State of the Colorado River System: Drought and the Outlook for 2016

Floodplain Management Conference Rancho Mirage, CASeptember 10, 2015

Presentation Overview

• Overview of the Colorado River Basin

• Drought and Current Reservoir Conditions

• Outlook for 2016• 2016 El Niño and Potential

Impacts• Summary

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Colorado River Basin

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Natural FlowColorado River at Lees Ferry Gaging Station, Arizona

Water Year 1906 to 2015

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Colorado River at Lees Ferry, AZ - Natural Flow

Average 10-yr Average

Provisional data, subject to change Estimated values for 2013-2015

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Colorado River Basin

Lower Colorado River Basin

Colorado River Basin “Law of the River”

• Colorado River Compact, 1922• Boulder Canyon Project Act, 1928• US-Mexico Water Treaty, 1944• Upper Colorado River Basin Compact,

1948• Colorado River Storage Project Act,

1956• Consolidated Supreme Court Decree,

Arizona v. California, 1964 (and following)

• Colorado River Basin Salinity Control Act, 1974 (and following)

• Colorado River Basin Project Act, 1968

• Also includes more recent operating agreements (i.e, 2007 Interim Guidelines and IBWC Minute 319)

Sketch of proposed Boulder Canyon dam site and reservoir, circa 1921

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1928 Boulder Canyon Project Act, Section 6

• Authorizes… “[t]hat the dam and reservoir provided for by section 1 hereof shall be used:

– First, for river regulation, improvement of navigation, and flood control;

– second, for irrigation and domestic uses and satisfaction of present perfected rights in pursuance of Article VIII of said Colorado River compact; and

– third, for power.”

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Operation of Lake Mead and Hoover Dam

• Two modes of operation govern the releases from Lake Mead– Flood Control (releases in

excess to downstream water delivery requests)

– Meet the downstream water delivery requests

• Flood Control operations governed by U.S. Army Corps of Engineers regulations

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Colorado River 2000-2015 Historic Drought• Driest 16-year period in 110 years of recorded history• One of most severe 16-year droughts in over 1200 years• Chance of Lower Basin shortage conditions as early as 2017

Lake Mead near

Hoover Dam 2000

Lake Mead near

Hoover Dam 2015

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State of the System (Water Years 1999-2015)1

118%

64% 65%

24%57% 55%

118%

80% 81%112%

94%78%

147%

45% 47%

96% 94%

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100%

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2015

Percent CapacityVo

lum

e in

MAF

End of Water Year

Unregulated Inflow into Lake PowellPowell-Mead Storage and Percent Capacity

Powell and Mead Storage (MAF) Unregulated Inflow into Powell (MAF) Powell and Mead Percent Capacity2

1Values for water year 2015 are projected. Unregulated inflow is based on the latest CBRFC forecast dated September 1, 2015. Storage and percent capacity are based on the August 2015 24-Month Study. 2Percentages at the top of the light blue bars represent percent of average unregulated inflow into Lake Powell for a given water year. The percent of average is based on the period of record from 1981-2010.

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Colorado River Basin Storage(as of September 7, 2015)

Current Storage Percent Full MAF Elevation

(Feet)

Lake Powell 52% 12.6 3,608

Lake Mead 38% 9.9 1,078

Total System Storage* 52% 30.7 NA

*Total system storage was 30.1 maf or 51% this time last year

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End of CY 2015 Projection:3,602.5 feet

End of CY 2016 Projection:3,603.9 feet (Range: 3,575 to 3,647 feet)

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Lake Powell operating tiers pursuant to the 2007 Interim Guidelines: http://www.usbr.gov/lc/region/programs/strategies/RecordofDecision.pdf.

End of CY 2015 Projection:1,082.3 feet

End of CY 2016 Projection: 1,079.6 feet (Range: 1,077 to 1,110 feet)

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Lake Mead operating conditions pursuant to the 2007 Interim Guidelines: http://www.usbr.gov/lc/region/programs/strategies/RecordofDecision.pdf.

What about El Niño in Winter 2015-2016?

Source for graphics: Climate Prediction Center website: http://www.cpc.noaa.gov/ (September 9, 2015).

Per the CPC, this figure above was provided by the International Research Institute (IRI) for Climate and Society (updated August 18, 2015).

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Comparison of Lake Powell Inflowand ENSO Events since 1964

Source: CBRFC website.

Projected Lake Mead Elevations1

2015-2020

1 Projections based on Reclamation’s August 2015 simulation of the Colorado River Mid-term Operations Probabilistic Model (MTOM) (currently in development).16

STATUS OF USACE & SRP RESERVOIRS IN ARIZONA

as of September 2, 2015

Painted Rock DamElevation: 535.0 feetCapacity: 0%Inflow: 0 cfsOutflow: 0 cfs

Painted Rock DamStewart Mtn. Dam

Mormon Flat Dam

Horse Mesa Dam

Roosevelt Dam

Salt River ProjectCapacity: 50%Content: 1.15 maf

Horseshoe Dam

Bartlett Dam

Alamo Dam

Parker Dam

Davis Dam

Hoover Dam Alamo DamElevation: 1,089.29 feetCapacity: 6%Content: 55 kafInflow: 4.2 cfsOutflow: 25 cfs

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Closing thoughts…• The Colorado River Basin is

currently experiencing an unprecedented 16-year drought

• It would take a very wet hydrologic sequence to replenish storage in the system

• Climate projections indicate more extreme conditions are possible, with longer, more severe wet and dry periods

• Cooperation and collaboration is key to finding sustainable solutions and addressing current and future challenges

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Thank You

For further information, please visit our websites:

www.usbr.gov/uc/www.usbr.gov/lc/

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Overview of the Colorado River System

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• 16.5 million acre-feet (maf) allocated annually- 7.5 maf each to Upper and Lower Basins- 1.5 maf to Mexico

• 13.0 to 14.5 maf of consumptive use annually

• 16 maf of average annual “natural flow”- 14.8 maf in the Upper Basin and 1.3 maf in

the Lower Basin• Inflows are highly variable year to year• 60 maf of storage (4 times the annual

inflow)• Operations and water deliveries governed

by the “Law of the River”