and Demand Study

C7-20 December 2012

TABLE C7-2 

Total Demand within Study Area under Current Projected (A) Scenario

LEGEND: 999 From States 999 From State Plans

Units are thousand acre-feet per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 91 91 107 4 4 4 95 95 111 1, 2

Per-Acre Water Delivery (Diversion) [af/ac/yr] 10.29 10.29 9.34 10.29 10.29 9.34 10.29 10.29 9.34 3

Consumptive factor [%] 44% 44% 49% 44% 44% 49% 44% 44% 49% 4

Demand (Consumptive) 412 412 490 19 19 19 430 430 509 5, 6

Municipal and Industrial (M&I) Population [thousands] 7 14 28 7 14 28 7

M&I Per Capita Use (Diversion) [gpcd] 442 505 522 442 505 522 8

Consumptive factor [%] 69% 68% 67% 69% 68% 67% 9

M&I Demand (Consumptive) 2 5 11 2 5 11 10

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0

Demand (Consumptive) 2 5 11 2 5 11

Energy Demand (Consumptive) 5 5 5 15 8 8 20 13 13

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 11

Tribal Demand (Consumptive) 0 0 0 92 92 92 92 92 92 12

Total Hydrologic Basin Demand (Consumptive) 0 0 0 0 0 0 0 0 0 417 416 495 129 125 130 546 541 625

Adjacent Areas

Agricultural Irrigated Acreage[thousands] 477 485 490 62 50 50 74 53 40 613 588 580 13, 14, 15

Per-Acre Water Delivery (Diversion)[af/ac/yr] 5.4 5.2 5.2 3.57 3.57 3.57 4.0 4.0 4.0 5.04 4.94 5.00 16, 17

Demand (Diversion) 2,567 2,510 2,563 222 180 180 300 214 162 3,089 2,904 2,905 18,19,20

Municipal and Industrial (M&I) Population [thousands] 181 260 360 19,956 22,474 26,200 295 599 1,040 20,432 23,333 27,600 21, 22, 23

M&I Per Capita Use (Diversion)[gpcd] 185 187 187 172 162 144 452 425 423 176 170 155 24

M&I Demand (Diversion) 37 55 76 3,850 4,091 4,234 149 285 493 4,037 4,431 4,803 25, 26, 27

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 30 62 106 30 62 106 28

Demand (Diversion) 37 55 76 3,850 4,091 4,234 180 347 599 4,067 4,492 4,908

Energy Demand (Diversion) 33 96 144 0 0 0 33 96 144 29

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Demand (Diversion) 115 15 25 11 11 11 126 26 36 30, 31

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0

Other Demand (Diversion) 48 58 75 0 0 318 0 0 0 48 58 393 32 33

Total Adjacent Areas Demand (Diversion) 2,800 2,733 2,882 4,072 4,271 4,732 490 571 771 0 0 0 0 0 0 7,362 7,575 8,386

Total Demand in the Study Area 2,800 2,733 2,882 4,072 4,271 4,732 490 571 771 417 416 495 129 125 130 7,908 8,117 9,011 34

Demand that may be met by Other Sources 0 10 10 2,822 3,021 3,482 98 112 315 0 0 0 0 0 0 2,928 3,143 3,807 35

Potential Colorado River Demand 2,791 2,723 2,872 1,250 1,250 1,250 392 459 456 417 416 495 129 125 130 4,979 4,974 5,203 36, 37

Agricultural Colorado River Demand 2,559 2,501 2,554 0 0 0 240 172 96 412 412 490 19 19 19 3,230 3,103 3,159 38

Municipal and Industrial Colorado River Demand 37 54 75 1,250 1,250 1,250 144 279 354 0 0 0 2 5 11 1,433 1,589 1,690

Energy Colorado River Demand 32 96 144 0 0 0 0 0 0 5 5 5 15 8 8 53 108 156

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 115 15 25 0 0 0 8 8 6 0 0 0 0.6 0.6 0.6 124 24 32

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 92 92 92 92 92 92

Other Colorado River Demand 48 58 75 0 0 0 0 0 0 0 0 0 48 58 75

STATE TOTAL

Notes

IID MWD CVWD PVID Mainstem
Appendix C7 — California Water Demand 

Scenario Quantification

December 2012 C7-21

Notes

1) PVID: Roger Henning, personal communication, Aug 19, 2011; in 2015 assume 25,947 acres in the Forbearance and Fallowing Program with MWD; 

in 2035 assume 23,352 acres in the Forbearance and Fallowing Program with MWD.

2) Mainstem: computed as consumptive demand divided by consumptive factor divided by per-acre water delivery. 

3) Mainstem: applied water use as determined for PVID in 2015, 2035 and 2060.

4) PVID: Derived from Reclamation's Decree Accounting reports. The 2015 and 2035 factors are based on the 1964 to 2004 excluding fallowing years. 

The 2060 factor is the maximum historical value. 

5) PVID: Roger Henning, personal communication, Aug 19, 2011; in 2015 assume 78,327 af provided to MWD under Forbearance and Fallowing 

Program; in 2035 assume 78,327 af provided to MWD under Forbearance and Fallowing Program.

6) Mainstem: Chris Harris, personal communication. Provided as CRSS input, includes Miscellaneous Agricultural Present Perfected Rights and Bard 

Unit.

7) Mainstem: population projections for city of Needles based on personal communication Dave Brownlee; 2015 Winterhaven projected increase from 

2010 census based on 2010 to 2015 increase reflected in Population Projection from table 3, Lower Colorado Water Supply Study, California, 

Planning Report (Reclamation,1986). 2035 and 2060 Winterhaven projected increase based on 2010 to 2015 increase in 1986 study continuing in 

each 5-year period through 2060, and Big River projected increase based on growth rate computed from the 2000 and 2010 census.

8) Mainstem: calculated based on population, consumptive demand, and consumptive factor.

9) Mainstem: Based on aggregate consumptive factor determined from Reclamation's 2010 Decree Accounting reports for Needles and Winterhaven, 

and the 2009 Decree Accounting Report for miscellaneous Present Perfected Rights.

10) Mainstem M&I: Values from CRSS demand input tool for City of Needles, Winterhaven and Miscellaneous Domestic Present Perfected Rights and 

Lower Colorado Water Supply Project Municipal and Industrial Use.

11) Mainstem Fish, Wildlife and Recreation: 612 af for Bureau of Land Management county park leases.

12) Mainstem: Chris Harris, personal communication. Provided as CRSS input, includes Fort Mohave, Chemehuevi, Colorado River, and Quechan 

federally recognized tribes.

13) IID: 2035: IID 2011 Crop Report plus additional 10,000 acres of reclaimed lands; 2060: IID 2011 Crop Report plus additional 15,000 acres reclaimed 

lands

14) MWD: Irrigated Acreage for 2015, 2035, and 2060 equal to Agricultural Demand divided by MWD per-acre water delivery.

15) CVWD: Form 7-2045 2010 Crop and Water Report. 2010 Irrigable Acres from Form 7-2045; 2015, 2035 and 2060: determined from demand over 

2010 water use. 

16) IID, CVWD: computed simply as Agricultural Demand (Diversion) divided by irrigated acres in 2011. In CVWD, values assumed to be the same for 

other years. In IID, other years are computed in same fashion as 2011. Actual Applied Water Use varies throughout IID depending on factors such 

as soil type and cropping patterns.

17) MWD per-acre water delivery (af/ac/yr) for 2015, 2035, and 2060 assumed to be the same as for 2010. 2010 per-acre water delivery equal to 

Agricultural Demand (Diversion) divided by Irrigated Acreage estimate from Southern California Association of Governments 2005 data and San 

Diego Association of Governments 2007 data.

18) IID: Exhibit B CRWDA. Revised w/+5 kaf for IID/MWD and + 50 kaf in 2060 for MWD obligation to CVWD; less M&I, FWR, Other, and existing (2011) 

energy demands
Colorado River Basin 

Water Supply and Demand Study

C7-22 December 2012

19) MWD: 2015 and 2035 from MWD Regional Urban Water Management Plan (RUWMP) (2010), Determined as 2015 and 2035 demands from 

page A.1-10, table A.1-7; 2035 value assumed constant through 2060.

Approximately 7 percent of Metropolitan's retail demands are used for agricultural purposes. Agricultural uses are expected to decline through 2030. 

For example, irrigated acreage declined by 51,361 acres between 2001–2007. 

20) CVWD: 2010 Coachella Valley Water Management Plan (CVWMP) update. page 3-14, table 3-2.

21) IID: IID Integrated Regional Water Management Planning (preliminary data).

22) MWD: 2015 and 2035: RUWMP 2010 table A.1-2; 2060: provided by J. Matusak. Report of the Blue Ribbon Committee (Blue Ribbon Committee, 

2011), based on moderate demand, sustained imports scenario 40 percent increase from 2010. 

23) CVWD: 2010 CVWMP update. 2010, 2015, 2035, 2045 page 3-6, table 3-1, East Valley Population. 2060 assumed as 1.5 times growth from 2035 to 

2045.

24) MWD: Future changes assume continued water savings due to conservation measures such as water savings resulting from plumbing codes, price 

effects, and the continuing implementation of utility-funded conservation Best Management Practices.

25) IID: 2035 and 2060: calculated based on M&I efficiency from 2011 and years population, where 2011 M&I efficiency was calculated as af/person/year 

based on 2011 population and M&I demand in af. 2015: interpolated from 2011 and 2035 estimate.

26) MWD: 2015, 2035: RUWMP 2010, table A.1-6; 2060: Blue Ribbon Committee Report, table B.2., Scenario 1.

27) CVWD: 2010 CVWMP update, table 3-2, page 3-14.

28) CWWD: 2010 CVWMP update and CVWD annual report on golf course water use. Total Industrial table 3-2, page 3-14 times percent of population in 

East Valley plus golf course water use. Assumed all golf growth occurs in East Valley.

29) IID: IID Integrated Regional Water Management Planning (preliminary data). 

30) IID: values from Mike King personal communication, Oct 7, 2011 includes water sent to the Salton Sea via an exchange with SDCWA and CVWD to 

mitigate for Quantitative Settlement Agreement transfers through 2017. The transfer to San Diego is accounted for as a deduction to IID’s priority 3 

consumptive use cap.

31) CVWD: 2010 CVWMP update. Total Fish Farms and Duck Clubs table 3-2, page 3-14.

32) IID: Tina Shields personal communication, Aug 3, 2011; accounts for service pipes and miscellaneous uses, assumes 1 percent annual increase.

33) MWD: Represents demand of 268,200 af for seawater barrier and groundwater replenishment, and 50,000 af to account for uncertain regional growth 

and water demand projections. The demands shown are based on the April 12, 2011 Report of Blue Ribbon Committee.

34) Calculated from the sum of Hydrologic Basin (Consumptive) Demand and Adjacent Areas (Diversion) Demand. Adjacent Areas (Diversion) Demand 

is net of return flows to the Colorado River, (i.e. Depletions).

35) CVWD: Patti Reyes personal communication, Aug 11, 2011; groundwater and recycled water.

36) MWD: 2015, 2035 and 2060 assume nearly full Colorado River Aqueduct.

37) All values presented in table are contingent on the continued implementation of the Quantitative Settlement Agreement. 

38) For MWD, all potential Colorado River demand is M&I. For IID and CVWD, distribute Colorado River demand among categories according to 

distribution of total Study Area demand.

Colorado River Basin 

Water Supply and Demand Study

C7-24 December 2012

TABLE C7-3 

Total Demand within Study Area under Slow Growth (B) Scenario

CALIFORNIA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 91 91 107 4 4 4 95 95 111 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 10.29 10.29 9.34 10.29 10.29 9.34 10.29 10.29 9.34 2

Consumptive factor [%] 44% 44% 49% 44% 44% 49% 44% 44% 49%

Demand (Consumptive) 412 412 490 19 19 19 430 430 509

Municipal and Industrial (M&I) Population [thousands] 0 0 0 7 14 28 7 14 28 3

M&I Per Capita Use (Diversion) [gpcd] 0 0 0 442 505 522 442 505 522 4

Consumptive factor [%] 0% 0% 0% 69% 68% 67% 69% 68% 67%

M&I Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Energy Demand (Consumptive) 5 5 5 15 8 8 20 13 13 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 8

Tribal Demand (Consumptive) 0 0 0 92 92 92 92 92 92 9

Total Hydrologic Basin Demand (Consumptive) 0 0 0 0 0 0 0 0 0 417 416 495 129 125 130 546 541 625

Adjacent Areas

Agricultural Irrigated Acreage[thousands] 477 485 490 62 50 50 74 53 40 613 588 580 10

Per-Acre Water Delivery (Diversion)[af/ac/yr] 5.38 5.17 5.23 3.57 3.57 3.57 4.04 4.04 4.04 5.04 4.94 5.00 11

Demand (Diversion) 2,567 2,510 2,563 222 180 180 300 214 162 3,089 2,904 2,905

Municipal and Industrial (M&I) Population [thousands] 170 229 270 19,424 19,943 18,427 295 599 1,040 19,889 20,771 19,737 12a, 12b

M&I Per Capita Use (Diversion)[gpcd] 185 184 180 172 162 144 452 425 423 176 170 159 13a, 13b

M&I Demand (Diversion) 35 47 54 3,747 3,630 2,978 149 285 493 3,932 3,962 3,525

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 30 62 106 30 62 106 14

Demand (Diversion) 35 47 54 3,747 3,630 2,978 180 347 599 3,962 4,024 3,631

Energy Demand (Diversion) 33 96 144 0 0 0 33 96 144 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 115 15 25 11 11 11 126 26 36 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Other Demand (Diversion) 48 58 75 0 0 318 0 0 0 48 58 393

Total Adjacent Areas Demand (Diversion) 2,798 2,726 2,861 3,969 3,810 3,476 490 571 771 0 0 0 0 0 0 7,257 7,107 7,109

Total Demand in the Study Area 2,798 2,726 2,861 3,969 3,810 3,476 490 571 771 417 416 495 129 125 130 7,803 7,649 7,734

Demand that may be met by Other Sources 9 10 10 2,719 2,560 2,226 98 112 315 0 0 0 0 0 0 2,826 2,682 2,551 19

Potential Colorado River Demand 2,789 2,716 2,851 1,250 1,250 1,250 392 459 456 417 416 495 129 125 130 4,977 4,966 5,182

Agricultural Colorado River Demand 2,559 2,501 2,554 0 0 0 240 172 96 412 412 490 19 19 19 3,229 3,103 3,158 20

Municipal and Industrial Colorado River Demand 35 47 54 1,250 1,250 1,250 144 279 354 0 0 0 2 5 11 1,431 1,581 1,669

Energy Colorado River Demand 32 96 143 0 0 0 0 0 0 5 5 5 15 8 8 53 108 156

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 115 15 25 0 0 0 8 8 6 0 0 0 0.6 0.6 0.6 124 24 32

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 92 92 92 92 92 92

Other Colorado River Demand 48 58 75 0 0 0 0 0 0 48 58 75

Notes

IID MWD CVWD PVID Mainstem STATE TOTAL
Appendix C7 — California Water Demand 

Scenario Quantification

December 2012 C7-25

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) No changes from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12a) IID: Based on regional trends, assume 2060 population is 25 percent less than that of Current Projected. 

12b) MWD: Population projections extrapolated from California Department of Water Resources (DWR) low growth county population projections for 

California Water Plan Update, 2009. 

13a) Based on very slow reduction to satisfy the California 20X2020 statute for the IID planning area.

13b) No changes from Current Projected for other planning areas.

14) No changes from Current Projected.

15) No changes from Current Projected.

16) No changes from Current Projected.

17) No changes from Current Projected.

18) No changes from Current Projected.

19) MWD: Reduced from Current Projected to reflect lower demand with lower population projection. Others: no changes from Current Projected.

20) For MWD, all potential Colorado River demand is M&I. For IID and CVWD, distribute Colorado River demand among categories according to 

distribution of total Study Area demand. 
Colorado River Basin 

Water Supply and Demand Study

C7-26 December 2012

TABLE C7-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

CALIFORNIA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 91 91 107 4 4 4 95 95 111 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 10.29 10.29 9.34 10.29 10.29 9.34 10.29 10.29 9.34 2

Consumptive factor [%] 44% 44% 49% 44% 44% 49% 44% 44% 49%

Demand (Consumptive) 412 412 490 19 19 19 430 430 509

Municipal and Industrial (M&I) Population [thousands] 0 0 0 7 14 28 7 14 28 3

M&I Per Capita Use (Diversion) [gpcd] 0 0 0 442 505 522 442 505 522 4

Consumptive factor [%] 0% 0% 0% 69% 68% 67% 69% 68% 67%

M&I Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Energy Demand (Consumptive) 5 5 5 15 47 100 20 52 105 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 8

Tribal Demand (Consumptive) 0 0 0 92 92 92 92 92 92 9

Total Hydrologic Basin Demand (Consumptive) 0 0 0 0 0 0 0 0 0 417 416 495 129 164 222 546 580 717

Adjacent Areas

Agricultural Irrigated Acreage[thousands] 477 485 490 62 50 50 74 53 40 613 588 580 10

Per-Acre Water Delivery (Diversion)[af/ac/yr] 5.38 5.17 5.23 3.57 3.57 3.57 4.04 4.04 4.04 5.04 4.94 5.00 11

Demand (Diversion) 2,567 2,510 2,563 222 180 180 300 214 162 3,089 2,904 2,905

Municipal and Industrial (M&I) Population [thousands] 192 291 450 20,743 26,026 33,117 295 599 1,040 21,230 26,916 34,607 12a, 12b

M&I Per Capita Use (Diversion)[gpcd] 176 174 159 172 162 144 452 425 423 176 168 153 13a, 13b

M&I Demand (Diversion) 38 57 80 4,002 4,738 5,352 149 285 493 4,189 5,079 5,925

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 30 62 106 30 62 106 14

Demand (Diversion) 38 57 80 4,002 4,738 5,352 180 347 599 4,219 5,141 6,031

Energy Demand (Diversion) 41 120 180 0 0 0 41 120 180 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 115 15 25 11 11 11 126 26 36 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Other Demand (Diversion) 48 58 75 0 0 318 0 0 0 48 58 393

Total Adjacent Areas Demand (Diversion) 2,808 2,760 2,923 4,224 4,917 5,850 490 571 771 0 0 0 0 0 0 7,522 8,248 9,544

Total Demand in the Study Area 2,808 2,760 2,923 4,224 4,917 5,850 490 571 771 417 416 495 129 164 222 8,068 8,828 10,261

Demand that may be met by Other Sources 9 10 10 2,974 3,667 4,600 98 112 315 0 0 0 0 0 0 3,080 3,790 4,925 19

Potential Colorado River Demand 2,800 2,750 2,913 1,250 1,250 1,250 392 459 456 417 416 495 129 164 222 4,987 5,039 5,336

Agricultural Colorado River Demand 2,559 2,501 2,554 0 0 0 240 172 96 412 412 490 19 19 19 3,230 3,103 3,159 20

Municipal and Industrial Colorado River Demand 38 57 80 1,250 1,250 1,250 144 279 354 0 0 0 2 5 11 1,433 1,591 1,695

Energy Colorado River Demand 41 120 179 0 0 0 0 0 0 5 5 5 15 47 100 61 171 284

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 115 15 25 0 0 0 8 8 6 0 0 0 0.6 0.6 0.6 124 24 32

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 92 92 92 92 92 92

Other Colorado River Demand 48 58 75 0 0 0 0 0 0 48 58 75

Notes

IID MWD CVWD PVID Mainstem STATE TOTAL
Appendix C7 — California Water Demand 

Scenario Quantification

December 2012 C7-27

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Increased demand on Mainstem from Current Projected.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12a) IID: Based on regional trends, assume 2060 population is 25 percent more than that of Current Projected. 

12b) MWD: Population projections extrapolated from California DWR high growth county population projections for California Water Plan Update, 2009.

13a) Based on slow reduction to satisfy the California 20X2020 statute for the IID planning area.

13b) No changes from Current Projected for other planning areas.

14) No changes from Current Projected.

15) Increased demand from Current Projected based on rapid geothermal technology.

16) No changes from Current Projected.

17) IID: No reference. 

18) No changes from Current Projected.

19) MWD: Increased from Current Projected to reflect higher demand with higher population projection. Others: no changes from Current Projected.

20) For MWD, all potential Colorado River demand is M&I. For IID and CVWD, distribute Colorado River demand among categories according to 

distribution of total Study Area demand. 
Colorado River Basin 

Water Supply and Demand Study

C7-28 December 2012

TABLE C7-5 

Total Demand within Study Area under Rapid Growth (C2) Scenario

CALIFORNIA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 91 91 107 4 4 4 95 95 111 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 10.29 10.29 9.34 10.29 10.29 9.34 10.29 10.29 9.34 2

Consumptive factor [%] 44% 44% 49% 44% 44% 49% 44% 44% 49%

Demand (Consumptive) 412 412 490 19 19 19 430 430 509

Municipal and Industrial (M&I) Population [thousands] 0 0 0 7 14 28 7 14 28 3

M&I Per Capita Use (Diversion) [gpcd] 0 0 0 442 505 522 442 505 522 4

Consumptive factor [%] 0% 0% 0% 69% 68% 67% 69% 68% 67%

M&I Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Energy Demand (Consumptive) 5 5 5 15 8 8 20 13 13 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 8

Tribal Demand (Consumptive) 0 0 0 92 92 92 92 92 92 9

Total Hydrologic Basin Demand (Consumptive) 0 0 0 0 0 0 0 0 0 417 416 495 129 125 130 546 541 625

Adjacent Areas

Agricultural Irrigated Acreage[thousands] 477 485 490 62 50 50 74 53 40 613 588 580 10

Per-Acre Water Delivery (Diversion)[af/ac/yr] 5.38 5.17 5.23 3.57 3.57 3.57 4.04 4.04 4.04 5.04 4.94 5.00 11

Demand (Diversion) 2,567 2,510 2,563 222 180 180 300 214 162 3,089 2,904 2,905

Municipal and Industrial (M&I) Population [thousands] 192 291 450 20,743 26,026 33,117 295 599 1,040 21,230 26,916 34,607 12a, 12b

M&I Per Capita Use (Diversion)[gpcd] 172 150 141 172 162 144 452 425 423 176 168 153 13a, 13b

M&I Demand (Diversion) 37 49 71 4,002 4,738 5,352 149 285 493 4,188 5,071 5,916

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 30 62 106 30 62 106 14

Demand (Diversion) 37 49 71 4,002 4,738 5,352 180 347 599 4,218 5,133 6,022

Energy Demand (Diversion) 33 98 147 0 0 0 33 98 147 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 115 16 27 11 11 11 126 26 37 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Other Demand (Diversion) 48 58 75 0 0 318 0 0 0 48 58 393

Total Adjacent Areas Demand (Diversion) 2,800 2,730 2,882 4,224 4,917 5,850 490 571 771 0 0 0 0 0 0 7,514 8,219 9,504

Total Demand in the Study Area 2,800 2,730 2,882 4,224 4,917 5,850 490 571 771 417 416 495 129 125 130 8,059 8,760 10,129

Demand that may be met by Other Sources 9 10 10 2,974 3,667 4,600 98 112 315 0 0 0 0 0 0 3,080 3,790 4,925 19

Potential Colorado River Demand 2,791 2,720 2,872 1,250 1,250 1,250 392 459 456 417 416 495 129 125 130 4,979 4,971 5,203

Agricultural Colorado River Demand 2,559 2,501 2,554 0 0 0 240 172 96 412 412 490 19 19 19 3,230 3,103 3,159 20

Municipal and Industrial Colorado River Demand 37 49 71 1,250 1,250 1,250 144 279 354 0 0 0 2 5 11 1,433 1,583 1,685

Energy Colorado River Demand 33 98 146 0 0 0 0 0 0 5 5 5 15 8 8 54 110 159

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 115 16 27 0 0 0 8 8 6 0 0 0 0.6 0.6 0.6 124 25 33

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 92 92 92 92 92 92

Other Colorado River Demand 48 58 75 0 0 0 0 0 0 48 58 75

Notes

IID MWD CVWD PVID Mainstem STATE TOTAL
Appendix C7 — California Water Demand 

Scenario Quantification

December 2012 C7-29

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Increased demand from Current Projected based on efficient geothermal technology.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12a) IID: Based on regional trends, assume 2060 population is 25 percent more than that of Current Projected. 

12b) MWD: Population projections extrapolated from California DWR high growth county population projections for California Water Plan Update, 2009.

13a) Based on California 20X2020 statute for 20 percent reduction in demand by 2020 for the IID planning area.

13b) No changes from Current Projected for other planning areas.

14) No changes from Current Projected.

15) Increased demand from Current Projected based on efficient geothermal technology.

16) No changes from Current Projected.

17) IID: No reference. 

18) No changes from Current Projected.

19) MWD: Increased from Current Projected to reflect higher demand with higher population projection. Others: no changes from Current Projected.

20) For MWD, all potential Colorado River demand is M&I. For IID and CVWD, distribute Colorado River demand among categories according to 

distribution of total Study Area demand.
Colorado River Basin 

Water Supply and Demand Study

C7-30 December 2012

TABLE C7-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

CALIFORNIA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 91 91 107 4 4 4 95 95 111 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 10.29 10.29 9.34 10.29 10.29 9.34 10.29 10.29 9.34 2

Consumptive factor [%] 44% 44% 49% 44% 44% 49% 44% 44% 49%

Demand (Consumptive) 412 412 490 19 19 19 430 430 509

Municipal and Industrial (M&I) Population [thousands] 0 0 0 7 14 28 7 14 28 3

M&I Per Capita Use (Diversion) [gpcd] 0 0 0 442 442 442 442 442 442 4

Consumptive factor [%] 0% 0% 0% 69% 68% 67% 69% 68% 67%

M&I Demand (Consumptive) 0 0 0 2 5 9 2 5 9

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 0 0 0 2 5 9 2 5 9

Energy Demand (Consumptive) 5 5 5 15 8 7 20 12 12 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 8

Tribal Demand (Consumptive) 0 0 0 92 92 92 92 92 92 9

Total Hydrologic Basin Demand (Consumptive) 0 0 0 0 0 0 0 0 0 417 416 495 129 124 128 546 540 622

Adjacent Areas

Agricultural Irrigated Acreage[thousands] 477 485 490 62 50 50 74 53 40 613 588 580 10

Per-Acre Water Delivery (Diversion)[af/ac/yr] 5.38 5.17 5.23 3.57 3.57 3.57 4.04 4.04 4.04 5.04 4.94 5.00 11

Demand (Diversion) 2,567 2,510 2,563 222 180 180 300 214 162 3,089 2,904 2,905

Municipal and Industrial (M&I) Population [thousands] 181 260 360 19,956 22,474 26,200 295 599 1,040 20,432 23,333 27,600 12a, 12b

M&I Per Capita Use (Diversion)[gpcd] 172 150 141 172 155 133 452 423 423 176 162 144 13a, 13b

M&I Demand (Diversion) 35 44 57 3,850 3,902 3,904 149 284 493 4,034 4,230 4,453

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 30 62 106 30 62 106 14

Demand (Diversion) 35 44 57 3,850 3,902 3,904 180 346 599 4,064 4,292 4,559

Energy Demand (Diversion) 31 88 127 0 0 0 31 88 127 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 115 17 28 11 11 11 126 27 39 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Other Demand (Diversion) 48 58 75 0 0 318 0 0 0 48 58 393

Total Adjacent Areas Demand (Diversion) 2,796 2,716 2,849 4,072 4,082 4,402 490 570 771 0 0 0 0 0 0 7,358 7,368 8,022

Total Demand in the Study Area 2,796 2,716 2,849 4,072 4,082 4,402 490 570 771 417 416 495 129 124 128 7,904 7,909 8,645

Demand that may be met by Other Sources 9 10 10 2,822 2,832 3,152 98 111 315 0 0 0 0 0 0 2,928 2,953 3,477 19

Potential Colorado River Demand 2,787 2,706 2,839 1,250 1,250 1,250 392 459 456 417 416 495 129 124 128 4,975 4,955 5,168

Agricultural Colorado River Demand 2,559 2,501 2,554 0 0 0 240 172 96 412 412 490 19 19 19 3,229 3,103 3,158 20

Municipal and Industrial Colorado River Demand 35 44 57 1,250 1,250 1,250 144 278 354 0 0 0 2 5 9 1,431 1,577 1,670

Energy Colorado River Demand 31 88 126 0 0 0 0 0 0 5 5 5 15 8 7 52 100 138

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 115 16 28 0 0 0 8 8 6 0 0 0 0.6 0.6 0.6 124 26 35

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 92 92 92 92 92 92

Other Colorado River Demand 48 58 75 0 0 0 0 0 0 48 58 75

Notes

IID MWD CVWD PVID Mainstem STATE TOTAL
 Appendix C7 — California Water Demand 

 Scenario Quantification

December 2012 C7-31

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Decreased demand from Current Projected based on increasingly efficient geothermal technology.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12a) IID: No changes from Current Projected.

12b) No changes from Current Projected.

13a) MWD: Increased federal investment in water-saving technology and conservation programs results in a further substantive decrease in per capita 

water use (for example, WaterSmart, EnergyStar, landscape technology). 

Based on California 20X2020 statute for 20 percent reduction in demand by 2020 for the IID planning area.

13b) No changes from Current Projected for other planning areas.

14) No changes from Current Projected.

15) Decreased demand from Current Projected based on increasingly efficient geothermal technology.

16) No changes from Current Projected.

17) IID: No reference. 

18) No changes from Current Projected.

19) No changes from Current Projected.

20) For MWD, all potential Colorado River demand is M&I. For IID and CVWD, distribute Colorado River demand among categories according to 

distribution of total Study Area demand. 
Colorado River Basin 

Water Supply and Demand Study

C7-32 December 2012

TABLE C7-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

CALIFORNIA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 91 91 107 4 4 4 95 95 111 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 10.29 10.29 9.34 10.29 10.29 9.34 10.29 10.29 9.34 2

Consumptive factor [%] 44% 44% 49% 44% 44% 49% 44% 44% 49%

Demand (Consumptive) 412 412 490 19 19 19 430 430 509

Municipal and Industrial (M&I) Population [thousands] 0 0 0 7 14 28 7 14 28 3

M&I Per Capita Use (Diversion) [gpcd] 0 0 0 442 505 522 442 505 522 4

Consumptive factor [%] 0% 0% 0% 69% 68% 67% 69% 68% 67%

M&I Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Self Served Industrial Demand (Consumptive) 0 0 0 0 0 0 0 0 0 5

Demand (Consumptive) 0 0 0 2 5 11 2 5 11

Energy Demand (Consumptive) 5 5 5 15 8 8 20 13 13 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 0.6 0.6 0.6 0.6 0.6 0.6 8

Tribal Demand (Consumptive) 0 0 0 92 92 92 92 92 92 9

Total Hydrologic Basin Demand (Consumptive) 0 0 0 0 0 0 0 0 0 417 416 495 129 125 130 546 541 625

Adjacent Areas

Agricultural Irrigated Acreage[thousands] 477 485 490 62 50 50 74 53 40 613 588 580 10

Per-Acre Water Delivery (Diversion)[af/ac/yr] 5.38 5.17 5.23 3.57 3.57 3.57 4.04 4.04 4.04 5.04 4.94 5.00 11

Demand (Diversion) 2,567 2,510 2,563 222 180 180 300 214 162 3,089 2,904 2,905

Municipal and Industrial (M&I) Population [thousands] 192 291 450 20,743 26,026 33,117 295 599 1,040 21,230 26,916 34,607 12a, 12b

M&I Per Capita Use (Diversion)[gpcd] 172 150 141 172 162 144 452 425 423 176 168 153 13a, 13b

M&I Demand (Diversion) 37 49 71 4,002 4,738 5,352 149 285 493 4,188 5,071 5,916

Self Served Industrial Demand (Diversion) 0 0 0 0 0 0 30 62 106 30 62 106 14

Demand (Diversion) 37 49 71 4,002 4,738 5,352 180 347 599 4,218 5,133 6,022

Energy Demand (Diversion) 31 88 127 0 0 0 31 88 127 15

Minerals Demand (Diversion) 0 0 0 0 0 0 0 0 0 16

Fish, Wildlife, and Recreation Demand (Diversion) 115 17 28 11 11 11 126 27 39 17

Tribal Demand (Diversion) 0 0 0 0 0 0 0 0 0 18

Other Demand (Diversion) 48 58 75 0 0 318 0 0 0 48 58 393

Total Adjacent Areas Demand (Diversion) 2,798 2,722 2,863 4,224 4,917 5,850 490 571 771 0 0 0 0 0 0 7,512 8,210 9,485

Total Demand in the Study Area 2,798 2,722 2,863 4,224 4,917 5,850 490 571 771 417 416 495 129 125 130 8,057 8,751 10,110

Demand that may be met by Other Sources 9 10 10 2,974 3,667 4,600 98 112 315 0 0 0 0 0 0 3,080 3,790 4,925 19

Potential Colorado River Demand 2,789 2,712 2,853 1,250 1,250 1,250 392 459 456 417 416 495 129 125 130 4,977 4,962 5,184

Agricultural Colorado River Demand 2,559 2,501 2,554 0 0 0 240 172 96 412 412 490 19 19 19 3,230 3,103 3,158 20

Municipal and Industrial Colorado River Demand 37 49 71 1,250 1,250 1,250 144 279 354 0 0 0 2 5 11 1,433 1,583 1,685

Energy Colorado River Demand 31 88 126 0 0 0 0 0 0 5 5 5 15 8 8 52 101 139

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 115 16 28 0 0 0 8 8 6 0 0 0 0.6 0.6 0.6 124 25 35

Tribal Colorado River Demand 0 0 0 0 0 0 0 0 0 0 0 0 92 92 92 92 92 92

Other Colorado River Demand 48 58 75 0 0 0 0 0 0 48 58 75

Notes

IID MWD CVWD PVID Mainstem STATE TOTAL
 Appendix C7 — California Water Demand 

 Scenario Quantification

December 2012 C7-33

Notes

1) No changes from Current Projected.

2) No changes from Current Projected.

3) No changes from Current Projected.

4) No changes from Current Projected.

5) No changes from Current Projected.

6) Decreased demand from Current Projected based on increasingly efficient geothermal technology.

7) No changes from Current Projected.

8) No changes from Current Projected.

9) No changes from Current Projected.

10) No changes from Current Projected.

11) No changes from Current Projected.

12a) IID: Based on regional trends, assume 2060 population is 25 percent more than that of Current Projected. 

12b) MWD: Population projections extrapolated from California DWR high growth county population projections for California Water Plan Update, 2009.

13a) Based on California 20X2020 statute for 20 percent reduction in demand by 2020 for the IID planning area.

13b) No changes from Current Projected for other planning areas.

14) No changes from Current Projected.

15) Decreased demand from Current Projected based on increasingly efficient geothermal technology.

16) No changes from Current Projected.

17) IID: No reference. 

18) No changes from Current Projected.

19) MWD: Increased from Current Projected to reflect higher demand with higher population projection. Others: no changes from Current Projected.

20) For MWD, all potential Colorado River demand is M&I. For IID and CVWD, distribute Colorado River demand among categories according to 

distribution of total Study Area demand.
Colorado River Basin 

Water Supply and Demand Study

C7-34 December 2012

4.0 References 

Blue Ribbon Committee. 2011. Report of the Blue Ribbon Committee, The Metropolitan 

Water District of Southern California. April 12. 

Bureau of Land Management. 2012. Personal communication with Reclamation. 

Bureau of Reclamation (Reclamation). 1986. Lower Colorado Water Supply Study, 

California, Planning Report 

Bureau of Reclamation (Reclamation). 2000. Colorado River Interim Surplus Criteria Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2007. Colorado River Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2007 and 2010. 5-year reports. Provisional Upper 

Colorado River Basin Consumptive Uses and Losses Report 2001–2008. Retrieved 

from http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

California Department of Water Resources (DWR), 2009. California Water Plan, Update 

2009. Bulletin 160-09. 

Colorado River Board (CRB). 2000. California’s Colorado River Water Use Plan. 

Colorado River Board (CRB). 2011. Personal communication with Reclamation. 

Coachella Valley Water District (CVWD).2010a. Coachella Valley Water Management Plan. 

Coachella Valley Water District (CVWD). 2010b. 2010 Crop and Water Report. 

Imperial Irrigation District (IID). 2011a. IID Crop Report. 

Imperial Irrigation District (IID). 2011b. Personal communication with Reclamation. 

Metropolitan Water District of Southern California (MWD). 2010. The Regional Urban 

Water Management Plan. 

Palo Verde Irrigation District (PVID). 2011 Personal communication with Reclamation. 

The Secretary of the Interior. 2003. Colorado River Water Delivery Agreement Federal 

Quantification Settlement Agreement for purposes of Section 5(B) of Interim 

Surplus Guidelines. 
Appendix C8

Nevada Water Demand

Scenario Quantification

December 2012 C8-1 

Appendix C8 ─ Nevada Water Demand

Scenario Quantification

1.0 Introduction

This appendix summarizes the data sources used in scenario quantification for Colorado River 

demand1 for the state of Nevada and presents the results of quantification. As presented in figure

C8-1, Nevada is divided into planning areas that correspond to the Southern Nevada Water 

Authority (SNWA) service area and other service areas where Colorado River water is delivered. 

Data collection and development were completed at the planning area level, and the compiled 

water demands are discussed in the results section.

The following sections present background information that summarizes the state’s planning 

areas as well as data sources used to quantify demand scenarios by category. Following the 

background section, results of demand scenario quantification are presented. The results section 

is broken out into a Nevada Study Area summary, followed by Colorado River demand by 

geography, and finally by category. 

2.0 Background 

The SNWA was formed in 1991 by cooperative agreement among seven Las Vegas area water 

and wastewater agencies. SNWA is responsible for the water treatment and delivery as well as 

acquiring and managing the long-term water resources for Southern Nevada. SNWA has 

produced a number of planning reports over time that examine long-term water resources for 

Southern Nevada. 

SNWA, with support from member agencies, coordinated Nevada’s efforts to provide 

information for water demand scenario quantification. These efforts largely relied on information 

previously generated through SNWA water resource planning, including SNWA’s current plan, 

which was developed in 2009 (SNWA, 2009). Adjustments from the 2009 plan reflect the 

development of the range of scenarios established in support of the Study. 

2.1 Data Sources for Quantification

This section discusses data sources for demand quantification by use category. Some category 

projections were based on relevant parameter data, while other category projections were 

developed directly as water demand. Sources include state, regional, and national agency reports. 

• Agricultural Demand: There are no reported Colorado River agricultural demands in 

Nevada.

• Energy: There are no reported Colorado River energy demands in Nevada. 

• Minerals: There are no reported Colorado River minerals demands in Nevada. 

 

1 Colorado River demand as computed by Study Area demand minus other supplies. 
Colorado River Basin 

Water Supply and Demand Study

C8-2 December 2012

FIGURE C8-1 

Colorado River Hydrologic Basin and Export Service Areas in Nevada
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-3 

• Fish, Wildlife, and Recreation: Fish, wildlife, and recreation demands were provided 

by SNWA based on contracted recreation use outside of SNWA's service area. 

• Tribal: The quantification of tribal demands relied on information submitted by the 

Ten Tribes Partnership for use in the Colorado River Interim Surplus Criteria Final 

Environmental Impact Statement (Bureau of Reclamation [Reclamation], 2000) and used 

in the more recent Colorado River Interim Guidelines for Lower Basin Shortages and 

Coordinated Operations for Lake Powell and Lake Mead Final Environmental Impact 

Statement (Reclamation, 2007a), and Reclamation’s 2005 to 2009 Decree Accounting 

Report (Reclamation, 2007b and 2010). Tribal diversion-based demands reflect full use 

of Fort Mojave water rights. 

3.0 Results of Water Demand Scenario Quantification

This section summarizes Nevada’s Colorado River water demand trends by category across the 

initial scenarios. The purpose of this section is to describe changes in demands, both temporally 

and geographically, parameters that influence changes in demands, and how the parameters and 

demands differ amongst scenarios. 

Demands were first developed for areas that may be potentially served by Colorado River water 

(Study Area demands), independent of the source of supply. The communities within the 

Colorado River Basin, including the SNWA service area and other service areas, also rely on 

other sources of supply, including local non-tributary and imported Nevada groundwater 

supplies; banked resources created through local and interstate agreements (for example, Arizona 

Water Bank, California Water Bank, and Southern Nevada Water Bank); and projects that result 

in Intentionally Created Surpluses (ICS) (for example, Virgin/Muddy Rivers, Tributary 

Conservation ICS, Coyote Spring Valley Groundwater Imported ICS, and Brock Reservoir 

System Efficiency ICS). 

The SNWA 2009 plan includes imported Nevada groundwater to help meet future SNWA 

demands, and the SNWA is pursuing development of this resource by securing related Nevada 

groundwater right permits and corresponding federal environmental permits for this project. 

Nevada’s Colorado River demand for the Study includes water for the long term as temporary 

resources (for example, System Efficiency ICS and banked resources) are exhausted without use 

of imported Nevada groundwater. This approach is being applied for the Study to analyze 

Nevada’s potential future Colorado River water demands for planning purposes. If SNWA is 

successful in obtaining these permits for imported Nevada groundwater, this resource, along with 

existing and future Colorado River resources, would be integrated in local planning efforts. The 

subsequent Nevada Colorado River water demand may or may not differ, depending upon the 

application of the available resources in meeting future demands.

To develop estimates of the Colorado River demand, the Study Area demand was reduced by 

estimates of available supply from other sources, as discussed above. This appendix focuses on 

Colorado River demands, but includes discussion of the Study Area parameters that led to these 

demands. For the purpose of the study, additional Virgin River Basin demands in Nevada are not 

included. The SNWA is currently not seeking to develop its Virgin River surface water rights 

under Permit No. 58591 as agreed to under the Agreement Concerning Colorado River 

Management and Operations signed April 23, 2007, by the Seven Basin States which is a key 
Colorado River Basin 

Water Supply and Demand Study

C8-4 December 2012

agreement supporting the Colorado River Interim Guidelines for Lower Basin Shortages and the 

Coordinated Operations for Lake Powell and Lake Mead (U.S. Department of the Interior, 

2007). 

The following sections summarize the results of demand scenario quantification, presenting 

Study Area demand and Colorado River water demand, Colorado River Demand for the state and 

individual planning areas across the six scenarios, and Colorado River water demand by category 

across the six scenarios. Parameters and demands for all categories and all scenarios, along with 

references for data sources, are included. 

3.1 Summary Results of Scenario Quantification

Values were developed for parameters to quantify Study Area demand for each of the scenarios. 

Colorado River demand was calculated as Study Area demand minus other supplies. Table C8-1 

presents summary results for the demand scenarios considered in the Study. The table presents 

agricultural and M&I demand parameters for the entire Study Area that distinguish the scenarios, 

the resulting Study Area demands, and finally the Colorado River demands by category. Because 

other supplies may vary among scenarios, trends observed in the parameters and Study Area 

demands may not be reflected identically in Colorado River demand trends. 

Nevada estimates that between 2.3 and 2.6 million people will reside in Nevada’s Study Area by 

2015. Population is expected to increase to 4.2 to 5.1 million by 2060. The greatest population 

growth is associated with the Rapid Growth (C1 and C2) scenarios and the Enhanced 

Environment (D2) scenario. The Slow Growth (B) scenario has the smallest population in 2060 

of the scenarios (4.2 million by 2060), but still represents a growth of 73 percent over 

2015 estimates. 

The growing municipal population, however, will continue to be more efficient in its per capita 

water use than today. Per capita water use, based on passive and active conservation to achieve 

existing conservation targets, is expected to be 20 percent less in 2060 than in 2015. M&I is the 

largest component of Colorado River demand, and is the only component of change in Colorado 

River demand. The increase in M&I demand is driven by an increase in population that outpaces 

a decrease in per capita usage. 

Figure C8-2 presents demands across the scenarios in three panels as follows: 1) Study Area 

demand with other supplies and Colorado River demand identified, 2) Colorado River demand, 

and 3) change in Colorado River demand by demand category. 

From panel one it can be seen that Study Area demand increases from about 377 thousand acrefeet (kaf) in 2015 to between 514 and 624 kaf in 2060. The range in Study Area demand growth 

across scenarios in 2060 is projected to be about 110 kaf. 

Panel two provides a view of the range across scenarios of Colorado River demand. This demand 

increases from about 300 kaf in 2015 to between 490 and 600 kaf in 2060 (or growth of 63 to 

100 percent), depending on the scenario. This difference results in a Colorado River demand 

range of about 110 kaf across the scenarios in 2060, or about 20 percent. 

Panel three shows how specific categories affect the projected change in Colorado River demand 

by scenario. Growth in M&I demand is the only factor affecting Colorado River demand across 

the scenarios.
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-5 

Figure C8-3 ties historical water use to the range of Colorado River demand in the quantified 

scenarios. The scenarios of future Colorado River demand provided in figure C8-3 do not show a 

smooth growth pattern, primarily due the influence of replacing temporary resources with 

Colorado River water. The 110 kaf range across scenarios in 2060 is easily discernible, with a 

relatively even spread over the range across the scenarios. In addition, it appears that the 

quantified scenarios track well with the peaks in historical uses that likely represent the least 

supply limited conditions or actual demand. 

TABLE C8-1 

Summary Results of Nevada Water Demand Scenario Quantification by 2060

Key Study Area Demand Scenario Parameters

20151 2060 Scenario Parameters

A B C1 C2 D1 D2

Population (millions) 2.6 4.4 4.2 5.1 5.1 4.4 5.1

Change in per capita water usage (%), 

from 2015 — –20% –20% –20% –20% –20% –20%

Irrigated acreage (millions of acres) 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Change in per acre water delivery (%), 

from 2015 — n/a n/a n/a n/a n/a n/a

Study Area Demand (thousand acre-feet [kaf])

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 0 0 0 0 0 0 0

M&I demand 366 530 503 613 613 530 613

Energy demand 0 0 0 0 0 0 0

Minerals demand 0 0 0 0 0 0 0

FWR demand 2.0 2.0 2.0 2.0 2.0 2.0 2.0

Tribal demand 9.0 9.0 9.0 9.0 9.0 9.0 9.0

Total Study Area Demand2 377 541 514 624 624 541 624

Colorado River Demand (kaf)

20151 2060 Scenario Demands

A B C1 C2 D1 D2

Ag demand 0 0 0 0 0 0 0

M&I demand 289 506 479 589 589 506 589

Energy demand 0 0 0 0 0 0 0

Minerals demand 0 0 0 0 0 0 0

FWR demand 2.0 2.0 2.0 2.0 2.0 2.0 2.0

Tribal demand 9.0 9.0 9.0 9.0 9.0 9.0 9.0

Total Colorado River Demand2 300 517 490 600 600 517 600

1 If range across scenarios is less than 10 percent, Current Projected (A) is presented. Otherwise, range (min – max) is 

presented. 2 Excludes potential losses (reservoir evaporation, phreatophytes, and/or operational inefficiencies) that may be charged to

state. 
Colorado River Basin 

Water Supply and Demand Study

C8-6 December 2012

FIGURE C8-2 

Study Area, Colorado River, and Change in Colorado River Demand 

0

100

200

300

400

500

600

700

Thousand Acre-Feet per Year

Study Area Demand in Nevada 

2015 2035 2060

Potential Colorado River 

Demand shown with solid 

color

Demandsthat may be 

met by Other Supplies

shown with off-white and 

colored border

250

300

350

400

450

500

550

600

650

2015 2035 2060

Thousand Acre-Feet per Year

Colorado River Demand in Nevada

0

50

100

150

200

250

300

350

Thousand Acre-Feet per Year

Change in Colorado River Demand in Nevada, from 2015

Agricultural

Municipal and Industrial

Energy

Minerals

Fish and Wildlife and 

Recreation

Tribal

Net Change

2015 2035 2060

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

0

1

2

3

4

5

6

KAF

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-7 

FIGURE C8-3 

Historical Use and Future Projected Demand1 

1

This figure presents the range of potential scenarios. However, some of the scenarios overlap and are not discernible on 

this format.

3.2 Colorado River Water Demand by Geography 

Colorado River water demand for areas served by the Colorado River is presented in 

figures C8-4 and C8-5. These figures show two geographic levels: Study Area in Nevada, and 

individual planning areas. Demands at each geographic level are shown across the scenarios. 

The columns to the right show the Colorado River demand at a point in time (2015, 2035, or 

2060) by relative contribution of the categories. 

The change in both magnitude and percentage of Colorado River demand varies considerably 

across scenarios. Colorado River demand2 in Nevada is primarily in the SNWA service area. The 

primary demand category in the other service areas is tribal, with a small amount of fish, 

wildlife, and recreation demand. 

Figure C8-6 shows the change in Colorado River demand by category from 2015 across the 

scenarios. All change in Colorado River demand is due to change in M&I demand in the SNWA 

service area. 

 

2 Potential Colorado River demand is based on changes in parameters such as population and for the purpose of the Study is not 

 limited by apportionment. 

0

100

200

300

400

500

600

700

1970 1980 1990 2000 2010 2020 2030 2040 2050 2060

Thousand Acre-Feet per Year

Year

Historical Use

Current Projected (A)

Slow Growth (B)

Rapid Growth (C1)

Rapid Growth (C2)

Enhanced Environment (D1)

Enhanced Environment (D2)

<-- Historical

Use

Projected

Demand -->

Apportionment
Colorado River Basin 

Water Supply and Demand Study

C8-8 December 2012

FIGURE C8-4 

Colorado River Demand in Nevada
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-9 

FIGURE C8-5 

Colorado River Demand by Category
Colorado River Basin 

Water Supply and Demand Study

C8-10 December 2012

FIGURE C8-6 

Change in Colorado River Demand in Nevada from 2015 by Category
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-11

3.3 Colorado River Demand by Category

3.3.1 Agricultural

Agricultural demand includes demand from irrigated agriculture, livestock, and stock ponds. No 

agricultural demands are projected for Nevada under any of the scenarios. The only agricultural 

demand is included in the Colorado River water supplied for the Fort Mojave Indian Reservation 

and is accounted for in the tribal category. 

3.3.2 Municipal and Industrial

M&I water demand can be estimated from population and M&I per capita water use, with the 

addition of self-served industrial (SSI) demand. M&I per capita water use is a measure of the 

amount of water produced or diverted per person in a given municipality. Because this measure 

examines all water produced by a given municipality, it often includes industrial, commercial, 

and institutional demand as well as residential demand. A number of factors may influence the 

M&I per capita water use of a given community, including the amount of industrial demand, 

climate, number of institutional facilities, and number of visitors. 

SSI are industries located in a given area that have their own water supply systems and are 

therefore not directly related to local measures of population and M&I per capita water use. 

Figure C8-7 presents the following by scenario in 2015, 2035, and 2060: 

• Change in M&I demand for Colorado River water in the Study Area

• Change in M&I demand for Colorado River water in individual planning areas 

• M&I demand as a portion of Colorado River water demand (right hand side of graph) 

As can be seen from figure C8-7, M&I water demand is by far the largest component of 

Colorado River demand, increasing from 96 percent in 2015 to 98 percent of Colorado River 

demand in 2060, depending on which scenario is considered. 

Colorado River demand for M&I use increases over time from 2015 to 2060 across all scenarios. 

The increase is primarily due to population increase as M&I per capita water use decreases over 

time across all scenarios and SSI is relatively small. 

In examining the planning areas, nearly all of the increase in M&I demand for Colorado River 

water from 2015 to 2060 over time is due to population increase in the SNWA service area 

across all scenarios. The remaining increase in demand is primarily from a small increase in SSI 

demand in the other areas. 

Increases in population are somewhat tempered by decreases in M&I per capita water use of 

20 percent by 2060. 

3.3.3 Energy

SNWA member agencies provide some retail water service for energy production. This water 

usage is captured in the SNWA M&I demand. 

3.3.4 Minerals Extraction

Nevada does not currently use or plan to use Colorado River Water for minerals extraction.
Colorado River Basin 

Water Supply and Demand Study

C8-12 December 2012

FIGURE C8-7 

Change in Colorado River Demand in Nevada from 2015 for M&I 

0

100

200

300

2015 2035 2060

KAF

SNWA

0

100

200

300

2015 2035 2060

KAF

Other

201520352060

A

A

B

B

C1

C1

C2

C2

D1

D1

D2

D2

0

50

100

150

200

250

300

350

2015 2035 2060

Thousand Acre-Feet per Year (KAF)

Change in Colorado River Demand in Nevada, from 2015

Municipal and Industrial

M&I is 96.3% of Colorado River demand*

M&I is 96.9 - 97.4% of Colorado River demand*

M&I is 97.7 - 98.2% of Colorado River demand*

Six columns per time 

period represent six 

scenarios. From left to 

right: A, B, C1, C2, D1, D2

*Percentages shown 

represent the range 

across scenarios
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-13

3.3.5 Fish, Wildlife, and Recreation

Recreational demands were included to account for the Lake Mead National Recreation Area. 

Total fish, wildlife, and recreation demands are estimated at about 2,000 acre-feet per year and 

are constant through time and across scenarios. No additional future environmental or nonconsumptive demands were included. 

3.3.6 Tribal

The Fort Mojave Indian Tribe diverts Colorado River water under water rights assigned to 

reservation land in Nevada. 

The Tribe does not currently use its full diversion right as established by the Consolidated 

Decree of the United States Supreme Court in Arizona v. California, 547 U.S. 150 (2006); 

however, it is expected that it will fully use the right in the future. Associated projected tribal 

demands are constant over time and across scenarios. Fort Mojave use from 2015 to 2060 is 

represented as a constant demand at its right of 12.5 kaf with 9 kaf of consumptive use. 

For additional information on tribal demand, see appendix C9. 

3.4 Summary Tables of Parameters and Demands by Category

Tables C8-2 to C8-7 present the specific parameter data collected by planning area. Each table is 

a complete set of data for a given scenario. These data were used to develop Study Area demands 

and subsequently Colorado River demands once other supplies were considered. These tables 

provide the specific information used in the creation of the summary and category plots 

previously discussed and provide reference information for the data provided. 
Colorado River Basin 

Water Supply and Demand Study

C8-14 December 2012

TABLE C8-2 

Total Demand within Study Area under Current Projected (A) Scenario

Notes

1) Center for Business and Economic Research (CBER). 2008. (CBER, 

2008), beyond 2035 annual absolute annual growth of 37,600. SNWA 

services ~97 percent of Clark County's population.

2) Water Resource Plan. (SNWA, 2009). Personal communication (SNWA, 

2011). STATE TOTAL only based on SNWA planning area.

3) Water Resource Plan. (SNWA, 2009).

4) Consistent with methodologies in the SNWA Water Resources Plan, 

2009, municipal SNWA demand (computed as population times per 

capita use) is reduced by groundwater supply and reclaimed waters 

before multiplying by 1/1.7 (59 percent) to obtain consumptive municipal 

demand. 

5) M&I demand in "Other" Category provided by SNWA based on 

contracted build-out of development outside of SNWA's service area.

5a) Row 13 (SSI) in 2011, SNWA planning area -water added to the AZ 

groundwater bank.

6) FWR demand in "Other" Category provided by SNWA based on 

contracted recreation use outside of SNWA's service area.

7) Tribal demand in "Other" Category based on the Ten Tribes Partnership 

schedule included in the Colorado River Interim Surplus Criteria Final 

Environmental Impact Statement (Reclamation, 2000).

8) Total Hydrologic Basin in "Other" Category based on contracted amount. 

Users will grow into their contract amount (28,405) by 2031.

9) Calculated from the sum of Hydrologic Basin (Consumptive) Demand 

and Adjacent Areas (Diversion) Demand.

10) Includes potential consumptive use banked water through ICS (Coyote 

Spring, Muddy/Virgin, Drop 2) and AZ groundwater bank.

11) Calculated as total demand minus other sources.

12) Colorado River demand is distributed among categories according to 

distribution of total Study Area demand in that planning area. 

NEVADA LEGEND: 999 From States 999 From State Plans

Units are thousand acre-feet per year, unless otherwise noted 999 Calculated 999 From Study Team

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 0 0 0 0 0 0 0 0 0

Per-Acre Water Delivery (Diversion) [af/ac/yr] 0 0 0 0 0 0 0 0 0

Consumptive factor [%] 0% 0% 0% 0% 0% 0% 0% 0% 0%

Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Municipal and Industrial (M&I) Population [thousands] 2,561 3,525 4,434 0 0 0 2,561 3,525 4,434 1

M&I Per Capita Use (Diversion) [gpcd] 237 199 190 237 199 190 2

Consumptive factor [%] 59% 59% 59% 59% 59% 59% 3

M&I Demand (Consumptive) 358 421 513 0 0 0 358 421 513 4

Self Served Industrial Demand (Consumptive) 0 0 0 8 17 17 8 17 17 5

Demand (Consumptive) 358 421 513 8 17 17 366 438 530

Energy Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 2 2 2 2 2 2 6

Tribal Demand (Consumptive) 0 0 0 9 9 9 9 9 9 7

Total Hydrologic Basin Demand (Consumptive) 358 421 513 19 28 28 377 449 541 8

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population[thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 358 421 513 19 28 28 377 449 541 9

Demand that may be met by Other Supplies 77 64 24 0 0 0 77 64 24 10

Potential Colorado River Demand 281 357 489 19 28 28 300 385 517 11

Agricultural Colorado River Demand 0 0 0 0 0 0 0 0 0

Municipal and Industrial Colorado River Demand 281 357 489 8 17 17 289 374 506 12

Energy Colorado River Demand 0 0 0 0 0 0 0 0 0

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 2 2 2 2 2 2

Tribal Colorado River Demand 0 0 0 9 9 9 9 9 9

SNWA Other STATE TOTAL

Notes
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-15

TABLE C8-3 

Total Demand within Study Area under Slow Growth (B) Scenario

Notes

1) No change from Current Projected.

2) No change from Current Projected.

3) 2009 Water Resource Plan - Clark County Short 

Term Adjustment to CBER. 2008. Population 

Forecast. SNWA services ~97 percent of Clark 

County's population.

4) No change from Current Projected.

5) No change from Current Projected.

6) No change from Current Projected.

7) No change from Current Projected.

8) No change from Current Projected.

9) No change from Current Projected.

10) No change from Current Projected.

11) Colorado River demand is distributed among 

categories according to distribution of total Study 

Area demand in that planning area. 

NEVADA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 0 0 0 0 0 0 0 0 0 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 0.00 0.00 0.00 0.00 0.00 0.00 0 0 0 2

Consumptive factor [%] 0% 0% 0% 0% 0% 0% 0% 0% 0%

Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Municipal and Industrial (M&I) Population [thousands] 2,375 3,306 4,215 0 0 0 2,375 3,306 4,215 3

M&I Per Capita Use (Diversion) [gpcd] 237 199 190 237 199 190 4

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Consumptive) 329 392 485 0 0 0 329 392 485

Self Served Industrial Demand (Consumptive) 0 0 0 8 17 17 8 17 17 5

Demand (Consumptive) 329 392 485 8 17 17 337 410 503

Energy Demand (Consumptive) 0 0 0 0 0 0 0 0 0 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 2 2 2 2 2 2 8

Tribal Demand (Consumptive) 0 0 0 9 9 9 9 9 9 9

Total Hydrologic Basin Demand (Consumptive) 329 392 485 19 28 28 348 421 514

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population[thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 329 392 485 19 28 28 348 421 514

Demand that may be met by Other Supplies 48 64 24 0 0 0 48 64 24 10

Potential Colorado River Demand 281 328 461 19 28 28 300 357 490

Agricultural Colorado River Demand 0 0 0 0 0 0 0 0 0 11

Municipal and Industrial Colorado River Demand 281 328 461 8 17 17 289 346 479

Energy Colorado River Demand 0 0 0 0 0 0 0 0 0

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 2 2 2 2 2 2

Tribal Colorado River Demand 0 0 0 9 9 9 9 9 9

SNWA Other STATE TOTAL

Notes
Colorado River Basin 

Water Supply and Demand Study

C8-16 December 2012

TABLE C8-4 

Total Demand within Study Area under Rapid Growth (C1) Scenario

Notes

1) No change from Current Projected.

2) No change from Current Projected.

3) Clark County population: for 2011 used 2008 CBER 

population from 2012 to 2030 marginally increased 

population projection by the 2008 CBER annual growth 

rates to illustrate an Expansive Scenario, then a fixed 

absolute annual growth of ~52,000 annually. SNWA 

services ~97 percent of Clark County's population.

4) No change from Current Projected.

5) No change from Current Projected.

6) No change from Current Projected.

7) No change from Current Projected.

8) No change from Current Projected.

9) No change from Current Projected.

10) No change from Current Projected.

11) Colorado River demand is distributed among 

categories according to distribution of total Study Area 

demand in that planning area. 

NEVADA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 0 0 0 0 0 0 0 0 0 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 0.00 0.00 0.00 0.00 0.00 0.00 0 0 0 2

Consumptive factor [%] 0% 0% 0% 0% 0% 0% 0% 0% 0%

Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Municipal and Industrial (M&I) Population [thousands] 2,576 3,840 5,097 0 0 0 2,576 3,840 5,097 3

M&I Per Capita Use (Diversion) [gpcd] 237 199 190 237 199 190 4

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Consumptive) 360 462 596 0 0 0 360 462 596

Self Served Industrial Demand (Consumptive) 0 0 0 8 17 17 8 17 17 5

Demand (Consumptive) 360 462 596 8 17 17 368 480 613

Energy Demand (Consumptive) 0 0 0 0 0 0 0 0 0 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 2 2 2 2 2 2 8

Tribal Demand (Consumptive) 0 0 0 9 9 9 9 9 9 9

Total Hydrologic Basin Demand (Consumptive) 360 462 596 19 28 28 379 491 624

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population[thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 360 462 596 19 28 28 379 491 624

Demand that may be met by Other Supplies 79 64 24 0 0 0 79 64 24 10

Potential Colorado River Demand 281 398 572 19 28 28 300 427 600

Agricultural Colorado River Demand 0 0 0 0 0 0 0 0 0 11

Municipal and Industrial Colorado River Demand 281 398 572 8 17 17 289 416 589

Energy Colorado River Demand 0 0 0 0 0 0 0 0 0

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 2 2 2 2 2 2

Tribal Colorado River Demand 0 0 0 9 9 9 9 9 9

SNWA Other STATE TOTAL

Notes
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-17

TABLE C8-5 

Total Demand within Study Area under Rapid Growth (C2) Scenario

Notes

1) No change from Current Projected.

2) No change from Current Projected.

3) Clark County population: for 2011 used 2008 CBER 

Population from 2012 to 2030 marginally increased 

population projection by the 2008 CBER annual growth 

rates to illustrate an Expansive Scenario, then a fixed 

absolute annual growth of ~52,000 annually. SNWA 

services ~97 percent of Clark County's population.

4) No change from Current Projected.

5) No change from Current Projected.

6) No change from Current Projected.

7) No change from Current Projected.

8) No change from Current Projected.

9) No change from Current Projected.

10) No change from Current Projected.

11) Colorado River demand is distributed among categories 

according to distribution of total Study Area demand in 

that planning area. 

NEVADA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 0 0 0 0 0 0 0 0 0 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 0.00 0.00 0.00 0.00 0.00 0.00 0 0 0 2

Consumptive factor [%] 0% 0% 0% 0% 0% 0% 0% 0% 0%

Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Municipal and Industrial (M&I) Population [thousands] 2,576 3,840 5,097 0 0 0 2,576 3,840 5,097 3

M&I Per Capita Use (Diversion) [gpcd] 237 199 190 237 199 190 4

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Consumptive) 360 462 596 0 0 0 360 462 596

Self Served Industrial Demand (Consumptive) 0 0 0 8 17 17 8 17 17 5

Demand (Consumptive) 360 462 596 8 17 17 368 480 613

Energy Demand (Consumptive) 0 0 0 0 0 0 0 0 0 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 2 2 2 2 2 2 8

Tribal Demand (Consumptive) 0 0 0 9 9 9 9 9 9 9

Total Hydrologic Basin Demand (Consumptive) 360 462 596 19 28 28 379 491 624

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population[thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 360 462 596 19 28 28 379 491 624

Demand that may be met by Other Supplies 79 64 24 0 0 0 79 64 24 10

Potential Colorado River Demand 281 398 572 19 28 28 300 427 600

Agricultural Colorado River Demand 0 0 0 0 0 0 0 0 0 11

Municipal and Industrial Colorado River Demand 281 398 572 8 17 17 289 416 589

Energy Colorado River Demand 0 0 0 0 0 0 0 0 0

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 2 2 2 2 2 2

Tribal Colorado River Demand 0 0 0 9 9 9 9 9 9

SNWA Other STATE TOTAL

Notes
Colorado River Basin 

Water Supply and Demand Study

C8-18 December 2012

TABLE C8-6 

Total Demand within Study Area under Enhanced Environment (D1) Scenario

Notes

1) No change from Current Projected.

2) No change from Current Projected.

3) No change from Current Projected.

4) No change from Current Projected.

5) No change from Current Projected.

6) No change from Current Projected.

7) No change from Current Projected.

8) No change from Current Projected.

9) No change from Current Projected.

10) No change from Current Projected.

11) Colorado River demand is distributed among 

categories according to distribution of total Study Area 

demand in that planning area.

NEVADA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 0 0 0 0 0 0 0 0 0 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 0.00 0.00 0.00 0.00 0.00 0.00 0 0 0 2

Consumptive factor [%] 0% 0% 0% 0% 0% 0% 0% 0% 0%

Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Municipal and Industrial (M&I) Population [thousands] 2,561 3,525 4,434 0 0 0 2,561 3,525 4,434 3

M&I Per Capita Use (Diversion) [gpcd] 237 199 190 237 199 190 4

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Consumptive) 358 421 513 0 0 0 358 421 513

Self Served Industrial Demand (Consumptive) 0 0 0 8 17 17 8 17 17 5

Demand (Consumptive) 358 421 513 8 17 17 366 438 530

Energy Demand (Consumptive) 0 0 0 0 0 0 0 0 0 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 2 2 2 2 2 2 8

Tribal Demand (Consumptive) 0 0 0 9 9 9 9 9 9 9

Total Hydrologic Basin Demand (Consumptive) 358 421 513 19 28 28 377 449 541

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population[thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 358 421 513 19 28 28 377 449 541

Demand that may be met by Other Supplies 77 64 24 0 0 0 77 64 24 10

Potential Colorado River Demand 281 357 489 19 28 28 300 385 517

Agricultural Colorado River Demand 0 0 0 0 0 0 0 0 0 11

Municipal and Industrial Colorado River Demand 281 357 489 8 17 17 289 374 506

Energy Colorado River Demand 0 0 0 0 0 0 0 0 0

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 2 2 2 2 2 2

Tribal Colorado River Demand 0 0 0 9 9 9 9 9 9

SNWA Other STATE TOTAL

Notes
Appendix C8 — Nevada Water Demand

Scenario Quantification

December 2012 C8-19

TABLE C8-7 

Total Demand within Study Area under Enhanced Environment (D2) Scenario

Notes

1) No change from Current Projected.

2) No change from Current Projected.

3) No change from Current Projected.

4) No change from Current Projected.

5) No change from Current Projected.

6) No change from Current Projected.

7) No change from Current Projected.

8) No change from Current Projected.

9) No change from Current Projected.

10) No change from Current Projected.

11) Colorado River demand is distributed among categories 

according to distribution of total Study Area demand in 

that planning area. 

NEVADA LEGEND: 999 From Current Projected Data Sheet 999 Computed

Units are thousand acre-feet per year, unless otherwise noted 999 Input Parameter

Planning Area

Hydrologic Basin Year 2015 2035 2060 2015 2035 2060 2015 2035 2060

Agricultural Irrigated Acreage [thousands] 0 0 0 0 0 0 0 0 0 1

Per-Acre Water Delivery (Diversion) [af/ac/yr] 0.00 0.00 0.00 0.00 0.00 0.00 0 0 0 2

Consumptive factor [%] 0% 0% 0% 0% 0% 0% 0% 0% 0%

Demand (Consumptive) 0 0 0 0 0 0 0 0 0

Municipal and Industrial (M&I) Population [thousands] 2,576 3,840 5,097 0 0 0 2,576 3,840 5,097 3

M&I Per Capita Use (Diversion) [gpcd] 237 199 190 237 199 190 4

Consumptive factor [%] 59% 59% 59% 59% 59% 59%

M&I Demand (Consumptive) 360 462 596 0 0 0 360 462 596

Self Served Industrial Demand (Consumptive) 0 0 0 8 17 17 8 17 17 5

Demand (Consumptive) 360 462 596 8 17 17 368 480 613

Energy Demand (Consumptive) 0 0 0 0 0 0 0 0 0 6

Minerals Demand (Consumptive) 0 0 0 0 0 0 0 0 0 7

Fish, Wildlife, and Recreation Demand (Consumptive) 0 0 0 2 2 2 2 2 2 8

Tribal Demand (Consumptive) 0 0 0 9 9 9 9 9 9 9

Total Hydrologic Basin Demand (Consumptive) 360 462 596 19 28 28 379 491 624

Adjacent Areas

Agricultural Irrigated Acreage [thousands]

Per-Acre Water Delivery (Diversion) [af/ac/yr]

Consumptive factor [%]

Demand (Diversion)

Demand (Consumptive)

Municipal and Industrial (M&I) Population[thousands]

M&I Per Capita Use (Diversion) [gpcd]

Consumptive factor [%]

M&I Demand (Diversion)

Self Served Industrial Demand (Diversion)

Demand (Diversion)

Demand (Consumptive)

Energy Demand (Diversion)

Minerals Demand (Diversion)

Fish, Wildlife, and Recreation Demand (Diversion)

Tribal Demand (Diversion)

Total Adjacent Areas Demand (Diversion) 0 0 0 0 0 0 0 0 0

Total Demand in the Study Area 360 462 596 19 28 28 379 491 624

Demand that may be met by Other Supplies 79 64 24 0 0 0 79 64 24 10

Potential Colorado River Demand 281 398 572 19 28 28 300 427 600

Agricultural Colorado River Demand 0 0 0 0 0 0 0 0 0 11

Municipal and Industrial Colorado River Demand 281 398 572 8 17 17 289 416 589

Energy Colorado River Demand 0 0 0 0 0 0 0 0 0

Minerals Colorado River Demand 0 0 0 0 0 0 0 0 0

Fish, Wildlife, and Recreation Colorado River Demand 0 0 0 2 2 2 2 2 2

Tribal Colorado River Demand 0 0 0 9 9 9 9 9 9

SNWA Other STATE TOTAL

Notes
Colorado River Basin 

Water Supply and Demand Study

C8-20 December 2012

4.0 References 

Center for Business and Economic Research (CBER). 2008. Population Forecasts: LongTerm Projections for Clark County, Nevada 2008–2035. 

Consolidated Decree of the United States Supreme Court. 2006. Arizona v. California, 547 

U.S. 150. 

Bureau of Reclamation (Reclamation). 2000. Colorado River Interim Surplus Criteria Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2007a. Colorado River Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations of Lake Powell and Lake Mead Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2007b and 2010. 5 year reports. Provisional Upper 

Colorado River Basin Consumptive Uses and Losses Report 2001–2008. Retrieved 

from http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html.

Southern Nevada Water Authority (SNWA). 2009. SNWA. Water Resource Plan. 

Southern Nevada Water Authority (SNWA). 2011. Personal communication with 

Reclamation.

U.S. Department of the Interior. 2007. Record of Decision for Colorado River Lower Basin 

Shortages and Coordinated Operations for Lake Powell and Lake Mead. 
Appendix C9 

Tribal Water Demand

Scenario Quantification

December 2012 C9-1 

Appendix C9 ─ Tribal Water Demand 

Scenario Quantification

1.0 Introduction

Federally recognized tribes (tribes) hold quantified rights to a significant amount of water from 

the Colorado River and its tributaries (approximately 2.9 million acre-feet of annual diversion 

rights). In many cases, these rights are senior to other uses. Therefore, representing these rights

and the associated demand is a critical component to assessing future water demand in the 

Colorado River Basin (Basin). An additional component of future demand is an assessment of 

demands by tribes that have unquantified rights or claims. Where information on these 

unquantified rights or claims was provided by tribes, it was included in the Study, as appropriate, 

however, this information is not reflected in future tribal water demand projections

Based on quantified rights and with additional input from tribes, future demand for water by 

tribes in the Basin has been quantified by the Study. The term “quantified rights,” as used in the 

context of the Study, is defined as the amount of rights reserved by or granted to tribes by federal 

court decrees, state court decrees, treaties, agreements, and Executive Orders. This appendix 

presents tribal rights and the associated future tribal demand for Colorado River water under the 

Study’s various water demand scenarios. 

Throughout the Study, the Bureau of Reclamation (Reclamation) met with tribes in the 

Upper Colorado River Basin, Lower Colorado River mainstem, and tribes served by water provided 

(directly or pursuant to exchanges) through the Central Arizona Project (CAP) facilities under 

contracts between tribes and the United States (see the Tribal discussion in the Colorado River 

Water Demand by Category section). In addition, Reclamation worked collaboratively with the Ten 

Tribes Partnership (Partnership), whose members have landholdings in the Upper and Lower 

Basins through which the Colorado River and various tributaries flow, as well as the Inter Tribal 

Council of Arizona (ITCA), whose members are the governments of 20 tribes with land in 

Arizona. 

1.1 Indian Trust Assets

The United States has a trust responsibility to protect and maintain rights reserved by or granted to 

tribes by federal court decrees, state court decrees, treaties, agreements, and Executive Orders. The 

Indian Trust Assets (ITAs) entitled to protection under the trust responsibility include tribes’ 

federally reserved water rights. A tribe may also have other off-reservation interests and concerns 

that must be taken into account.

Each tribe’s water rights determination is multifaceted and contains numerous provisions. The 

information in this appendix is limited to the United States’ obligations with regard to current 

and future Colorado River water delivery to tribes, including tributaries in the Upper Basin. 

The information in this appendix is not intended to provide an interpretation of the water rights 

of any tribe. 

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Colorado River Basin 

Water Supply and Demand Study

C9-2 December 2012

2.0 Process for Quantifying Tribal Demand

The Study implemented a scenario planning process to examine the uncertainty in future water 

supply and demand through the development of multiple future scenarios (see Technical 

Report A – Scenario Development). Representatives of several organizations participated in the 

development of the water demand scenarios, including water management entities, federal 

resource management agencies, tribes, conservation organizations, and others interested in the 

Basin. This collaboration was accomplished through a variety of means, including participation 

in a Water Demand Sub-Team, and direct contact with representatives of specific organizations. 

The scenario planning process involves identifying the key driving forces (factors that likely will 

have the greatest influence on the future state of the system and thereby the performance of the 

system over time); ranking the driving forces as to their relative importance and relative 

uncertainty; and associating the highly uncertain and highly important driving forces, identified 

as critical uncertainties, with either water supply or water demand. One of the key critical 

uncertainties associated with Colorado River water demand relates to tribes. This critical 

uncertainty is titled, “Changes in water availability due to tribal water use and settlement of tribal 

water rights claims.”

To frame the plausible uncertainty, six demand scenarios were developed with the following 

themes: Current Projected (A), Slow Growth (B), Rapid Growth (C1 and C2), and Enhanced 

Environment (D1 and D2). The Water Demand Sub-Team then developed storylines for each 

scenario. Storylines are narrative descriptions of how the future may unfold and provide the plot 

for describing the scenario. The scenario storylines related to the uncertainty in future tribal 

demand are listed in table C9-1.

TABLE C9-1 

Storylines Related to Tribal Water Use 

Storyline Related to Tribal Water Use Scenario

Tribal use develops according to quantified rights and current use patterns. Current Projected (A) 

Tribal use continues to develop but at slower than planned rates. Slow Growth (B) 

Tribal use and development occur faster than currently planned. In addition, 

new tribal claims and settlements are realized. Rapid Growth (C1) 

Tribal use and development occur faster than currently planned. In addition, 

new tribal claims and settlements are realized. Rapid Growth (C2) 

Tribal use develops according to quantified rights and current use patterns. Enhanced Environment (D1) 

Tribal use and development occur faster than currently planned. In addition, 

new tribal claims and settlements are realized. Enhanced Environment (D2) 

The scenario storylines were published in Technical Report A – Scenario Development and 

comments received suggested that the factors driving the trajectory of certain critical uncertainties 

(for example, changes in water needs for energy or changes in agricultural land use) are different 

from those that drive the uncertainty related to tribal water use. Specifically, tribal comments 

pointed out that factors such as increased population and economic development may not be the 

primary drivers for future tribal demands. Tribal governments exercise direct and immediate 
Appendix C9—Tribal Water Demand

Scenario Quantification

December 2012 C9-3 

control over land use decisions and development on tribal trust lands, and these decisions may be 

independent of economic drivers. For instance, under economic conditions where a private entity 

might choose to fallow land, a tribal government may keep land in production simply to cover 

irrigation assessment costs and/or to provide employment. After considering these comments, it 

was decided to change the storyline narratives related to tribal water use by removing economic 

factors. For example, the storyline for the Slow Growth (B) scenario was changed from “Tribal use 

continues to develop but at slower than planned rates due to economic conditions and pressure to 

reduce tribal expenditures or federal settlement expenditures,” to “Tribal use continues to develop 

but at slower than planned rates.” 

In most cases, the quantification of tribal demands relied on information submitted by the 

Partnership, referred to as “the Ten Tribes Partnership Schedule” in this appendix, for use in the 

Colorado River Interim Surplus Criteria Final Environmental Impact Statement (Reclamation, 

2000) and in the more recent Colorado River Interim Guidelines for Lower Basin Shortages and 

Coordinated Operations for Lake Powell and Lake Mead Final Environmental Impact Statement

(Reclamation, 2007). Some revisions to these projections were made, and alternative demand 

scenarios were quantified based on discussions with and information submitted by individual 

tribes, the Partnership, and the ITCA. 

2.1 Summary of Tribal Colorado River Rights and Demands by Scenario

Tribes with rights to Colorado River water can be organized into three categories based on 

location: Upper Colorado River Basin tribes, Lower Colorado River Mainstem tribes, and tribes 

served by water provided through the CAP, as described in table C9-2. 

Tables C9-3 to C9-5 summarize tribal water rights and future demands organized by location and 

tribe in acre-feet per year (afy). Section 3, Tribal Summaries of this appendix provides moredetailed information on each tribe’s rights and projected future demands. In Arizona, both 

Colorado River mainstem water and water that might be conveyed through the CAP facilities 

have been reserved for future settlements. 

In addition to those tribes whose rights to Colorado River water have been confirmed by court 

decree or final settlements, there are tribes whose rights to water have not yet been quantified or 

that have been quantified for only some of their tribal lands. Such tribes are listed in the 

following section. 

The applicability of the storylines in projecting future tribal demand varies for each tribe. For 

some tribes, the storylines provide a range of future demands; for other tribes, the storylines do 

not apply and there is no variation in future demands. Additionally, some tribes currently use 

their full right and in these cases there is also no variation in future demands. 
Colorado River Basin 

Water Supply and Demand Study

C9-4 December 2012

TABLE C9-2 

Upper Colorado River Basin Tribes, Lower Colorado River Mainstem Tribes, and Tribes Served by Water Provided 

through the CAP

Upper Colorado River Basin Tribes

Jicarilla Apache Nation New Mexico

Navajo Nation Arizona, New Mexico, and Utah

Southern Ute Indian Tribe Colorado

Ute Indian Tribe of the Uintah and Ouray Reservation Utah

Ute Mountain Ute Tribe Colorado, New Mexico, and Utah

Lower Colorado River Mainstem Tribes1

Chemehuevi Indian Tribe California

Cocopah Indian Tribe Arizona 

Colorado River Indian Tribes Arizona and California

Fort Mojave Indian Tribe Arizona, Nevada, and California

Hopi Tribe Arizona 

Quechan Indian Tribe Arizona and California

Tribes served through the Central Arizona Project 

Ak-Chin Indian Community Arizona 

Fort McDowell Yavapai Nation Arizona 

Gila River Indian Community Arizona 

Pascua Yaqui Tribe Arizona 

Salt River Pima-Maricopa Indian Community Arizona 

San Carlos Apache Tribe Arizona 

Tohono O'odham Nation Arizona 

Tonto Apache Tribe Arizona 

White Mountain Apache Tribe Arizona 

Yavapai-Apache Nation Arizona 

Yavapai-Prescott Tribe Arizona 

1 The Zuni Indian Tribe has rights to Little Colorado River water in Arizona and the Moapa Band of Paiutes has rights to water in 

the Muddy River, Nevada. The modeling of these tributaries assume future demand to be consistent with historical demand on 

these rivers. See Technical Report C – Water Demand Assessment, for more information on the modeling of Lower Basin 

tributaries.
Appendix C9 — Tribal Water Demand 

Scenario Quantification

December 2012 C9-5 

TABLE C9-3 

Upper Colorado River Basin Tribal Rights and Future Demands

State Tribe

Diversion

Entitlement 

(Water 

Right) (afy)

Depletion 

Entitlement 

(Water 

Right) (afy) Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 (afy) 2035 (afy) 2060 (afy)

NM Jicarilla Apache 

Nation

45,683 34,195 Current Projected (A) 36,932 27,650 44,841 33,295 45,683 34,195

Slow Growth (B) 36,932 27,650 44,841 33,295 45,683 34,195

Rapid Growth (C1) 36,932 27,650 45,683 34,195 45,683 34,195

Rapid Growth (C2) 36,932 27,650 45,683 34,195 45,683 34,195

Enhanced Environment ( D1) 36,932 27,650 44,841 33,295 45,683 34,195

Enhanced Environment (D2) 36,932 27,650 45,683 34,195 45,683 34,195

NM Navajo Nation1 606,660 325,670 Current Projected (A) 506,348 271,820 608,085 326,435 612,863 329,000

Slow Growth (B) 506,348 271,820 608,085 326,435 612,863 329,000

Rapid Growth (C1) 517,972 278,060 699,633 375,580 915,756 491,600

Rapid Growth (C2) 517,972 278,060 699,633 375,580 915,756 491,600

Enhanced Environment (D1) 506,348 271,820 608,085 326,435 612,863 329,000

Enhanced Environment (D2) 517,972 278,060 699,633 375,580 915,756 491,600

AZ Navajo Nation 

(Upper Basin)

NA NA Current Projected (A) 49,125 47,987 49,207 47,707 49,207 47,707

Slow Growth (B) 49,125 47,987 49,207 47,707 49,207 47,707

Rapid Growth (C1) 43,437 42,431 61,088 59,226 77,621 75,255

Rapid Growth (C2) 43,437 42,431 61,088 59,226 77,621 75,255

Enhanced Environment (D1) 49,125 47,987 49,207 47,707 49,207 47,707

Enhanced Environment (D2) 43,437 42,431 61,088 59,226 77,621 75,255

AZ Navajo Nation 

(Lower Basin)

NA NA Current Projected (A) 0 0 0 0 0 0 

Slow Growth (B) 0 0 0 0 0 0 

Rapid Growth (C1) 16,456 16,075 74,055 71,798 126,767 122,903

Rapid Growth (C2) 16,456 16,075 74,055 71,798 126,767 122,903

Enhanced Environment (D1) 0 0 0 0 0 0 

Enhanced Environment (D2) 16,456 16,075 74,055 71,798 126,767 122,903
Colorado River Basin 

Water Supply and Demand Study

C9-6 December 2012

TABLE C9-3 

Upper Colorado River Basin Tribal Rights and Future Demands

State Tribe

Diversion

Entitlement 

(Water 

Right) (afy)

Depletion 

Entitlement 

(Water 

Right) (afy) Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 (afy) 2035 (afy) 2060 (afy)

UT Navajo Nation NA NA Current Projected (A) 0 0 0 0 0 0 

Slow Growth (B ) 0 0 0 0 0 0 

Rapid Growth (C1) 26,204 13,102 79,876 39,938 156,692 78,346

Rapid Growth (C2) 26,204 13,102 79,876 39,938 156,692 78,346

Enhanced Environment (D1) 0 0 0 0 0 0 

Enhanced Environment (D2) 26,204 13,102 79,876 39,938 156,692 78,346

CO Southern Ute 

Indian Tribe

137,090 74,318 Tribal demand in Colorado is embedded in other demand categories within the state.

UT Ute Indian Tribe 

of the Uintah 

and Ouray 

Reservation2

480,594 258,943 Current Projected (A) 480,594 258,943 480,594 258,943 480,594 258,943

Slow Growth (B) 316,354 170,451 447,747 241,245 480,594 258,943

Rapid Growth (C1) 480,594 258,943 480,594 258,943 480,594 258,943

Rapid Growth (C2) 480,594 258,943 480,594 258,943 480,594 258,943

Enhanced Environment (D1) 480,594 258,943 480,594 258,943 480,594 258,943

Enhanced Environment (D2) 480,594 258,943 480,594 258,943 480,594 258,943

CO Ute Mountain 

Ute Tribe

88,358 51,081 Tribal demand in Colorado is embedded in other demand categories within the state.

1 The diversion and depletion demands of the Navajo Nation from the Colorado River in the Upper Basin in New Mexico are not limited by the Navajo Nation San Juan River in 

New Mexico Water Rights Settlement; however, the Navajo Nation agrees to be bound by the terms of that settlement so long as the Settlement is effective. To the extent that the 

Navajo Nation demands exceed the amounts provided in the settlement, the Nation may seek to acquire water from other users or from sources other than the Colorado River to meet 

any unmet demands.

2 The diversion and depletion associated with the demand for the Ute Indian Tribe of the Uintah and Ouray Reservation is dependent upon the re-ratification of the Revised Ute 

Indian Compact of 1990 by the tribe and the State of Utah. 
Appendix C9 — Tribal Water Demand 

Scenario Quantification

December 2012 C9-7 

TABLE C9-4 

Lower Colorado River Mainstem Tribal Rights and Future Demands

State Tribe

Diversion 

Entitlement 

(Water 

Right) (afy)1 Net Acres2 Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 (afy) 2035 (afy) 2060 (afy)

CA Chemehuevi Indian 

Tribe 11,340 1,900 All Scenarios 11,340 8,000 11,340 8,000 11,340 8,000

AZ Cocopah Indian 

Tribe

10,847 1,714 Current Projected (A) 10,847 9,412 10,847 9,412 10,847 9,412

Slow Growth (B) 5,311 4,607 5,311 4,607 5,311 4,607

Rapid Growth (C1) 10,847 9,412 10,847 9,412 10,847 9,412

Rapid Growth (C2) 10,847 9,412 10,847 9,412 10,847 9,412

Enhanced Environment (D1) 10,847 9,412 10,847 9,412 10,847 9,412

Enhanced Environment (D2) 10,847 9,412 10,847 9,412 10,847 9,412

AZ Colorado River 

Indian Tribes

662,402 99,375 Current Projected (A) 662,402 463,000 662,402 463,000 662,402 463,000

Slow Growth (B) 650,596 386,721 650,596 386,721 650,596 386,721

Rapid Growth (C1) 662,402 463,000 662,402 463,000 662,402 463,000

Rapid Growth (C2) 662,402 463,000 662,402 463,000 662,402 463,000

Enhanced Environment (D1) 662,402 463,000 662,402 463,000 662,402 463,000

Enhanced Environment (D2) 662,402 463,000 662,402 463,000 662,402 463,000

CA Colorado River 

Indian Tribes 56,846 8,528 All Scenarios 56,846 39,000 56,846 39,000 56,846 39,000

AZ Fort Mojave Indian 

Tribe

103,535 16,018 Current Projected (A) 103,535 73,000 103,535 73,000 103,535 73,000

Slow Growth (B) 72,757 40,671 72,757 40,671 72,757 40,671

Rapid Growth (C1) 103,535 73,000 103,535 73,000 103,535 73,000

Rapid Growth (C2) 103,535 73,000 103,535 73,000 103,535 73,000

Enhanced Environment (D1) 103,535 73,000 103,535 73,000 103,535 73,000

Enhanced Environment (D2) 103,535 73,000 103,535 73,000 103,535 73,000

CA Fort Mojave Indian 

Tribe 16,720 2,587 All Scenarios 16,720 8,995 16,720 8,995 16,720 8,995

NV Fort Mojave Indian 

Tribe 12,534 1,939 All Scenarios 12,534 9,000 12,534 9,000 12,534 9,000
Colorado River Basin 

Water Supply and Demand Study

C9-8 December 2012

TABLE C9-4 

Lower Colorado River Mainstem Tribal Rights and Future Demands

State Tribe

Diversion 

Entitlement 

(Water 

Right) (afy)1 Net Acres2 Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 (afy) 2035 (afy) 2060 (afy)

AZ Hopi Tribe 6,028 Current Projected (A) 4,278 2,984 4,278 2,984 4,278 2,984

Slow Growth (B) 4,278 3,133 4,278 3,133 4,278 3,133

Rapid Growth (C1) 4,278 2,984 4,278 2,984 4,278 2,984

Rapid Growth (C2) 4,065 2,835 4,065 2,835 4,065 2,835

Enhanced Environment (D1) 4,278 2,984 4,278 2,984 4,278 2,984

Enhanced Environment (D2) 4,065 2,835 4,065 2,835 4,065 2,835

CA Quechan Indian 

Tribe 71,616 10,742 All Scenarios 71,616 36,000 71,616 36,000 71,616 36,000

AZ Quechan Indian 

Tribe

6,350 952 Current Projected (A) 6,350 3,670 6,350 3,670 6,350 3,670

Slow Growth (B) 1,256 726 1,256 726 1,256 726

Rapid Growth (C1) 6,350 3,670 6,350 3,670 6,350 3,670

Rapid Growth (C2) 6,350 3,670 6,350 3,670 6,350 3,670

Enhanced Environment (D1) 6,350 3,670 6,350 3,670 6,350 3,670

Enhanced Environment (D2) 6,350 3,670 6,350 3,670 6,350 3,670

AZ Future settlements 

in Colorado River 

Simulation System 

(CRSS) 

NA NA All Scenarios 0 0 3,500 3,500 3,500 3,500

1 The quantity of water in each instance is measured by (i) diversions or (ii) consumptive use required for irrigation of the respective acreage and for satisfaction of related uses, 

whichever of (i) or (ii) is less. 

2 Net acres from Arizona v. California
Appendix C9 — Tribal Water Demand 

Scenario Quantification

December 2012 C9-9 

TABLE C9-5 

Tribes with CAP allocations, Tribal Rights and Future Demands

State Tribe

Diversion 

Entitlement 

(Water Right) (afy)

Scenario

Diversion Diversion Diversion

2015 (afy) 2035 (afy) 2060 (afy)

AZ Ak-Chin Indian Community (CAP) 25,0001 All Scenarios 25,000 25,000 25,000

AZ Ak-Chin Indian Community (Mainstem water) 50,000 All Scenarios 50,000 50,000 50,000

AZ Fort McDowell Yavapai Nation 18,233 All Scenarios 18,233 18,233 18,233

AZ Gila River Indian Community 208,200 All Scenarios 208,200 208,200 208,200

AZ Gila River Indian Community NIAR 

(Non-Indian Agriculture Relinquished) 120,600 All Scenarios 0 120,600 120,600

AZ Pascua Yaqui Tribe 500 All Scenarios 500 500 500

AZ Salt River Pima-Maricopa Indian Community 13,300 All Scenarios 13,300 13,300 13,300

AZ Salt River Pima-Maricopa Indian Community 

(Priority 3 Mainstem water) 22,000 All Scenarios 22,000 22,000 22,000

AZ San Carlos Apache Tribe 30,845 All Scenarios 30,845 30,845 30,845

AZ San Carlos Apache Tribe – Ak Chin Transfer2 33,300 All Scenarios 12,655 12,655 12,655

AZ Tohono O'odham Nation – Sif Oidak 8,000 All Scenarios 8,000 8,000 8,000

AZ Tohono O'odham Nation – San Xavier 27,000 All Scenarios 27,000 27,000 27,000

AZ Tohono O'odham Nation – San Xavier NIAR 23,000 All Scenarios 7,340 23,000 23,000

AZ Tohono O'odham Nation – Schuk Toak 10,800 All Scenarios 10,800 10,800 10,800

AZ Tohono O'odham Nation – Schuk Toak NIAR 5,200 All Scenarios 1,660 5,200 5,200

AZ Tonto Apache Tribe 128 All Scenarios 128 128 128

AZ White Mountain Apache Tribe 25,000 All Scenarios 2,031 25,000 25,000

AZ Yavapai-Apache Nation 1,200 All Scenarios 1,200 1,200 1,200

AZ Yavapai-Prescott Tribe 500 All Scenarios 500 500 500

AZ Future Settlements3

 NA All Scenarios 1,487 43,518 43,518

1 When sufficient surface water is available in the CAP canal, Ak-Chin Indian Community is entitled to up to 10,000 afy in addition to the 75,000 afy shown in this row and the 

next row. For all scenarios, it is assumed that there is demand for this water.

2 Assumes remaining entitlement will be leased and represented as non-tribal demand in the Study.

3 42.3 thousand acre-feet of these future settlement waters are provided through NIAR.
Colorado River Basin 

Water Supply and Demand Study

C9-10 December 2012

3.0 Tribal Summaries 

The following sections describe quantified water rights and future tribal demands for each tribe 

or community. 

3.1 Upper Colorado River Basin Tribes

3.1.1 Jicarilla Apache Nation

The Jicarilla Apache Nation Indian Reservation is located in the upper reaches of the San Juan 

River Basin and the Rio Chama Basin in northwestern New Mexico. The reservation straddles 

the Continental Divide. 

In 1992, Congress enacted the Jicarilla Apache Tribe Water Rights Settlement Act, Pub. L. 

No. 102-441,106 Stat.2237 (1992) (Settlement Act). Pursuant to the Settlement Act, the Nation 

is authorized to divert 40,000 afy from the San Juan River Basin, 32,000 afy of which may be 

depleted. The Settlement Act provides the Nation the right to divert 33,500 afy or deplete 

25,500 afy of its total water right from either the Navajo Reservoir supply or directly from the 

Navajo River as it crosses the Jicarilla Apache Indian Reservation. It also authorizes the Nation 

to divert and deplete 6,500 afy from the San Juan River Basin through the San Juan-Chama 

Project. In a settlement contract between the Nation and the Secretary of the Interior, the Nation 

agreed to subordinate its 1880 priority date for the 40,000 afy (diversion) of “future use” federal 

reserved water rights in exchange for the 1955 priority date associated with the two federal 

projects. The settlement contract is ratified by the Settlement Act. These are fully adjudicated 

rights, which, by virtue of the Settlement Act, the Nation may market to the full extent that the 

law allows. The Nation’s long-term plans for this water include both off-reservation leasing and 

on-reservation development. 

In addition to the water rights adjudicated in accordance with the Settlement Act, the Nation also 

has adjudicated rights to divert 5,683.92 afy or to deplete 2,195 afy, whichever is less, for 

historical and existing water uses. Therefore, the Nation’s total water diversion rights from the 

San Juan River Basin amount to 45,683 afy, and the Nation’s overall depletion rights from the 

San Juan Basin total 34,195 afy. Table C9-6 lists these diversion and depletion water rights. 

TABLE C9-6 

Summary of Jicarilla Apache Nation Water Rights (afy)

River Basin Right Diversion Location Diversion Right Depletion Right 

San Juan Navajo Reservoir or Navajo River within 

Jicarilla Apache Indian Reservation 

33,500 25,500

Via San Juan-Chama Project 6,500 6,500

Historical Uses 5,683.92 2,195

Total 45,683 34,195
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-11

Jicarilla Apache Nation Projected Water Demand

In CRSS, the diversion locations for the Nation are represented by seven demand points. There 

are two points on the upper San Juan River above Archuleta. A third point represents exports via 

the San Juan-Chama Project. A fourth and fifth point represent Navajo-Gallup Water Supply 

Project diversions, including water leased to the City of Gallup. A sixth point represents 

evaporation from irrigation and recreation lakes, and a seventh point represents water leases from 

Navajo Reservoir for the San Juan Generating Station. 

Under the Current Projected (A), Slow Growth (B), and Enhanced Environment (D1) scenarios, 

demands increase from 2015 demands to the Nation’s full right by 2060. Under the Rapid 

Growth (C1 and C2) and Enhanced Environment (D2) scenarios, demands increase more rapidly 

and reach the Nation’s full right by 2035. Table C9-7 presents the Nation’s projected demand 

schedule by demand scenario.

TABLE C9-7 

Future Jicarilla Apache Nation Projected Demands by Scenario (afy) 

Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 (afy) 2035 2060

Current Projected (A) 36,932 27,650 44,841 33,295 45,683 34,195

Slow Growth (B) 36,932 27,650 44,841 33,295 45,683 34,195

Rapid Growth (C1 and C2) 36,932 27,650 45,683 34,195 45,683 34,195

Enhanced Environment (D1) 36,932 27,650 44,841 33,295 45,683 34,195

Enhanced Environment (D2) 36,932 27,650 45,683 34,195 45,683 34,195

3.1.2 Navajo Nation 

The Navajo Nation encompasses an area in excess of 17 million acres, located almost entirely 

within the Basin, in both the Upper Basin and the Lower Basin, within the states of Arizona, 

New Mexico, and Utah. The Nation possesses water rights that are largely unquantified except in 

the San Juan River Basin in New Mexico, Upper Basin. The Nation claims historical, 

appropriative, and reserved rights to the use of all the water necessary for the Nation to be the 

permanent homeland for the Navajo people. Both the U.S. Supreme Court and the Arizona 

Supreme Court have recognized such rights to water. See Winters v. United States, 207 U.S. 564, 

567 (1908) and In re the General Adjudication of All Rights to Use Water in the Gila River 

System and Source, 35 P. 3d 68, 76 (2001). These rights are not lost through non-use and cannot 

be abandoned. 

On March 30, 2009, Congress enacted Public Law 111-11, the Northwestern New Mexico Rural 

Water Project Act (Act), which authorized the United States, acting through the Secretary of 

Interior, to execute an agreement among the Nation, the state of New Mexico, and the United 

States settling the Nation’s water rights to the San Juan River Basin in New Mexico. The 

Secretary executed the Navajo Settlement Agreement (Agreement) on December 17, 2010. 

There are several deadlines that must be met in order for the Agreement to be considered final 

(P.L. 111-11 10701 (e) (1)). For instance, although the Agreement settles the Nation claims 

portion of an underlying water rights adjudication, the court overseeing the adjudication must 
Colorado River Basin 

Water Supply and Demand Study

C9-12 December 2012

enter two proposed decrees recognizing the Nation’s water rights (P.L. 111-11 section 10701 (e) 

(1) (A) (iii), and (v)). The entry of the decrees is pending. Although all deadlines are specifically 

identified in the Act, as a general matter all deadlines must be met by March 2025 for the 

settlement to be considered effective (P.L. 111-11 section 10703 (d)). 

Through the settlement, the Nation is entitled to divert 606,660 afy and deplete 325,670 afy 

within New Mexico's apportionment of Colorado River water. The settlement provides for 

reductions of certain Nation diversions if needed to accommodate New Mexico's obligations 

under the Colorado River Compact. Part of the Nation’s Upper Basin San Juan River rights in 

the state of New Mexico will be met with water from the Animas-La Plata Project’s Nighthorse 

Reservoir in Colorado. The amount involved is a diversion of 4,468 afy and a depletion of 

2,340 afy. 

Table C9-8 provides information contained in the proposed Partial Final Decree contemplated 

by the Agreement, which primarily addresses the Nation’s water rights associated with the 

San Juan River and groundwater uses in the San Juan River Basin. 

TABLE C9-8 

Navajo Nation San Juan River Water Rights as Described in the Proposed Partial Final Decree (afy) 

Diversion Depletion Priority

Navajo Indian Irrigation Project 508,000 270,000 06/17/19551

Fruitland-Cambridge Irrigation Project 18,180 7,970 06/01/1868

Hogback-Cudei Irrigation Project 48,550 21,280 06/01/1868

Navajo-Gallup Water Supply Project 22,650 20,780 06/17/19551 

12/16/19682

Animas-La Plata Project 4,680 2,340 05/01/19561

San Juan River municipal and industrial (M&I) 

uses 2,600 1,300 06/01/1868

Reserved groundwater uses3 2,000 2,000 06/01/1868

TOTAL: 606,660 325,670

1 Priorities of June 1, 1868, administered with more recent priorities.

2 Priority for water from inflows arising below Navajo Dam (per Permit No. 3215).

3 Pursuant to the proposed Partial Final Decree, the Navajo Nation’s groundwater uses in total, including under the proposed 

rights with a priority date of June 1, 1868, shown in this table, under any additional groundwater rights that might be provided under 

the proposed Supplemental Partial Final Decree, and under any additional rights that might be established under future 

appropriations, may have no more than a 2,000 afy net depletion impact on the San Juan River. Any cumulative impact on river flow 

exceeding 2,000 afy from Navajo Nation groundwater uses would have to be offset by curtailment of Navajo Nation surface water 

uses.

Navajo Nation Projected Water Demand 

In CRSS, the diversion locations for the Nation are represented by 15 demand points. There is 

one point on the upper San Juan River for the Navajo Indian Irrigation Project. Four points 

represent Navajo-Gallup Water Supply Project diversions. A sixth point represents AnimasLa Plata rights. A seventh point represents other M&I uses on the Animas River. Three points 

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Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-13

represent irrigation uses below Farmington; two points represent M&I uses below Farmington. 

One point represents small reservoir evaporation. The 14th point represents industrial uses below 

Shiprock, and the 15th point represents tributary irrigation below Four Corners. 

Table C9-9 presents the Nation’s projected demand schedules for the six demand scenarios.

TABLE C9-9 

Future Navajo Nation Projected Demands by Scenario (afy)

State Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060

AZ 

(Upper 

Basin)

Current Projected (A) 49,125 47,987 49,207 47,707 49,207 47,707

Slow Growth (B) 49,125 47,987 49,207 47,707 49,207 47,707

Rapid Growth (C1 and C2) 43,437 42,431 61,088 59,226 77,621 75,255

Enhanced Environment (D1) 49,125 47,987 49,207 47,707 49,207 47,707

Enhanced Environment (D2) 43,437 42,431 61,088 59,226 77,621 75,255

AZ 

(Lower 

Basin)

Current Projected (A) 0 0 0 0 0 0 

Slow Growth (B) 0 0 0 0 0 0 

Rapid Growth (C1 and C2) 16,456 16,075 74,055 71,798 126,767 122,903

Enhanced Environment (D1) 0 0 0 0 0 0 

Enhanced Environment (D2) 16,456 16,075 74,055 71,798 126,767 122,903

UT Current Projected (A) 0 0 0 0 0 0 

Slow Growth (B) 0 0 0 0 0 0 

Rapid Growth (C1 and C2) 26,204 13,102 79,876 39,938 156,692 78,346

Enhanced Environment (D1) 0 0 0 0 0 0 

Enhanced Environment (D2) 26,204 13,102 79,876 39,938 156,692 78,346

NM1 Current Projected (A) 506,348 271,820 608,085 326,435 612,863 329,000

Slow Growth (B) 506,348 271,820 608,085 326,435 612,863 329,000

Rapid Growth (C1 and C2) 517,972 278,060 699,633 375,580 915,756 491,600

Enhanced Environment (D1) 506,348 271,820 608,085 326,435 612,863 329,000

Enhanced Environment (D2) 517,972 278,060 699,633 375,580 915,756 491,600

1 The diversion and depletion demands of the Navajo Nation from the Colorado River in the Upper Basin in New Mexico are not 

limited by the Navajo Nation San Juan River in New Mexico Water Rights Settlement; however, the Navajo Nation agrees to be 

bound by the terms of that settlement so long as the Settlement is effective. To the extent that the Navajo Nation demands exceed 

the amounts provided in the settlement, the Nation may seek to acquire water from other users or from sources other than the 

Colorado River to meet any unmet demands.

The projected demands include both quantified and unquantified rights and claims. The projected 

demands were provided by the Navajo Nation Department of Water Resources and modified to 

fit the storyline narratives regarding tribal use under each scenario. Specifically, the Rapid 

Growth (C1 and C2) scenarios and the Enhanced Environment (D2) scenario assume the 

realization of new tribal claims and settlements, whereas the Current Projected (A) scenario, the 

Slow Growth (B) scenario, and the Enhanced Environment (D1) scenario assume development 

according to quantified rights and current use patterns. Exceptions include the Nation’s demands 

in the Upper Basin of approximately 50,000 afy in Arizona that have not been quantified through 
Colorado River Basin 

Water Supply and Demand Study

C9-14 December 2012

an adjudication or settlement. Given that most of the Upper Basin land area is within the 

boundaries of the Nation and most historical and current water development and use have been 

by the Nation, these demands have been included in all scenarios. 

3.1.3 Southern Ute Indian Tribe 

The Southern Ute Indian Tribe is located in southwestern Colorado just west of the Navajo 

Reservoir. The Tribe settled its water rights pursuant to agreement with the State of Colorado 

and the Colorado Ute Indian Water Rights Settlement Act of 1988, Pub. L. No. 100-585, 

102 Stat. 2973 (1988). The Tribe’s water rights are included in Consent Decrees entered

December 19, 1991. The Settlement Agreement quantified the Southern Ute Indian Tribe’s 

water rights from several rivers and projects, including the Animas-La Plata Project (Project). 

The settlement legislation was subsequently amended in 2000 to eliminate the irrigation 

component and reduce the proposed water depletions for the Project. The construction of the 

Project is almost complete. Reclamation completed filling the reservoir in June 2011 and will 

transfer the Project from construction status to operation and maintenance status in 2012. The 

Settlement Agreement also provides the Tribe with a variety of direct flow rights, with priorities 

ranging from 1868 to 1976 in streams and rivers passing through the Southern Ute Reservation. 

Table C9-10 summarizes the Tribe’s decreed diversion and depletion rights. 

TABLE C9-10

Southern Ute Indian Tribe Diversion and Depletion Rights (afy)

Basin Diversion Right Depletion Right

San Juan 5,729 3,204

Piedra 6,521 3,580

Pine1 75,149 40,651

Florida 4,603 3,689

Animas 42,244 21,586

La Plata 2,843 1,607

Mancos 1 1

Total 137,090 74,318

1 Uses not assigned to a specific basin (oil and gas, road construction) included in Pine.

Southern Ute Indian Tribe Projected Water Demand

The Tribe’s water use is a part of the state of Colorado’s apportionment. For the Study, at the 

request of the Southern Ute Indian Tribe, tribal demands were not separated from other categories 

within the state of Colorado’s demands. Consequently, the Tribe’s future demands are not shown 

separately from the state’s future demands. 

3.1.4 Ute Indian Tribe of the Uintah and Ouray Reservation

The Ute Indian Tribe is located in northeastern Utah in the Green River watershed, including 

the Uintah Basin. The Uintah Valley Reservation, created by Executive Order in 1861, and the 

Uncompahgre Reservation, established by Executive Order in 1882, became the Uintah and 

Ouray Reservation for the Uintah, White River, and Uncompahgre Utes. Quantification of the 

Tribe’s reserved water rights began in 1923 when two federal court decrees were issued for 

reserved water rights on some of the tribal lands under the Uintah Indian Irrigation Project. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-15

With the authorization of the initial phase of the Central Utah Project under the Colorado River 

Storage Project Act of 1956, 70 Stat. 105, came the realization that the Bonneville Unit of the 

Central Utah Project could not proceed without an agreement with the Tribe to defer the 

development and use of its reserved water rights on 15,242 irrigable acres of Indian lands west 

of the Green River. The 1960 Decker report (Water Right Claims, Uintah and Ouray Indian 

Reservation, Utah) identified and divided the irrigable lands on the reservation into seven groups. 

An agreement between the Tribe, the United States, and the Central Utah Water Conservancy 

District was executed in 1965 (and later recognized by the state of Utah), and resulted in the 

parties’ “full and complete recognition of the water rights of the Tribe, with a priority date of 

1861” (west of the Green River), without resort to litigation (Decker, 1960). 

In the 1980s, the state of Utah and the Tribe ratified the Ute Water Compact, adopting the 

land designations and quantified reserved water rights identified in the Decker report. In 1992, 

Congress approved the Revised Ute Indian Compact of 1990 (Compact), including the 

historically recognized reserved water rights plus irrigable lands east of the Green River. 

The Compact is currently pending re-ratification by the Tribe and the state of Utah.

Under the Compact, the Tribe has recognized water rights within the Upper Colorado River 

Basin amounting to 480,594 afy of federal reserved, surface water diversions (and 258,943 afy 

by depletion). The source, use, priority, and quantification of tribal water rights are shown in 

table C9-11. 

TABLE C9-11

Ute Indian Tribe of the Uintah and Ouray Reservation Diversion and Depletion Rights (afy)

Basin Use Priority Date Diversion Depletion

Duchesne River Irrigation 1861 116,092 39,446

Lake Fork River1 Irrigation 1861 46,165 45,756

Yellowstone River1 Irrigation 1861 1,489 657

Uinta River1 Irrigation 1861 63,651 38,378

Whiterocks River1 Irrigation 1861 44,336 24,515

White River Irrigation 1882 61,598 30,796

Green River Irrigation 1882 18,981 9,363

M&I2 1861 10,000 10,000

Unspecified 1861 113,378 57,948

Bitter Creek Irrigation 1882 1,068 454

Sweet Water Creek Irrigation 1882 368 156

Willow Creek Irrigation 1882 2,852 1,212

Hill Creek Irrigation 1882 616 262

Total – – 480,594 258,943

1 The storage rights to 18,311 acre-feet (af) of diversions sourced from the Lake Fork, Yellowstone, Uinta, and Whiterocks 

Rivers are for presently unconstructed facilities. The Tribe also holds rights to store water in various existing tribal and Reclamation 

facilities for recreation, irrigation, and M&I uses. These facilities include Starvation, Bottle Hollow, Midview, Cedar View, Towave, 

and Weaver Reservoirs. In addition, the Tribe retains the right to convert any direct flow rights listed above to storage rights, and rights to 

fill stockwater impoundments. 

2 M&I rights are sourced by depletion from the Green River but available for development and use throughout the reservation.
Colorado River Basin 

Water Supply and Demand Study

C9-16 December 2012

Ute Indian Tribe of the Uintah and Ouray Reservation Projected Water Demand

The Tribe has five demand points modeled in CRSS: two demand points on the Green River, two 

demand points on the Duchesne River, and one point on the White River. Table C9-12 presents 

the tribe’s projected demand schedule. 

The demands were provided by the Tribe, and under all scenarios except Slow Growth (B), 

the Tribe considers it reasonably foreseeable that the full use of its rights will occur beginning 

in 2015. 

TABLE C9-12

Future Ute Indian Tribe of the Ouray and Uintah Reservation Projected Demands by Scenario1 (afy) 

Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060 

Current Projected (A) 480,594 258,943 480,594 258,943 480,594 258,943

Slow Growth (B) 316,354 170,451 447,747 241,245 480,594 258,943

Rapid Growth (C1 and C2) 480,594 258,943 480,594 258,943 480,594 258,943

Enhanced Environment (D1) 480,594 258,943 480,594 258,943 480,594 258,943

Enhanced Environment (D2) 480,594 258,943 480,594 258,943 480,594 258,943

1 The diversion and depletion associated with the demand for the Ute Indian Tribe of the Uintah and Ouray Reservation is 

dependent upon the re-ratification of the Revised Ute Indian Compact of 1990 by the Tribe and the state of Utah.

3.1.5 Ute Mountain Ute Tribe 

The Ute Mountain Ute Reservation (UMUR) is located in the Four Corners area and within the 

states of Colorado, New Mexico, and Utah. All UMUR lands are located within the San Juan 

River Basin. The Ute Mountain Ute Tribe (UMUT) has litigated and settled its water rights for 

UMUR lands located in the state of Colorado—see the Colorado Ute Indian Water Rights 

Settlement Agreement (December 10, 1986) (Colorado Settlement Agreement); Colorado 

Ute Indian Water Settlement Act, Pub. L. No. 100-585, 102 Stat. 2973 (November 3, 1988), 

subsequently amended; and Colorado Ute Settlement Act Amendments of 2000, Pub. L. 

No. 106-554, 114 Stat 2763 (December 21, 2000) (2000 Amendments) with minor amendments 

in Pub. L. 110-161 (December 26, 2007). UMUT is currently litigating its federal reserved water 

rights in the state of New Mexico. UMUT has not yet litigated or quantified its federal reserved 

water rights in the state of Utah. 

Ute Mountain Ute Reservation (within Colorado) 

The Colorado Settlement Agreement quantified the Colorado Ute Tribes’ water rights from 

several rivers and projects, including the Dolores Project and the Animas-La Plata Project.

UMUT’s quantified rights in the Dolores Project include 23,300 afy of agricultural irrigation 

water, 1,000 afy of M&I water, and 800 afy of fish and wildlife development water. The 

Animas-La Plata Project originally included 32,300 afy (26,300 afy of agricultural irrigation 

water and 6,000 afy of M&I water) for UMUT. The 2000 Amendments eliminated the irrigation 

component and reduced the UMUT’s water depletions to 16,525 afy of M&I water; see the 2000 

Amendments. Table C9-13 summarizes the UMUT rights in Colorado. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-17

TABLE C9-13

Ute Mountain Ute Tribe Water Rights (Colorado)

Basin Diversion (afy) Depletion (afy)

San Juan River 1,715.51 915.51

Animas River 33,050 16,525

La Plata River 4 4 

Mancos River 28,176 15,510

McElmo River 613 347

Dolores River 24,800 17,780

Total 88,358 51,081

The Colorado Settlement Agreement also quantified water rights on rivers in the San Juan and 

Dolores Basins other than the Animas and La Plata Rivers, all of which are tributary to the 

Colorado River. With respect to UMUT, these water rights include the following: 

• On the Mancos River, UMUT retained a non-project reserved right with an 1868 priority date 

(subordinated to all rights with an adjudication date prior to 1985) for direct flow diversions 

and/or storage of 21,000 afy. 

• On Navajo Wash, UMUT retained a non-project reserved right with an 1868 priority date 

(subordinated to all rights with an adjudication date prior to 1985 and subject to the decree in 

Colorado Water Court Division 7 case number 81CW126) for direct flow diversions of 4,800 

afy. 

• On the San Juan River within the southwestern part of the UMUR in Colorado, UMUT 

retained a non-project reserved right with an 1868 priority date for direct flow diversions of 

1,600 afy (with a maximum diversion rate of 10 cubic feet per second). 

• From all drainages within the UMUR, UMUT retained a reserved water right with an 1868 

priority date for 2 afy for use in connection with oil and gas development and a reserved 

water right with an 1868 priority date for 1 afy for use in connection with road construction. 

• UMUT retained a reserved water right with an 1868 priority date for 1,850 afy of tributary 

groundwater for future individual domestic and livestock wells (350 afy from the McElmo 

Creek drainage basin and 1,500 afy from all other UMUR drainage basins). 

• Other existing beneficial uses of surface water and groundwater, in addition to those 

provided above, were identified and quantified as follows: 

– Mancos River/Navajo Wash Diversions: 674 af for irrigation (ditch D1101), 122.33 af for 

stock ponds and catchment basins, 4.03 af for domestic wells, 36.59 af for stock wells, 

and 35.79 af for springs for stock. 

– McElmo Creek Basin Diversions: 189 af for irrigation, 30.45 af for stock ponds, 8.06 af

for domestic wells, 2.65 af for stock wells, and 32.21 af for springs for stock. 

– San Juan River Diversions: 73.49 af for stock ponds, 22.67 af for stock wells, and 19.35 

af (for springs for stock. 

– La Plata River Diversions: 4.03 af for stock ponds, and 0.01 af for stock wells. 
Colorado River Basin 

Water Supply and Demand Study

C9-18 December 2012

The UMUT owns or leases additional, non-reserved water in the State of Colorado. The UMUT 

leases additional Dolores Project water for use in its Farm & Ranch enterprise (which uses more 

water than the UMUT is allocated in the Dolores Project under the Colorado Settlement 

Agreement). The UMUT also owns significant water resources associated with its offreservation ranch properties (and those water rights are decreed under Colorado state law in 

Division 7 and Division 4 in Colorado). Neither the leased water nor the water decreed under 

Colorado state law is included in the prior table. 

Ute Mountain Ute Reservation (within New Mexico)

UMUT is currently participating in the San Juan River general stream adjudication to quantify its 

reserved water rights on the portion of the UMUR located within the state of New Mexico (State 

of New Mexico v. United States of America, CV 75-184.). The current scheduling order in that 

case anticipates addressing UMUT claims starting in 2020, which means that the UMUT federal 

reserved water rights in New Mexico are currently unquantified. 

At this point in the litigation, both the United States and UMUT have entered separate federal 

reserved rights claims on behalf of UMUT. The United States has entered a claim for a federal 

reserved right to divert and deplete 10,950 afy from groundwater resources (United States’ 

Amended Supplemental Answer with Respect to Claims on Behalf of the Ute Mountain Ute 

Tribe [October 1, 2007]). That claim includes diversion of 470 afy (with depletion of 141 afy) 

for domestic purposes, 610 afy (with a depletion of 61 afy) for commercial purposes, and 

9,870 afy (depletion and diversion) for industrial purposes. UMUT has entered a claim for the 

right to divert between 7,300 and 9,300 afy from surface water resources (Statement of the 

Claim of the Ute Mountain Ute Tribe [May 25, 2005]). 

These unquantified rights were not incorporated into UMUT’s demand schedules. 

Ute Mountain Ute Reservation (within Utah) 

UMUR lands in Utah comprise lands held in trust for UMUT and for individual UMUT 

members. The UMUT federal reserved rights claims associated with UMUR lands in Utah are 

currently unquantified, and there is currently no process (litigation or otherwise) engaged for 

quantifying those claims.

Ute Mountain Ute Tribe Projected Water Demand

UMUT’s water use is part of the State of Colorado’s apportionment. For the Study, at the request 

of UMUT, tribal demands were not separated from other categories within the State of 

Colorado’s demands. Consequently, UMUT’s future demands are not shown separately from 

the State’s.

3.2 Lower Colorado River Mainstem Tribes 

The March 9, 1964 Arizona v. California Decree and several supplemental decrees (consolidated 

in 2006 into the Consolidated Decree of the U.S. Supreme Court in Arizona v. California, 547 

U.S. 150 [2006]) quantified the reserved water rights of the Chemehuevi, Cocopah, Colorado 

River Indian, Fort Mojave, and Fort Yuma Indian Reservations. The amounts of water (diversion 

entitlements), priority dates for these water rights, net acres of irrigated land, and the states 

where the water rights are perfected for these Indian reservations are discussed below by tribe. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-19

The purchase of farmland with a pre-existing water right established a Hopi Tribe water right, 

which is also discussed below. 

3.2.1 Chemehuevi Indian Tribe

The Chemehuevi Indian Reservation is located in Southern California near Lake Havasu. The land 

of the Chemehuevi Reservation is mostly on the plateau above the shoreline of Lake Havasu. 

Present agricultural water use is limited.

The Chemehuevi Indian Tribe holds present perfected federal reserved water rights from the 

Colorado River mainstem pursuant to the Supreme Court’s 2006 Consolidated Decree. The Tribe 

has a right to divert up to 11,340 afy in California. The amounts, priority dates, and state where 

the rights are perfected are shown in table C9-14.

TABLE C9-14

Chemehuevi Indian Tribe Colorado River Diversion Entitlement (Water Rights) 

Reservation State 

Diversion 

Entitlement 

(Water Right) 

(afy)1

Net 

Acres1

Present 

Perfected 

Right (PPR) 

Number1

Priority 

Within 

State 

Priority 

Date1

Chemehuevi 

Reservation

California 11,340 1,900 22 PPR Feb. 2, 1907

Totals – 11,340 1,900 – – – 

1 Source: Consolidated Decree of March 27, 2006. The quantity of water in each instance is measured by (i) diversions or (ii) 

consumptive use required for irrigation of the respective acreage and for satisfaction of related uses, whichever of (i) or (ii) is less.

Chemehuevi Indian Tribe Projected Water Demand

Currently, CRSS includes a demand point for the Chemehuevi Indian Reservation on the reach 

between Davis and Parker Dams. Table C9-15 presents the Tribe’s projected demand schedule by 

demand scenario. Under all scenarios, the projected depletion for the Chemehuevi Indian Tribe 

was based on the Ten Tribes Partnership Schedule. 

TABLE C9-15

Future Chemehuevi Indian Tribe Projected Demands by Scenario (afy) 

Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060

All Scenarios 11,340 8,000 11,340 8,000 11,340 8,000

3.2.2 Cocopah Indian Tribe

The Cocopah Indian Reservation, located in southwestern Arizona, is made up of three separate 

land areas: North Cocopah, West Cocopah, and East Cocopah. The North and West Cocopah 

areas lie on floodplain lands along the Colorado River, and the East Cocopah area lies on the 

Yuma Mesa. The largest area of the Cocopah Reservation is West Cocopah, which is bordered 

by the United Mexican States (Mexico), with the Colorado River forming the boundary between 

West Cocopah and Mexico. 

The Cocopah Indian Reservation was established through Executive Order No. 2711 on 

September 27, 1917; additional acres were added to the reservation in 1974. The Cocopah Indian 
Colorado River Basin 

Water Supply and Demand Study

C9-20 December 2012

Tribe’s economy is centered on agriculture. The Tribe possesses present perfected federal 

reserved water rights from the Colorado River mainstem pursuant to the decree in Arizona v. 

California and supplemental decrees (1979 and 1984). The amounts, priority dates, and state 

where the rights are perfected are presented in table C9-16.

TABLE C9-16

Cocopah Indian Tribe Colorado River Diversion Entitlement (Water Rights)

Reservation State

Diversion 

Entitlement (Water 

Right) (afy)1 Net Acres1 PPR Number1

Priority 

Within 

State Priority Date1

Cocopah Indian 

Reservation 

Arizona 1,140 190 8 1 1915

7,681 1,206 1 Sept 27, 1917

2,026 318 - 4 June 24, 1974

Totals – 10,847 1,714 – – 

1 Source: Consolidated Decree of March 27, 2006. The quantity of water in each instance is measured by (i) diversions or (ii) 

consumptive use required for irrigation of the respective acreage and for satisfaction of related uses, whichever of (i) or (ii) is less.

The 1974 decreed right for the Cocopah Indian Reservation is unique because of its more-recent 

priority date (post-1968). The 1984 Supplemental Decree in Arizona v. California recognized the 

decreed right for the Cocopah Indian Reservation dated June 24, 1974, and amended paragraph 2 

of Article II (D) of the 1964 Decree to reflect this 1974 right. The Tribe is involved in litigation 

to claim rights to a total of 2,400 acres of irrigable lands. Proving this claim would further 

increase the water rights for the reservation.

Cocopah Indian Tribe Projected Water Demand

Water diversions for the Tribe are listed at two demand points in CRSS on two of the model 

reaches. A demand point on the Imperial Dam diversion reach accounts for all of the Tribe's 

priority 1 rights and current uses in Arizona. Another point is provided for future pumped 

priority 4 diversions below Imperial Dam, but it has a diversion of 0 afy at the current time. 

Under all scenarios except the Slow Growth (B) scenario, the projected diversion is full 

entitlement. Depletion is computed assuming the average 2005 to 2009 return flow ratio from 

the Decree Accounting Report (Reclamation, 1972 to 2009). Under the Slow Growth (B)

scenario, the State of Arizona assumed less investment in maintenance of irrigation systems, 

resulting in a 5 percent increase in the projected depletion value of 4,388 af, where the projected 

depletion was based on the 2005 to 2009 Decree Accounting Report average use. Table C9-17 

presents the Tribe’s projected demand schedule by demand scenario. 

3.2.3 Colorado River Indian Tribes 

The Colorado River Indian Reservation is located in southwestern Arizona and southern 

California south of Parker, Arizona. The Colorado River provides 90 miles of shoreline for the 

Arizona portion of the Colorado River Indian Reservation. The Colorado River Indian Tribes’ 

(CRIT) economy is based on agriculture, recreation, and light industry. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-21

TABLE C9-17

Future Cocopah Indian Tribe Projected Demands by Scenario (afy)

Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060 

Current Projected (A) 10,847 9,412 10,847 9,412 10,847 9,412

Slow Growth (B) 5,311 4,607 5,311 4,607 5,311 4,607

Rapid Growth (C1 and C2) 10,847 9,412 10,847 9,412 10,847 9,412

Enhanced Environment

(D1 and D2) 10,847 9,412 10,847 9,412 10,847 9,412

CRIT possesses present perfected federal reserved water rights from the Colorado River mainstem 

pursuant to the decree in Arizona v. California and supplemental decrees (1979 and 1984). The 

amounts, priority dates, and states where the rights are perfected are presented in table C9-18.

TABLE C9-18

Colorado River Indian Tribes Colorado River Diversion Entitlement (Water Rights) 

Reservation State 

Diversion 

Entitlement 

(Water Right) (afy)1 Net Acres1 PPR Number1

Priority 

Within 

State Priority Date1

Colorado River 

Indian 

Reservation

AZ 358,400 53,768 2 1 Mar. 3, 1865

252,016 37,808 Nov. 22, 1873

51,986 7,799 Nov. 16, 1874

CA 10,745 1,612 24 1 Nov. 22, 1873

40,241 6,037 Nov. 16, 1874

5,860 879 May 15, 1876

Totals – 719,248 107,903 – – 

1 Source: Consolidated Decree of March 27, 2006. The quantity of water in each instance is measured by (i) diversions or (ii) 

consumptive use required for irrigation of the respective acreage and for satisfaction of related uses, whichever of (i) or (ii) is less.

Colorado River Indian Tribes Projected Water Demand

CRSS presently has two demand points listed for CRIT on the reach between Parker and

Imperial Dam. The water diversions are split between California demands and Arizona demands. 

Under all scenarios except the Slow Growth (B) scenario, projected depletion for CRIT was based 

on the Ten Tribes Partnership Schedule. Under the Slow Growth (B) scenario, the State of Arizona 

assumed less investment in maintenance of irrigation systems, resulting in a 5 percent increase in 

the projected depletion value of 368,306 af, where the projected depletion was based on the 2005 to 

2009 Decree Accounting Report average use (Reclamation, 1972 to 2009). 

Under all scenarios, the State of California projected depletion for CRIT was based on the Ten 

Tribes Partnership Schedule. Table C9-19 presents CRIT’s projected demand schedule by 

demand scenario. 
Colorado River Basin 

Water Supply and Demand Study

C9-22 December 2012

TABLE C9-19

Future Colorado River Indian Tribes Projected Demands by Scenario (afy) 

State Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060 

AZ Current Projected (A) 662,402 463,000 662,402 463,000 662,402 463,000

Slow Growth (B) 650,596 386,721 650,596 386,721 650,596 386,721

Rapid Growth (C1 

and C2) 662,402 463,000 662,402 463,000 662,402 463,000

Enhanced Environment 

(D1 and D2) 662,402 463,000 662,402 463,000 662,402 463,000

CA All Scenarios 56,846 39,000 56,846 39,000 56,846 39,000

3.2.4 Fort Mojave Indian Tribe

The Fort Mojave Indian Reservation is located adjacent to the Colorado River where Arizona, 

California, and Nevada meet, with a portion of the reservation located in each of the three states. 

The Fort Mojave Indian Tribe diverts Colorado River water directly from the river and from 

wells in the Colorado River floodplain. 

Pursuant to the Consolidated Decree of 2006, federal reserved water rights for Colorado River 

water were quantified for the Fort Mojave Indian Reservation in Arizona with priority dates of 

September 18, 1890, and February 2, 1911; in California with a priority date of September 18, 

1890; and in Nevada with a priority date of September 18, 1890. The amounts, including added 

lands, priority dates, and states where the water rights are perfected are presented in table C9-20. 

TABLE C9-20

Fort Mojave Indian Tribe Colorado River Diversion Entitlement (Water Rights) 

Reservation State 

Diversion 

Entitlement 

(Water Right) 

(afy)1 Net Acres1 PPR Number1

Priority 

Within 

State Priority Date1

Fort Mojave 

Reservation

Arizona 27,969 4,327 3 1 Sept 18, 1890

75,566 11,691 Feb 2, 1911

California 16,720 2,587 25 1 Sept. 18, 1890

Nevada 12,534 1,939 81 1 Sept. 18, 1890

Totals – 132,789 20,544 – – 

1 Source: Consolidated Decree of March 27, 2006. The quantity of water in each instance is measured by (i) diversions or (ii) 

consumptive use required for irrigation of the respective acreage and for satisfaction of related uses, whichever of (i) or (ii) is less.

Fort Mojave Indian Tribe Projected Water Demand

CRSS contains three demand points for the Tribe's water diversions, which are divided among 

three states. The points are on the reach between Davis and Parker Dams and divided by state. 

Under all scenarios except the Slow Growth (B) scenario, projected depletions for the Tribe in 

Arizona were based on the Ten Tribes Partnership Schedule. Under the Slow Growth (B) 

scenario, the state of Arizona assumed less investment in maintenance of irrigation systems, 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-23

resulting in a 5 percent increase in the projected depletion value of 38,735 af, where the 

projected depletion was based on the 2005 to 2009 Decree Accounting Report average use

(Reclamation, 1972 to 2009). 

Under all scenarios, California and Nevada projected depletions for the Tribe were based on the 

Ten Tribes Partnership Schedule. Table C9-21 presents the Tribe’s projected demand schedule 

by demand scenario. 

TABLE C9-21

Future Fort Mojave Indian Tribe Projected Demands by Scenario (afy)

State Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060 

AZ Current Projected (A) 103,535 73,000 103,535 73,000 103,535 73,000

Slow Growth (B) 72,757 40,671 72,757 40,671 72,757 40,671

Rapid Growth (C1 and 

C2) 103,535 73,000 103,535 73,000 103,535 73,000

Enhanced Environment 

(D1 and D2) 103,535 73,000 103,535 73,000 103,535 73,000

CA All Scenarios 16,720 8,995 16,720 8,995 16,720 8,995

NV All Scenarios 12,534 9,000 12,534 9,000 12,534 9,000

3.2.5 Hopi Tribe

The primary home of the Hopi Tribe is the Hopi Indian Reservation, a 1,620,335-acre tract of 

land in northern Arizona. In addition to this reservation, tribal lands in northern Arizona consist 

of various parcels of trust land and fee land outside of the reservation. These areas include 

Moenkopi, a 61,852-acre exclave located west of the reservation. The Tribe also owns fee land 

on the Colorado River flood plain at Cibola, Arizona. 

The Tribe has rights to divert water from the Colorado River at Cibola, Arizona. These rights 

were established through the Tribe’s purchase of farmland with pre-existing water rights within 

the Cibola Valley Irrigation and Drainage District. Contract No. 04-XXX-30-W0432, 

December 14, 2004 was amended October 9, 2008, with the Tribe and Reclamation having 

assigned these rights among specific state of Arizona priorities for Colorado River water use, as 

listed in table C9-22. 

TABLE C9-22

Summary of Hopi Tribe Water Rights at Cibola, Arizona

Type of Water Use Contact Date State of Arizona Priority Annual Diversion (afy)

Irrigation January 31, 1983 4 4,278 

Irrigation January 31, 1983 5 750 

Irrigation January 31, 1983 6 1,000 

Total Annual Diversion: 6,028 
Colorado River Basin 

Water Supply and Demand Study

C9-24 December 2012

Hopi Tribe Projected Water Demand

For the Study, future demand was calculated based on the Tribe’s fourth-priority water rights and 

anticipated usage. Table C9-23 presents the Tribe’s projected demand schedule by demand 

scenario. 

Under the Current Projected (A), Rapid Growth (C1), and Enhanced Environment (D1) 

scenarios, the priority 4 depletion for the Hopi Tribe was based on the total priority 4 diversion 

entitlement of 4,278 afy. This value is divided by the diversion-to-depletion ratio of 1:43, which 

results in a depletion of 2,984 afy. The diversion-to-depletion ratio was based on the average 

ratio from the 2005 to 2009 Decree Accounting Reports (Reclamation, 1972 to 2009). For the 

Slow Growth (B) scenario, the state of Arizona assumed less investment in maintenance of 

irrigation systems, resulting in a 5 percent increase in the priority 4 depletion. For the Rapid 

Growth (C2) and Enhanced Environment (D2) scenarios, the state of Arizona assumed moreefficient operations for the same production, thereby decreasing the priority 4 depletion by 

5 percent.

TABLE C9-23

Future Hopi Tribe Projected Demands by Scenario (afy) 

Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060 

Current Projected (A) 4,278 2,984 4,278 2,984 4,278 2,984

Slow Growth (B) 4,278 3,133 4,278 3,133 4,278 3,133

Rapid Growth (C1) 4,278 2,984 4,278 2,984 4,278 2,984

Rapid Growth (C2) 4,065 2,835 4,065 2,835 4,065 2,835

Enhanced Environment (D1) 4,278 2,984 4,278 2,984 4,278 2,984

Enhanced Environment (D2) 4,065 2,835 4,065 2,835 4,065 2,835

3.2.6 Quechan Indian Tribe

The Fort Yuma Reservation of the Quechan Indian Tribe is located in southwestern Arizona 

and southern California near Yuma, Arizona. 

The Tribe possesses present perfected federal reserved water rights from the Colorado River

mainstem pursuant to the decree in Arizona v. California, supplemental decrees (1979 and 

1984), and final Consolidated Decree (2006). The amounts, including added lands, priority 

dates, and states where the water rights are perfected are presented in table C9-24. 

Quechan Indian Tribe Projected Water Demand

Water for the Tribe is diverted from the Colorado River at Imperial Dam and delivered through 

the Yuma Project Reservation Division-Indian Unit. The Tribe has other small uses at homestead 

sites south of Yuma, Arizona. These uses are accounted for in CRSS with two diversion points on 

the Imperial Dam Diversions reach, divided by state. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-25

TABLE C9-24

Quechan Indian Tribe Colorado River Diversion Entitlement (Water Rights) 

Reservation State 

Diversion 

Entitlement 

(Water 

Right) (afy)1 Net Acres1 PPR Number1

Priority 

Within 

State Priority Date1

Fort Yuma-Quechan 

Reservation

Arizona 6,350 952 3a 1 Jan. 9, 1884

California 71,616 10,742 23 PPR Jan. 9, 1884

Totals – 77,966 11,694 – – 

1 Source: Consolidated Decree of March 27, 2006. The quantity of water in each instance is measured by (i) diversions or (ii) 

consumptive use required for irrigation of the respective acreage and for satisfaction of related uses, whichever of (i) or (ii) is less.

Under all scenarios except the Slow Growth (B) scenario, the projected diversion is full 

entitlement. Depletion is computed assuming the average 2005 to 2009 return flow ratio from 

the Decree Accounting Report (Reclamation, 1972 to 2009). For the Slow Growth (B) scenario, 

the state of Arizona assumed less investment in maintenance of irrigation systems, resulting in a 

5 percent increase in the projected depletion. 

Under all scenarios, projected depletion in California for the Tribe was based on the Ten Tribes 

Partnership Schedule. Table C9-25 presents the Tribe’s projected demand schedule by demand 

scenario. 

TABLE C9-25

Future Quechan Indian Tribe Projected Demands by Scenario (afy)

State Scenario

Diversion Depletion Diversion Depletion Diversion Depletion

2015 2035 2060

AZ Current Projected (A) 6,350 3,670 6,350 3,670 6,350 3,670

Slow Growth (B) 1,256 726 1,256 726 1,256 726

Rapid Growth (C1 

and C2) 6,350 3,670 6,350 3,670 6,350 3,670

Enhanced 

Environment (D1 

and D2)

6,350 3,670 6,350 3,670 6,350 3,670

CA All Scenarios 71,616 36,000 71,616 36,000 71,616 36,000

3.3 Central Arizona Tribes with Allocations from the Central Arizona Project

The CAP makes Colorado River water available to tribes located in central Arizona in addition 

to the ITA entitlements discussed previously. Over the years, several secretarial decisions have 

allocated water to 10 tribes in central Arizona. All of these tribes, with the exception of the Gila 

River Indian Community, signed CAP water delivery contracts in 1980. The Gila River Indian 

Community, with the largest allocation of CAP water, signed its CAP water delivery contract in 

1992. Each of the CAP water delivery contracts contained a provision that the tribes’ CAP water 

would be credited against their Winters right (Winters v. United States, 207 U.S. 564 [1908]), if 

and when such rights were finally determined. Over the years, water rights settlements have been 
Colorado River Basin 

Water Supply and Demand Study

C9-26 December 2012

implemented for 8 of the 10 tribes. Within the terms of these settlements, the eight tribes 

generally have a right to lease their CAP water; the CAP water to which tribes have rights does 

not have to have a history of use for a tribe to use or lease such water at any time in the future. 

The tribes that receive CAP water are listed below, together with the counties in which their 

reservations are located:

Ak-Chin Indian Community Pinal

Fort McDowell Yavapai Nation Maricopa

Gila River Indian Community Maricopa and Pinal

Pascua Yaqui Tribe Pima

Salt River Pima Maricopa Indian Community Maricopa

San Carlos Apache Tribe Gila, Pinal and Graham

Tohono O'Odham Nation Pima, Maricopa and Pinal

Tonto Apache Tribe Gila

White Mountain Apache Tribe Apache, Gila and Navajo

Yavapai-Apache Nation Yavapai

Yavapai-Prescott Tribe Yavapai

For the CAP, there are four pools of water. The first pool, Colorado River priority 3 Indian 

Water Rights Settlement Water (for the Ak-Chin Indian Community – 50,000 af and Salt River 

Pima-Maricopa Indian Community – 22,000 af), has the highest priority in the CAP system. The 

Indian Water Rights Settlement Water was obtained from the Yuma Mesa Irrigation and Drainage 

District (50,000 af) and the Wellton-Mohawk Irrigation and Drainage District (22,000 af) which 

are priority 3 Colorado River mainstem contractors. After accounting for CAP delivery system 

loss of 5 percent, the 72,000 af is reduced to 68,400 af. 

The next pool is the CAP Colorado River priority 4 water allocated to tribal and M&I 

subcontractors, which have the highest co-equal priority for CAP priority 4 deliveries. The CAP 

Indian priority water totals 343,079 af. The M&I priority water totals 638,823 af through 2043. 

After 2043, the amount is 686,126 af, due to the conversion 47,303 af of non-Indian agriculture 

(NIA) priority water to CAP M&I priority. Thus, the total amount of CAP Indian and M&I 

priority water is 981,902 af through 2043; after 2043, the amount is 1,029,205 af. 

The third pool, NIA Relinquished Water pool (hereafter referred to as the NIA Priority Pool), has 

been allocated 364,698 af through 2043. In 2044, 47,303 af converts to CAP M&I priority, 

leaving 317,395 af for the NIA Priority Pool. This pool was created as part of the Arizona Water 

Settlements Act when the CAP NIA contractors relinquished their NIA priority water 

subcontracts (due to high cost) for a pool of less-costly CAP excess water.

The fourth pool is the remaining CAP supply and is termed the Excess Pool. The priority of 

delivery within this pool is as follows: NIA Settlement water, which decreases according to the 

following schedule: 400,000 af through 2016; 300,000 af, from 2017 through 2023; and 225,000 

af, from 2024 through 2030; the Arizona Water Banking Authority and the Central Arizona 

Groundwater Replenishment District replenishment reserve (they have co-equal priority) pool; 

and other excess water deliveries (such as short-term contracts). The Arizona Water Banking 

Authority/Central Arizona Groundwater Replenishment District and short-term contracts supplies 

are variable because they are dependent on CAP’s annual priority 4 supply and on the total annual 

demand of the CAP’s higher-priority users. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-27

The following sections describe the water rights and demands of each of the tribes served by 

the CAP.

3.3.1 Ak-Chin Indian Community

In 1912, President Taft created a reservation at Ak-Chin encompassing 21,840 acres. In 1961, the 

Ak-Chin Tribal Council was formally recognized under the Indian Reorganization Act of 1934. 

The Ak-Chin Indian Reservation is located in Pinal County, 50 miles south of Phoenix. Farming 

(Ak-Chin Farms) is a major part of the reservation’s economy. 

The Ak-Chin Reservation’s water rights settlement of 1978, Pub. L. No. 95-328, 92 Stat 409 

(1978), was the first of a series of Indian water rights settlements in central Arizona. The 1978 

Settlement Act was amended in 1984. Under the 1984 water rights settlement, the Ak-Chin 

Indian Reservation has the right to receive up to 75,000 afy of water at the southeastern corner of 

the reservation. When sufficient surface water is available in the CAP canal, the United States 

may deliver up to an additional 10,000 afy of water to the Ak-Chin Indian Reservation 

(maximum of 85,000 afy). In years of Colorado River shortage, the United States must pay 

damages if less than 72,000 afy is delivered to the Ak-Chin Indian Reservation. The United 

States acquired 50,000 afy of Colorado River water entitlement from the Yuma Mesa Division of 

the Gila Project to partially meet the requirement to deliver required quantities to the Ak-Chin 

Indian Reservation. After losses, 47,500 afy is delivered to the Ak-Chin Indian Community with 

a priority date that precedes the date of enactment of the Colorado River Basin Project Act, and 

therefore has a higher priority during times of shortage than other CAP water.

The Ak-Chin Indian Reservation was provided with the right to lease some of its water supplies 

within Arizona, and the Ak-Chin Indian Reservation has leased a portion of its water to the Del 

Webb Corporation. The Ak-Chin Indian Reservation’s water infrastructure is in place, and with 

the exception of water that the Ak-Chin Indian Community has leased, all of its CAP water is 

being used for farming purposes. 

Ak-Chin Indian Community Projected Water Demand

For the Study, future diversions result from the tribal water rights and anticipated usage. 

Table C9-26 presents the Community’s projected demand schedule by demand scenario. 

TABLE C9-26

Future Ak-Chin Indian Tribe Projected Demands by Scenario (afy)

Scenario Priority 2015 2035 2060

All Scenarios Colorado River Priority 3 50,000 50,000 50,000

CAP Indian Priority1 25,000 25,000 25,000

1 When sufficient surface water is available in the CAP canal, the Community is entitled to up to 10,000 afy of water in addition 

to the 75,000 afy. It is assumed that demand exists for the water under all scenarios.

3.3.2 Fort McDowell Yavapai Nation

The Fort McDowell Reservation is located in Maricopa County, Arizona, about 23 miles 

northeast of Phoenix. The Verde River flows north to south through the reservation. The Fort 

McDowell Reservation was created by Executive Order in 1903 for the Yavapai, Mojave, and 

Apache Indian tribes. 
Colorado River Basin 

Water Supply and Demand Study

C9-28 December 2012

Under its water rights settlement, the Fort McDowell Indian Community Water Rights Settlement 

Act of 1990, Pub. L. No. 101-628, Title IV, 104 Stat. 4480 (1990), the Fort McDowell 

Reservation received a combination of water resources from both the Salt River Project (SRP) and 

the CAP. With respect to the Colorado River supplies, the Fort McDowell Reservation received 

the rights to delivery of up to 18,233 afy of Colorado River water. This consisted of 4,300 afy of 

CAP water that the Fort McDowell Reservation had contracted for in 1980, plus an additional 

13,933 afy of CAP water that the United States acquired from the Harquahala Valley Irrigation 

District. The acquired Harquahala Valley Irrigation District water was converted from its CAP 

NIA priority water to CAP Indian priority water through this settlement. The Fort McDowell 

Yavapai Nation has leased 4,300 afy of its CAP water to the City of Phoenix for a 100-year 

period, and will be using its remaining 13,933 afy through various means. 

In accordance with the terms and conditions of the settlement, the SRP is required to allow the 

McDowell Yavapai Nation to divert Verde River water in exchange for delivery of the Nation’s 

CAP water allocation. The Nation is entitled to divert an additional amount of 959 af from the 

Verde River to account for return flows, for a total Verde River diversion right of 19,192 af. It 

should be noted that this return flow right does not impact its CAP entitlement of 18,233 afy 

from the Colorado River, nor the amount to be delivered to SRP through the exchange. 

Fort McDowell Yavapai Nation Projected Water Demand 

For the Study, future diversions result from the tribal water rights and anticipated usage. 

Table C9-27 presents the Nation’s projected demand schedule by demand scenario. 

TABLE C9-27 

Future Fort McDowell Yavapai Nation Projected Demands by Scenario1 (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 18,233 18,233 18,233

1 Demand scenarios reflect only Colorado River demand physically diverted from the CAP and therefore do not reflect the 

Nation’s entitlement from the SRP settlement to divert an additional 959 acre feet of Verde River water to account for return flows. 

The Nation’s total Verde River diversion right is 19,192 af. 

3.3.3 Gila River Indian Community

The Gila River Reservation was established by an act of Congress in 1859 for Pima and 

Maricopa Indians. The 583.9-square-mile reservation is located in Maricopa and Pinal Counties. 

The Gila River Indian Community established Gila River Farms during the late 1960s, with 

approximately 16,000 acres in production. The Gila River Reservation is the homeland for two 

distinct tribes, the Pima and the Maricopa.

The 2004 Gila River Indian Community Water Rights Settlement Act, Pub. L. No. 108-451, Title 

II, 118 Stat. 3499 (2004), provides the Community with 328,800 afy of CAP water, consisting of 

120,600 afy of CAP NIA priority water, 191,200 afy of CAP Indian priority water, and 17,000 

afy of CAP M&I priority water, contingent on the execution of an exchange and lease agreement 

with Asarco in accordance with Section 204(b)(1)(C) of the Arizona Water Settlements Act. 

Under this Act, the State of Arizona is required to provide a backup water supply of 15,000 afy 

of the CAP NIA priority water so that it has a reliability equivalent to CAP Indian priority and 

M&I priority water over a 100-year period ending in 2108. Construction of the infrastructure to 

deliver CAP water to the Gila River Reservation for farming purposes is ongoing. Within the 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-29

terms of the 2004 settlement, the Gila River Reservation has the right to lease its CAP water for 

a term of up to 99 years. 

Gila River Indian Community Projected Water Demand 

For the Study, future diversions result from the tribal water rights and anticipated usage. 

Table C9-28 presents the Community’s projected demand schedule by demand scenario. 

TABLE C9-28

Future Gila River Indian Community Projected Demands by Scenario (afy)

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 191,200 191,200 191,200

CAP M&I Priority 17,000 17,000 17,000

CAP NIA Priority 0 120,600 120,600

3.3.4 Pascua Yaqui Tribe

The Pascua Yaqui Tribe is located in southeastern Arizona near Tucson, Arizona. The Tribe 

has a water delivery contract with the United States dated December 11, 1980, that provides 

500 af of CAP water to the Tribe. Although overall Tribal water demand exceeds 500 afy, it is 

unknown whether additional Colorado River water will be used to provide additional water to the 

Tribe or if water will be obtained from some other source. 

Pascua Yaqui Tribe Projected Water Demand

For the Study, future diversions result from the tribal water rights and anticipated usage. 

Table C9-29 presents the Tribe’s projected demand schedule by demand scenario. 

TABLE C9-29

Future Pascua-Yaqui Projected Demands by Scenario (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 500 500 500

3.3.5 Salt River Pima-Maricopa Indian Community

The Salt River Reservation is located in Arizona, adjacent to the boundaries of Mesa, Tempe, 

Scottsdale, and Fountain Hills in the metropolitan Phoenix area. The reservation was created in 

1879. The Salt River Reservation is occupied by two tribes, the Pima and the Maricopa, with a 

combined enrolled population exceeding 9,400. The Salt River Reservation consists of 53,600 

acres and maintains 19,000 acres as a natural preserve. Approximately 12,000 acres are under 

cultivation; cotton, melons, onions, broccoli, and carrots are the major crops.

Under the Salt River Pima-Maricopa Indian Community Water Rights Settlement Act, Pub. L. 

No. 100-512,102 Stat.2549 (1988), the United States obtained the rights to 22,000 afy of 

Colorado River water entitlement from the Wellton-Mohawk Irrigation and Drainage District, 

near Yuma, Arizona. This right is senior to CAP. Pursuant to the settlement, this water was 

contracted by the Secretary of the Interior to several Phoenix area cities and the Community 

agreed to accept delivery of an equivalent amount of SRP water. 
Colorado River Basin 

Water Supply and Demand Study

C9-30 December 2012

The Salt River Reservation has the right to receive up to 13,300 afy of CAP Indian priority 

water. Under the terms of the settlement, the Salt River Reservation has the right to lease its CAP 

water and has leased all of its CAP water to several Phoenix-area cities until December 30, 2098. 

This water supply is considered an ITA.

Salt River Pima-Maricopa Indian Community Projected Water Demand

For the Study, future diversions result from the tribal water rights and anticipated usage. 

Table C9-30 presents the Community’s projected demand schedule by demand scenario. 

TABLE C9-30

Salt River Pima-Maricopa Indian Community Projected Demands by Scenario (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios Colorado River Priority 3 22,000 22,000 22,000

CAP Indian Priority 13,300 13,300 13,300

3.3.6 San Carlos Apache Tribe

The San Carlos Reservation is located in southeastern Arizona. The reservation was established 

by Executive Order in 1871 and covers 2,910.6 square miles. Approximately one-third of the 

San Carlos Apache Tribe’s land is forested or wooded. San Carlos Lake is a hub of recreational 

activity, especially for fishing.

Under the San Carlos Apache Tribe Water Rights Settlement Act of 1992, Pub. L. No. 102-575, 

Title XXXVII, 106 Stat.4740 (1992), the San Carlos Reservation has the rights to delivery of 

64,145 afy of CAP water in the following categories: 12,700 afy of CAP Indian priority water, 

18,145 afy of CAP M&I priority water (previously allocated to Phelps Dodge and the town of 

Globe), and additional water made available by the Ak-Chin Indian Community Water Rights 

Settlement Act of 1984. The additional Ak-Chin water is unquantified in the settlement and 

estimated to be 33,300 afy before losses are considered. The San Carlos Apache Tribe’s right to 

receive the additional Ak-Chin water is subordinate to the Secretary’s obligation to deliver water 

to the Ak-Chin Indian Reservation under the Ak-Chin water rights settlement. Given that the San 

Carlos Reservation is not able to physically divert CAP water, the Tribe would need to 

implement water exchanges to benefit from its CAP water supplies. The San Carlos Reservation 

has the right to lease CAP water under its 1992 settlement and has entered into a 50-year lease 

for 14,000 afy to Phelps Dodge through an exchange with the SRP. The San Carlos Reservation 

has also entered into a 100-year lease with the City of Scottsdale for 12,500 afy of CAP M&I 

priority water.

San Carlos Apache Tribe Projected Water Demand

For the Study, future diversions result from the tribal water rights and anticipated usage. 

Table C9-31 presents the Tribe’s projected demand schedule by demand scenario. 

3.3.7 Tohono O’odham Nation 

The Tohono O’odham Nation sits in the heart of the Sonora Desert, west of Tucson, Arizona. 

The Tohono O’odham Nation is divided into 11 Districts totaling more than 4,342 square miles. 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-31

TABLE C9-31

San Carlos Apache Tribe Projected Demands by Scenario (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 30,845 30,845 30,845

Ak-Chin Settlement 12,655 12,655 12,655

Under the Southern Arizona Water Rights Settlement Act of 1982, as amended by the Southern 

Arizona Water Rights Settlement Amendments Act of 2004, the Nation is entitled to receive a 

total of 66,000 afy of CAP water. Of that amount, 50,000 afy may be used within the San Xavier 

District, or otherwise used by the Nation. The remaining 16,000 afy may be used within the 

Schuk Toak District, or otherwise used by the Nation. 

The Nation’s 66,000 acre-foot entitlement consists of 37,800 af of CAP Indian priority water and 

28,200 afy of CAP NIA priority water. With respect to the 28,200 af of NIA priority water, the 

United States is required to “firm” the 28,200 af so that the NIA priority water, for a 100-year 

period, will be deliverable during CAP shortages at the same priority and in the same manner as 

the CAP M&I priority water is delivered. 

In addition to this settlement water, the Nation has an annual entitlement of 8,000 af of CAP 

Indian priority water under a 1980 Water Delivery Contract. At present, that water must be used 

within the Sif Oidak District of the Nation.

Construction of the works necessary for the Nation to take delivery of this water under the 1982 

Settlement Act, as amended, is ongoing. The works necessary to deliver water to the Schuk Toak 

and San Xavier Districts have been completed. CAP water is currently in use within the Schuk 

Toak and San Xavier Districts. Additional uses will occur within the San Xavier District when 

additional lands are developed or rehabilitated within the District. 

Tohono O’odham Indian Tribe Projected Water Demand

For the Study, future demands result from the tribal water rights and anticipated usage. 

Table C9-32 presents the tribe’s projected demand schedule by demand scenario. 

TABLE C9-32

Tohono O’odham Projected Demands (in total) by Scenario (afy) 

Scenario 2015 2035 2060 

All Scenarios 54,800 74,000 74,000

3.3.8 Tonto Apache Tribe

The Tonto Apache Tribe is located in eastern Arizona on the Tonto Apache Reservation near 

Payson, Arizona. The Tribe has a CAP water delivery contract with the United States dated 

December 11, 1980. This CAP contract provides 128 af of CAP water to the Tribe. 

Given that the Reservation is located such that the Tribe is not able to physically divert CAP 

water, the Tribe will need to implement a water exchange to benefit from its CAP water supplies. 
Colorado River Basin 

Water Supply and Demand Study

C9-32 December 2012

The most likely scenario is that the Tribe will exchange water from the C.C. Craigin Reservoir 

through an exchange with the SRP. 

Tonto Apache Tribe Projected Water Demand

For the Study, future demands result from the tribal water rights and anticipated usage. 

Table C9-33 presents the Tribe’s projected demand schedule by demand scenario. 

TABLE C9-33

Tonto Apache Tribe Projected Demands by Scenario (afy)

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 128 128 128

3.3.9 White Mountain Apache Tribe

The White Mountain Apache Tribe Homeland is on the Fort Apache Indian Reservation, located 

within its ancestral aboriginal lands, and consists of 1.67 million acres of land held in trust in 

east-central Arizona in parts of Navajo, Gila, and Apache Counties. The reservation contains 

headwaters for the Salt River.

The water rights of the Tribe were settled under the White Mountain Apache Tribe Water Rights 

Quantification Agreement of January 13, 2009 (Agreement). The Agreement was ratified by 

Congress in the White Mountain Apache Tribe Water Rights Quantification Act of 2010, Pub. L. 

111–291, Title III, December 8, 2010 (Act). 

Under the Act, the Tribe is entitled to 25,000 afy of Colorado River water delivered via the CAP. 

None of the CAP water will be delivered to the reservation. Of that amount, 22,500 af will be 

leased to the various cities, and 2,500 af will be leased back to the Central Arizona Water 

Conservation District.

White Mountain Apache Tribe Projected Water Demand

For the Study, future demands result from the tribal water rights and anticipated usage. 

Table C9-34 presents the Tribe’s projected demand schedule by demand scenario. 

TABLE C9-34

White Mountain Apache Tribe Projected Demands by Scenario (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 2,031 25,000 25,000

3.3.10 Yavapai-Apache Nation

The Yavapai-Apache Nation is located in central Arizona, near the communities of Camp Verde 

and Clarkdale. The Nation has a CAP water delivery contract with the United States dated 

December 11, 1980. This CAP contract provides 1,200 af of CAP water to the Nation. While 

overall tribal water demand exceeds 1,200 afy, it is unknown whether additional Colorado River 

water will be used to provide additional water to the Nation or if water will be obtained from 

some other source. Given that the reservation is located such that the Nation is not able to 

physically divert CAP water, the Nation will need to implement a water exchange to benefit from 
Appendix C9 — Tribal Water Demand

Scenario Quantification

December 2012 C9-33

its CAP water supplies. The most likely scenario is that the Nation will exchange water from the 

Verde River through an exchange with the SRP. 

Yavapai-Apache Nation Projected Water Demand

For the Study, future demands result from the tribal water rights and anticipated usage. 

Table C9-35 presents the Nation’s projected demand schedule by demand scenario. 

TABLE C9-35

Yavapai-Apache Nation Projected Demands by Scenario (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 1,200 1,200 1,200

3.3.11 Yavapai-Prescott Tribe

Under the Yavapai-Prescott Indian Tribe Water Rights Settlement Act of 1994, Pub. L. 103-434, 

108 Stat. 4526 (1994), the Yavapai Reservation permanently assigned and transferred its CAP 

contractual right of 500 afy to the city of Scottsdale, Arizona, in return for funds to develop 

alternative water supplies. Because the Yavapai-Prescott Reservation no longer has a right to

CAP water, no trust asset is attributable to the Yavapai-Prescott Reservation.

Yavapai-Prescott Tribe Projected Water Demand

For the Study, future demands result from the tribal water rights and anticipated usage. 

Table C9-36 presents the Yavapai-Prescott Tribe’s projected demand schedule by 

demand scenario. 

TABLE C9-36

Yavapai-Prescott Tribe Projected Demands by Scenario (afy) 

Scenario Priority 2015 2035 2060 

All Scenarios CAP Indian Priority 500 500 500

4.0 Ongoing and Potential Settlement Discussions and 

Potential Litigation 

There are 13 tribes whose water rights within the Colorado River Basin have yet to be fully 

adjudicated or quantified. These tribes are as follows:

• Upper Colorado River Basin: 

− Navajo Nation

− Ute Indian Tribe of the Uintah and Ouray Reservation

− Ute Mountain Ute Tribe 

• Lower Colorado River Basin: 

− Havasupai Tribe

− Hopi Tribe 

− Hualapai Tribe
Colorado River Basin 

Water Supply and Demand Study

C9-34 December 2012

− Kaibab Band of Paiute Indians 

− Navajo Nation

− Pascua Yaqui Tribe 

− San Carlos Apache Tribe

− San Juan Southern Paiute Tribe 

− Tohono O’odham Nation 

− Tonto Apache Tribe

− Yavapai Apache Nation

Reclamation is participating in and providing technical assistance and/or funding for ongoing 

federally recognized tribal water rights settlement negotiations in both the Upper and Lower 

Colorado River Basins. These settlement negotiations include:

• Ute Indian Tribe regarding the proposed Revised Ute Indian Compact of 1990 and water 

rights settlement

• Navajo Nation regarding implementation of the Navajo-San Juan Settlement

• The La Jolla, Pala, Pauma, Rincon, and San Pasqual Bands in southern California regarding 

the San Luis Rey Indian Water Rights Settlement Act, as amended

• The Navajo Nation and Hopi Tribe in a joint settlement of the Little Colorado River claims

• The San Carlos Apache Tribe

• The Yavapai Apache Nation

• The Tohono O’odham Nation 

Reclamation is also participating in and funding tribal water assessments in the Lower Colorado 

River Basin. These settlement assessments are for the following tribes:

• Havasupai Tribe

• Hualapai Tribe

5.0 References 

Decker, E.L. 1960. Water Right Claims, Uintah and Ouray Indian Reservation, Utah 

(as amended). 

Bureau of Reclamation (Reclamation). 1972 to 2009. Water Accounting Reports. Colorado River 

Accounting and Water Use Report Arizona, California, and Nevada. Retrieved from 

http://www.usbr.gov/lc/region/g4000/wtracct.html#Decree. 

Bureau of Reclamation (Reclamation). 2000. Colorado River Interim Surplus Criteria Final 

Environmental Impact Statement. 

Bureau of Reclamation (Reclamation). 2007. Colorado River Interim Guidelines for Lower Basin 

Shortages and Coordinated Operations for Lake Powell and Lake Mead Final 

Environmental Impact Statement. 
 

Appendix C10

Historical Consumptive 

Use and Loss Detail By State

December 2012 C10-1 

Appendix C10 — Historical Consumptive 

Use and Loss Detail By State

1.0 Overview

This appendix presents a series of three figures showing historical consumptive use of Colorado 

River water for each state to facilitate understanding of the total consumptive uses by category, 

the relative consumptive use of Colorado River water by category, and the consumptive use of 

Colorado River water by category over the period 1971 to 2010. To indicate the change in 

consumptive use by category over time, the average use and loss for each category over the 

period 1971 to 1980 was used to represent the historical pattern and was then compared to the 

maximum value for each category in the recent period, 1999 to 2010. The maximum from 1999 

to 2010 was taken to offset the potential impact on use due to the recent drought. 

This appendix summarizes historical consumptive use of Colorado River water. Throughout this 

appendix, the term “consumptive use” refers to consumptive use of Colorado River water only, 

not total consumptive use (including other water sources) in the state. 

2.0 Colorado

Figure C10-1 shows historical (1971 to 2010) state of Colorado consumptive use of Colorado 

River water by category. Colorado’s consumptive use of Colorado River water has grown from 

approximately 1.8 million acre-feet (maf) in 1971 to a high of 2.3 maf in 1989 (exclusive of 

reservoir evaporation), an increase of 29 percent. Agriculture is the largest consumptive use 

category in Colorado, followed by exports. Exports consist of trans-Colorado River Basin 

(Basin) diversions from within the hydrologic boundaries of the Basin to Front Range areas east 

of the Continental Divide in Colorado. The detailed information necessary to disaggregate the 

trans-Basin diversions into use categories was not available at the time of publication of this 

appendix. 

Colorado has identified some concerns with the data and methodologies used in Bureau of 

Reclamation’s (Reclamation) Consumptive Uses and Losses Reports (Reclamation, 2005, 2012a, 

2012b, 2012c) from which these data are based, including: high-altitude crop coefficients are not 

used in appropriate locations (i.e., grass pasture at elevations above 6,500 feet); the Crop 

Irrigation Water Requirement shortage estimates underestimate shortages; non-Colorado River 

Storage Project reservoir evaporation is underestimated; and agricultural incidental losses are 

overestimated. Reclamation and Colorado are continuing to work collaboratively to resolve these 

concerns.

Figure C10-2 displays the percent of Colorado consumptive use by category in the past (1971 to 

1980 average) and recently (1999 to 2010 maximum). Although Colorado River consumptive 

use has increased over time, the distribution across consumptive use categories appears to have 

remained relatively unchanged.
Colorado River Basin 

Water Supply and Demand Study

C10-2 December 2012

FIGURE C10-1 

Historical Colorado Consumptive Use of Colorado River Water by Category, 1971–2010 

FIGURE C10-2 

Historical Colorado Consumptive Use of Colorado River Water by Category, 1971–2010

0

500

1,000

1,500

2,000

2,500

1971197219731974197519761977197819791980

19811982198319841985198619871988198919901991

1992199319941995199619971998199920002001

200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-3 

Figure C10-3 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is agriculture, followed by exports. Agriculture is the most 

variable category year to year. The agriculture category is strongly influenced by supply, which 

can result in reduced requests for diversion in years with abundant precipitation and result in 

shortages during years of drought. The remaining categories comprise a small percentage of 

Colorado’s consumptive use. 

FIGURE C10-3

Historical Colorado Consumptive Use of Colorado River Water by Category, 1971–2010

3.0 New Mexico 

Figure C10-4 shows historical (1971 to 2010) state of New Mexico consumptive use1 of 

Colorado River water by category. New Mexico consumptive use of Colorado River water has 

grown from approximately 163 thousand acre-feet (kaf) in 1971 to a high of 425 kaf in 2005 

(exclusive of reservoir evaporation), an increase of 122 percent. Agriculture is the largest 

consumptive use category in New Mexico. 

 

1 Excluding consumptive use in Lower Basin tributaries.

0

500

1,000

1,500

2,000

2,500

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals
Colorado River Basin 

Water Supply and Demand Study

C10-4 December 2012

FIGURE C10-4 

Historical New Mexico Consumptive Use of Colorado River Water by Category1, 1971–2010

1 San Juan-Chama project diversions are determined annually based on bypass flow requirements and maximum inyear and decadal diversions. Variations from year to year are due to flow limitations and not changes in demand.

Figure C10-5 displays the percent of New Mexico consumptive use by category in the past (1971 

to 1980 average) and recently (1999 to 2010 maximum). New Mexico consumptive use 

distribution across categories appears to have shifted slightly in the recent period, with municipal 

and industrial (M&I) agricultural and energy uses increasing.

Figure C10-6 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is agriculture, followed by M&I. Both agriculture and M&I 

(via the San Juan-Chama project) are the most variable categories year to year. The agriculture 

category is strongly influenced by supply, which can result in reduced requests for diversion in 

years with abundant precipitation and result in shortages during years of drought. Diversions for 

the San Juan-Chama project that serve both agricultural and M&I categories are determined 

annually based on bypass flow requirements and maximum in-year and decadal diversions. 

Variations from year to year are attributable to diversion limitations and not changes in demand. 

The next largest category is energy, with the remaining categories comprising a small percentage 

of New Mexico’s consumptive use. 

0

50

100

150

200

250

300

350

400

450

19711972197319741975197619771978

19791980198119821983198419851986198719881989

19901991199219931994199519961997199819992000

2001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Fish and Wildlife and Recreation

Minerals
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-5 

FIGURE C10-5 

Historical New Mexico Consumptive Use of Colorado River Water Percent by Category

FIGURE C10-6 

Historical New Mexico Consumptive Use of Colorado River Water by Category1, 1971–2010

1 San Juan-Chama project diversions are determined annually based on bypass flow requirements and maximum inyear and decadal diversions. Variations from year to year are due to flow limitations and not changes in demand.

0

50

100

150

200

250

300

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Fish and Wildlife and Recreation

Minerals
Colorado River Basin 

Water Supply and Demand Study

C10-6 December 2012

4.0 Utah 

Figure C10-7 shows historical (1971 to 2010) state of Utah consumptive use2 of Colorado River 

water by category. Utah consumptive use of Colorado River water has grown from 

approximately 707 kaf in 1971to a high of 903 kaf in 1994 (exclusive of reservoir evaporation), 

an increase of 29 percent. Agriculture is the largest consumptive use category in Utah. 

FIGURE C10-7 

Historical Utah Consumptive Use of Colorado River Water by Category, 1971–2010

Figure C10-8 displays the percent of Utah consumptive use by category in the past (197 to 1980 

average) and recently (1999 to 2010 maximum). Utah consumptive use distribution across 

categories appears to have shifted in the recent period, with an increase in M&I and energy, and 

a decrease in agricultural use.

Figure C10-9 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is agriculture, followed by M&I. Both agriculture and M&I 

are the most variable categories year to year. The agriculture category is strongly influenced by 

supply, which can result in reduced requests for diversion in years with abundant precipitation 

and result in shortages during years of drought. Agricultural use in 1977 was significantly 

 

2 Excluding consumptive use in Lower Basin tributaries.

0

100

200

300

400

500

600

700

800

900

1,000

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-7 

affected by reduced natural flows in the Basin, which were 36 percent below the annual longterm average at the Colorado River at Lees Ferry, Arizona. The next-largest category is energy, 

with the remaining categories comprising a small percentage of Utah’s consumptive use. 

FIGURE C10-8 

Historical Utah Consumptive Use of Colorado River Water Percent by Category 

FIGURE C10-9 

Historical Utah Consumptive Use of Colorado River Water by Category, 1971–2010

0

100

200

300

400

500

600

700

800

900

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals
Colorado River Basin 

Water Supply and Demand Study

C10-8 December 2012

5.0 Wyoming

Figure C10-10 shows historical (1971 to 2010) state of Wyoming consumptive use of Colorado 

River water by category. Wyoming consumptive use of Colorado River water has grown from 

approximately 338 kaf in 1971 to a high of 566 kaf in 1994 (exclusive of reservoir evaporation), 

an increase of 59 percent. Agriculture is the largest consumptive use category in Wyoming. 

Figure C10-11 displays the percent of Wyoming consumptive use by category in the past (1971 

to 1980 average) and recently (1999 to 2010 maximum). Wyoming consumptive use distribution 

across categories appears to have shifted slightly in the recent period, with an increase in energy, 

M&I, and agriculture uses, as well as a decrease in minerals use.

Figure C10-12 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is agriculture. The agriculture category is strongly 

influenced by supply, which can result in reduced requests for diversion in years with abundant 

precipitation and result in shortages during years of drought. Agricultural use in 1977 was 

significantly affected by reduced natural flows in the Basin, which were 36 percent below the 

annual long-term average at the Colorado River at Lees Ferry, Arizona. The next largest category 

is energy, followed by M&I, with the remaining categories comprising a small percentage of 

Wyoming’s consumptive use. 

FIGURE C10-10

Historical Wyoming Consumptive Use of Colorado River Water by Category, 1971–2010

0

100

200

300

400

500

600

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-9 

FIGURE C10-11

Historical Wyoming Consumptive Use of Colorado River Water Percent by Category 

FIGURE C10-12

Historical Wyoming Consumptive Use of Colorado River Water by Category, 1971–2010

0

100

200

300

400

500

600

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Minerals
Colorado River Basin 

Water Supply and Demand Study

C10-10 December 2012

6.0 Arizona

Upper Basin. Figure C10-13 shows historical (1971 to 2010) state of Arizona Upper Basin 

consumptive use of Colorado River water by category. Arizona Upper Basin consumptive use of 

Colorado River water has grown from approximately 5 kaf in 1971 to a high of 40 kaf in 1985 

(exclusive of reservoir evaporation), an increase of 318 percent. Energy is the largest 

consumptive use category for Arizona’s Upper Basin use and accounts for most of the increase. 

Figure C10-14 displays the percent of Arizona consumptive use of Colorado River water by 

category in the past (1971 to 1980 average) and recently (1999 to 2010 maximum). Arizona 

Upper Basin consumptive use of Colorado River water distribution across categories appears to 

have shifted in the recent period, with an increase in energy use and a decrease in agricultural 

use.

Figure C10-15 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is energy. Water used within the energy category serves the 

Navajo Generating Station, which began operation in 1974. The remaining categories comprise a 

small percentage of Arizona’s Upper Basin consumptive use. 

FIGURE C10-13

Historical Arizona Upper Basin Consumptive Use of Colorado River Water by Category, 1971–2010

0

5

10

15

20

25

30

35

40

45

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-11

FIGURE C10-14

Historical Arizona Upper Basin Consumptive Use of Colorado River Water Percent by Category 

FIGURE C10-15

Historical Arizona Upper Basin Consumptive Use of Colorado River Water by Category1, 1971–2010

1 Water used within the energy category serves the Navajo Generating Station, which began operation in 1974.

0

5

10

15

20

25

30

35

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy
Colorado River Basin 

Water Supply and Demand Study

C10-12 December 2012

Lower Basin. Figure C10-16 shows historical (1971 to 2010) state of Arizona Lower Basin 

consumptive use of Colorado River water by category. Arizona’s Lower Basin consumptive use 

of Colorado River water has grown from approximately 1.3 maf in 1971 to a high of 2.8 maf in 

2003 (exclusive of reservoir evaporation), an increase of 115 percent. Agriculture is the largest 

use category. The agriculture and M&I consumptive use categories show an increase beginning 

in the late 1980s, largely due to the construction of the Central Arizona Project (CAP). 

Arizona also provided a breakdown by use category of CAP deliveries from the mainstem to the 

Gila River Basin, with three additional use categories. These are CAP M&I Recharge, 

representing the activities of the Central Arizona Groundwater Replenishment District, Arizona 

Water Banking Authority, and interstate banking; CAP tribes, representing the CAP water 

delivered to meet tribal use; and CAP Canal and Reservoir Evaporation, representing losses 

within the CAP delivery system. Tribal use in Arizona except for CAP deliveries is included as a 

component of the agriculture and/or M&I demand categories. The CAP data by use category, 

however, should be considered preliminary and may be updated in the future. 

Figure C10-17 displays the percent of Arizona Lower Basin consumptive use by category in the 

past (1971 to 1980 average) and recently (1999 to 2010 maximum). Arizona’s use distribution 

across categories appears to have shifted in the recent period, with a significant increase in M&I 

portion of total use and a significant decrease in the agriculture portion of total use. 

Figure C10-18 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is agriculture, while M&I sharply increases after deliveries 

from the CAP begin in 1985. Agriculture, M&I, and M&I Recharge are the most variable 

categories year to year. The remaining categories comprise a small percentage of Arizona’s 

consumptive use. 
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-13

FIGURE C10-16 

Historical Arizona Lower Basin Consumptive Use of Colorado River Water by Category1, 1971–2010

1 CAP began deliveries in 1985.

FIGURE C10-17

Historical Arizona Lower Basin Consumptive Use of Colorado River Water Percent by Category 

0

500

1,000

1,500

2,000

2,500

3,000

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

CAP M&I Recharge

CAP Tribes

CAP Canal and Reservoir 

Evaporation

Energy

Fish and Wildlife and 

Recreation

Minerals
Colorado River Basin 

Water Supply and Demand Study

C10-14 December 2012

FIGURE C10-18

Historical Arizona Lower Basin Consumptive Use of Colorado River Water by Category, 1971–2010

7.0 California 

Figure C10-19 shows historical (1971 to 2010) state of California consumptive use of Colorado 

River water by category. California consumptive use of Colorado River water increased from 

approximately 5.2 maf in 1971 to a high of 5.4 maf in 1974, then decreased to approximately 4.4 

maf over the period 2003 to 2010, a decrease of 19 percent. California’s use above its 

apportionment of 4.4 maf per year was attributable to available unused apportionment in the 

Lower Basin and surplus water supply conditions for the Lower Division states. 

Figure C10-20 displays the percent of California consumptive use by category in the past (1971 

to 1980 average) and recently (2003 to 2010 maximum). A period from 2003 to 2010 was used 

instead of 1999 to 2010 to represent recent use because the Colorado River Water Delivery 

Agreement (Federal Quantification Settlement Agreement), an integral part of implementing 

California’s “4.4 Plan,” was signed in 2003. Although California consumptive use has decreased 

over time, the distribution across categories remains relatively unchanged. 

0

500

1,000

1,500

2,000

2,500

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

CAP M&I Recharge

CAP Tribes

CAP Canal and Reservoir 

Evaporation

Energy

Minerals

Fish and Wildlife and Recreation
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-15

FIGURE C10-19

Historical California Consumptive Use of Colorado River Water by Category1, 1971–2010

1 California’s use above its normal apportionment of 4.4 million acre-feet per year (mafy) was attributable to available 

unused apportionment in the Lower Basin and surplus water supply conditions for the Lower Division states.

FIGURE C10-20

Historical California Consumptive Use of Colorado River Water Percent by Category 

0

1,000

2,000

3,000

4,000

5,000

6,000

1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Fish and Wildlife and Recreation
Colorado River Basin 

Water Supply and Demand Study

C10-16 December 2012

Figure C10-21 displays the consumptive use for each category. It can again be seen that the 

largest category of consumptive use is agriculture followed by M&I.3 The M&I and agriculture 

categories show significant variability from year to year. Delivery losses incurred by the 

irrigation districts have been included in the agriculture category. The remaining categories 

comprise a small percentage of California’s consumptive use.

FIGURE C10-21

Historical California Consumptive Use1 of Colorado River Water by Category, 1971–2010

1 California’s use above its normal apportionment of 4.4 mafy was attributable to available unused apportionment in 

the Lower Basin and surplus water supply conditions for the Lower Division states.

8.0 Nevada 

Figure C10-22 shows historical (1971 to 2010) state of Nevada consumptive use of Colorado 

River water by category. Nevada consumptive use of Colorado River water has grown from 

approximately 51 kaf in 1971 to a high of 325 kaf in 2002, an increase of 537 percent. Nevada’s 

use above its apportionment of 300 thousand acre-feet per year (kafy) is attributable to surplus 

 

3 M&I includes entities served by the Metropolitan Water District of Southern California, Imperial Irrigation District, and 

 Coachella Valley Water District.

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Fish and Wildlife and Recreation
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-17

water supply conditions for the Lower Division States. M&I is essentially the only consumptive 

use category in Nevada. Although there is a small amount of agricultural use by the Fort Mohave 

Indian Reservation, all of that use has been categorized as M&I. 

Figure C10-23 displays the percent of Nevada consumptive use by category in the past (1971 to 

1980 average) and recently (1999 to 2010 maximum). Beginning in 2006, water use by the 

Southern California Edison Company declined to approximately 500 acre-feet per year (afy),

accounting for the decrease in the energy category. Figure C10-24 displays the consumptive use 

for each category. 

FIGURE C10-22

Historical Nevada Consumptive Use of Colorado River Water by Category1,2, 1971–2010

1 Nevada’s use above its 300 kafy apportionment was attributable to surplus water supply conditions for the Lower 

Division states.

2 Beginning in 2006, water use by the Southern California Edison Company (energy category) declined to 

approximately 500 afy.

0

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1971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010

Thousand Acre-Feet per Year

Year

Agricultural

Municipal and Industrial

Energy

Fish and Wildlife and Recreation
Colorado River Basin 

Water Supply and Demand Study

C10-18 December 2012

FIGURE C10-23

Historical Nevada Consumptive Use of Colorado River Water Percent by Category 

FIGURE C10-24

Historical Nevada Consumptive Use of Colorado River Water by Category1,2, 1971–2010

1 Nevada’s use above its 300 kafy apportionment was attributable to surplus water supply conditions for the Lower 

Division states.

2 Beginning in 2006, water use by the Southern California Edison Company (energy category) declined to 

approximately 500 afy.

0

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200

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300

350

1970 1975 1980 1985 1990 1995 2000 2005 2010

Thousand Acre-Feet per Year

Year

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Municipal and Industrial

Energy

Fish and Wildlife and Recreation
Appendix C10 — Historical Consumptive

Use and Loss Detail By State

December 2012 C10-19

9.0 References 

Bureau of Reclamation (Reclamation). 2005. Upper Colorado River Basin Consumptive Uses 

and Losses Report As Revised After Peer Review 1971 to 1995. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012a. Colorado River Basin Consumptive Uses and 

Losses Report 1996–2000. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation).2012b. Upper Colorado River Basin Consumptive Uses 

and Losses Report 2001–2005. Retrieved August, from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012c. Provisional Upper Colorado River Basin 

Consumptive Uses and Losses Report 2006–2010. Retrieved August, from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/pdfs/cul2006-2010prov.pdf. 
 

Appendix C11 

Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-1 

Appendix C11 — Modeling of 

Lower Basin Tributaries in the 

Colorado River Simulation System

1.0 Overview

The Colorado River Simulation System (CRSS) is the primary modeling tool used in the Bureau 

of Reclamation’s (Reclamation) long-term planning studies for the Colorado River Basin (Basin)

and is the primary modeling tool for the Colorado River Basin Water Supply and Demand Study 

(Study). CRSS simulates the operation of the major Colorado River system reservoirs on a 

monthly time step and provides information regarding the projected future state of the system in 

terms of output variables, which include the amount of water in storage, reservoir elevations, 

releases from the dams, diversions to and return flows from the water users, and the amount of 

water flowing at various points throughout the system. Major inputs to the model include 

projected natural flows1 at 29 locations throughout the Basin (20 in the Upper Basin upstream of 

and including the Lees Ferry gaging station in Arizona, and 9 below Lees Ferry, including the 

Paria River and inflow points in the Lower Basin2). For four of the inflow points below Lees 

Ferry (the Paria, Little Colorado, Virgin, and Bill Williams rivers), CRSS uses historical inflows

(not natural flows) based on U.S. Geological Survey (USGS) streamflow records. In addition, the 

Gila River is not included in CRSS. 

Many Colorado River planning studies have been completed over the past two decades in which 

this treatment of the major Lower Basin tributaries was used; however, questions regarding the 

adequacy of the treatment of the Lower Basin tributaries in CRSS for the Study arose during the 

phases focused on assessing future water supply and demand. Although some limitations were

imposed on the Study by this treatment, through other approaches the Study was able to examine

several important issues, including potential climate change impacts on the tributaries 

represented in CRSS, future demand scenarios on those tributaries, and future demand scenarios 

for the Colorado River from the central Arizona planning area (Gila River Basin) factoring in 

other water supplies within that basin (see subsequent discussions). 

This appendix provides technical information regarding the treatment of the Lower Basin

tributaries in CRSS, including the availability of the data and information necessary to compute 

natural flows. Additionally, three commitments are made to engage in efforts independent of the 

Study: 1) to resolve and correct the methodological and data inconsistencies in Reclamation’s 

Consumptive Uses and Losses Reports (CU&L Reports) (Reclamation, 2005, 2012a, 2012b, 

2012c) pertaining to all of the Lower Basin tributaries, in collaboration with the Colorado River 

Basin States (Basin States); and 2) to develop natural flows for the Little Colorado, Virgin, and 

Bill Williams rivers and to modify CRSS to use natural flows for those tributaries; and 3) to 

 

1 Natural flow represents the flow that would have occurred at the location had depletions and reservoir regulation not been 

 present upstream of that location. 

2 The Lower Basin includes those parts of the states of Arizona, California, Nevada, New Mexico, and Utah within and from 

 which waters naturally drain into the Colorado River System below Lee Ferry. 
Colorado River Basin 

Water Supply and Demand Study

C11-2 December 2012

explore the feasibility and necessity of computing natural flows for the Gila River Basin and 

adding that tributary to CRSS.

1.1 Introduction

This appendix first provides background regarding the methodologies that have been used to 

estimate and report historical consumptive uses and losses data throughout the Basin. The efforts

over the past decade to resolve inconsistencies in the Upper Basin data are summarized, as well 

as the efforts in the Lower Basin, which to date have been directed primarily toward measuring 

and reporting consumptive uses and losses from the mainstem of the Colorado River. Next, for 

each Lower Basin tributary, the current representation in CRSS is discussed along with the data 

from Reclamation’s CU&L Reports. Discussion is also provided on additional sources of data 

and information relevant to the estimate of consumptive uses and losses on these tributaries. 

Finally, commitments are made for work independent of the Study to resolve the technical issues 

identified. 

2.0 Background 

CRSS, which evolved from programming efforts in the late 1970s and early 1980s, is used to 

simulate the future conditions of the Colorado River system for planning studies. The basis of the 

simulation is a mass balance calculation that accounts for water entering the system, water 

leaving the system (e.g., from consumptive use of water, trans-Basin diversions, evaporation, 

etc.), and water moving through the system (i.e., water stored in reservoirs or flowing in river 

reaches). 

Input data and information for the model include physical parameters, initial reservoir 

conditions, reservoir operating rules, and the diversion and return flow schedules for entities in 

the Basin States and the United Mexican States. Input data for the model also include natural 

flow at 29 locations throughout the system (20 in the Upper Basin upstream of and including the 

Lees Ferry gaging station in Arizona, and 9 below Lees Ferry, including the Paria River and 

inflow points in the Lower Basin), where natural flow represents the flow that would have 

occurred at the location had depletions and reservoir regulation not been present upstream of that 

location. Using these inputs, the model simulates the future state of the system in terms of output 

variables, which include the amount of water in storage, reservoir elevations, releases from the 

dams, diversions to and return flows from the water users, and the amount of water flowing at 

various points throughout the system. 

The computation of natural flows for use in CRSS began in the early 1980s. At that time, 

different approaches (in terms of the methodologies and data) were taken for the computations of 

Upper Basin and Lower Basin natural flows. Over time, although the data and, in some cases, the 

methodologies, have been improved, these differences have remained. The following sections 

summarize these data, methodologies, and differences. 

2.1 Computation of Natural Flows above Lees Ferry, AZ

The first computation of natural flows above Lees Ferry was done in the 1980s and is described 

in the DRAFT Colorado River Simulation System Hydrology Data Base report (Reclamation, 

1983). This report describes the methods employed to determine natural flows (and the salinity

of those flows) at the 20 locations in the Upper Basin mainstem and tributaries for the time 
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-3 

period 1906 to 1970. The accompanying data provide the monthly consumptive uses and losses 

and reservoir regulation data that were used in those computations. 

In 1968, the Colorado River Basin Project Act (CRBPA) directed the Secretary of the Interior 

(Secretary) to

make reports as to the annual consumptive uses and losses of water from the 

Colorado River system after each successive five-year period starting on October 

1, 1970. Such reports shall include a detailed breakdown of the beneficial 

consumptive use of water on a State-by-State basis. Specific figures on quantities 

consumptively used from the major tributary streams flowing into the Colorado 

River shall also be included on a State-by-State basis. Such reports shall be 

prepared in consultation with the States of the lower basin individually and with 

the Upper Colorado River Commission, and shall be transmitted to the President, 

the Congress, and to the Governors of each State signatory to the Colorado River 

Compact... 

These reports (the CU&L Reports3) have been prepared by Reclamation, in collaboration with 

the Basin States, for every five-year period from 1971 to 2005. To date, the report covering 2001 

to 2005 is in final review and a provisional report covering the period 2006 to 2008 has been 

prepared. 

The CU&L Reports estimate consumptive uses and losses across eight categories: reservoir 

evaporation, irrigated agriculture, livestock, stockponds, thermal electric power, minerals, 

municipal and industrial (M&I), and exports and imports. Specific methodologies are employed 

for each category and a large amount of data from a variety of sources is required. For example, 

to estimate consumptive use for irrigated agriculture, information regarding the actual acreage 

for specific crop types is coupled with weather data (precipitation, temperature, and frost dates) 

to estimate net evapotranspiration. Other specific information used includes data drawn from 

other published reports such as the USGS water use reports4 as well as data supplied by specific 

entities. 

Over a multi-year period in the early 2000s, the natural flow and salinity data for the Upper 

Basin was reviewed and re-developed for the period 1971 to 1995. A major component of this 

effort was resolving data and methodological inconsistencies found throughout the CU&L 

Reports up to that time. Based on these efforts, consistent data collection and computational 

methodologies were developed and are continually reviewed and updated to provide the best 

available information. 

The review and re-development effort of the consumptive uses and losses data included: 

1. Review and collection of weather data (precipitation, temperature, and frost dates) used 

within the modified Blaney-Criddle method required to estimate net evapotranspiration from 

irrigated croplands.

 

3 Available at: http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html.

4 Available at: http://water.usgs.gov/watuse/.
Colorado River Basin 

Water Supply and Demand Study

C11-4 December 2012

2. Review and computation of irrigated acres estimates to ensure an objective methodology to 

estimate acreage from multiple datasets (geographic information systems coverage, Census 

of Agriculture reports, and county agriculture statistics report) was employed when possible.

3. Review and computation of irrigated agriculture consumptive use to ensure a consistent 

representation of the modified Blaney-Criddle method within a single software package.

4. Review and correction of reservoir evaporation estimates to ensure that the same set of 

reservoirs were used from one reporting period to the next, including the incorporation of 

new reservoirs constructed after 1971.

5. Review and correction of USGS water use records used to assist in estimates of mineral and 

M&I uses.

6. Review and collection of export and import uses to ensure consistent reporting of trans-Basin 

exports and imports from one report period to the next, including the proper accounting of 

trans-Basin exports and imports constructed or decommissioned since 1971.

7. Correction of data entry errors and design of data entry and storage methods to assist in the 

implementation of quality control measures. 

The estimates from the CU&L Reports are used to compute natural flow5 in the Upper Basin for 

the period after 1970. As the consumptive uses and losses information is updated, the Upper 

Basin natural flows are also re-computed to ensure consistency. To this end, the Upper Basin 

states have raised issues regarding limitations, inconsistencies, and problems with the current 

consumptive uses and losses information, and Reclamation will continue to improve the 

consumptive uses and losses data through coordination and discussion with the Basin States. 

2.2 Computation of Natural Flows below Lees Ferry, AZ

Methodologies and data used to develop the flows (and the salinity of those flows) for the nine 

inflow points below Lees Ferry from 1906 through 1982 for the tributaries and from 1935 

through 1982 for the mainstem are described in Colorado River Simulation System, Hydrology 

Data Base Lower Colorado Region (Lees Ferry to Imperial Dam) (Reclamation, 1985). These 

nine inflow points represent tributary inflows as well as “gains and losses” within mainstem

reaches. The inflow points representing tributary inflows are the Paria River, the Little Colorado 

River, the Virgin River, and the Bill Williams River. The inflow points representing mainstem

gains and losses are Lees Ferry to Grand Canyon, Grand Canyon to Hoover Dam, Hoover Dam 

to Davis Dam, Davis Dam to Parker Dam, and Parker Dam to Imperial Dam.

Flows on the tributaries are computed not as natural flows, but instead by using historical, gaged

streamflows. The report details the methodologies used to fill in missing records and extend the 

available records for these tributaries back to 1906. 

Flows representing historical gains and losses along the mainstem reaches are estimates of 

natural flows, calculated by adjusting historical gaged streamflows for reservoir regulation and 

consumptive uses and losses that occurred in the reach. The report details the methodologies 

 

5 Additional information is available at http://www.usbr.gov/lc/region/g4000/NaturalFlow/current.html.
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-5 

used to fill in the missing consumptive use and historical gaged streamflow records to compute 

the reach gains back to 1935. 

Regarding the Gila River, located in Reach 6 (defined in the 1985 report as “Imperial Dam to 

International Boundary with Mexico”), the report states “Reach 6 is scheduled for completion 

during 1985. It is presently assumed that the reach gains, losses, and tributary inflows between 

Imperial Dam and the International Boundary sum to zero” (Reclamation, 1985). If any further 

work was done to estimate natural flows on this reach, it was not documented. The configuration 

of CRSS reflects this statement in that the Gila River is not included.

In 1992, the methodologies of the May 1985 report were reviewed and updated in Colorado 

River Simulation System, Hydrology Data Base Lower Colorado Region (Lees Ferry to Imperial 

Dam) (Reclamation, 1992). Data discrepancies were corrected and the flows on the mainstem

reaches were extended back to 1906, in most cases using monthly averages from a later period. 

Both the mainstem reach flows and the tributary inflows have since been re-visited and 

re-developed using methodologies described in Lee and Salas (2006). This was necessary as new 

information and techniques for record extension became available. The record extension 

technique is based on a multiple linear regression model that includes an error term in order to 

maintain a degree of variability in the extended records comparable to those of available 

historical reference gages. 

As noted above, in 1968, the CRBPA directed the Secretary, in consultation with the Basin 

States, to report on the annual consumptive uses and losses of water from the Colorado River 

system after each successive 5-year period, starting on October 1, 1970, and directed that

such reports shall include a detailed breakdown of the beneficial consumptive use 

of water on a State-by-State basis. Specific figures on quantities consumptively 

used from the major tributary streams flowing into the Colorado River shall also 

be included on a State-by-State basis... 

In addition to this direction, the 1964 U.S. Supreme Court Decree in Arizona v. California

(Consolidated Decree, 2006) directed the Secretary to make annual reports available that include 

the 

diversions of water from the mainstream, return flow of such water to the stream 

as is available for consumptive use in the United States or in satisfaction of the 

Mexican Treaty obligation, and consumptive use of such water. These quantities 

shall be stated separately as to each diverter from the mainstream, each point of 

diversion, and each of the States of Arizona, California and Nevada.

Reclamation accounts for the use of Colorado River water from the mainstem in the Lower Basin 

using a “diversion minus return flow” methodology, whereby the diversions and return flows are 

measured or estimated for each water user. Reclamation publishes this information each year in 

the Colorado River Accounting and Water Use Reports: Arizona, California, and Nevada (Water 

Accounting Reports6). As the Lower Basin mainstem use has grown to its full apportionment, 

the Decree accounting process has evolved into a real-time accounting system that tracks Lower 

Basin mainstem use daily and provides updates of the estimated use-to-date and projected use to

 

6 Available at: http://www.usbr.gov/lc/region/g4000/wtracct.html.
Colorado River Basin 

Water Supply and Demand Study

C11-6 December 2012

the end of the calendar year7, in addition to providing the official Water Accounting Report after 

the completion of each calendar year. 

The CU&L Reports include information taken from the Water Accounting Reports for mainstem

Lower Basin use and also estimate consumptive uses and losses in the Lower Basin tributaries 

back to 1971. The methodologies used in the CU&L Reports to estimate Lower Basin tributary 

use are similar to those used for the Upper Basin. Due to the Lower Colorado Region’s focus on 

Decree accounting and the real-time monitoring system, the data, information, and 

methodologies for estimating Lower Basin tributary consumptive uses and losses have not 

received a great deal of attention over the past several years, and the quality of the resulting 

information has suffered (see data presented in the following section). Similar issues that were 

corrected with the Upper Basin tributary data are likely to exist and will need to be corrected for 

the Lower Basin; however, these investigations have not occurred to date. 

Reclamation updates the natural flow8 for the five locations on the mainstem annually using the 

data provided in the Water Accounting Reports. The approach for the four tributary locations has 

not been modified since the May 1985 report (i.e., Reclamation has not attempted to compute 

natural flows at these locations) and these flows are updated annually using the latest USGS 

streamflow records.

In the following sections, a preliminary examination of the Lower Basin tributary data is 

presented and specific commitments are made to engage in efforts independent of the Study to 

improve the information regarding Lower Basin consumptive uses and losses and to enhance the 

capabilities of CRSS.

3.0 Current Information Pertaining to the Little Colorado, 

Virgin, and Bill Williams Rivers 

3.1 Current Representation in CRSS

For the Little Colorado River, the Virgin River, and the Bill Williams River, flows at specific 

gage locations near the confluence of the tributary and the Colorado River mainstem have been 

used to generate future inflow sequences for input to CRSS. A similar approach has also been 

used for the Paria River. This approach is inconsistent, and therefore work will be completed as 

described below; however, due to timing and resource limitations, this work was not completed 

within the Study. 

By using gage data to represent the flow at these locations, it was assumed that historical 

consumptive uses and losses above the gages on those tributaries may be ignored for modeling 

purposes. As discussed in Technical Report C – Water Demand Assessment, the Study explored a 

range of plausible demand scenarios and the current representation of these tributaries did not 

preclude the exploration of additional future demands on those tributaries. 

The approach is as follows: the USGS streamflow gage with the longest historical record nearest 

the confluence of the tributary and the Colorado River mainstem is used for the period that it is 

 

7 Available at: http://www.usbr.gov/lc/region/g4000/hourly/forecast11.pdf.

8 Available at: http://www.usbr.gov/lc/region/g4000/NaturalFlow/Final-MethodsCmptgNatFlow.pdf.
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-7 

available, and a record extension technique (see Lee and Salas, 2006, for more information) is 

used to reconstruct the flows back to 1906. The record extension technique is based on a multiple 

linear regression model that includes an error term in order to maintain a degree of variability in 

the extended records comparable to those of available historical reference gages. 

Figures C11-1 through C11-3 present the historical inflow record used to generate future inflow 

sequences for input to CRSS for the Little Colorado, Virgin, and Bill Williams rivers. The flow 

record includes the historical USGS streamflow (solid line) and the reconstructed flow using the 

record extension technique discussed above (dotted line). 

FIGURE C11-1 

Historical Flow for the Little Colorado River near Cameron, AZ, 1906–2008
Colorado River Basin 

Water Supply and Demand Study

C11-8 December 2012

FIGURE C11-2 

Historical Flow for the Virgin River at Littlefield, AZ, 1906–2008

FIGURE C11-3 

Historical Flow for the Bill Williams River below Alamo Dam, AZ, 1906–2008
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-9 

3.2 Consumptive Uses and Losses Data

3.2.1 Data from Reclamation’s Consumptive Uses and Losses Reports from 

1971 to 2005

Consumptive uses and losses data for the Lower Basin tributaries have been reported from 1971 

to 2005 in the CU&L Reports; however, as discussed above, these data have not received the 

same level of scrutiny and analysis as the Upper Basin data. 

Figure C11-4 shows Little Colorado River consumptive uses and losses from the CU&L Reports. 

Inconsistencies due to the 5-year reporting periods are evident in the reservoir evaporation 

category, particularly in the sudden decline in the 1981 to 1985 and the 2001 to 2005 periods. A 

similar inconsistency can be seen in the M&I category, which has the lowest use (averaging 

about 10,000 acre-feet per year) during 1981 to 1985. 

FIGURE C11-4 

Historical Consumptive Uses and Losses for the Little Colorado River1, 1971–2005

1 Data shown in cross hatch are currently being investigated and likely contain data and methodological inconsistencies.

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19891990199119921993

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19992000200120022003

20042005

Thousand Acre-Feet per Year

Year

Agriculture

M&I

Energy

Fish, wildlife, recreation

Minerals

Reservoir Evaporation

Export
Colorado River Basin 

Water Supply and Demand Study

C11-10 December 2012

These inconsistencies from one reporting period to another may result from several factors, 

including (1) different methods to determine M&I uses and losses employed each reporting 

period, (2) different personnel creating the report each reporting period, and (3) a lack of 

considering previous reports when computing the estimate for a current report. As discussed 

previously, similar problems existed in the Upper Basin CU&L Reports prior to Reclamation’s 

review and re-computation of the data, and these reasons were identified for the inconsistencies 

in that data.

The Little Colorado River originates in New Mexico and flows through northeastern Arizona 

before discharging into the Colorado River in the Grand Canyon. Figure C11-5 shows Arizona 

(left) and New Mexico (right) consumptive uses and losses on the Little Colorado River from the 

CU&L Reports. The inconsistencies originating from the 5-year reporting periods are again 

evident in the both the reservoir evaporation and M&I category for Arizona. Note the New 

Mexico y-axis is double the scale of Figure C11-4 to allow visualization of individual categories. 

The 5-year reporting periods are again evident in the agriculture, reservoir evaporation, and 

mineral categories.

FIGURE C11-5 

Arizona portion (left) and New Mexico portion (right) of Little Colorado River Consumptive Uses and Losses1, 1971–2005

1 Data shown in cross hatch are currently being investigated and likely contain data and methodological inconsistencies.

The Virgin River originates in Utah and flows through the northwest corner of Arizona and a 

portion of eastern Nevada before discharging into Lake Mead. Figure C11-6 shows consumptive 

uses and losses on the Virgin River from the CU&L Reports. The 5-year reporting periods are 

again evident, especially in the agriculture category. Obvious shifts in agriculture use occur 

between reporting periods. In particular, there is a large shift upward in agricultural consumptive 

use in 2001 to 2005 that is likely due to data and methodological inconsistencies and is currently 

being investigated. 

Figure C11-7 shows the Arizona (top-left), Nevada (top-right), and Utah (bottom-left) 

consumptive uses and losses on the Virgin River. Again, shifts in categories consistently occur at 

the transition of reporting periods. Note the y-axis is increased by 2 for Arizona and by 10 for 

Nevada from Figure C11-7 to allow visualization of individual categories.
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-11

FIGURE C11-6 

Historical Consumptive Uses and Losses for the Virgin River1, 1971–2005

1 Data shown in cross hatch are currently being investigated and likely contain data and methodological inconsistencies.

The Bill Williams River originates in the west-central portion of Arizona and discharges into 

Lake Havasu near Parker Dam. Figure C11-8 shows consumptive uses and losses on the Bill 

Williams River from the CU&L Reports. The 5-year reporting periods are again evident in the 

agriculture, mineral, and reservoir evaporation categories. Shifts in these categories consistently 

occur at the transition of reporting periods. In particular, there is a large shift upward in 

agricultural consumptive use in 2001 to 2005 that is likely due to data and methodological 

inconsistencies and is currently being investigated. 

3.2.2 Other Data and Information Sources

Several sources beyond Reclamation’s CU&L Reports provide information regarding 

consumptive uses and losses on the Little Colorado, Virgin, and Bill Williams rivers. For the 

Little Colorado and Bill Williams rivers, information sources include the Arizona Water Atlas 

published by the Arizona Department of Water Resources (ADWR), studies by the State of New 

Mexico, USGS, the U.S. Army Corps of Engineers, and Reclamation. 

For the Virgin River, information sources include reports prepared as part of the Utah State 

Water Plan, the Arizona Water Atlas, studies by the Natural Resources Conservation Service, and 

Dixie Project investigations by Reclamation. 

0

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500

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700

19711972

197319741975

197619771978197919801981198219831984198519861987198819891990199119921993

19941995

1996199719981999200020012002200320042005

Thousand Acre-Feet per Year

Year

Agriculture

M&I

Energy

Fish, wildlife, recreation

Minerals

Reservoir Evaporation

Export
Colorado River Basin 

Water Supply and Demand Study

C11-12 December 2012

FIGURE C11-7 

Arizona (top-left), Nevada (top-right), and Utah (bottom-left) portions of Virgin River Consumptive Uses and Losses1, 1971–

2005

1 Data shown in cross hatch are currently being investigated and likely contain data and methodological inconsistencies.

In addition, the Lower Colorado Region, recognizing the need to improve information on 

historical flows for these tributaries, has been collaborating with the University of Arizona’s 

Laboratory of Tree-Ring Research to develop tree-ring reconstructions of streamflow for these 

tributaries since 2005. Information gained from this effort can be used to further the development 

of natural flows on these tributaries. 

3.2.3 Future Work

The consumptive uses and losses reported in the CU&L Reports for the Little Colorado, Virgin, 

and Bill Williams rivers show inconsistencies similar to those observed in the Upper Basin 

reports before Reclamation’s multi-year effort to address and correct data and methodological 

inconsistencies undertaken in the early 2000s. Furthermore, the methodologies used in the 

CU&L Reports do not distinguish between consumptive uses and losses from tributary water and 

non-tributary water along these tributaries. In efforts independent of the Study, Reclamation will 

work to resolve these issues in collaboration with the states in the Lower Basin. 

Additionally, in efforts independent of the Study, natural flows for the Little Colorado, Virgin, 

and Bill Williams rivers will be developed along with the necessary modifications to CRSS in 

order to use these natural flows. Major activities required to develop natural flows for these 

tributaries include:

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Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-13

FIGURE C11-8 

Historical Consumptive Uses and Losses for the Bill Williams River1, 1971–2005

1 Data shown in cross hatch are currently being investigated and likely contain data and methodological inconsistencies.

• Collect data and develop methodologies to extend consumptive uses and losses estimates for 

these Lower Basin tributaries from 1971 (the earliest data reported in the CU&L Reports) 

back to 1906 (the start of the natural flow record) 

• Collect data and apply methodologies to remove the effects of historical reservoir regulation 

on these tributaries (e.g., Alamo Dam on the Bill Williams River), and account for reservoir 

regulation in the future 

• Develop projected future demand schedules for uses along these tributaries for input to the 

model in collaboration with the states of the Lower Basin

4.0 Current Information Pertaining to the Gila River 

4.1 Current Representation in CRSS

Although the Gila River drains a large portion of the Colorado River Basin, it has not been 

represented in CRSS since the model’s inception. Flows from the Gila River seldom reach the 

mainstem of the Colorado River, and when they do, the flows are very sporadic and are typically 

0

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19711972

197319741975

197619771978197919801981198219831984198519861987198819891990199119921993

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Thousand Acre-Feet per Year

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Agriculture

M&I

Energy

Fish, wildlife, recreation

Minerals

Reservoir Evaporation

Export
Colorado River Basin 

Water Supply and Demand Study

C11-14 December 2012

of high magnitude, as illustrated in Figure C11-9. The confluence of the Gila River and the 

Colorado River mainstem is downstream of all the major storage reservoirs in the United States. 

Although the Gila River is not explicitly represented in CRSS, exploration of future water 

demands and water supplies in the Gila River Basin was implicitly accomplished for the Study 

by the representation of Arizona’s demand as expressed in the quantified demand scenarios. 

Figure C11-9 shows the USGS gage for the Gila River near Dome, Arizona (upstream of 

confluence with Colorado River) and illustrates the sporadic nature of the Gila River flow. The 

dataset is complete back to 1930 but incomplete from 1906 to 1930. 

FIGURE C11-9 

Historical Flow for the Gila River near Dome, AZ, 1906 and 1930–2008

4.2 Consumptive Uses and Losses Data

4.2.1 Data from Reclamation’s Consumptive Uses and Losses Reports from 

1971 to 2005

Figure C11-10 shows the consumptive uses and losses on the Gila River from the CU&L 

Reports. Figure C11-11 shows these losses broken out by state: Arizona and New Mexico. Data 

inconsistencies associated with the 5-year reporting periods are suspected although they are more 

difficult to discern because the magnitudes of those inconsistencies are likely smaller relative to 

the total use in the Gila River tributary. The CU&L Reports report the annual CAP delivery, but 
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-15

do not provide information regarding the category of use of that water9. Furthermore, the 

contribution of the non-tributary groundwater use and supplies are not considered in the CU&L 

Reports. Other tributaries have sources of water other than tributary water; however, the issue is 

more significant with respect to the Gila River because the other sources supply a relatively 

larger portion of the consumptive use. 

FIGURE C11-10

Historical Consumptive Uses and Losses for the Gila River, 1971–2005

4.2.2 Other Data and Information Sources

Several sources beyond Reclamation’s CU&L Reports provide information regarding 

consumptive uses and losses on the Gila River. These sources include the Arizona Water Atlas

published by the ADWR and studies by the State of New Mexico, USGS, and Reclamation. In 

addition, the Western Water Assessment at the University of Colorado is presently developing 

tree-ring reconstructions of streamflow on the Gila River. 

 

9 Arizona provided a breakdown by use category of CAP deliveries from the mainstem to the Gila River Basin (see 

 appendix C6). 

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

19711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005

Thousand Acre-Feet per Year

Year

Agriculture

M&I

Energy

Fish, wildlife, recreation

Minerals

Reservoir Evaporation
Colorado River Basin 

Water Supply and Demand Study

C11-16 December 2012

FIGURE C11-11

Arizona (left) and New Mexico (right) Gila River Consumptive Uses and Losses, 1971–2005

4.2.3 Future Work

The consumptive uses and losses reported in the CU&L Reports for the Gila River show 

inconsistencies similar to those observed in the Upper Basin reports before Reclamation’s multiyear effort to address and correct data and methodological inconsistencies undertaken in the 

early 2000s. Furthermore, the methodologies used in the CU&L Reports do not distinguish 

between consumptive uses and losses from tributary water and non-tributary water in the Gila 

River Basin. In efforts independent of the Study, Reclamation will work to resolve these issues 

in collaboration with the Basin States. In addition, a commitment is made to explore the 

feasibility and usefulness of computing natural flows for the Gila River Basin and the feasibility 

and usefulness of adding that basin to CRSS. 

5.0 Summary

In the current configuration of CRSS, historical inflows based on USGS streamflow records have 

been used to generate future inflow sequences for the Little Colorado, Virgin, and Bill Williams 

rivers, inconsistent with the approach taken for the other tributaries (with the exception of the 

Paria River). In addition, the Gila River is not included in CRSS. This approach was used for 

past Colorado River planning studies; however, questions regarding the adequacy of the 

treatment of the Lower Basin tributaries in CRSS for the Study arose during the phases focused 

on assessing future water supply and demand. Although some limitations were imposed on the 

Study by this treatment the Study was able to examine several important issues, including 

potential climate change impacts on the tributaries represented in CRSS, future demand 

scenarios on those tributaries, and future demand scenarios for the Colorado River from the 

central Arizona planning area (Gila River Basin) factoring in other water supplies within that 

basin through other approaches. 

Consumptive uses and losses estimates reported in Reclamation’s CU&L Reports show 

methodological and data inconsistencies for these Lower Basin tributaries. Similar 

inconsistencies were present in the Upper Basin estimates before Reclamation’s multi-year effort 

in the early 2000s to resolve them. Reclamation, in collaboration with the Basin States, is 

committed to resolving the issues on the Lower Basin tributaries in an effort independent of the 

Study. Additional data and information sources are available, and research efforts are ongoing 

0

1,000

2,000

3,000

4,000

5,000

Thousand Acre-Feet per Year

Year

0

50

100

150

200

250

Thousand Acre-Feet per Year

Year
Appendix C11 — Modeling of Lower Basin Tributaries

in the Colorado River Simulation System

December 2012 C11-17

concerning consumptive uses and losses estimates on these tributaries. These sources will be 

utilized and coordination with ongoing efforts will be accomplished as appropriate. 

Also, in an effort independent of the Study, Reclamation is committed to developing natural 

flows on the Little Colorado, Virgin, and Bill Williams rivers and modifying CRSS to use these 

flows. This effort will require the extension of consumptive use and loss estimates from 1906 to 

1971, the development of methodologies to account for past and future reservoir regulation, and 

the development of future demand schedules for those tributaries. In addition, a commitment is 

made to explore the feasibility and usefulness of computing natural flows for the Gila River 

Basin and the feasibility and usefulness of adding that basin to CRSS. 

6.0 References 

Bureau of Reclamation (Reclamation). 1983. DRAFT Colorado River Simulation System 

Hydrology Data Base. Bureau of Reclamation, Upper Colorado Region, Salt Lake City, 

Utah.

Bureau of Reclamation (Reclamation). 1985. Colorado River Simulation System, Hydrology 

Data Base Lower Colorado Region (Lees Ferry to Imperial Dam). Boulder City, Nevada. 

May.

Bureau of Reclamation (Reclamation). 1992. Colorado River Simulation System, Hydrologic 

Flow and Salt Data Base for the Lower Colorado Region, Lees Ferry to Imperial Dam. 

Boulder City, Nevada. 

Bureau of Reclamation (Reclamation). 2005. Upper Colorado River Basin Consumptive Uses 

and Losses Report As Revised After Peer Review 1971 to 1995. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012a. Colorado River Basin Consumptive Uses and 

Losses Report 1996–2000. Retrieved from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012b. Upper Colorado River Basin Consumptive Uses 

and Losses Report 2001–2005. Retrieved August, from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/crsul.html. 

Bureau of Reclamation (Reclamation). 2012c. Provisional Upper Colorado River Basin 

Consumptive Uses and Losses Report 2006–2010. Retrieved August, from 

http://www.usbr.gov/uc/library/envdocs/reports/crs/pdfs/cul2006-2010prov.pdf. 

Colorado River Basin Project Act (CRBPA). 1968. 82 Stat. 886, 43 U.S.C. §§ 1501 to 1556. 

Consolidated Decree. 2006.U.S. Supreme Court Decree in the case of Arizona v. California. 547 

U.S. 150. 

Lee, T. and J.D. Salas. 2006. Record Extension of Monthly Flows for the Colorado River 

System., Colorado State University. Fort Collins, Colorado. 
Appendix C12

Plausible Range of Parameters 

December 2012 C12-1 

Appendix C12 — Plausible Range of 

Parameters 

Table C12-1 describes the parameters range for each parameter of the Current Projected 

scenario. The storyline for the Current Projected scenario is that growth, development patterns, 

and institutions will continue along recent trends. 

TABLE C12-1 

Plausible Range of Parameters for Each Critical Uncertainty Associated with Water Demand

General 

Driving Force 

Categories Critical Uncertainties1

Description of 

Parameters if Current 

Projected Continues

Plausible Low End of 

Range

Plausible High End 

of Range

Demographic 

and land use

Changes in population 

and distribution [4] 

Best estimate of

population growth

Slow growth:

• Increases principally 

in existing urban 

areas

Rapid, expansive 

growth:

• Focused in urban 

centers and 

“sprawl” to 

traditionally nonurban areas (likely 

driven by economic 

growth)

Changes in agricultural 

land use (e.g., irrigated 

agricultural areas, crop 

mixes, etc.) [5]

Nominal increase in 

irrigated agricultural 

lands due to the buildout of currently planned 

agricultural supply 

projects:

• Varies from state to 

state with some 

natural decreases 

also occurring 

Significant decrease in 

agricultural lands in 

many basin states

• Due to permanent

agricultural. 

retirement

Slightly faster 

increase in irrigated 

agricultural lands 

(varies from state to 

state) due to the 

build-out of currently 

planned agricultural 

supply projects

Technology 

and

economics

Changes in agricultural 

water use efficiency [8]

Continued Current 

Projected in agricultural

water use efficiency:

• Salinity control 

projects continue to 

be pursued

Decreased agricultural

efficiency resulting 

from aging 

infrastructure and 

minimal capital 

investment in 

repair/replacement

Externally driven 

increases in water 

saving technology

Rapid adoption of 

new water saving 

technologies

Changes in municipal 

and industrial water use 

efficiency [9]

Water use efficiency is 

increasing according to 

current policy and 

technology:

• External factors 

limiting water use of 

appliances/fixtures 

(e.g., federal statutes 

dictating water use 

efficiency of fixtures)

• Policies in place 

affecting future—vary 

by municipality and 

state

M&I consumer 

efficiency continues 

according to Current 

Projected: 

• Aging infrastructure 

could have effects 

on water efficiency

Diversification of 

supply portfolios and 

increased costs, 

leading to increased 

water use efficiency:

• Increased 

implementation of 

WaterSense, 

EnergyStar, 

efficient 

landscaping 

technology, etc.
Colorado River Basin 

Water Supply and Demand Study

C12-2 December 2012

General 

Driving Force 

Categories Critical Uncertainties1

Description of 

Parameters if Current 

Projected Continues

Plausible Low End of 

Range

Plausible High End 

of Range

Technology 

and

economics

(cont.)

Changes in water needs 

for energy generation 

(e.g., solar, oil shale, 

thermal, nuclear, etc.) 

[12]

Water needs for energy 

expand:

• Some expansion of 

oil shale/fossil fuel 

development 

• Some expansion of 

thermal solar 

development

• Existing requirements 

for renewable energy 

are applied

Decreases in water for 

energy based on 

reduced freshwater for 

cooling (e.g., dry 

cooling) or technology 

improvements:

• High technology 

adaptation

• Increased 

requirements for 

renewable as a 

percentage of 

energy portfolio, with 

emphasis on dry 

technologies

Increased water use 

for energy, including 

solar, oil shale, and 

nuclear:

• Low technology 

adaptation

• Economic drivers 

encouraging 

growth in energy 

production

Social and

governance

Changes in institutional 

and regulatory 

conditions (e.g. laws, 

regulations, etc.) [10]

No anticipated changes

in institutional and 

regulatory conditions

Same as Current 

Projected

Increased institutional 

and regulatory 

conditions

National climate 

change regulations 

implemented (related 

to greenhouse gas

management)

Changes in flowdependent ecosystem 

needs for Endangered 

Species Act (ESA)-listed 

species [13]

No change in currently 

realized ESA-listed 

species needs

Same as Current 

Projected

ESA flow targets for 

existing listed species 

are met and recovery 

is maintained

Changes in other flowdependent ecosystem 

needs [14]

No change in current 

planning and/or 

projections associated 

with ecosystem needs 

or practices

Same as Current 

Projected

Institutional 

agreements for 

ecological flows 

sufficient to ensure a 

resilient ecosystem (in 

timing, amount and 

location)

Changes in social 

values affecting water 

use [15]

Social values affecting 

water use are similar to 

recent past:

• Continue along 

current trend of 

increased 

conservation, 

increased support in 

parts of the Basin for 

meeting 

environmental flows

Societal focus on 

economic efficiency

Societal values result 

in greater flexibility of 

water use for multiple 

purposes:

• Acceptance of 

water recycling

• Social values 

affecting water use 

accelerate current 

trend of increased 

conservation

Changes in water 

availability due to tribal 

water use and 

settlement of tribal water 

rights claims [17]

Tribal water use 

continues as projected 

in settlements

Slower implementation 

of development within 

the settlements

Faster implementation 

of development within 

the settlements

• Additional tribal 

claims and 

settlements 

realized

1 Bracketed number reflects the number assigned to the 18 driving forces listed in Technical Report A – Scenario 

 Development.
Appendix C13

Parameters Assigned to Each Scenario

December 2012 C13-1 

Appendix C13 — Parameters Assigned to 

Each Scenario

In the spring of 2011, the Water Demand Sub-Team developed and refined the demand 

scenarios. As part of this process, each parameter was assigned a plausible range (e.g., 

population – low, medium, and high growth). Once these ranges were developed, using the 

storylines as a guide, the Water and Demand Sub-Team assigned appropriate parameter state for 

each scenario. Table C13-1 presents the final parameter state assigned to each scenario. 
Colorado River Basin 

Water Supply and Demand Study

C13-2 December 2012

TABLE C13-1 

Parameters Assigned to Each Scenario

General 

Driving 

Force 

Categories

Critical 

Uncertainties1

Scenario

Current Projected – 

Growth, development 

patterns, and 

institutions continue 

along recent trends

Slow Growth – 

Low growth with 

emphasis on 

economic 

efficiency

Rapid Growth – Economic 

resurgence (population and energy) 

and current preferences toward 

human and environmental values

Enhanced Environment– Expanded 

environmental awareness and 

stewardship with growing 

economy

A B 

C1

Slower 

technology 

adoption

C2

Rapid technology 

adoption and slight 

increase in social 

values

D1

Current 

growth 

trend

D2

Higher growth and 

technology

Demographic 

and land use

Changes in 

population and 

distribution [4] 

Best estimate of

population growth

Slow growth:

• Increase 

principally in 

existing urban 

areas

Rapid, expansive growth:

• Focused in urban centers and 

“sprawl” to traditionally non-urban 

areas (likely driven by economic 

growth) 

Same as 

Current 

Projected

Rapid, expansive 

growth: 

• Focused in urban 

centers and “sprawl”

to traditionally nonurban areas (likely 

driven by economic 

growth) 

Changes in 

agricultural land 

use (e.g., 

irrigated 

agricultural 

areas, crop 

mixes, etc.) [5]

Nominal increase in 

irrigated agricultural 

lands due to the buildout of currently planned 

agricultural supply 

projects:

• Varies from state to 

state, with some 

natural decreases 

also occurring 

Same as Current 

Projected

Slightly faster increase in irrigated 

agricultural lands (varies from state to 

state) due to the build-out of currently 

planned agricultural supply projects

Same as Current Projected

Technology 

and 

economics

Changes in 

agricultural 

water use 

efficiency [8]

Continued current trends 

in agricultural water use 

efficiency:

• Salinity control projects 

continue to be pursued

Decreased 

agricultural

efficiency resulting 

from aging 

infrastructure and 

minimal capital 

investment in 

repair/replacement

Decreased 

agricultural

efficiency resulting 

from aging 

infrastructure and 

minimal capital 

investment in 

repair/replacement

Externally driven 

increases in water

saving technology

Rapid adoption of 

new water saving 

technologies

Same as 

Current 

Projected

Externally driven 

increases in watersaving technology 

Rapid adoption of new 

water- saving 

technologies
Appendix C13 — Parameters Assigned to Each Scenario

December 2012 C13-3 

General 

Driving 

Force 

Categories

Critical 

Uncertainties1

Scenario

Current Projected – 

Growth, development 

patterns, and 

institutions continue 

along recent trends

Slow Growth – 

Low growth with 

emphasis on 

economic 

efficiency

Rapid Growth – Economic 

resurgence (population and energy) 

and current preferences toward 

human and environmental values

Enhanced Environment– Expanded 

environmental awareness and 

stewardship with growing 

economy

A B 

C1

Slower 

technology 

adoption

C2

Rapid technology 

adoption and slight 

increase in social 

values

D1

Current 

growth 

trend

D2

Higher growth and 

technology

Technology 

and 

economics, 

continued

Changes in 

municipal and 

industrial water 

use efficiency [9]

Water use efficiency is 

increasing according to 

current policy and 

technology:

• External factors limiting 

water use of 

appliances/fixtures 

(e.g., federal statutes 

dictating water use 

efficiency of fixtures)

• Policies in place 

affecting future—vary 

by municipality and 

state

M&I consumer 

efficiency continues 

according to current 

trends:

• Aging 

infrastructure 

could have 

effects on water 

efficiency

M&I consumer 

efficiency continues 

according to 

current trends:

• Aging 

infrastructure 

could have 

effects on water 

efficiency

Diversification of 

supply portfolios and 

increased costs 

leading to increased 

water use efficiency:

• Increased 

implementation of 

WaterSense, 

EnergyStar, 

efficient 

landscaping 

technology, etc.

Diversification of supply portfolios and 

increased costs, leading to increased 

water use efficiency:

• Increased implementation of 

WaterSense, EnergyStar, efficient 

landscaping technology, etc.

Changes in 

water needs for 

energy 

generation (e.g., 

solar, oil shale, 

thermal, nuclear, 

etc.) [12]

Water needs for energy 

expand:

• Some expansion of oil 

shale/fossil fuel 

development 

• Some expansion of 

Thermal Solar 

development

• Existing requirements 

for renewable energy 

are applied

Same as Current 

Projected

Increased water 

use for energy, 

including solar, oil 

shale, and nuclear:

• Low technology 

adaptation

• Economic 

drivers 

encouraging 

growth in energy 

production

Decreases in water 

for energy based on 

reduced freshwater 

for cooling (e.g., dry 

cooling) or 

technology 

improvements:

• High technology 

adaptation

• Increased 

requirements for 

renewable as a 

percentage of 

energy portfolio, 

with emphasis on 

dry technologies

Decreases in water for energy based on 

reduced freshwater for cooling (e.g., dry 

cooling) or technology improvements:

• High technology adaptation

• Increased requirements for 

renewable as a percent of energy 

portfolio, with emphasis on dry 

technologies
Colorado River Basin 

Water Supply and Demand Study

C13-4 December 2012

General 

Driving 

Force 

Categories

Critical 

Uncertainties1

Scenario

Current Projected – 

Growth, development 

patterns, and 

institutions continue 

along recent trends

Slow Growth – 

Low growth with 

emphasis on 

economic 

efficiency

Rapid Growth – Economic 

resurgence (population and energy) 

and current preferences toward 

human and environmental values

Enhanced Environment– Expanded 

environmental awareness and 

stewardship with growing 

economy

A B 

C1

Slower 

technology 

adoption

C2

Rapid technology 

adoption and slight 

increase in social 

values

D1

Current 

growth 

trend

D2

Higher growth and 

technology

Social and 

governance

Changes in 

institutional and 

regulatory 

conditions (e.g. 

laws, 

regulations, etc.) 

[10]

No anticipated change in 

regulations (2007 Interim 

Guidelines2 extended 

through 2060)

Same as Current 

Projected

Same as Current 

Projected

• Increased 

institutional and 

regulatory 

conditions

• National climate 

change 

regulations 

implemented, 

(related to 

greenhouse gas 

management)

• Increased institutional and regulatory 

conditions

• National climate change regulations 

implemented (related to greenhouse 

gas management)

Changes in flowdependent 

ecosystem 

needs for 

Endangered 

Species Act 

(ESA)-listed 

species [13]

No change in currently 

realized ESA-listed 

species needs

Same as Current 

Projected

Same as Current Projected ESA flow targets for existing listed 

species are met and recovery is 

maintained

Changes in 

other flowdependent 

ecosystem 

needs [14]

No change in current 

planning and/or 

projections associated 

with ecosystem needs or 

practices

Same as Current 

Projected

Same as Current Projected Institutional agreements for ecological 

flows sufficient to ensure a resilient 

ecosystem (in timing, amount and 

location)
Appendix C13 — Parameters Assigned to Each Scenario

December 2012 C13-5 

General 

Driving 

Force 

Categories

Critical 

Uncertainties1

Scenario

Current Projected – 

Growth, development 

patterns, and 

institutions continue 

along recent trends

Slow Growth – 

Low growth with 

emphasis on 

economic 

efficiency

Rapid Growth – Economic 

resurgence (population and energy) 

and current preferences toward 

human and environmental values

Enhanced Environment– Expanded 

environmental awareness and 

stewardship with growing 

economy

A B 

C1

Slower 

technology 

adoption

C2

Rapid technology 

adoption and slight 

increase in social 

values

D1

Current 

growth 

trend

D2

Higher growth and 

technology

Social and 

governance, 

continued

Changes in 

social values 

affecting water 

use [15]

Social values affecting 

water use are similar to 

recent past:

• Continue along current 

trend of increased 

conservation, 

increased support in 

parts of the Basin for 

meeting environmental 

flows

Societal focus on 

economic efficiency

Same as Current 

Projected

Societal values 

result in greater 

flexibility of water 

use for multiple 

purposes:

• Acceptance of 

water recycling

• Social values 

affecting water 

use accelerate 

current trend of 

increased 

conservation

Societal values result in greater 

flexibility of water use for multiple 

purposes:

• Acceptance of water recycling

• Social values affecting water use 

accelerate current trend of increased 

conservation

• Increased support for meeting 

environmental flows 

• Tourism economy booms creating 

more demand for in-stream flows

Changes in 

water availability 

due to tribal 

water use and 

settlement of 

tribal water 

rights claims [17]

Tribal water use continues 

as projected in 

settlements

Slower 

implementation of 

development within 

the settlements

• Faster implementation of development 

within the settlements

• Additional tribal claims and settlements 

realized

Same as 

Current 

Projected

• Faster implementation 

of development within 

the settlements

• Additional tribal claims 

and settlements 

realized

1 Bracketed column reflects the number assigned to the 18 driving forces listed in Technical Report A – Scenario Development, table A-1.

2 U.S. Department of the Interior. 2007. Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake 

Mead. 
Appendix C14

Water Demand Scenario Storylines

December 2012 C14-1 

Appendix C14 — Water Demand

Scenario Storylines

The scenario narratives, or storylines, are described in this appendix, and are organized by the 

general driving force categories (Demographics and Land Use, Technology and Economics, and 

Social and Governance) and by specific parameters. The characteristics of each parameter are 

briefly described. During quantification, these descriptions were refined to maintain consistency 

and provide coherent descriptions of each scenario. 

1.0 Storyline for the Current Projected (A) Scenario

1.1 Demographics and Land Use

Population1 – Populations in the Colorado River Basin (Basin), the adjacent areas, and the 

southwestern United States grow at rates commensurate with the “best estimate” demographic 

projections. Population growth generally occurs centered in existing urban areas. 

Agricultural Land Use – There are decreases in irrigated agricultural lands due to conversion of 

agricultural land use to urban land use and lower-economic value crops being phased out in some 

areas. Agricultural land use reductions vary by location, with some increases in acreage due to 

build-out of currently planned agricultural water supply projects. 

1.2 Technological and Economics

Agricultural Water Use Efficiency – Current trends in agricultural water use efficiency 

continue making modest improvements to on-farm and system efficiency through projects such 

as those supported under the Salinity Control Program. These improvements result in minimal

change to Basin consumptive use. No radical changes in technology are anticipated. Agricultural 

uses are generally consistent with today’s practices (for example, no major changes in 

techniques, crops, or practices). 

Municipal and Industrial (M&I) Water Use Efficiency – Water use efficiency increases 

according to current Basin water provider policies (for example, Southern Nevada Water 

Authority’s [SNWA’s] current gallons per capita per day [gpcd] planning goals) and technology. 

External factors beyond the control of Basin water providers that limit the water use of fixtures 

and appliances (for example, federal statutes) continue, resulting in “natural” increases in inhome efficiency. Water use efficiency changes vary by location according to local goals and mix 

of water use categories. No radical changes in technology are anticipated.

Water Needs for Energy – Water needs for energy expand relative to population growth and 

current regulations, policies, and planning for the energy industry. Current requirements for 

renewables are met according to current schedules. Fossil fuel development, and in particular, oil 

shale development, occurs according to current plans. No dramatic changes to global economies 

 1 Population estimates for each state correspond with different reference points based on state, local information, and 

 planning, and consider long-term trends to represent “best estimate” projections.
Colorado River Basin 

Water Supply and Demand Study

C14-2 December 2012

or energy demand that would spur additional consideration occur (for example, increased fossil 

fuel prices).

1.3 Social and Governance

Institutional and Regulatory – Federal and state laws and regulations affecting the Basin 

continue in a similar manner as today. Despite the potential for sunsetting of future regulations 

and agreements, the operations of the Colorado River are relatively unchanged. 

Flow-dependent Endangered Species Act (ESA) Needs – There is no expansion of the federal 

endangered species program, change to the needs of currently listed ESA species, or updates of 

existing Biological Opinions. Operations for ESA needs continue according to recent practices, 

agreements, and regulations. 

Flow-dependent non-ESA Needs – No change is anticipated in currently realized ecosystem 

needs or operational practices to meet needs. Operations to meet ecosystem needs continue 

according to recent practices.

Social Values – Social values that affect water use in all categories remain consistent with the 

recent past. These values include continued support for ongoing, planned M&I and agricultural 

conservation efforts as well as support for the ESA and its implementation. 

Tribal Use – Tribal use develops according to quantified rights and current use patterns. 

2.0 Storyline for the Slow Growth (B) Scenario

2.1 Demographics and Land Use

Population – Populations continue to grow primarily in urban centers, but at slower rates than 

the current projected scenario. Population growth is consistent with moderate to low economic 

growth, followed by economic and subsequent population growth that is less robust than that of 

the recent past. 

Agricultural Land Use – There are decreases in irrigated agricultural lands due to conversion of 

agricultural land use to urban land use and lower-economic value crops being phased out in some 

areas. Agricultural land use reductions vary by location, with some increases in acreage due to 

build-out of currently planned agricultural water supply projects. 

2.2 Technological and Economics

Agricultural Water Use Efficiency – Lack of economic growth results in decreased revenues 

and reduced capital investment for routine and long-term maintenance. Reduced maintenance 

results in an overall decline in on-farm and delivery efficiency. These efficiency reductions 

require greater diversions to meet consumptive use requirements. However, Basin consumption 

changes little as additional losses are returned to the Colorado River system. 

M&I Water Use Efficiency – Water use efficiency increases according to current policies (for 

example, SNWA’s current gpcd planning goals) and technology. External factors that limit the 

water use of fixtures and appliances (for example, federal statutes) continue, resulting in 

“natural” increases in in-home efficiency. Water use efficiency changes vary by location 

according to local goals and mix of water use categories. No radical changes in technology are 
Appendix C14 — Water Demand

Scenario Storylines 

December 2012 C14-3 

anticipated. Aging infrastructure and lack of capital investment due to slow growth result in 

some acute water loss events. However, these events are generally absorbed by the long-term 

natural trends toward greater efficiency.

Water Needs for Energy – Water needs for energy expand relative to population growth and 

current regulations, policies, and planning for the energy industry. Current requirements for 

renewables are met according to current schedules. Despite the regional slow growth, global 

energy demand, and in particular, fossil fuel development (including oil shale development), 

occurs according to current plans. No dramatic changes to global economies or energy demand 

that would spur additional consideration occur (for example, increased fossil fuel prices). 

2.3 Social and Governance

Institutional and Regulatory – Slow growth and focus on economic efficiency lead to no 

significant change in institutional and regulatory requirements. Existing federal and state laws 

and regulations affecting the Basin continue. 

Flow-dependent ESA Needs – No change is anticipated in currently realized ecosystem needs 

or operational practices to meet needs. Operations to meet ecosystem needs continue according 

to recent practices.

Flow-dependent non-ESA Needs – No change is anticipated in currently realized ecosystem 

needs or operational practices to meet needs. Operations for ecosystem needs continue according 

to recent practices.

Social Values – Economic efficiency is the overwhelming driver affecting social values. Social 

values that affect water use in all categories trend toward preferences for human water use and 

systems over other concerns. This focus is driven largely by a lack of funds for capital outlay and 

a lack of societal willingness to take on new programs.

Tribal Use – Tribal use continues to develop, but at slower than planned rates. 

3.0 Storyline for the Rapid Growth (C1 and C2) Scenarios 

This storyline includes two branches: (C1) slower technology adoption, and (C2) rapid 

technology adoption and slight increase in social values. 

3.1 Demographics and Land Use

Population – Rapid population growth, focused around urban centers with sprawl to outlying 

areas, is driven by prolonged growth following patterns of recent history. This population growth 

is similar to typical “high” demographic projections for the Southwest.

Agricultural Land Use – Agricultural land use decreases at a slightly faster rate than the 

Current Projected (A) scenario, primarily because of economic growth resulting in an increased 

rate of urbanization. Agricultural land use reductions vary by location, with some increases due 

to development of currently planned projects. 
Colorado River Basin 

Water Supply and Demand Study

C14-4 December 2012

3.2 Technological and Economics

Agricultural Water Use Efficiency – (C1) Lack of economic growth in the agricultural sector 

results in decreased revenues and reduced capital investment for routine and long-term 

maintenance. Reduced maintenance results in an overall decline in on-farm and delivery 

efficiency. These efficiency reductions require greater diversions to meet consumptive use 

requirements. However, Basin consumption changes little as additional losses are returned to the 

Colorado River system. 

(C2) Economic conditions result in investment and rapid adoption of new technologies, resulting 

in significant increases in agricultural water use efficiency. These technologies result in denser 

cropping patterns and higher yields, with subsequent greater overall consumptive use demand. 

Irrigation techniques and delivery system water control are significantly improved over those in 

the Current Projected (A) scenario. Gains in distribution efficiency partially offset the increased 

consumptive use. 

M&I Water Use Efficiency – (C1) Water use efficiency increases according to current policies 

(for example, SNWA’s current gpcd planning goals) and technology. External factors that limit 

the water use of fixtures and appliances (for example, federal statutes) continue, resulting in 

“natural” increases in in-home efficiency. Water use efficiency changes vary by location 

according to local goals and mix of water use categories. No radical changes in technology are 

anticipated. 

(C2) Increased federal investment in water-saving technology and conservation programs results 

in a substantive increase in water-saving technology (for example, WaterSmart, EnergyStar, and 

landscape technology). These technologies are applied Basin-wide, resulting in reduced demand 

and consumptive use. 

Water Needs for Energy – (C1) Water needs for energy expand relative to population growth 

and current regulations, policies, and planning for the energy industry. Current requirements for 

renewables are met according to schedules. Fossil fuel development, and in particular, oil shale 

development, occurs at a faster rate due to economic drivers spurring growth in energy 

production. 

(C2) Water needs for energy expand relative to population growth and current regulations, 

policies, and planning for the energy industry. However, investment in technology results in 

adoption of water-saving techniques (for example, dry cooling). Renewable energy requirements 

continue, with an emphasis on dry cooling due to an increase in social considerations related to 

carbon production. Economic conditions do not favor new fossil fuel development in the 

Southwest. 

3.3 Social and Governance

Institutional and Regulatory – (C1) Federal and state laws and regulations affecting the Basin 

continue in a similar manner as today. Despite the potential for sunsetting of future regulations 

and agreements, the operations of the Colorado River are relatively unchanged. 

(C2) Changing social values lead to increased governmental regulation, including the enactment 

of climate change and greenhouse gas mitigation measures. These measures primarily manifest 

themselves in more-integrated management of water and energy (water use efficiency). 
Appendix C14 — Water Demand

Scenario Storylines 

December 2012 C14-5 

Flow-dependent ESA Needs – No change is anticipated in currently realized ecosystem needs 

or operational practices to meet needs. Operations to meet ecosystem needs continue according 

to recent practices. 

Flow-dependent non-ESA Needs – No change is anticipated in currently realized ecosystem 

needs or operational practices to meet needs. Operations for ecosystem needs continue according 

to recent practices.

Social Values – (C1) Social values that affect water use in all categories remain consistent with 

the recent past. These values include continued support for ongoing planned M&I and 

agricultural conservation efforts as well as support for the ESA and its implementation. 

(C2) A slight increase in social values and subsequent pressure focused on conservation efforts 

results in management of the Basin, with increased flexibility for multiple water uses (for 

example, recreational). Trends continue toward M&I conservation adoption. 

Tribal Use – Tribal use and development occur faster than currently planned. In addition, new 

tribal claims and settlements are realized.

4.0 Storyline for the Enhanced Environment Scenarios (D1 

and D2)

This storyline includes two branches: (D1) current projected growth, and (D2) rapid growth and 

technology. 

4.1 Demographics and Land Use

Population – (D1) Populations in the Basin, the adjacent water-dependent basins, and the 

southwestern United States grow at rates commensurate with the best estimate demographic 

projections. Population growth generally occurs centered in existing urban areas. 

(D2) Rapid population growth focused around urban centers is driven by prolonged economic 

growth following patterns of recent history. This population growth is similar to typical “high” 

demographic projections for the Southwest. 

Agricultural Land Use – There are nominal increases in irrigated agricultural lands, primarily 

due to the build-out of currently planned agricultural water supply projects. Agricultural land use 

growth varies by location, with some conversion of agricultural land to urban land and lowereconomic value crops being phased out in some areas. 

4.2 Technological and Economics

Agricultural Water Use Efficiency – (D1) Current trends in agricultural water use efficiency 

continue making modest improvements to on-farm and system efficiency through projects such 

as those supported under the Salinity Control Program. These improvements result in little 

change to Basin consumptive use. No radical changes in technology are anticipated. Agricultural 

uses are generally consistent with today’s practices (for example, no major changes in 

techniques, crops, or practices). 

(D2) Economic conditions result in investment and rapid adoption of new technologies, resulting 

in significant increases in agricultural water use efficiency. These technologies result in denser 
Colorado River Basin 

Water Supply and Demand Study

C14-6 December 2012

cropping patterns and higher yields with subsequent greater overall consumptive use demand. 

Irrigation techniques and delivery system water control are significantly improved over those in 

the Current Projected (A) scenario. Gains in distribution efficiency partially offset the increased 

consumptive use. 

M&I Water Use Efficiency – Increased federal investment in water-saving technology and 

conservation programs results in a substantive increase in water-saving technology (for example, 

WaterSmart, EnergyStar, and landscape technology). These technologies are applied Basin-wide, 

resulting in reduced demand and consumptive use. 

Water Needs for Energy – Water needs for energy expand relative to population growth and 

current regulations, policies, and planning for the energy industry. However, investment in 

technology results in adoption of water-saving techniques (for example, dry cooling). Renewable 

energy requirements continue, with an emphasis on dry cooling due to an increase in social 

considerations related to carbon production. Economic conditions do not favor new fossil fuel 

development in the Southwest. 

4.3 Social and Governance

Institutional and Regulatory – Changing social values lead to increased governmental 

regulation, including the enactment of climate change and greenhouse gas mitigation measures. 

These measures primarily manifest themselves in more-integrated management of water and 

energy (water use efficiency). 

Flow-dependent ESA Needs – ESA flow targets for existing listed species are met and recovery 

of the species is maintained.

Flow-dependent non-ESA Needs – Increased social values lead to institutional agreements for 

ecological flows sufficient to support a healthy river system (in timing, amount, and location). 

Social Values – Increase in social values and subsequent pressure focused on conservation 

efforts results in management of the Basin with increased flexibility for multiple water uses (for 

example, recreational). Trends continue toward M&I conservation adoption and public demand 

for in-stream flows (for example, tourism and Wild and Scenic Rivers).

Tribal Use – (D1) Tribal use develops according to quantified rights and current use patterns. 

(D2) Tribal use and development occur faster than currently planned. In addition, new tribal 

claims and settlements are realized.
Appendix C15

Climate Change Effects on 

Water Demand and Losses

December 2012 C15-1 

Appendix C15 ─ Climate Change Effects on 

Water Demand and Losses

1.0 Introduction

The purpose of the Colorado River Basin Water Supply and Demand Study (Study) is to conduct 

a comprehensive study to define current and future imbalances in water supply and demand in 

the Colorado River Basin (Basin) and the adjacent areas of the seven Colorado River Basin 

States (Basin States) that receive Colorado River water over the next 50 years, and to develop

and analyze adaptation and mitigation strategies to resolve those imbalances. One of the potential 

influences that is explored is impact to water supply and demand related to changes in climate 

and meteorological inputs to the Basin. This appendix compares the approaches to and results of 

adjusting demands and losses to reflect projected changes in future climate. The potential effects 

of climate change on future water supply are described in Technical Report B – Water Supply 

Assessment. 

2.0 Background 

This section summarizes relevant previous work that evaluated the effect of climate change on 

potential evapotranspiration (PET), compares methods for estimating PET, and describes how 

results may differ among the methods examined. 

As summarized in Bormann (2011), approaches used to compute PET include those based on 

aerodynamic concepts, temperature-based approaches, radiation-based approaches, and 

combination equations, including resistance-type approaches. In general, the methods can be 

divided into empirical and physically based methods. Empirical methods (for example, BlaneyCriddle method [Stephens and Stewart, circa 1960]) relate complex evaporation and transpiration 

processes into an equation based on crop type and temperature. Physically based methods (for 

example, Penman-Monteith method [Monteith, 1965]) calculate PET based on a more explicit 

physical process, but are data-intensive as well as data-sensitive. PET estimates can vary widely 

among the various methods, but the Penman-Monteith method has been shown to estimate actual 

PET most accurately when compared to lysimeter and field studies (American Society of Civil 

Engineers [ASCE], 2005; Jensen et al., 1990; and Hill et al., 1983). 

Researchers suggest that different PET methods produce different results under similar climate 

change assumptions (McKenney and Rosenberg, 1993; Kingston et al., 2009; Bormann, 2011). 

For example, Kingston et al. (2009) investigated the global response of six different PET 

methods: 1) Penman-Monteith, 2) Hamon, 3) Hargreaves, 4) Priestley-Taylor, 5) Blaney-Criddle, 

and 6) Jensen-Haise, to a 2-degree Celsius rise in global mean temperature. They observed that 

all PET methods applied in the study indicate increases in PET due to assumed climate warming; 

however, the methods’ resultant estimates of PET change varied by more than 100 percent. 

Another study by Yates and Strzepek (1994) compared results of different PET methods for four 

river basins: the Blue Nile River basin of Africa; the Vistula River basin in Poland; the East 

River, a tributary of the Colorado River in the United States; and the Mulberry River, a tributary 
Colorado River Basin 

Water Supply and Demand Study

C15-2 December 2012

of the Arkansas River in the United States. PET methods evaluated included physically based 

(Penman-Monteith, Priestly-Taylor) and empirical (Hargreaves, Thonthwaite, Blaney-Criddle) 

methods. On average, these methods resulted in about a 3 to 8 percent increase in PET per 

degree Celsius warming. The authors found that the Penman-based methods are on average the 

least sensitive to warming, but have the greatest amount of variability. In contrast, they observe a 

range of variability, but with less climate sensitivity in the empirical methods (Hargreaves, 

Thonthwaite, and Blaney-Criddle). Although different results are found under the same climate 

scenarios for a given basin, the authors argue that it is difficult to draw definitive conclusions 

between the empirical and physical methods because different climatological regions show 

different trends. 

2.1 PET Methods Used Historically in Reclamation Colorado River Studies

Reclamation has historically used an empirically based approach, the Blaney-Criddle or modified 

Blaney-Criddle method, for calculating consumptive uses and losses in the Basin. To estimate 

streamflow changes under future projected climate, Reclamation uses the Variable Infiltration 

Capacity (VIC) hydrologic model to calculate runoff in the Basin. The VIC model incorporates 

the Penman-Monteith method for estimating potential and actual evapotranspiration in runoff 

calculations. The VIC hydrologic modeling was used to support the water supply analysis for the 

Study (see Technical Report B – Water Supply Assessment). 

3.0 Selection of PET Method for Application to 

Basin Demands

This section summarizes the process used to select an appropriate PET method for application to 

Basin demands in the Study. Parameter and demand estimates were provided by the Basin States 

and were generally derived from the states’ planning processes, or in some cases, planning of 

individual water agencies, such as the Southern Nevada Water Authority and Metropolitan Water 

District of Southern California. The Basin States have developed their demands through 2060 

without consideration of future climate change. However, it was assumed that demands through 

2010 reflect the effects of climate change through 2010. This appendix presents an approach to 

scale these demands for future climate realizations that are developed as a part of the Study. 

This section first provides a comparison of VIC-simulated PET to observed PET at selected 

locations, then compares the PET sensitivity to warming considering Penman-Monteith methods 

(embedded in VIC and in an external program) and three other PET methods (Blaney-Criddle, 

Hargreaves, and Priestley-Taylor, and last describes the selected method for incorporating the 

effects of climate change on agricultural demand, outdoor urban demand, phreatophyte use, and 

reservoir evaporation. 

3.1 Evaluations of VIC-simulated PET to Observed PET

To compare VIC-simulated PET with measured station data, historical observed meteorology for 

one location was simulated using the VIC model. Figure C15-1 compares PET measured at the 

California Irrigation Management Information System (CIMIS) station and VIC-simulated PET

under historical observed meteorology (Maurer et al., 2002). CIMIS PET data are taken from a 

station at Calipatria/Mulberry (CIMIS station #41) in the Imperial Valley, California (black color 

curve in figure C15-1). The VIC-simulated PET values are taken from the nearest VIC grid cell 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-3 

(blue color curve in figure C15-1). The PET values have been averaged for the period 1984 to 

1999, which represents the historical overlapping period. 

FIGURE C15-1 

Comparison of Observed PET and Simulated PET for the Calipatria/Mulberry 

Station (CIMIS station #41) in California’s Imperial Valley

The results indicate a reasonable comparison for most of the year, but an overestimation by the 

VIC model in the summer months. However, the comparison may have some discrepancies due 

to the following: (1) the CIMIS PET calculation is based on the CIMIS Penman-Monteith

equation (a modified version) but the PET implementation in VIC is based on Penman-Monteith; 

(2) the CIMIS PET data represent the PET for a specific location, but VIC values are 

representative for a grid cell with an area of approximately 144 square kilometers, such that sitespecific conditions are averaged; and (3) there could be potential differences between the 

historical meteorology data applied in the VIC simulations and the measured meteorology at the 

CIMIS station. Detailed validation or recalibration for site-specific conditions has not been 

conducted in the Study.

3.2 Comparison of VIC-simulated PET Changes under Climate Warming to 

Other Methods

To investigate the difference in PET change due to PET calculation methodology, PET was 

calculated using five different methods for a 1-degree Celsius increase in daily average warming.

VIC-simulated PET was compared to four other PET calculation methods implemented in an 

external program, REF-ET (Reference Evapotranspiration Calculator, Version – Windows 3.1, 

July 2011, available at http://www.kimberly.uidaho.edu/ref-et/). The REF-ET program is 

considered one of the most robust applications for PET estimation. For the purpose of comparison, 

the reference crop was fixed to short grass for all applicable methods. The five PET methods are 

presented in tables C15-1 and C15-2. Table C15-1 provides the method, reference, and type, 

ranging from temperature-based to energy and aerodynamic processes. Table C15-2 shows the 

general data requirements for the selected PET methods. 
Colorado River Basin 

Water Supply and Demand Study

C15-4 December 2012

TABLE C15-1 

Approaches Used for Estimation of PET Sensitivity

PET Method Reference Method Type

VIC-ET PenmanMonteith Penman-Monteith Implemented in VIC (Allen et al., 

1998; Liang et al., 1996 and 1994)

Combinations of energy and 

aerodynamic process

REF-ET PenmanMonteithFAO56 Penman-Monteith for 0.12 m grass ET with rs = 

70 s/m (Allen et al., 1998)1 Energy-based 

REF-ET BlaneyCriddle FAO-ID-24 Blaney-Criddle (Doorenbos and Pruitt, 1977) Temperature-based 

REF-ET 

Hargreaves 

1985 Hargreaves (Hargreaves and Samani, 1985) Temperature-based 

REF ET PriestleyTaylor Priestley-Taylor (Priestley and Taylor, 1972) Radiation-based 

1

In 2005, ASCE and the Irrigation Association formally adopted a new standard for reference PET estimation based on a 

parameterization of the Penman-Monteith equation (ASCE, 2005), called the ASCE Standardized Penman-Monteith equation. 

ASCE Penman-Monteith Standardized Form is identical to the FAO56 Penman-Monteith for a grass reference.

TABLE C15-2 

Data Requirements for the Selected Formulae for PET, Modified from McKenney and Rosenberg (1993)

PET Method Temperature

Solar 

Radiation/Net 

Radiation Humidity

Wind 

Speed

Latitude/

day-length

Plant 

Physiological 

Characteristics

VIC-ET PenmanMonteith X X X X X 

REF-ET PenmanMonteithX X X X X 

REF-ET BlaneyCriddle X X 

REF-ET Hargreaves X X X 

REF ET 

Priestley-Taylor 

X X 

Tables C15-3 and C15-4 show the results comparing the temperature sensitivity of PET using 

PET computed from VIC and PET computed using the four different methods noted in 

table C15-1 and implemented in REF-ET under a 1-degree Celsius warming in daily average 

temperature. The locations included in tables C15-3 and C15-4 represent selected VIC model

grid cells for each state planning area within the Study Area. 

Figures C15-2 and C15-3 show the selected VIC grid locations for each of the planning areas. 

The agricultural grid cells were selected based on the following: density of agricultural lands, 

location of long-term evapotranspiration measurement stations, and location outside of federally

managed lands (figure C15-2). For municipal and industrial (M&I) demands, the grid cells were 

selected to be near the city with highest population or approximately in the center of urban 

clusters (figure C15-3). 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-5 

FIGURE C15-2 

Selected VIC Grid Cells for Agricultural Regions for Each of the Planning Areas (dotted area represents irrigated land)

Temperature sensitivity of PET (change in PET per degree of warming), presented in tables 

C15-3 and C15-4, was computed over the period 1950 to 1999. Daily gridded meteorological 

observations of maximum daily temperature, minimum temperature, and wind speed were 

obtained from the Surface Water Modeling Group at the University of Washington 

(http://www.hydro.washington.edu; Maurer et al., 2002). In the REF-ET program, maximum, 

minimum and average daily temperatures, average daily wind speed, net radiation, relative 

humidity, and vapor pressure were supplied as input. Net radiation, relative humidity, and vapor 

pressure are estimated in VIC based on daily maximum temperature, minimum temperature, and 

temperature range based on empirical relationships (Maurer et al., 2002). 

REF-ET computes average daily dew point and daily solar radiation using empirical equations. 

Standard values for grass height and surface resistances are used in the REF-ET (grass reference 

height is 0.12 meter [m] and grass surface resistance for the above grass height is 70 seconds per 

meter [s/m]).
Colorado River Basin 

Water Supply and Demand Study

C15-6 December 2012

FIGURE C15-3 

Selected VIC Grid Cells for Urban Regions for Each of the Planning Areas

Circles represent population centers.

As can be seen in tables C15-3 and C15-4, there is considerable spatial variation in PET 

sensitivity across the Study Area. The average PET sensitivity computed from the locations 

considered for agricultural locations are 2.2, 2.5, 5.7, 3.3, and 2.0 percent using the methods 

VIC-ET Penman-Monteith, REF-ET Penman-Monteith, REF-ET Blaney-Criddle, REF-ET 

Hargreaves, and REF ET Priestley-Taylor, respectively. The values computed by these methods

for the locations considered for urban regions are 2.2, 2.4, 5.4, 3.2, and 1.7 percent, respectively. 

The VIC-simulated PET suggests a lower sensitivity than that reported under the Blaney-Criddle 

estimates (Reclamation, 2011) (see also tables C15-3 and C15-4). However, the VIC- simulated 

PET compares reasonably well to PET simulated under the REF-ET program using the PenmanMonteith method. At high elevations (generally above 1,800 m), the VIC-simulated PET shows 

lesser sensitivity (figure C15-4) than other methods. Specifically, the PET sensitivity computed 

using the VIC model shows slightly higher sensitivity at the lower elevations (arid locations), but 

lower sensitivity at the higher elevations (energy-limited locations) compared to the REF-ET 

implemented Penman-Monteith application. Because both models use the standard 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-7 

Penman-Monteith equation, it appears that the differences in PET sensitivity are due to 

parameterization of meteorological inputs. 

TABLE C15-3 

PET Method Sensitivity for Agricultural Demands

PET Sensitivity due to 1-degree Celsius warming computed using VIC and four different PET methods implemented in the REFET program for the locations considered to adjust agricultural demands. 

State Planning Area Latitude Longitude1 Elevation (m) 

PET Sensitivity (%)

VIC 

PM 

REFET 

PM 

REFET 

BC

REFET 

Harg

REF 

ET 

PrsTylr

CO Colorado RiverCisco UT 39.1875 -108.8125 1451 2.2 2.4 5.6 3.3 2.0

CO Dolores RiverCisco 38.1875 -108.3125 2117 2.0 3.0 6.8 3.7 2.9

CO San Juan-Bluff 37.4375 -108.6875 1988 1.9 2.9 6.0 3.4 2.8

CO White RiverWatson 39.8125 -108.3125 2051 2.0 3.3 7.7 3.9 3.4

CO Yampa Maybell 40.4375 -106.9375 2145 1.8 3.8 8.8 4.1 4.5

CO Gunnison RiverGrand Junction 38.6875 -108.0625 1576 2.2 2.3 5.5 3.3 2.2

CO South Platte 39.6875 -105.0625 1655 2.6 2.7 5.5 3.3 2.0

CO Arkansas 38.3125 -104.6875 1505 2.8 2.5 5.1 3.2 1.5

NM San Juan 36.8125 -108.1875 1736 2.2 2.3 5.3 3.3 1.7

NM Adjacent Areas 35.0625 -106.5625 1633 2.5 2.2 4.6 3.0 1.3

NM Southwest 32.9375 -108.5625 1455 2.4 2.2 4.6 3.1 1.4

NM Northwest 35.0625 -108.5625 2157 2.2 2.6 6.1 3.6 2.2

UT Southeast 

Colorado River 37.8125 -109.3125 2064 1.9 3.0 6.5 3.6 2.9

UT West Colorado 

River 39.0625 -111.0625 1801 2.4 2.5 5.9 3.4 1.8

UT Kanab Creek-Virgin 

River 37.1875 -113.5625 1185 2.0 1.9 4.4 2.9 1.2

UT Uintah Basin 40.3125 -110.0625 1636 2.4 2.4 6.3 3.5 1.7

UT Wasatch Front 40.6875 -112.0625 1398 2.0 2.5 5.4 3.2 2.1

WY Green River to 

Greendale 41.3125 -110.4375 2125 2.3 3.2 7.8 3.9 3.0

WY Wyoming Uses on 

the Little Snake 41.1875 -107.5625 2104 2.3 3.3 8.1 3.9 3.0

WY Green River above 

Fontenelle 42.9375 -109.9375 2255 2.6 3.7 10.8 4.4 3.8

WY Fontenelle to 

Green River 42.0625 -109.4375 2013 2.7 3.0 8.7 4.0 2.4

WY North Platte 41.1875 -106.4375 2535 1.7 4.3 10.3 4.4 5.1
Colorado River Basin 

Water Supply and Demand Study

C15-8 December 2012

State Planning Area Latitude Longitude1 Elevation 

(m) 

PET Sensitivity (%)

VIC 

PM 

REFET 

PM 

REFET 

BC

REFET 

Harg

REF 

ET 

PrsTylr

AZ Central Arizona 33.5625 -112.4375 372 2.0 1.6 3.4 2.5 0.7

AZ Mainstem 32.6875 -114.6875 45 2.1 1.6 3.2 2.5 0.6

AZ Central Yavapai 

Highlands 34.8125 -112.4375 1410 2.1 2.1 4.8 3.1 1.5

AZ Upper San Pedro 

River 31.5625 -110.1875 1291 2.2 1.8 3.9 2.8 1.1

AZ North Central 35.6875 -112.0625 1921 1.8 2.6 5.6 3.3 2.4

CA IID 33.0625 -115.4375 -32 2.0 1.6 3.0 2.4 0.6

CA CVWD 33.8125 -116.4375 149 2.1 1.6 3.2 2.5 0.6

CA MWD 34.1875 -118.4375 241 2.8 2.2 3.9 2.8 1.0

CA Mainstem 33.1875 -114.8125 270 2.0 1.6 3.3 2.5 0.6

CA PVID 33.5625 -114.6875 90 2.0 1.5 3.2 2.4 0.6

NV SNWA 36.1875 -115.1875 655 2.1 1.7 3.7 2.6 0.7

NV Other 35.1875 -114.6875 744 2.1 1.7 3.7 2.6 0.7

Average 2.2 2.5 5.6 3.2 1.9

Max 2.8 4.3 10.8 4.4 5.1

Min 1.7 1.5 3.0 2.4 0.6

1 Longitude values are negative west of the prime meridian.

PM – Penman-Monteith

BC – Blaney-Criddle

Harg – Hargreaves

Prs-Tylr – Priestley-Taylor

The Blaney-Criddle method produced the highest PET sensitivity to climate warming (greatest 

increase in PET per degree of warming) compared to the other methods. The Penman-Monteith 

method is a physically based method and is more likely to capture the dynamic responses of PET 

under meteorological changes. It was found that the Penman-Monteith method produced changes 

in PET of approximately 2 to 3 percent per degree Celsius warming. This sensitivity was greater 

than that estimated under the Priestly-Taylor method and less than that under the Hargreaves 

method, but results were generally within 1 percentage point of these two methods. Conversely, 

the Blaney-Criddle method, when simulated under identical meteorological conditions, suggests 

a change of almost double that in the other methods. 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-9 

TABLE C15-4 

PET Method Sensitivity for Urban Demands

PET sensitivity due to 1-degree Celsius Warming Computed using VIC and four different PET methods implemented in the REFET Program for the locations considered to adjust urban demands.

State Planning Area Latitude Longitude1 Elevation 

(m) 

PET Sensitivity (%)

VIC 

PM 

REFET 

PM 

REFET 

BC

REFET 

Harg

REF 

ET 

PrsTylr

CO Colorado RiverCisco UT 39.0625 -108.5625 1449 2.2 2.2 5.2 3.1 1.6

CO Dolores RiverCisco 38.6875 -108.9375 1760 2.1 2.5 5.8 3.4 2.1

CO San Juan-Bluff 37.3125 -107.8125 2303 1.5 3.3 7.2 3.8 3.4

CO White RiverWatson 40.0625 -107.9375 2025 2.0 3.2 7.3 3.8 3.2

CO Yampa Maybell 40.4375 -107.0625 2121 1.7 3.6 8.3 4.0 3.9

CO Gunnison RiverGrand Junction 38.4375 -107.8125 1898 2.2 2.6 6.1 3.5 2.2

CO South Platte 39.6875 -104.8125 1692 2.6 2.7 5.6 3.3 1.9

CO Arkansas 38.8125 -104.8125 1879 2.9 2.8 5.9 3.5 2.0

NM San Juan 36.8125 -108.1875 1736 2.2 2.3 5.3 3.3 1.7

NM Adjacent Areas 35.0625 -106.6875 1532 2.5 2.2 4.5 3.0 1.2

NM Southwest 32.9375 -108.8125 1856 2.5 2.4 5.4 3.4 1.7

NM Northwest 34.9375 -108.8125 2138 2.3 2.6 6.1 3.5 2.2

UT Southeast 

Colorado River 38.5625 -109.5625 1385 2.1 2.1 5.0 3.1 1.4

UT West Colorado 

River 39.5625 -110.8125 1717 2.2 2.5 5.7 3.3 2.0

UT Kanab CreekVirgin River 37.1875 -113.4375 1074 2.0 1.9 4.3 2.9 1.1

UT Uintah Basin 40.4375 -109.5625 1703 2.4 2.6 6.7 3.6 2.0

UT Wasatch Front 40.6875 -112.0625 1398 2.0 2.5 5.4 3.2 2.1

WY Green River to 

Greendale 41.5625 -109.1875 1996 2.4 2.9 7.2 3.7 2.5

WY

Wyoming Uses 

on the Little 

Snake

41.3125 -107.6875 2026 2.5 3.0 7.7 3.8 2.7

WY Green River 

above Fontenelle 42.6875 -109.6875 2165 2.6 3.5 10.1 4.3 3.3

WY Fontenelle to 

Green River 41.9375 -109.4375 2049 2.6 3.0 8.3 4.0 2.4

WY North Platte 41.1875 -104.8125 1879 2.9 2.9 6.6 3.6 2.1

AZ Central Arizona 33.5625 -112.0625 415 2.1 1.6 3.4 2.5 0.8
Colorado River Basin 

Water Supply and Demand Study

C15-10 December 2012

State Planning Area Latitude Longitude1 Elevation 

(m) 

PET Sensitivity (%)

VIC 

PM 

REFET 

PM 

REFET 

BC

REFET 

Harg

REF 

ET 

PrsTylr

AZ Mainstem 32.6875 -114.5625 55 2.0 1.6 3.2 2.4 0.6

AZ Central Yavapai 

Highlands 34.6875 -111.9375 1048 2.0 1.8 4.1 2.8 1.1

AZ Upper San Pedro 

River 31.5625 -110.3125 1435 2.2 1.9 4.2 2.9 1.2

AZ North Central 35.1875 -111.4375 1966 2.0 2.6 6.2 3.5 2.3

CA IID 32.8125 -115.5625 -17 2.1 1.7 3.2 2.5 0.6

CA CVWD 33.6875 -116.1875 -2 2.1 1.6 3.1 2.4 0.5

CA MWD 34.0625 -118.3125 100 2.9 2.4 3.9 2.8 1.1

CA Mainstem 32.9375 -114.8125 244 2.1 1.6 3.3 2.5 0.6

CA PVID 33.5625 -114.6875 90 2.0 1.5 3.2 2.4 0.6

NV SNWA 36.1875 -115.0625 566 2.1 1.7 3.6 2.6 0.6

NV Other 35.1875 -114.6875 744 2.1 1.7 3.7 2.6 0.7

Average 2.2 2.4 5.4 3.2 1.7

Max 2.9 3.6 10.1 4.3 3.9

Min 1.5 1.5 3.1 2.4 0.5

1 Longitude values are negative west of the prime meridian.

PM – Penman-Monteith

BC – Blaney-Criddle

Harg – Hargreaves

Prs-Tylr – Priestley-Taylor

3.3 Selection of PET Method for Estimating Change in Demand

Based on these analyses and in order to be consistent between the calculations used to estimate 

supply changes under future climate conditions, the Penman-Monteith method, as implemented 

in the VIC model, was proposed for estimating potential change in demands due to climate 

change. However, because VIC Penman-Monteith appears to potentially underestimate the 

response of warming to PET change at high elevations (approximately above 1,800 m), the REFET Penman-Monteith sensitivity factors were used to adjust demands for these areas. 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-11

FIGURE C15-4 

PET Method Sensitivity by Elevation and Temperature

PET change in response to a change in temperature as predicted by Penman-Monteith method implemented in VIC and four 

different PET methods implemented in the REF-ET program for computing PET. PET changes computed over the grid locations 

presented in tables C15-3 and C15-4 are plotted against corresponding average location elevations. Different methods are 

represented by different symbols in the plot. 

4.0 Method of Incorporating Effects of Climate Change on 

Demands, Phreatophyte Losses, and Reservoir 

Evaporation

In order to incorporate the effects of climate change on demands included in the Study, a method 

has been developed to adjust the agricultural and outdoor M&I demands. As discussed

previously, the water demands for each of the scenarios have been developed without 

consideration of future climate change. However, it is assumed that demands provided by the 

states for this Study reflect the effects of changes in climate through 2010. 

The method applied in the Study consists of indexing the agricultural and outdoor M&I demands 

to changes in PET associated with the particular climate projection included in the Downscaled 

GCM Projected water supply scenario. No direct changes are made to the demand scenarios; 

however, these demands are indexed by each future climate realization based on projections of 

PET and precipitation (P) (as described below). This methodology is applied for all agricultural 

and outdoor M&I demands in the Study Area. A similar method is applied for phreatophyte 

losses and reservoir evaporation. 

The climatic factors are computed for two representative VIC grid coordinates for each planning 

area, as shown in figures C15-2 and C15-3; one grid cell is used to adjust agricultural demands 

-500

0

500

1000

1500

2000

2500

3000

0 5 10

Elevation (m)

PET Sensitivity (% change per degree C)

VIC-ET PM

REF-ET PM

REF-ET BC

REF-ET Harg

REF ET Prs-Tylr
Colorado River Basin 

Water Supply and Demand Study

C15-12 December 2012

and the second grid cell is used to adjust outdoor M&I demands. The climatic factor used to 

adjust the agricultural demand is also used to adjust phreatophyte losses in the Lower Basin. In 

addition, a set of VIC grid cells are identified where climatic factors are estimated to adjust 

reservoir evaporation rates in response to potential climate change. 

The climatic factors are computed for the period 1985 to 2060. Because changes in climate 

through the year 2010 are assumed to be included in the agricultural and M&I demands provided 

by the Basin States, the 1985 to 2060 factors are “anchored” or normalized to one in 2010, and 

the resultant factors for the period 2010 to 2060 are used to modify the demand scenarios. For

other losses, such as phreatophytes, which do not have climate change built into projected 

demands, the 1985 to 2060 factors are applied directly, without anchoring. 

4.1 Method to Compute Climate Indexing Factor to Adjust Agricultural, Outdoor 

Urban Demands and Phreatophyte Losses

The method consists of the following steps: 

1. Extract the monthly PET and P for each VIC simulation as driven by the downscaled 

climate model simulations. The VIC simulations cover the time period 1950 to 2099, 

with 1950 to 2000 representing historical climate and 2001 to 2099 representing 

projected climate. 

2. Adjust the VIC-simulated PET for grid cells above 1,800 m based on the simulated REFET Penman-Monteith values. 

3. Compute PET minus P for each month. If PET is greater than P, then this value is an 

indicator of the irrigation demand. If this value is less than zero, set the (PET-P) equal to 

zero for that month. 

4. Compute the annual sum of the monthly (PET-P) values. 

5. Compute a 31-year moving average of annual (PET-P) values, with the averaging 

window centered on the year of calculation. For example, the 1985 value represents the 

average of 1970 to 2000. The moving average is employed to minimize short-term 

fluctuations in simulated climate. 

6. Develop “raw” factors to adjust agricultural, outdoor urban demands, and phreatophyte 

losses. For each year, for the period 1985 to 2060, the 31-year moving average annual 

(PET-P) is divided by the (PET-P) annual value averaged over the 1970 to 2000 historical 

climatological period. Using this approach, the raw factors are exactly 1 in 1985 for all 

climate projections. 

7. For agricultural and outdoor M&I demands provided by the Basin States, adjust the raw 

factor by “anchoring” to 2010 to account for the assumption that changes in climate 

through 2010 have been incorporated. Projected losses, such as phreatophytes, do not 

have climate change through 2010 already built in; accordingly, the raw factors from 

number 6 above are multiplied directly by projected phreatophyte demands to calculate 

climate-affected phreatophyte demands. 

8. Steps 1 to 7 are repeated for each of the selected VIC grid cells. Note that step 2 is only 

performed for the VIC grid cells located at high elevation (approximately above 

1,800 m). 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-13

4.2 Method to Compute Climate Indexing Factor to Adjust Reservoir Evaporation

The climate indexing factor to adjust reservoir evaporation loss is calculated with the same 

methods described to compute the climate indexing factor to adjust agricultural, outdoor M&I 

demands and phreatophyte losses. However, in this case, the following four changes are applied. 

1. PET is considered from VIC-simulated open water surface (evaporation only). 

2. No adjustments are made to the VIC-simulated open water surface evaporation for high 

elevations because it is not known whether the VIC high-elevation underestimation is 

also present in the calculation of open water surface evaporation. 

3. The net evaporation term (PET-P) was not set to equal zero, if (PET-P) <0, to reflect the 

potential for precipitation to produce negative net evaporation in some months/years. 

4. Raw factors are applied (i.e., no anchoring). 

VIC grid coordinates, depicted in figure C15-5, were selected for the reservoirs considered in the 

Colorado River Simulation System (CRSS) to compute climate indexing factors to adjust 

reservoirs evaporation losses. 

FIGURE C15-5 

Selected VIC Grid Cells to Adjust Reservoirs Evaporation Losses
Colorado River Basin 

Water Supply and Demand Study

C15-14 December 2012

4.3 Summary Results of VIC Model Methods

Figure C15-6 illustrates the raw (left, 1985 to 2060) and “anchored” (right, 2010 to 2060) 

(PET-P) factors for one agricultural location (Imperial Irrigation District, California). Thinner 

curves represent the (PET-P) fractions simulated by VIC as driven by 112 downscaled climate 

projections. Thicker curves represent the 10th, 50th, and 90th percentiles computed from 112 

simulations. Results exhibit considerable variability in the projections. The median of the 

projections at this location indicates an increase in annual PET of about 1.2 percent in 2035 and 

about 3.1 percent by 2060, from 2010. The median across all projections and all agricultural 

locations indicates an increase in annual PET of 1.5 percent in 2035 and 3.7 percent in 2060. 

Figure C15-7 shows the raw (left, 1985 to 2060) and “anchored” (right, 2010 to 2060) (PET-P) 

factors for one M&I location (Central Arizona). The median of the projections indicates an 

increase in demands at this location of about 1.8 percent in 2035 and almost 4.9 percent by 2060. 

The median across all projections and all M&I locations indicates an increase in demands of 

about 1.4 percent in 2035 and about 3.6 percent by 2060. 
 Appendix C15 — Climate Change Effects on 

 Water Demand and Losses

December 2012 C15-15

FIGURE C15-6 

Climate Indexing for Agricultural Demands

Raw (left, anchoring change to mid-point of 1971–2000) and anchored (right, anchoring change to 2010) climate indexing factor for agricultural demands in the Imperial Valley 

based on 112 climate projections (thick red lines represent the 10th, 50th, and 90th percentile of the projections). 

1990 2000 2010 2020 2030 2040 2050 2060

0.95

1

1.05

1.1

1.15

Factor

2010 2020 2030 2040 2050 2060

0.95

1

1.05

1.1

1.15

Factor
Colorado River Basin 

Water Supply and Demand Study

C15-16 December 2012

FIGURE C15-7 

Climate Indexing for Urban Demands

Raw (left, anchoring change to mid-point of 1971–2000) and anchored (right, anchoring change to 2010) climate indexing factor for a representative location in central Arizona to 

adjust outdoor urban demands based on 112 climate projections (thick red lines represent the 10th, 50th, and 90th percentile of the projections). 

1990 2000 2010 2020 2030 2040 2050 2060

0.95

1

1.05

1.1

1.15

Factor

2010 2020 2030 2040 2050 2060

0.95

1

1.05

1.1

1.15

Factor
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-17

Figure C15-8 shows the (PET-P) fraction for the period 1985 to 2060 for a grid cell near Lake 

Mead, displaying a representative fraction used to adjust reservoir evaporation. Thinner curves 

represent the (PET-P) fractions simulated by VIC as driven by 112 downscaled climate model 

projections. Thicker curves represent the 10th, 50th, and 90th percentiles computed from 

112 simulations. The median of the projections indicates an increase in net evaporation loss of 

about 1.3 percent in 2035 and almost 3 percent by 2060. 

FIGURE C15-8 

Climate Indexing for Reservoir Evaporation

Climate indexing factor (raw; these were not adjusted) used to adjust reservoir evaporation in Lake Mead based on 112 climate 

projections (thick red lines represent the 10th, 50th, and 90th percentile of the projections). 

 

Figure C15-9 presents the monthly shifts in PET under various future climate periods. VICsimulated PET values are taken from a VIC grid cell near the CIMIS station at Calipatria/

Mulberry (CIMIS station #41) in the Imperial Valley. The results show an increase in PET under 

each projected future climate with respect to the model-simulated historical period. The figure 

also shows a marked increase in PET for January through August. Very little increase is 

projected during September through December. 

1990 2000 2010 2020 2030 2040 2050 2060

0.95

1

1.05

1.1

1.15

Factor
Colorado River Basin 

Water Supply and Demand Study

C15-18 December 2012

FIGURE C15-9 

Monthly Changes in Simulated PET 

Under three future conditions compared to historical climate.

Figures C15-10 and C15-11 present the raw (1971 to 2000) and anchored (2010) mean percent 

change in the climate indexing factor to adjust agricultural and outdoor M&I demands, 

respectively. There are some spatial variations in the climate indexing factor throughout the 

planning areas. The variability is controlled by projected changes in meteorological variables 

across the planning areas. The mean across all agricultural locations indicates an increase of 

about 4.2 percent, with a change ranging between about 1.8 percent and about 6.2 percent by 

2060 for agricultural demands. For outdoor M&I demands, the mean across all M&I locations 

indicates an increase of about 4.1 percent, with an increase ranging between about 2 percent and 

8 percent by 2060. Consideration of precipitation in the scaling factor calculations contributes to 

changes in the scaling factor. For some planning areas, precipitation changes reduce the net 

evapotranspiration demand due to projected wetter conditions during the irrigation season, while 

projected reduced precipitation during the irrigation season exacerbates the increases in PET. 

Figures C15-12 and C15-13 present the spatial distributions of the mean percent change in the 

climate indexing factor to adjust agricultural and outdoor M&I demands over the planning areas, 

respectively. The size of the circle reflects the relative projected change in demand. 

J F M A M J J A S O N D 50

100

150

200

250

300

Monthly PET (mm)

1971-2000

2011-2040

2041-2070

2066-2095
 Appendix C15 — Climate Change Effects on 

 Water Demand and Losses

December 2012 C15-19

FIGURE C15-10

Mean Climate Indexing Factor for Agricultural Demands Adjustment

Mean projected percent change in adjusted climate indexing factor by 2060 to adjust agricultural demands, raw (left, anchoring change to mid-point of 1971–2000) and anchored 

(right, anchoring change to 2010). Values are averaged from 112 climate simulations (red portion of the bar shows the demand change contribution from warming; the blue portion 

shows the contribution due to precipitation change; and the dashed bar reflects the net change). 

 

-4 -2 0 2 4 6 8 10 12

NV-SNWA 

NV-Other 

CA-IID

CA-CVWD

CA-MWD

CA-Mainstem

CA-PVID

AZ-Central Arizona

AZ-Mainstem

AZ-Central Yavapai Highlands

AZ-Upper San Pedro River

AZ-North Central

WY-Green River to Greendale

WY-Wyoming Uses on the Little Snake

WY-Green River above Fontenelle

WY-Fontenelle to Green River

WY-North Platte

UT-Southeast Colorado River

UT-West Colorado River

UT-Kanab Creek-Virgin River

UT-Uintah Basin

UT-Wasatch Front

NM-San Juan

NM-Adjacent Areas

NM-Southwest

NM-Northwest

CO-Colorado River-Cisco UT

CO-Dolores River-Cisco

CO-San Juan-Bluff

CO-White River-Watson

CO-Yampa-Maybell

CO-Gunnison River-Grand Junction

CO-Adjacent Areas - SouthPlatte

CO-Adjacent Areas - Arkansas

Projected Change (%)

-4 -2 0 2 4 6 8 10 12 -4 -2 0 2 4 6 8 10 12

NV-SNWA 

NV-Other 

CA-IID

CA-CVWD

CA-MWD

CA-Mainstem

CA-PVID

AZ-Central Arizona

AZ-Mainstem

AZ-Central Yavapai Highlands

AZ-Upper San Pedro River

AZ-North Central

WY-Green River to Greendale

WY-Wyoming Uses on the Little Snake

WY-Green River above Fontenelle

WY-Fontenelle to Green River

WY-North Platte

UT-Southeast Colorado River

UT-West Colorado River

UT-Kanab Creek-Virgin River

UT-Uintah Basin

UT-Wasatch Front

NM-San Juan

NM-Adjacent Areas

NM-Southwest

NM-Northwest

CO-Colorado River-Cisco UT

CO-Dolores River-Cisco

CO-San Juan-Bluff

CO-White River-Watson

CO-Yampa-Maybell

CO-Gunnison River-Grand Junction

CO-Adjacent Areas - SouthPlatte

CO-Adjacent Areas - Arkansas

Projected Change (%)

-4 -2 0 2 4 6 8 10 12
Colorado River Basin 

Water Supply and Demand Study

C15-20 December 2012

FIGURE C15-11

Mean Climate Indexing Factor for Urban Demands Adjustment

Mean projected percent change in adjusted climate indexing factor by 2060 to adjust outdoor M&I demands, raw (left, anchoring change to mid-point of 1971–2000) and anchored 

(right, anchoring change to 2010). Values are averaged from 112 climate simulations (red portion of the bar shows the demand change contribution from warming; the blue portion 

shows the contribution due to precipitation change; and the dashed bar reflects the net change). 

-4 -2 0 2 4 6 8 10 12

NV-SNWA 

NV-Other 

CA-IID

CA-CVWD

CA-MWD

CA-Mainstem

CA-PVID

AZ-Central Arizona

AZ-Mainstem

AZ-Central Yavapai Highlands

AZ-Upper San Pedro River

AZ-North Central

WY-Green River to Greendale

WY-Wyoming Uses on the Little Snake

WY-Green River above Fontenelle

WY-Fontenelle to Green River

WY-North Platte

UT-Southeast Colorado River

UT-West Colorado River

UT-Kanab Creek-Virgin River

UT-Uintah Basin

UT-Wasatch Front

NM-San Juan

NM-Adjacent Areas

NM-Southwest

NM-Northwest

CO-Colorado River-Cisco UT

CO-Dolores River-Cisco

CO-San Juan-Bluff

CO-White River-Watson

CO-Yampa-Maybell

CO-Gunnison River-Grand Junction

CO-Adjacent Areas - SouthPlatte

CO-Adjacent Areas - Arkansas

Projected Change (%)

-4 -2 0 2 4 6 8 10 12 -4 -2 0 2 4 6 8 10 12

NV-SNWA 

NV-Other 

CA-IID

CA-CVWD

CA-MWD

CA-Mainstem

CA-PVID

AZ-Central Arizona

AZ-Mainstem

AZ-Central Yavapai Highlands

AZ-Upper San Pedro River

AZ-North Central

WY-Green River to Greendale

WY-Wyoming Uses on the Little Snake

WY-Green River above Fontenelle

WY-Fontenelle to Green River

WY-North Platte

UT-Southeast Colorado River

UT-West Colorado River

UT-Kanab Creek-Virgin River

UT-Uintah Basin

UT-Wasatch Front

NM-San Juan

NM-Adjacent Areas

NM-Southwest

NM-Northwest

CO-Colorado River-Cisco UT

CO-Dolores River-Cisco

CO-San Juan-Bluff

CO-White River-Watson

CO-Yampa-Maybell

CO-Gunnison River-Grand Junction

CO-Adjacent Areas - SouthPlatte

CO-Adjacent Areas - Arkansas

Projected Change (%)

-4 -2 0 2 4 6 8 10 12
 Appendix C15 — Climate Change Effects on 

 Water Demand and Losses

December 2012 C15-21

FIGURE C15-12

Change in Mean Adjusted Climate Factor for Agricultural Demand

Spatial distribution of mean projected percent change in adjusted climate indexing factor by 2060 to adjust agricultural demands, raw (left, anchoring change to mid-point of 

1971–2000) and anchored (right, anchoring change to 2010). Values are averaged from 112 climate simulations. 
Colorado River Basin 

Water Supply and Demand Study

C15-22 December 2012

FIGURE C15-13

Change in Mean Adjusted Climate Factor for Urban Demand

Spatial distribution of mean projected percent change in adjusted climate indexing factor by 2060 to adjust agricultural demands, raw (left, anchoring change to mid-point of 

1971–2000) and anchored (right, anchoring change to 2010). Values are averaged from 112 climate simulations. 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-23

Figure C15-14 represents the mean percent change in climate indexing factor to adjust 

reservoir evaporation losses by 2060. The mean increase is projected to vary between about 

1 percent to 4.5 percent, with an average of a little over 3 percent. 

FIGURE C15-14

Mean Climate Indexing Factor for Reservoir Evaporation Adjustment

Mean projected percent change in climate indexing factor by 2060 to adjust reservoir evaporation loss. Values are averaged 

from 112 climate simulations (red portion of the bar shows the demand change contribution from warming, the blue portion 

shows the contribution due to precipitation change, and the dashed bar reflects the net change). 

-5 -3 -1 1 3 5

Havasu

Mohave

Mead

Powell

Crystal 

Morrow Point 

Blue Mesa 

Taylor Park

Starvation

Navajo

Flaming Gorge 

Fontenelle 

Projected Change (%)

-5 -3 -1 1 3 5
Colorado River Basin 

Water Supply and Demand Study

C15-24 December 2012

5.0 Summary and Limitations

Comparisons of VIC-simulated PET with station measurements of PET indicate general 

agreement, but discrepancies during summer months are likely due to scale and local 

meteorology differences. Warming exhibits an increase in PET and VIC-simulated PET 

shows increases on the order of 2 percent per degree Celsius of warming. The VIC 

simulations appear to underestimate PET changes at higher elevations (greater than about 

1,800 m) compared to the Penman-Monteith method implemented in the REF-ET program. 

The Blaney-Criddle method shows sensitivity almost double that of the sensitivities 

suggested by the Penman-Monteith, Hargreaves, and Priestley-Taylor methods, leading to the 

preference for application of the Penman-Monteith in the Study. Given that VIC PenmanMonteith underestimates the response of warming to PET change at high elevations 

(approximately above 1,800 m), the ratios of REF-ET Penman-Monteith sensitivity divided 

by the VIC Penman-Monteith sensitivity are applied to adjust the annual projected change in 

PET as driven by the downscaled climate model simulations at high elevations. 

PET estimated by the Penman-Monteith method embedded in VIC was used to construct the 

climate indexing factor. One of the future water supply scenarios is developed using the VIC 

simulations as driven by the same downscaled climate projections. These future water supply 

and water demand scenarios will be used in the CRSS to indicate the ability of the Colorado 

River to meet the needs of Basin resources under multiple future conditions. Overall, the 

approach described in this appendix provides an internally consistent methodology for 

including the potential effects of climate change on agricultural, outdoor urban demands, 

phreatophyte losses, and reservoir evaporation rates. 

5.1 Limitations

The Penman-Monteith method is a function of climatic variables, including temperature, 

solar radiation, relative humidity, wind speed, and vegetation physiological characteristics. 

Due to unavailability of downscaled climate information for use in VIC for relative humidity, 

solar radiation, and wind speed, humidity and downward solar and longwave radiation were 

estimated using the algorithms of Kimball et al. (1997) and Thornton and Running (1999), 

which are based on the daily temperature range and daily average temperature, respectively.

The Penman-Monteith method is sensitive to radiation inputs; however, due to the lack of 

observed data, particularly at the high elevation, no attempt was made to adjust the results for 

changes in radiation. Wind speed for the future climate was produced using resampling of the 

historical wind speed data taken from Maurer et al. (2002). Researchers have found that 

higher carbon dioxide concentrations cause partial stomatal closure in some crops, which 

decreases transpiration (for example, Ramirez and Finnerty, 1996). The PET implementation 

in the VIC model does not include any direct effect of ambient carbon dioxide concentrations 

and may overstate the changes in PET due to this limitation. 
Appendix C15 — Climate Change Effects on

Water Demand and Losses

December 2012 C15-25

6.0 References 

Allen, R.G., L.S. Pereira, D. Raes, and M. Smith. 1998. Crop evapotranspiration – 

Guidelines for computing crop water requirements. FAO Irrigation and Drainage 

paper, page 56. Food and Agriculture Organization of the United Nations, Rome. 

American Society of Civil Engineers (ASCE), 2005. The ASCE Standardized Reference 

Evapotranspiration Equation. EWRI of ASCE Standardization of Reference 

Evapotranspiration Task Committee. Final Report. 

Bormann, H. 2011. Sensitivity analysis of 18 different potential evapotranspiration 

models to observed climatic change at German climate stations. Climatic

Change. 104: pp. 729-753. 

Doorenbos J., and Pruitt. W.O.1977. CropWater Requirements. Irrigation and Drainage 

Paper 24, FAO. Rome, Italy. page 144. 

Hargreaves, G.H., and Samani, Z.A. 1985. Reference crop evapotranspiration from 

temperature. Appl. Eng. in Agric., 1(2): pp.96–99. 

Hill, R. W., E. L. Johns, and D. K. Frevert. 1983. Comparison of Equations used for 

Estimating Agricultural Crop Evapotranspiration with Field Research. U.S. Department of the Interior, Bureau of Reclamation. page 242. 

Jensen, M.E., R.D. Burman, and R.G. Allen. 1990. Evapotranspiration and Irrigation Water 

Requirements. American Society of Civil Engineers – Manuals and Reports on 

Engineering Practice – No. 70. 

Kimball, J.S., S.W. Running and R. Nemani. 1997. An improved method for estimating surface 

humidity from daily minimum temperature. Agric. For. Meteorol. pp. 85, 87–98.

Kingston, D.G., M.C. Todd, R.G. Taylor, J.R. Thompson, and N.W. Arnell. 2009. 

Uncertainty in the estimation of potential evaporation under climate change. Geophys 

Res Lett 36:L20403. doi:10.1029/2009GL040267. 

Liang, X., D.P. Lettenmaier, E.F. Wood. 1996. Surface Soil Moisture Parameterization of the 

VIC-2L Model: Evaluation and Modification. 

Liang, X., D.P. Lettenmaier, E.F. Wood, S.J. Burges. 1994. A Simple Hydrologically Based 

Model of Land Surface Water and Energy Fluxes for General Circulation Models. 

Journal of Geophysical Research, vol. 99, pp. 14415–14428. 

Maurer, E.P., A.W. Wood, J.C. Adam, D.P. Lettenmaier, B. Nijssen. 2002. A Long-Term 

Hydrologically-Based Data Set of Land Surface Fluxes and States for the 

Conterminous United States, Journal of Climate, pp. 15(22), 3237–3251. 

McKenney, M.S. and N.J. Rosenberg. 1993. Sensitivity of some potential evapotranspiration 

estimation methods to climate change. Agricultural and Forest Meteorology, pp. 64, 

81-110. 

Monteith, J.L. 1965. Evaporation and environment. Symp. Soc. Exp. Biol. pp. 19, 205–224. 
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C15-26 December 2012

Priestley, CHB, and R.J. Taylor. 1972. On the assessment of surface heat flux and 

evapotranspiration using large scale parameters. Mon Weather Rev 100: pp. 81–92. 

Ramirez, J.A., and Finnerty, B. 1996. CO2 and Temperature Effects on Evapotranspiration 

and Irrigated Agriculture. Journal of Irrigation and Drainage Engineering, 122(3), 

155–163. 

Stephens, J, and E. Stewart, E. circa 1960. A Comparison of Procedures for Computing 

Evaporation and Evapotranspiration. International Association of Hydrologic 

Sciences, available at: http://iahs.info/redbooks/a062/iahs_062_0123.pdf. 

Thornton, P.E. and S.W. Running. 1999. An improved algorithm for estimating incident 

daily solar radiation from measurements of temperature, humidity, and precipitation. 

Agric. For. Meteorol. 93, pp. 211–228. 

Yates, D. and K. Strzepek. 1994. Comparison of Models for Climate Change Assessment of 

River Basin Runoff. IIASA Working Paper WP-94-46, Laxenburg, Austria.