# Overview **of the Colorado River Basin**  **Wa ter Supply**  **and Demand Study GNEB Board Meeting**  **Te leconference**  **/ W ebinar**  **March 22, 2012**

# Colorado **River Basin W ater Supply**  **and Demand**  **Study** • Study Objective

- Assess future water supply and demand imbalances over the next 50 years

- Develop and evaluate opportunities for resolving imbalances 

### • Study being conducted by Reclamation and the Basin States, in collaboration with stakeholders throughout the Basin • A 2.5 year- Study beginning in January 2010 • A planning study - will not result in any decisions, but will provide the technical foundation for future activities

# Historical **Colorado River W ater**  **Supply &** **Use (Annual)** 

# 50 **Ye ars**  **of Colorado River Changes**  **1960 2010**  Demographics / Land Use • Population served 12 million 30 million • Acres irrigated < 3 million 3 million 

## Physical System • Storage capacity 30 maf 67 maf • Hydropower generation capacity 6,700 GW 12,400 GW 

## Natural System • Annual mean natural flow at L.F. • Lowest 10 -yr

average flow

at L.F. 15.1 maf (14.9)

12.5 maf ( 1931 - 1940) 15.0 maf 12.0 maf (2001 -2010) 

## Institutions, Governance • Legislation, Policies, Agreements • Colorado River Compact • Boulder Canyon Project Act • US - Mexico Water Treaty • UC River Basin Compact • CR Storage Project • Decree in AZ v . CA • NEP A • ESA • QSA • 2007 Interim Guidelines

# Study Phases **and Ta** **sks**

Phase 1: Water Supply Assessment 1.1 - Select Methods to Estimate Current Supply 1.2 - Select Methods to Project Future Supply 1.3 - Conduct Assessment of Current Supply 1.4 - Conduct Assessment of Future Supply Formulate

Approach to Include Uncertainty
Develop Future Supply and Demand Scenarios Phase 2:

Water Demand Assessment 2.1 - Select Methods to Estimate Current Demand 2.2 - Select Methods to Project Future Demand 2.3 - Conduct Assessment of Current Demand 2.4 - Conduct Assessment of Future Demand Phase 3: System Reliability Analysis
3.1 - Identify Reliability Metrics 3.2 - Estimate Baseline System Reliability 3.3 - Project Future System Reliability
3.3.5 -3.3.8 - Project Future Reliability with Opportunities Phase 4: Development & Evaluation of Opportunities 4.1 - Develop Opportunities

4.2 - Evaluate and Refine Opportunities

4.3 - Finalize Opportunities Complete, described in Interim Report No. 1 and subsequent technical updates Ongoing work since Interim Report No. 1 Kickof f in November 201 1

# Phase **1: W**

**ater Supply**  **Assessment** Scenarios *: • Observed Resampled • Paleo Resampled • Paleo Conditioned • Downscaled GCM Projected

**18 17**  Meko et al. **16 15**  **14 13**  **12 11**  **10 775**  **975 1175**  **1375 1575**  **1775 1975**  **Year** * 

### Multiple realizations for each scenario

# Phase **2: W**

**ater Demand**  **Assessment** Scenarios*:

• 

### Current Projected : growth, development patterns, and institutions continue along recent trends

• 

### Slow**G row** **th:** low growth with emphasis on economic ef ficiency

• 

### Rapid Grow**th:** economic resurgence (population and energy) and current preferences toward human and environmental values **

• 

### Enhanced Environment: expanded environmental awareness and stewardship with growing economy **
***** Preliminary - Scenario names subject to change ** Additional “branches” possible depending upon assumed trajectory of specific socio -economic factors

# Phase **3: System Reliability**  **Analysis** • Simulate the state of the system on a monthly time step over the next 50 years for each scenario, with and without options and strategies • Metrics will be used to quantify impacts to Basin resources



## • 

## Resource Categories  Wa ter Deliveries  Electrical Power Resources  Wa ter Quality  Flood Control  Recreational Resources  Ecological Resources

# Phase **4: Development and**  **Evaluation of**  **Opportunities to Balance**  **Supply & Demand**  • Consider a wide range of options and strategies • Will not result in selection or funding of a proposed project **Projected Future Colorado River Basin Supply & Demand** • Preliminary Assessment based on:

- “Current Projected” demand scenario

- supply scenario that considers a changing climate • A broad range of imbalances wi ll be considered wh en all supply and demand scenarios are combined

# Summary of Options Submitted • Over 140 options were submitted to the Study • Multiple sub - categories exist, e.g. desalination, watershed management, reuse, etc. • Option will be posted on the Study website in late March 

### Increase **Supply Reduce**  **Demand Modify**  **Operations Governance**  **& Implementation** 

# Process **for Developing & Evaluating**  **Options & Strategies**

# Milestones **& Updated Study T**  **imeline** February - January 2012 Quantify Demand Scenarios December - March 2012 Perform “Baseline” System Reliability Analysis November - March 2012 Develop Options & Strategies February - March 2012 Publish T echnical Updates March - April 2012 Perform System Reliability Analysis wi th Options & Strategies April - June 2012 Finalize & Evaluate Options & Strategies June 2012 Publish Draft Final Study Report July 2012 Publish Final Study Report

# Colorado **River Basin W ater Supply**  **and Demand Study**

Study Contact Information • We bsite: http://www.usbr.gov/lc/region/programs/crbstudy.html • Email: ColoradoRiverBasinStudy@usbr.gov • Te lephone: 702 -293 -8500; Fax: 702 -293 -8418