1. Overview of the Colorado River Basin Water Supply and Demand Study
Water Center at Colorado Mesa University
Upper Colorado River Basin Water Forum
October 31, 2011
Ted Kowalski,
Chief of the Interstate and Federal Section, Colorado Water Conservation Board

2. Colorado River Basin Water Supply and Demand Study
Overview and Status of the Study
Historical and Future Water Supply and Demand
Next Steps

3. Colorado River Basin Water Supply and Demand Study
Study Objective
Assess future water supply and demand imbalances and develop/evaluate opportunities for resolving imbalances
Studied being conducted by Reclamation and the Basin States, in collaboration with stakeholders throughout the Basin
Study began in January 2010 and will be completed by July 2012
Website:
A planning study – will not result in any decisions 3

4. Historic Colorado River Water Supply & Use (Annual)6 4

5. Study Outreach Native American Tribes and Communities Other Ecosystem
Basin Water Supply & Demand Study
Colorado River
Hydropower
Western, CREDA. others
Ecosystem
NGO collaborative.
others
Endangered Species
FWS, others
Other
General public, other interested stakeholder groups
Native American Tribes and Communities
Lower Basin, Upper Basin
Water Deliveries
Water Districts (agriculture, M&I use)
Recreation
NPS, Concessionaires, others

6. Options for Participation in the Study (not mutually exclusive)
Monitor project website, webinars, s
Review and comment on products
Receive periodic updates (formal and/or informal)
Establish points-of-contact with the “Study Team” (Reclamation and the Basin States representatives)
Participate in Study working groups (“Sub-Teams”)
Other

7. Study Phases and Tasks Green denotes essentially complete
Phase 1: Water Supply
Assessment
Phase 2: Water Demand Assessment
Phase 3: System Reliability Analysis
Phase 4: Development & Evaluation of Opportunities
1.1 – Select Methods to Estimate Current Supply
2.1 – Select Methods to Estimate Current Demand
3.1 – Identify Reliability Metrics
4.1 – Develop Opportunities
Formulate Approach to Include Uncertainty
3.2 – Estimate Baseline System Reliability
1.2 – Select Methods to Project Future Supply
2.2 – Select Methods to Project Future Demand
4.2 –
Evaluate and Refine Opportunities
1.3 – Conduct Assessment of Current Supply
2.3 – Conduct Assessment of Current Demand
3.3 – Project Future System Reliability
Develop Future Supply and Demand Scenarios
1.4 – Conduct Assessment of Future Supply
2.4 – Conduct Assessment of Future Demand
– Project Future Reliability with Opportunities
4.3 –
Finalize Opportunities
Green denotes essentially complete

8. Interim Report No. 1
Interim reports provide a comprehensive “snapshot” of the Study’s progress to date
Approach facilitates the integration of continuous technical developments and the ongoing input of stakeholders
Interim Report No. 1 is a “snapshot” as of January 31, 2011 and is available at:

9. Historic Colorado River Water Supply & Use (10-year Running Average)
Use Curve:
Upper Basin consumptive use (Sources: “Microfiche” prior to 1971; CU & L Reports 1971 forward)
Lower Basin consumptive use (Sources: data supplied from users prior to 1964, Mexico assumed to be 1.5 mafy; Decree Accounting Reports 1964 forward)
Losses
average evap at CRSP reservoirs, Mead, Mohave and Havasu
bypass flows
native vegetation in LB
does not include over-deliveries to Mexico (may re-think this decision and perhaps use the average excluding flood control years)
Supply Curve:
“Natural flow” at Imperial ( ) computed 6/16/08
Lower Basin tributaries inflows are not corrected for upstream uses (i.e., Virgin River, Gila River) 7 9

10. Natural Flow Colorado River at Lees Ferry Gaging Station, Arizonao 2011
Points to make:
103-year ( ) historical average is approximately 15 maf
2009, 2010, and 2011 are estimated values
Inflows are highly variable
Period from was the lowest 11-year average inflow—there were two years with above average inflow during the period
Period from has the lowest 12-year average inflow, but note there were a couple of good years in the period 10

11. Water Year Snowpack and Precipitation as of September 12, 2011
Colorado River Basin above Lake Powell
Water Year Precipitation (year-to-date)
123%
Source: CBRFC

12. Colorado River Basin Storage (as of September 11, 2011)
Current Storage
Percent Full
MAF
Elevation (Feet)
Lake Powell
73%
17.75
3,654
Lake Mead
49%
12.80
1,114
Total System Storage*
65%
38.85 NA
*Total system storage was maf or 56% this time last year 12

13. Addressing an Uncertain Future
The path of major influences on the Colorado River system is uncertain and can not be represented by a single view
An infinite number of plausible futures exist
A manageable and informative number of scenarios are being developed to explore the broad range of futures
(adapted from Timpe and Scheepers, 2003)

14. Water Supply Scenarios *
Observed Resampled: hydroclimatic trends and variability are similar to the past 100 years
Paleo Resampled: future hydroclimatic trends and variability are represented by reconstructions of streamflow for a much longer period in the past (nearly 1250 years) that show expanded variability
Paleo-Conditioned: future hydrologic trends and variability are represented by a blend of the wet-dry states of the longer paleo-reconstructed period (nearly 1250 years), but magnitudes are more similar to the observed period (about 100 years)
Downscaled GCM Projected: future climate will continue to warm with regional precipitation and temperature trends represented through an ensemble of future downscaled GCM projections
* Preliminary – Subject to change

15. Projections of Natural Flow at Lees Ferry
2011 – 2060 Period Mean Annual Flows
Observed mean: 15 maf (same as observed record)
Direct Paleo mean: 14.7 maf (same as paleo record)
Paleo Conditioned mean: 15.0 maf (same as observed record, this technique maintains the statistics of the observed record)
Climate Projections mean: 13.6 maf (9% decrease from the observed mean)
Climate Projections results SUBJECT TO CHANGE, known bias in VIC (about 650 kaf):
Actual Observed maf/yr
VIC Validation maf/yr
Box represents 25th – 75th percentile, whiskers represent min and max, and triangle represents mean of all traces
1988 – 2007 period mean
Preliminary

16. Water Demand Scenarios *
Current Trends: growth, development patterns, and institutions continue along recent trends
Economic Slowdown: low growth with emphasis on economic efficiency
Expansive Growth: economic resurgence (population and energy) and current preferences toward human and environmental values **
Enhanced Environment and Healthy Economy: expanded environmental awareness and stewardship with growing economy **
* Preliminary – Subject to change
** Additional “branches” possible depending upon assumed trajectory of specific socio-economic factors

17. System Reliability Metrics (Metrics)
Metrics Resource Categories
Depletions
Electrical Power Resources
Water Quality
Flood Control
Recreational Resources
Ecological Resources
Metrics are measures that indicate the ability of the system to meet the needs of Basin resources
Metrics will be used to quantify the impacts to Basin resources from future supply and demand imbalances
Interim Report No. 1 includes metrics defined as of January 31, 2011
Additional metrics are being considered
Flow-based indicator for ecosystem health
Indicator to show unused but allocated water, particularly for tribal water

18. Study Phases and Tasks Yellow denotes current and future steps..
Phase 1: Water Supply
Assessment
Phase 2: Water Demand Assessment
Phase 3: System Reliability Analysis
Phase 4: Development & Evaluation of Opportunities
1.1 – Select Methods to Estimate Current Supply
2.1 – Select Methods to Estimate Current Demand
3.1 – Identify Reliability Metrics
4.1 – Develop Opportunities
Formulate Approach to Include Uncertainty
3.2 – Estimate Baseline System Reliability
1.2 – Select Methods to Project Future Supply
2.2 – Select Methods to Project Future Demand
4.2 –
Evaluate and Refine Opportunities
1.3 – Conduct Assessment of Current Supply
2.3 – Conduct Assessment of Current Demand
3.3 – Project Future System Reliability
Develop Future Supply and Demand Scenarios
1.4 – Conduct Assessment of Future Supply
2.4 – Conduct Assessment of Future Demand
– Project Future Reliability with Opportunities
4.3 –
Finalize Opportunities
Yellow denotes current and future steps..

19. Milestones & Updated Study Timeline
February – August 2011
Quantify Demand Scenarios
August – November 2011
Perform “Baseline” System Reliability Analysis
September – December 2011
Develop Options & Strategies
October 2011
Publish Interim Report No. 2
November 2011 – February 2012
Perform System Reliability Analysis with Options & Strategies
March 2012
Publish Interim Report No. 3
April – May 2012
Finalize & Evaluate Options & Strategies
June 2012
Publish Draft Final Study Report
July 2012
Publish Final Study Report

20. Colorado River Basin Water Supply and Demand Study
Study Contact Information
Website:
Telephone: ; Fax:
Ted Kowalski, Colorado Water Conservation Board
Telephone: , Ext. 3220