RECLAMATION 

Managing Water in the ffest 

Colorado River Basin 

Water Supply and Demand Study 

Technical Report E - Approach to Develop and Evaluate 

u .s. Department of the Intenor 

Bureau 01 Reclamation 

Options and Strategies 

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 E — Approach to 

Develop and Evaluate Options and 

Strategies

December 2012 E-iii

Contents

Page

1.0 Introduction .............................................................................................................. E-1

2.0 Overview of Study Approach .................................................................................. E-2

2.1 Evaluation of System Reliability without Options 

and Strategies ................................................................................................. E-3

2.2 Characterization of System Vulnerabilities ................................................... E-5

2.3 Identification and Characterization of Options .............................................. E-6

2.4 Development of Portfolios of Options ........................................................... E-8

2.5 Evaluation of System Reliability with Options 

and Strategies ................................................................................................. E-9

3.0 Summary ................................................................................................................... E-10

4.0 References ................................................................................................................. E-11

Disclaimer ............................................................................................................................. E-13

Figure

E-1 Overall Study Approach ............................................................................................ E-2

Tables

E-1 Water Supply Scenarios and Number of Traces ........................................................ E-4

E-2 Water Demand Scenarios ........................................................................................... E-4

E-3 Summary of Representative Options ......................................................................... E-7

E-4 Criteria Used to Characterize Representative Options .............................................. E-8

E-5 Description of Portfolios Explored in the Study ........................................................ E-9

December 2012 E-v 

Acronyms and Abbreviations

2007 Interim 

Guidelines 

Record of Decision for Colorado River Interim Guidelines

for Lower Basin Shortages and Coordinated Operations 

for Lake Powell and Lake Mead

2007 Interim 

Guidelines Final 

EIS

Colorado River Interim Guidelines for Lower Basin

Shortages and Coordinated Operations for Lake Powell 

and Lake Mead Final Environmental Impact Statement

Basin Colorado River Basin

Basin States Colorado River Basin States

CRSS Colorado River Simulation System 

M&I municipal and industrial

Mexico United Mexican States

Reclamation Bureau of Reclamation

Study Colorado River Basin Water Supply and Demand Study

December 2012 E-1 

Technical Report E — Approach to Develop 

and Evaluate Options and Strategies

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 four 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 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 overallocated and that 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 variability on the 

Basin water supply have been the focus of many scientific studies that 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 technical report is a key component of 

that technical foundation and provides an overview of the Study’s approach to assess system 

reliability, to develop and evaluate options and strategies for balancing supply and demand, and 

to assess the effectiveness of various strategies. This technical report is meant to serve as a guide 

to understand how the multiple technical components of the Study are interconnected. A key 

component of the overall Study approach was the adoption of a scenario planning process that 

has resulted in multiple future plausible conditions for both Basin water supply and demand. 

This scenario planning process and the resulting scenarios are described in other technical 

reports. This report presents the additional elements of the overall approach, which include the 

assessment of system reliability, the development of options and strategies for balancing supply 

and demand, and the assessment of the effectiveness of implementing those options and 

strategies against multiple plausible future conditions. 
Colorado River Basin 

Water Supply and Demand Study

E-2 December 2012

Details regarding the quantification and analysis of the water supply and water demand scenarios 

are presented in Technical Report B – Water Supply Assessment and Technical Report C – Water 

Demand Assessment, respectively. Details regarding the development of options and strategies 

and the system reliability with and without options and strategies are presented in Technical 

Report F – Development of Options and Strategies and Technical Report G – System Reliability 

Analysis and Evaluation of Options and Strategies, respectively.

2.0 Overview of Study Approach 

The overall analytical approach followed in the Study is shown in figure E-1. The technical 

reports that correspond to various elements are denoted in italics in the figure. Technical Report 

A – Scenario Development and Technical Report E – Approach to Develop and Evaluate Options 

and Strategies (this report) describe the overarching technical approaches that guided the specific 

detailed technical reports. 

FIGURE E-1 

Overall Study Approach

The purpose and objectives defined in the Plan of Study (see Study Report, Appendix 1 – Plan of 

Study) were used to frame the focal questions that the Study must address: 

1. What is the future reliability of the Colorado River system to meet the needs of Basin 

resources through 2060? 

2. What are the options and strategies to mitigate future risks to these resources?

Framing of the Study

Development of Water 

Supply Scenarios

Development of Water 

Demand Scenarios

Identification of System 

Reliability Metrics

Identification and 

Characterization of Options

Development of Portfolios of 

Options

Evaluation of System Reliability without 

Options and Strategies

Characterization of System 

Vulnerabilities

Evaluation of System Reliability with 

Options and Strategies

Summary of Findings and 

Future Considerations

Plan of Study

Technical Report A

Technical 

Report F

Technical Report B

Study Report

Technical Report C Technical Report D

Technical Report E 

Technical 

Report G
Technical Report E — Approach to Develop

and Evaluate Options and Strategies

December 2012 E-3 

The first question requires an understanding of the underlying components of future reliability: 

water supply and water demand. Specifically, what are the factors that will determine the future 

availability of water, and what are the factors that will determine the future demand for water? 

The scenario development process, described in Technical Report A, addresses these questions 

and results in scenarios of the future that define a range of plausible water supply and water 

demand outcomes. The scenarios for water supply and demand are described in Technical Report 

B and Technical Report C, respectively. The first question also requires an understanding of the 

needs for Basin resources. These needs are identified via the system reliability metrics described 

in Technical Report D. 

Combined, Technical Reports A through D describe the components needed, i.e., future 

scenarios of water supply and demand and resource metrics, to address the first question. 

The process for evaluating system reliability without options and strategies, and the assessment 

of the outcome of that process (which can be described as the characterization of system

vulnerabilities) is described at a high level in this report and in more detail in Technical Report 

G, which presents the findings related to the first question. 

The second question asks—what are appropriate water management responses to mitigate and 

adapt to the potential impacts to Basin resources under alternative scenarios of the future? To

address this question, water management responses or options were identified and characterized. 

From those options, four portfolios, or collections of options, were developed to explore various 

strategies for resolving future supply and demand imbalances. The outcome of these two steps is 

the focus of Technical Report F. The effectiveness of the portfolios at reducing system 

vulnerabilities was then assessed through the evaluation of system reliability with options and 

strategies, and the outcomes of those evaluations are documented in Technical Report G. 

A summary of the results presented in each technical report, along with a discussion on future 

considerations and steps to be taken after the Study’s completion are provided in the Study 

Report. 

An overview of the approach followed for each of the key steps in the highlighted portion of 

figure E-1 is presented below.

2.1 Evaluation of System Reliability without Options and Strategies

The reliability of the system under the supply and demand scenarios, without additional 

management options, was evaluated. The primary evaluation tool used to assess system 

reliability was Reclamation’s Colorado River Simulation System (CRSS), which simulates the 

long-term operation of the major Colorado River system reservoirs. Modeling results were 

summarized for the Basin resources according to the metrics described in Technical Report D

and a subset of these metrics termed indicator metrics.

The scenario planning approach led to four water supply scenarios that considered observed 

historical hydrology, direct and conditioned paleo-reconstructions of longer historical hydrologic 

conditions, and potential future hydrology under projected climate change conditions. To 

quantify the uncertainty in each scenario relating to the sequencing of wet, dry, or average 

periods of runoff, various methods were used that resulted in more than 100 different traces

(monthly time series of natural flows) for each scenario over the Study period. Table E-1 depicts 

the scenarios and corresponding number of traces. The water supply scenarios are described in 

detail in Technical Report B.
Colorado River Basin 

Water Supply and Demand Study

E-4 December 2012

TABLE E-1 

Water Supply Scenarios and Number of Traces

Water Supply 

Scenario

Number of 

Traces Theme

Observed Resampled 103 Future hydrologic trends and variability are similar to the past 

approximately 100 years

Paleo Resampled 1,244

Future hydrologic trends and variability are represented by 

reconstructions of streamflow for a much longer period in the past 

(nearly 1,250 years) that show expanded variability

Paleo Conditioned 500

Future hydrologic trends and variability are represented by a blend 

of the wet-dry states of the longer paleo-reconstructed period 

(nearly 1,250 years), but magnitudes are more similar to the 

observed period (about 100 years)

Downscaled Global 

Climate Model 

Projected

112 

Future climate will warm with regional precipitation and temperature 

trends represented through an ensemble of downscaled Global 

Climate Model projections

Concurrently, six water demand scenarios were developed that reflect uncertainty in future 

demographics and land use, technology and economics, and social values and governance. Table 

E-2 depicts these scenarios, which are described in detail in Technical Report C. 

TABLE E-2 

Water Demand Scenarios

Water Demand Scenario Theme

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

following 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

Last, two operational assumptions were considered to reflect different criteria for the operation 

of Lakes Powell and Mead beyond 2026, when the Colorado River Interim Guidelines for Lower 

Basin Shortages and Coordinated Operations of Lakes Powell and Mead (2007 Interim 

Guidelines) (U.S. Department of Interior, 2007) expire. Under one operational assumption, these

2007 Interim Guidelines were assumed to be extended through 2060; under the other operational 

assumption, operations were assumed to revert to the No Action Alternative from the Colorado 

River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake 

Powell and Lake Mead Final Environmental Impact Statement (2007 Interim Guidelines Final 

EIS) (Reclamation, 2007). 

The water supply and water demand scenarios, along with the two operational assumptions, were 

combined to explore a wide range of plausible future conditions. The combination of these 

scenarios resulted in thousands of future traces that were input into CRSS to simulate the 

performance of the system under each of these future traces. 
Technical Report E — Approach to Develop

and Evaluate Options and Strategies

December 2012 E-5 

Technical Report D describes the process and identification of system reliability metrics for 

resources of interest in the Basin. Metrics are measures that indicate the ability of the Colorado 

River system to meet Basin resource needs. Metrics were identified for each of the six resources

categories identified: water deliveries, electrical power resources, water quality, flood control, 

recreational resources, and ecological resources. CRSS results were used to assess the 

performance of all quantitative metrics identified in Technical Report D, and a subset of these 

metrics termed indicator metrics. Some metrics were evaluated qualitatively due to their

complexity, limitations of the tools, or lack of quantifiable relationships. 

Indicator metrics from each of the six resource categories were developed to summarize the 

performance of the metrics identified in Technical Report D. Through the use of indicator 

metrics, the performance of Basin resources can be viewed in a more concise manner. 

The indicator metrics were developed to represent, as closely as possible, the performance of 

each individual metric within a resource category. In some cases, statistical analyses were used 

to develop indicator metrics and in others, individual metrics were selected as indicator metrics 

based on geographic location. For several resource categories, such as water deliveries or 

electrical power, indicator metrics that were representative or highly correlated to other 

individual metrics within the resource category were fairly apparent. 

Developing indicator metrics for the ecological resources metrics was challenging because these 

metrics vary substantially by geographic location, temporal characteristics, and type of 

vulnerability threshold. Ecological resources indicator metrics were largely chosen based on their 

location and how well they integrated upstream tributaries. Further, the ecological indicators 

metrics were limited to those specified in various Biological Opinions. The complete list of 

indicator metrics is provided in Technical Report G.

2.2 Characterization of System Vulnerabilities

System vulnerabilities, or those conditions in which a particular resource was defined to be 

vulnerable, were developed from each indicator metric. The system was defined as vulnerable if 

an indicator metric exceeded or dropped below the specific threshold value. For example, the 

system is vulnerable with respect to Lower Basin water deliveries if the Lake Mead pool 

elevation falls below 1,000 feet above mean sea level in any month. The percent of CRSSsimulated traces in which vulnerability occurs was used to summarize the simulated performance 

of the system under different scenarios without consideration of additional options and strategies, 

as well as to compare how options and strategies improve the reliability of the system in the 

future.

After system vulnerabilities were developed, the next step was to identify those conditions 

leading to vulnerabilities—referred to as vulnerable conditions. Statistical analysis (described in 

greater detail in Technical Report G) was performed to consider a wide range of conditions, such 

as natural flow at Lees Ferry or projected water demands, to identify which small set of external 

conditions concisely define when the system is approaching a vulnerable state. Characterizing 

the vulnerabilities in this way provided insight into the types of conditions that particularly strain 

the system. This, in turn, provided insight into the effectiveness of options and strategies at 

improving the resiliency of the system, or the ability of the system to perform under vulnerable 

conditions as measured by vulnerabilities. The conditions that cause vulnerabilities may be 

external and beyond the control of water management entities; however, by improving the 
Colorado River Basin 

Water Supply and Demand Study

E-6 December 2012

resilience of the system through implementing various options and strategies, the ability of the 

system to withstand such conditions can be improved. 

Finally, signposts, or those features of observable system conditions that are good predictors of 

impending vulnerabilities, were identified. CRSS simulations used these signposts to trigger the 

model implementation of options to avoid or reduce the occurrence of vulnerabilities. Signposts 

differ from vulnerable conditions in that they are observable before vulnerability occurs and they 

incorporate factors that vary with management of the system, reflecting benefits that accrue 

when options are implemented. Vulnerable conditions, in contrast, may be defined by the entire 

time sequence of conditions. For example, a combination of the 5-year running mean natural 

flow at Lees Ferry, coupled with the current-year Lake Mead elevation, was found to be an 

effective signpost to predict those occurrences in which resources dependent on particular Lake 

Mead elevations are vulnerable. If this signpost was triggered, additional options could be 

required to prevent Lake Mead elevations from dropping below certain threshold levels.

Effective signposts were identified by evaluating how well certain observable conditions 

performed in terms of accurately signaling an early warning when a simulated vulnerability was

imminent. In choosing signposts, the inherent tradeoff between the amounts of lead time a 

signpost provides and the accuracy with which it predicts vulnerability occurrences was 

assessed. The candidate signposts that best balanced these tradeoffs were used to implement 

options. 

2.3 Identification and Characterization of Options

To address projected future imbalances between supply and demand, the Study considered a 

range of potential options. Ideas to address the potential future imbalances were solicited from 

Study participants, interested stakeholders, and the general public from November 2011 through 

February 2012. Over 150 options were received during this period. The options were reviewed 

and organized into categories such as importation, desalination, and municipal and industrial 

(M&I) conservation. From these categories, about 40 representative options were described to 

capture the range of options submitted and considered. The resulting representative options are 

shown in table E-3. 

Most of the representative options were then evaluated based on the 17 characterization criteria 

shown in table E-4, as appropriate. For options that were not amenable to direct characterization 

based on the criteria, a qualitative description was provided. Option categories not reflected in 

table E-3 are Water Management and Allocation, Tribal Water, Data and Information. For 

options and concepts included in these categories, in addition to many options in the System 

Operations category, a qualitative description was provided rather than through ratings 

associated with the criteria. The criteria were selected based on those described in the Plan of 

Study and were used to provide a relative comparison among options as well as to express the 

strategy behind the development of portfolios. 

Each representative option assessed using the criteria was assigned either a quantitative value 

(e.g., dollars per acre-foot for the cost of water) or a qualitative letter score from “A” through 

“E” for each criterion. For most criteria, “C” is typically designated as mostly neutral; “A” is 

largely positive; and “E” is largely negative. Although the process of assignment of ratings was 

structured to be prescriptive, there is the potential for some subjectivity. A detailed description of 

the options and characterization process and limitations is provided in Technical Report F.
Technical Report E — Approach to Develop

and Evaluate Options and Strategies

December 2012 E-7 

TABLE E-3

Summary of Representative Options 

Option Type Option Category Representative Option

Increase Supply Importation Imports to the Colorado Front Range from the Missouri or Mississippi Rivers

Imports to the Green River from the Bear, Snake, or Yellowstone Rivers

Imports to Southern California via Icebergs, Waterbags, Tankers, or from the 

Columbia River1

Desalination Gulf of California

Pacific Ocean in California

Pacific Ocean in Mexico

Salton Sea Drainwater

Groundwater in Southern California

Groundwater in the Area Near Yuma, Arizona

Reuse Municipal Wastewater

Grey Water

Industrial Wastewater

Local Supply Treatment of Coal Bed Methane-Produced Water

Rainwater Harvesting

Watershed 

Management

Brush Control

Dust Control

Forest Management

Tamarisk Control

Weather Modification

Reduce 

Demand

M&I Water 

Conservation

M&I Water Conservation

Agricultural Water 

Conservation

Agricultural Water Conservation

Agricultural Water Conservation with Transfers 

Energy Water Use 

Efficiency

Power Plant Conversion to Air Cooling

Modify 

Operations

System Operations Evaporation Control via Canal Covers

Evaporation Control via Reservoir Covers

Evaporation Control via Chemical Covers on Canals or Reservoirs

Modified Reservoir Operations

Construction of New Storage

Water Transfers, 

Exchanges, and 

Banking

Water Transfers and Exchanges (same as Agricultural Water Conservation 

with Transfers)

Upper Basin Water Banking

1 Among the more than 150 options submitted to Reclamation as responsive to the Plan of Study, additional 

importation of water supplies from various sources, including importation of water from the Snake and Columbia 

River systems, were submitted to the Study. Such options were appropriately reflected in the Study but did not 

undergo additional analysis as part of a regional or river basin plan or any plan for a specific Federal water 

resource project. This Study is not a regional or river basin plan or proposal or plan for any Federal water resource 

project.
Colorado River Basin 

Water Supply and Demand Study

E-8 December 2012

TABLE E-4 

Criteria Used to Characterize Representative Options

Criteria Summary Description of Criteria

Quantity of Yield The estimated long-term quantity of water generated by the option— either 

an increase in supply or a reduction in demand

Timing Estimated first year that the option could begin operation 

Technical Feasibility Technical feasibility of the option based on the extent of the underlying 

technology or practices

Cost The annualized capital, operating, and replacement cost per acre-foot of 

option yield

Permitting Level of anticipated permitting requirements and precedence of success for 

similar projects

Legal Consistency with current legal frameworks and laws, or precedent with 

success in legal challenges

Policy Considerations Extent of potential changes to existing federal, state, or local policies that 

concern water, water use, or land management

Implementation Risk Risk of achieving implementation and operation of option based on factors 

such as funding mechanisms, competing demands for critical resources, 

challenging operations, or challenging mitigation requirements

Long-term Viability Anticipated reliability of the option to meet the proposed objectives over the 

long term 

Operational Flexibility Flexibility of option to be idled from year to year with limited financial or other 

impacts

Energy Needs Energy required to permit full operation of the option, including treatment, 

conveyance, and distribution

Energy Source Anticipated energy source to be used to allow option to be operational

Hydropower Anticipated increases or decreases in hydroelectric energy generation 

associated with implementation of the option

Water Quality Anticipated improvements or degradation in water quality associated with 

implementation of the option.

Recreation Potential impacts to recreational activities including in-river and shoreline 

activities

Other Environmental Factors Other environmental considerations, such as impacts to air quality, or 

aquatic, wetland, riparian, or terrestrial habitats

Socioeconomics Potential impacts to socioeconomic conditions in regions within or outside of 

the Basin as a result of implementing the option

2.4 Development of Portfolios of Options

Recognizing that no single option will be sufficient to resolve future projected supply and 

demand imbalances, groups of options, or portfolios, were developed to reflect different 

strategies. Portfolios were developed by prioritizing particular representative options based on 

their ratings of the criteria in table E-4 according to a specific strategy. For example, a portfolio 
Technical Report E — Approach to Develop

and Evaluate Options and Strategies

December 2012 E-9 

that relies on options with low implementation risk and high operational feasibility would only 

include options that meet these criteria. 

The portfolios defined the ordering of options to be implemented in response to emerging system

vulnerabilities. These portfolios were input to CRSS, which selected and implemented options, 

generally by cost-effectiveness, as signposts were triggered, indicating that the system was 

approaching a vulnerable state. The selected options and implementation timing for a given 

portfolio depended on the future hydrologic trace for which it was being evaluated. For example, 

a portfolio would implement more options for traces in which hydrologic conditions are dry and 

lead Lake Mead elevation to drop rapidly. 

Four portfolios, each with varying strategies, were considered and are shown in table E-5. It is 

important to note that these portfolios are meant to be exploratory and illustrative of a range of 

the types of combinations of options that could be considered in addressing future reliability, and 

that many portfolios strategies are possible. Once the set of options that was to be included in the 

portfolio was identified, the options were ordered by annual unit cost expressed as dollars per 

acre-foot per year of each option. The annual unit cost was calculated as the annualized capital, 

operating, and replacement cost per acre-foot of option yield. 

TABLE E-5 

Description of Portfolios Explored in the Study

Portfolio Name Portfolio Description 

Portfolio A Is the least restrictive in terms of options and contains all options that are in both 

Portfolio B and Portfolio C. 

Portfolio B Includes options with high technical feasibility and high long-term reliability; excludes 

options with high permitting, legal, or policy risks

Portfolio C Includes only options with relatively low energy intensity; includes options that result 

in increased instream flows; excludes options that have low feasibility or high 

permitting risk

Portfolio D Is the most selective in terms of options and includes only those common to Portfolio 

B and Portfolio C

2.5 Evaluation of System Reliability with Options and Strategies

The portfolios were evaluated using CRSS for each combination of the water supply and demand 

scenarios and the post-2026 Lakes Powell and Mead operations assumptions. For each CRSSsimulated trace, options were implemented according to the order specified by the portfolio in 

response to system conditions indicative of vulnerabilities. Fewer options were implemented for 

sequences that led to less-frequent vulnerabilities. 

The key results from the portfolio analysis include: (1) performance of the system relative to the

full suite of system reliability metrics, indicator metrics, and previously defined vulnerabilities 

for each trace; and (2) option implementation timing, aggregated costs, and characteristics of 

options implemented across traces. 

The results were analyzed to better understand tradeoffs between the ability of portfolios to 

reduce vulnerabilities and the costs and characteristics of the implemented options. For example, 

one portfolio may be more effective at reducing Upper Basin shortages than another. Another 

portfolio may cost more to reduce vulnerabilities. Other tradeoffs include the types or 
Colorado River Basin 

Water Supply and Demand Study

E-10 December 2012

characteristics of the options used to implement the different strategies. For example, two 

portfolios might address potential vulnerabilities similarly, but one might have less technically 

feasible options. 

Some options were included in all portfolios, yet were implemented by CRSS under only some 

future conditions. Some options were included in only some portfolios and were implemented in 

some or all futures. These final results, reported in Technical Report G provide the quantitative 

analysis for understanding the different strategies for addressing the future imbalances between 

supply and demand, but do not lead to a recommended portfolio. Rather, the analysis and 

discussion is intended to inform future decision making and developing next steps for additional 

study. 

3.0 Summary

This report describes the overall analytical approach taken in the Study to answer the questions 

that framed the purpose and objectives set forth in the Plan of Study. These questions are: 

1. What is the future reliability of the Colorado River system to meet the needs of Basin 

resources through 2060? 

2. What are the options and strategies to mitigate future risks to these resources?

In assessing the reliability of the system, multiple plausible future scenarios of water supply and 

demand were developed to capture a broad range of future conditions. Using the identified

system reliability metrics, the reliability of the system was compared under these plausible 

futures. The system reliability metrics also helped with defining system vulnerabilities, the 

external conditions that lead to those vulnerabilities, and signposts that can be monitored and 

indicate that the system is approaching a vulnerable state. 

Options and strategies that reduce these vulnerabilities and improve system reliability were 

explored through the characterization of representative options and the development of 

portfolios. The criteria used to characterize the representative options include potential yield, 

cost, technical feasibility, and energy needs. Based on the results of the characterization and the 

identification of a particular strategy, representative options were combined into portfolios for 

additional analysis. The Study explored four portfolios that demonstrate different strategies to 

resolve future supply and demand imbalances. Each portfolio was analyzed using CRSS across 

all scenario combinations to assess the effects on Basin resources, the effectiveness at reducing 

system vulnerabilities, and the improved resiliency of the Basin to vulnerable conditions. The 

implementation of options across alternative futures and the inclusion of options among the 

portfolios are summarized in Technical Report G. 

This analysis did not lead to a recommendation for specific options or a specific portfolio. 

Rather, it provides quantitative analysis needed to inform future discussions and additional study. 

A summary of findings and discussion regarding future considerations is provided in the Study 

Report. 
Technical Report E — Approach to Develop

and Evaluate Options and Strategies

December 2012 E-11

4.0 References 

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. 

U.S. Department of the Interior. 2007. Record of Decision for Colorado River Interim Guidelines 

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

Technical Report E — Approach to Develop

and Evaluate Options and Strategies

December 2012 E-13

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

(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.