1. Colorado River Update Terry Fulp Deputy Regional Director
Bureau of Reclamation, Lower Colorado Region
Southern California Water Dialogue
July 28, 2010

2. 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
Points to make:
Law of the River is not static; it has and continues to evolve over time; Interim guidelines are a great example
Basin is characterized by highly variable hydrology and we have constructed a large amount of storage to deal with that variability – 4x average annual inflow
Store water in the high flow years so that deliveries can be made in low flow years
As demand has increased over time, our margin has become tighter, particularly in the Lower Basin (will show that in a later slide)

3. 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 = 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
The slide about it is a “tight margin” particularly in the LB:
Point out that when Powell makes an 8.23 maf release, Mead goes down
at 100,000 ac-feet/foot, that is feet decline at Mead each year
why has the LB had 100% reliability in deliveries? Large amount of storage … we live off the high flow years
Data based on long-term averages

4. Natural Flow Colorado River at Lees Ferry Gaging Station, Arizona Water Year 1906 to 2009
Points to make:
101-year ( ) historical average is approximately 15 maf
2007 and 2008 are estimated values
Inflows are highly variable
Period from has the lowest 12-year average inflow, but note there were a couple of good years in the period 4

5. Unregulated inflow into Powell
State of the System ( ) WY
Unregulated inflow into Powell
% of Average
Powell and Mead
Storage
maf
% 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
2008
102
26.52 53
2009 88
26.40
2010* 68
24.78
Inflow based on latest CBRFC forecast; storage and percent capacity based on April Month Study 5

6. 2007 Interim Guidelines
Operations specified for full range of operation for Lake Powell and Lake Mead
Strategy for shortages in the Lower Basin
Mechanism in Lower Basin to encourage efficient and flexible use and management of Colorado River water (ICS)
In place for an interim period (through 2026) 6

7. Colorado River Basin Storage (as of July 25, 2010)
Current Storage
Percent Full
MAF
Elevation (Feet)
Lake Powell
64%
15.67
3,637
Lake Mead
40%
10.42
1,088
Total System Storage*
58%
34.26 NA
*Total system storage was maf or 60% this time last year 7

8. 2010 Upper Colorado Projected Apr–Jul Inflow as of July 15, 2010
Flaming Gorge – 59%
Blue Mesa – 69%
Navajo – 83%
Lake Powell – 73% 8

9. Lake Powell Capacity 24.3 maf Equalization Tier 15.67 maf
3,700 ft
24.3 maf
Equalization Tier
63ft
Equalization Elevation (WY 2010)
3,642 ft
15.67 maf
(64% of Live Capacity)
3,637 ft
Upper Elevation Balancing Tier
3,575 ft
147 ft
Mid-Elevation Release Tier
3,525 ft
Lower Elevation Balancing Tier
3,490 ft
Min Power
Pool
Inactive Pool (4.0 maf)
3,370 ft
Dead Pool
Dead Pool (1.9 maf)
Not to scale
As of Jul 25, 2010 9

10. Normal or ICS Surplus Conditions
Lake Mead Capacity
1,219.6 ft
25.9 maf
Surplus Conditions
132 ft
1,145 ft
15.9 maf
Normal or ICS Surplus Conditions
1,088 ft
10.42 maf
(40% of Live Capacity)
38 ft
1,075 ft
Shortage Conditions
Min Power
Pool
1,050 ft
Inactive Pool (7.5 maf)
1,000 ft
Lower SNWA Intake
Dead Pool Elevation
895 ft
Dead Pool (2.0 maf)
Not to scale
As of Jul 25, 2010 10

11. Colorado River Water Supply & Use
Use Curve:
Upper Basin consumptive use (Sources: “Microfiche” prior to 1971; CU & L Reports 1971 forward)
Lower Basin consumptive use (Sources: data supplied from users prior to 1964, Mexico assumed to be 1.5 mafy; Decree Accounting Reports 1964 forward)
Losses
average evap at CRSP reservoirs, Mead, Mohave and Havasu
bypass flows
native vegetation in LB
does not include over-deliveries to Mexico (may re-think this decision and perhaps use the average excluding flood control years)
Supply Curve:
“Natural flow” at Imperial ( ) computed 6/16/08
Lower Basin tributaries inflows are not corrected for upstream uses (i.e., Virgin River, Gila River) 11

12. Colorado River Basin Water Supply and Demand Study
Two-year, $2 million study cost shared by Reclamation and the Basin States
Assess future water supply and demand imbalance
Assess risks to all basin resources
Investigate options and strategies to mitigate impacts
A transparent, collaborative study with input from all stakeholders
Website:
programs/ crbstudy.html
Define current and future imbalances in water supply and demand within the study area over a 50-year horizon, particularly in light of potential impacts of climate change
Assess the risks to Basin resources including water deliveries, hydroelectric power generation, recreation, fish and wildlife and their habitat, water quality, flow and water-dependent ecological systems, and flood control management
Develop and evaluate adaptation and mitigation strategies to resolve those imbalances
REMIND THEM THAT WE HAVE A WEB SITE: address on last slide 12

13. Scenario Approach toward Addressing Uncertainties
Water Supply Scenarios
Water Demand Scenarios
Hydroclimatic Variability & Change (Past, Present, and Future)
Observed Historic Record
Paleo-Conditioning
Paleo Record
Downscaled Climate Projections
Storyline Approach to Plausible Future Demands
Baseline Demands
Alternative Futures by Storylines
More Intensive Demands
(higher population growth, less water use efficiency, lower technology use)
Less Intensive Demands
(stable population growth, more water use efficiency, rapid technology adoption)
Armin, I also added the word “based” to the title here.

14. Some Climate Change Projections for the Colorado River Basin
Source: Ray et al., 2008

15. Methodology to Incorporate Modeled Future Projections of Climate Change into Water Supply Projections
Emissions
Scenarios
Climate
Simulations
Spatial
Downscaling
Hydrologic
Model
Planning
3 Scenarios
16 GCMs
112 Projections
112 Traces
KEY POINTS
Reclamation (Technical Services Center) collaborated with Santa Clara University and Lawrence Livermore National Laboratory (LLNL) to develop an archive of 112 bias-corrected and spatially downscaled GCM projections over the contiguous United States
Reclamation (LC Region) is using data from this archive to test the framework for using GCM- based flow projections in the Colorado River Simulation System (CRSS), Reclamation’s long- term planning model for the Colorado River
DETAILS
112 bias-corrected and spatially downscaled GCM projections obtained from archive hosted by LLNL at:
16 GCMs, 3 emission scenarios (A1b-middle, A2-high, B1-low), multiple initial conditions resulted in GCM output for 112 projections.
Output from GCMs is bias-corrected and spatially downscaled using “simple” statistical downscaling technique (Wood et al. 2004, Maurer 2007).
Resulted in gridded (1/8° or approximately 12km), monthly values of precipitation and temperature from 1950 through 2099 over the contiguous United States
Each of the 112 GCM projections is run through the Variable Infiltration Capacity (VIC) hydrologic model (Liang, et al, 1994) to simulate runoff.
VIC is supported at the University of Washington; information available at:
Each of the resulting 112 runoff projections will be run through CRSS.
STATUS
A collaborative research project with AMEC Earth & Environmental in Boulder CO (formerly Hydrosphere Resource Consultants)
Anticipate CRSS results by March 2010 15

16. Preliminary Results of 112 Inflow Projections
Biased corrected using the Ratio method
Lot’s of variablity in any given year
Average shows about 10% decrease in annual average inflow

17. Timeline - Milestones Final Study Report and Appendices Complete
Jan 2012
Final Study Report and Appendices Complete
Oct
2011
Draft Study Report and Appendices Complete
Sep 2011
Options and Strategies Analysis Complete
April 2011
System Reliability Analysis Complete
Current and Future Water Supply Assessment Complete
Sep 2010
Current and Future Water Demand Assessment Complete

18. Colorado River Basin Water Supply and Demand Study
Website:
programs/ crbstudy.html
Define current and future imbalances in water supply and demand within the study area over a 50-year horizon, particularly in light of potential impacts of climate change
Assess the risks to Basin resources including water deliveries, hydroelectric power generation, recreation, fish and wildlife and their habitat, water quality, flow and water-dependent ecological systems, and flood control management
Develop and evaluate adaptation and mitigation strategies to resolve those imbalances
REMIND THEM THAT WE HAVE A WEB SITE: address on last slide 18