Colorado River Basin Water Supply and Demand Study Urban Water Institute

1. Colorado River Basin Water Supply and Demand Study Urban Water Institute 18th Annual Water Policy Conference August 26, 2011

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

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

4. 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 Email: ColoradoRiverBasinStudy@usbr.gov Website: http://www.usbr.gov/lc/region/programs/crbstudy.html A planning study – will not result in any decisions Colorado River Basin Water Supply and Demand Study

5. Study Outreach

6. Options for Participation in the Study(not mutually exclusive) • Monitor project website, webinars, emails • 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 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 3.2 – Estimate Baseline System Reliability Formulate Approach to Include Uncertainty 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 3.3 – Project Future System Reliability 2.3 – Conduct Assessment of Current Demand Develop Future Supply and Demand Scenarios 1.4 – Conduct Assessment of Future Supply 3.3.5-3.3.8 – Project Future Reliability with Opportunities 2.4 – Conduct Assessment of Future Demand 4.3 – Finalize Opportunities Green denotes essentially complete

8. 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 System Reliability Metrics (Metrics) • Metrics Resource Categories • Depletions • Electrical Power Resources • Water Quality • Flood Control • Recreational Resources • Ecological Resources

9. 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: http://www.usbr.gov/lc/region/programs/crbstudy.html • Submit comments by July 8, 2011 • Further instructions available on website

11. Historical and Future Water Supply and Demand

12. Historic Colorado River Water Supply & Use(10-year Running Average) 7

13. Natural FlowColorado River at Lees Ferry Gaging Station, ArizonaWater Year 1906 to 2011

15. State of the System (Water Years 1999-20111)

16. Water Year Snowpack and Precipitationas of August 22, 2011 Colorado River Basin above Lake Powell Water Year Precipitation (year-to-date) 124% Source: CBRFC

18. 2011 Upper ColoradoObservedApr–Jul InflowPreliminary valuesas of August 16 Flaming Gorge – 162% Blue Mesa – 124% Navajo – 74% Lake Powell – 163%

19. Colorado River Basin Storage(as of August 21, 2011) *Total system storage was 33.97 maf or 57% this time last year

20. Lake Powell & Lake MeadOperational Diagrams and Current Conditions 18.17 3,658 8/21/11 8/21/11 1,112 12.55 8/21/11 8/21/11

21. Historical Consumptive Use and Loss 1971-2008

22. 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)

23. Water Supply Scenarios * • Observed Resampled: hydroclimatic trends and variability are similar to the past 100 years • PaleoResampled: 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: futureclimate will continue to warm with regional precipitation and temperature trends represented through an ensemble of future downscaled GCM projections * Preliminary – Subject to change

24. Projections of Natural Flow at Lees Ferry 2011 – 2060 Period Mean Annual Flows Box represents 25th – 75th percentile, whiskers represent min and max, and triangle represents mean of all traces 1988 – 2007 period mean Preliminary

25. 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

26. Study Phases and Tasks 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 3.2 – Estimate Baseline System Reliability Formulate Approach to Include Uncertainty 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 3.3 – Project Future System Reliability 2.3 – Conduct Assessment of Current Demand Develop Future Supply and Demand Scenarios 1.4 – Conduct Assessment of Future Supply 3.3.5-3.3.8 – Project Future Reliability with Opportunities 2.4 – Conduct Assessment of Future Demand 4.3 – Finalize Opportunities Yellow denotes current and future steps

28. Colorado River Basin Water Supply and Demand Study • Study Contact Information • Website: http://www.usbr.gov/lc/region/programs/crbstudy.html • Email: ColoradoRiverBasinStudy@usbr.gov • Telephone: 702-293-8500; Fax: 702-293-8148