CWAG 2010

WATER LAW CONFERENCE

The Broadmoor Colorado Springs, Colorado

April 29 – 30, 2010

Colorado River Reservoir Operations

Terry FulpBureau of Reclamation, Lower Colorado Region

CWAG Water Law ConferenceApril 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 FlowColorado River at Lees Ferry Gaging Station, Arizona

Water Year 1906 to 2009

Annual Natural Flow at Lees FerryTree-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 = - 9.6 maf (AZ, CA, NV, and Mexico delivery + downstream regulation and gains/losses) Mead evaporation loss = - 0.6 maf Balance = - 1.2 maf

Data based on long-term averages

Colorado River Basin Storage (as of April 25, 2010)

Current StoragePercent

FullMAF

Elevation (Feet)

Lake Powell 57% 13.74 3,620

Lake Mead 44% 11.37 1,099

Total System Storage*

55% 32.78 NA

*Total system storage was 31.88 maf or 54% this time last year

2010 Upper ColoradoProjected

Apr–Jul Inflow as of April 15, 2010

Flaming Gorge – 45%

Blue Mesa – 74%

Navajo – 81%

Lake Powell – 66%

State of the System (1999-2010)

WYUnregulated inflow

into Powell% of Average

Powell and MeadStorage

maf

Powell and Mead

% Capacity

1999 109 47.59 95

2000 62 43.38 86

2001 59 39.01 78

2002 25 31.56 63

2003 52 27.73 55

2004 49 23.11 46

2005 104 27.16 54

2006 71 25.80 51

2007 70 24.43 49

2008 102 26.52 53

2009 88 26.40 53

2010* 68 24.78 49

* Inflow based on latest CBRFC forecast; storage and percent capacity based on April 2010 24-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 MeadOperational Diagrams and Current Conditions

4/18/10

1,099 11.424/18/10

4/18/10

3,619 13.63

4/18/10

Min Power Pool

3,490 ft

3,642 ft13.74 maf(57% of Live Capacity)

3,370 ft Dead Pool

Lake Powell Capacity3,700 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, 2010

3,575 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 Intake1,000 ft

1,099 ft 11.37 maf(44% of Live Capacity)

895 ft Dead Pool Elevation

Lake Mead Capacity1,219.6 ft 25.9 maf

Dead Pool (2.0 maf)

Not to scale

121 ft

As of Apr 25, 2010

1,145 ft

24ft

1,075 ft1st Level Shortage Conditions

1,050 ft

Surplus Conditions

Normal or ICS Surplus Conditions

Min PowerPool

15.9 maf

2nd Level Shortage Conditions

3rd Level Shortage Conditions1,025 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: http://www.usbr.gov/lc/riverops.htmlhttp://www.usbr.gov/lc/region/programs/ crbstudy.html

CWAG 2010

WATER LAW CONFERENCE

The Broadmoor Colorado Springs, Colorado

April 29 – 30, 2010