CWAG 2010 WATER LAW CONFERENCE The Broadmoor Colorado Springs, Colorado April 29 – 30, 2010

Colorado River Reservoir Operations Terry Fulp Bureau of Reclamation, Lower Colorado Region CWAG Water Law Conference April 30, 2010

Colorado River Basin Operation governed by the Law of the River including: –Colorado River Compact (1922) –Boulder Canyon Project Act (1928) –U.S. Mexican Water Treaty (1944) –Colorado River Storage Project (1956) –Supreme Court Consolidated Decree (1964 and following) –Colorado River Basin Project Act (1968) Variable hydrology 60 million acre-feet of storage capacity System operated on a tight margin

Natural Flow Colorado River at Lees Ferry Gaging Station, Arizona Water Year 1906 to 2009

Annual Natural Flow at Lees Ferry Tree-ring Reconstruction (Meko et al., 2007) 25-Year Running Mean

Water Budget at Lake Mead Given basic apportionments in the Lower Basin, the allotment to Mexico, and an 8.23 maf release from Lake Powell, Lake Mead storage declines Inflow = 9.0 maf (release from Powell + side inflows) Outflow = maf (AZ, CA, NV, and Mexico delivery + downstream regulation and gains/losses) Mead evaporation loss = maf Balance= maf Data based on long-term averages

Colorado River Basin Storage (as of April 25, 2010) Current Storage Percent Full MAF Elevation (Feet) Lake Powell57%13.743,620 Lake Mead44%11.371,099 Total System Storage* 55%32.78NA *Total system storage was maf or 54% this time last year

2010 Upper Colorado Projected Apr–Jul Inflow as of April 15, 2010 Flaming Gorge – 45% Blue Mesa – 74% Navajo – 81% Lake Powell – 66%

State of the System ( ) WY Unregulated inflow into Powell % of Average Powell and Mead Storage maf Powell and Mead % Capacity * * Inflow based on latest CBRFC forecast; storage and percent capacity based on April Month Study

Interim Guidelines for Operation of Lake Powell and Lake Mead In place for an interim period (through 2026) Key provisions: –Operation for Lake Powell and Lake Mead is specified throughout the full range of operation –Strategy for shortages in the Lower Basin is specified, including a provision for additional shortages if warranted –Mechanism (Intentionally Created Surplus or ICS) is established to encourage efficient and flexible water use in the Lower Basin

Lake Powell & Lake Mead Operational Diagrams and Current Conditions 4/18/10 1, /18/10 3, /18/10

Min Power Pool 3,490 ft 3,642 ft maf (57% of Live Capacity) 3,370 ft Dead Pool Lake Powell Capacity 3,700 ft 24.3 maf Dead Pool (1.9 maf) Inactive Pool (4.0 maf) Not to scale 80 ft 130 ft As of Apr 25, ,575 ft Lower Elevation Balancing Tier Mid-Elevation Release Tier 3,525 ft Equalization Tier Upper Elevation Balancing Tier Equalization Elevation (WY 2010) 3,620 ft

Lower SNWA Intake 1,000 ft 1,099 ft maf (44% of Live Capacity) 895 ft Dead Pool Elevation Lake Mead Capacity 1,219.6 ft 25.9 maf Dead Pool (2.0 maf) Not to scale 121 ft As of Apr 25, ,145 ft 24ft 1,075 ft 1 st Level Shortage Conditions 1,050 ft Surplus Conditions Normal or ICS Surplus Conditions Min Power Pool 15.9 maf 2 nd Level Shortage Conditions 3 rd Level Shortage Conditions 1,025 ft

Probability of Lower Basin Shortage

ICS may be created through extraordinary conservation measures including: –land fallowing, canal lining, desalination, importation, system efficiency There is a 5% system assessment when ICS is created (except for system efficiency projects) Delivery of ICS may occur in years after creation Intentionally Created Surplus (ICS) Construction of the Drop 2 Storage Reservoir

Colorado River Water Supply & Demand

Colorado River Basin Water Supply and Demand Study Two-year, $2 million study cost shared by Reclamation and the Basin States Objectives: Define current and future imbalances in water supply and demand Assess the risks to Basin resources Develop and evaluate adaptation and mitigation strategies A transparent, collaborative study with input from all stakeholders

Colorado River Reservoir Operations Additional Information: crbstudy.html

CWAG 2010 WATER LAW CONFERENCE The Broadmoor Colorado Springs, Colorado April 29 – 30, 2010