State of the Colorado River System: Drought and the Outlook for Floodplain Management Conference Rancho Mirage, CA September 10, 2015

Transcription

1 State of the Colorado River System: Drought and the Outlook for 2016 Floodplain Management Conference Rancho Mirage, CA September 10, 2015

2 Presentation Overview Overview of the Colorado River Basin Drought and Current Reservoir Conditions Outlook for El Niño and Potential Impacts Summary 2

3 3 Colorado River Basin

4 Natural Flow Colorado River at Lees Ferry Gaging Station, Arizona Water Year 1906 to 2015 Colorado River at Lees Ferry, AZ - Natural Flow Average 10-yr Average Annual Flow (MAF) Water Year Provisional data, subject to change Estimated values for

5 Colorado River Basin Lower Colorado River Basin 5

6 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

7 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. 7

8 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 8

9 Colorado River 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

10 State of the System (Water Years ) Unregulated Inflow into Lake Powell Powell-Mead Storage and Percent Capacity 100% 90% 80% 70% Volume in MAF % 60% 50% 40% 30% Percent Capacity % 64% 65% 24% 118% 57% 55% 80% 81% 112% 94% 78% 45% 47% 96% 94% 20% 10% 0% End of Water Year 2 Powell and Mead Storage (MAF) Unregulated Inflow into Powell (MAF) Powell and Mead Percent Capacity 1 Values for water year 2015 are projected. Unregulated inflow is based on the latest CBRFC forecast dated September 1, Storage and percent capacity are based on the August Month Study. 2 Percentages 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

11 Colorado River Basin Storage (as of September 7, 2015) Current Storage Percent Full MAF Elevation (Feet) Lake Powell 52% ,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 11

12 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) Lake Powell operating tiers pursuant to the 2007 Interim Guidelines: 12

13 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) Lake Mead operating conditions pursuant to the 2007 Interim Guidelines: 13

14 What about El Niño in Winter ? Source for graphics: Climate Prediction Center website: (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). 14

15 Comparison of Lake Powell Inflow and ENSO Events since 1964 Source: CBRFC website. 15

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

17 Hoover Dam Davis Dam Alamo Dam Elevation: 1, feet Capacity: 6% Content: 55 kaf Inflow: 4.2 cfs Outflow: 25 cfs STATUS OF USACE & SRP RESERVOIRS IN ARIZONA as of September 2, 2015 Alamo Dam Salt River Project Capacity: 50% Content: 1.15 maf Parker Dam Horseshoe Dam Bartlett Dam Painted Rock Dam Stewart Mtn. Dam Roosevelt Dam Mormon Flat Dam Horse Mesa Dam Painted Rock Dam Elevation: feet Capacity: 0% Inflow: 0 cfs Outflow: 0 cfs 17

18 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 18

19 Thank You For further information, please visit our websites:

20 Overview of the Colorado River System 16.5 million acre-feet (maf) allocated annually maf each to Upper and Lower Basins maf to Mexico 13.0 to 14.5 maf of consumptive use annually 16 maf of average annual natural flow 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 20