Click the link to read the letter on the Reclamation website (Noe Santos and Heather Patno). Click through to view the operating plans for all of the Colorado River Basin reservoirs. Here’s an excerpt:
The operation of Lake Powell and Lake Mead in this April 2022 24-Month Study is pursuant to the December 2007 Record of Decision on Colorado River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations of Lake Powell and Lake Mead (Interim Guidelines), and reflects the 2022 Annual Operating Plan (AOP). Pursuant to the Interim Guidelines, the August 2021 24-Month Study projections of the January 1, 2022, system storage and reservoir water surface elevations set the operational tier for the coordinated operation of Lake Powell and Lake Mead during 2022.
The August 2021 24-Month study projected the January 1, 2022, Lake Powell elevation to be less than 3,575 feet and at or above 3,525 feet and the Lake Mead elevation to be at or above 1,025 feet. Consistent with Section 6.C.1 of the Interim Guidelines the operational tier for Lake Powell in water year 2022 is the Mid- Elevation Release Tier and the water year release volume from Lake Powell will be 7.48 million acre-feet (maf).
The August 2021 24-Month Study projected the January 1, 2022 Lake Mead elevation to be at or below 1,075 feet and at or above 1,050 feet. Consistent with Section 2.D.1 of the Interim Guidelines, a Shortage Condition consistent with Section 2.D.1.a will govern the operation of Lake Mead for calendar year 2022. In addition, Section III.B of Exhibit 1 to the Lower Basin Drought Contingency Plan (DCP) Agreement will also govern the operation of Lake Mead for calendar year 2022. Efforts to conserve additional water in Lake Mead under a 2021 Lower Basin Memorandum of Understanding (MOU) to facilitate near-term actions to maintain the water surface elevation of Lake Mead will also take place in calendar year 2022.
The Upper Basin Drought Response Operations Agreement (DROA) provisions to protect a target elevation at Lake Powell of 3,525 feet have been incorporated into the April 2022 24-Month Study and includes an adjusted monthly release volume pattern for Glen Canyon Dam that will hold back a total of 0.350 maf in Lake Powell from January through April. There are continued discussions when and how that same amount of water (0.350 maf) will be released later in the water year. The annual release volume from Lake Powell for water year 2022 will continue to be 7.48 maf. If future projections indicate the monthly adjustments are insufficient to protect Powell’s elevation, Reclamation will again consider additional water releases from the upstream initial units of the Colorado River Storage Project later this year.
Current runoff projections into Lake Powell are provided by the National Weather Service’s Colorado Basin River Forecast Center and are as follows. The observed unregulated inflow into Lake Powell for the month of March was 0.329 maf or 55 percent of the 30-year average from 1991 to 2020. The April unregulated inflow forecast for Lake Powell is 0.600 maf or 66 percent of the 30-year average. The 2022 April through July unregulated inflow forecast is 4.100 maf or 64 percent of average.
In this study, the calendar year 2022 diversion for Metropolitan Water District of Southern California (MWD) is projected to be 1.110 maf. The calendar year 2022 diversion for the Central Arizona Project (CAP) is projected to be 0.989 maf. Consumptive use for Nevada above Hoover (SNWP Use) is projected to be 0.251 maf for calendar year 2022.
Due to changing Lake Mead elevations, Hoover’s generator capacity is adjusted based on estimated effective capacity and plant availability. The estimated effective capacity is based on projected Lake Mead elevations. Unit capacity tests will be performed as the lake elevation changes. This study reflects these changes in the projections.
Hoover, Davis, and Parker Dam historical gross energy figures come from PO&M reports provided by the Lower Colorado Region’s Power Office, Bureau of Reclamation, Boulder City, Nevada. Questions regarding these historical energy numbers can be directed to Colleen Dwyer at (702) 293-8420.
Runoff and inflow projections into upper basin reservoirs are provided by the Colorado River Forecasting Service through the National Weather Service’s Colorado Basin River Forecast Center and are as follows in thousand acre-feet (kaf):
The 2022 AOP is available online at: https://www.usbr.gov/lc/region/g4000/aop/AOP22.pdf.
The Interim Guidelines are available online at: https://www.usbr.gov/lc/region/programs/strategies/RecordofDecision.pdf.
The Colorado River DCPs are available online at: https://www.usbr.gov/dcp/finaldocs.html.
The 2021 Lower Basin MOU is available online at: https://www.usbr.gov/lc/region/g4000/2021_MOU.pdf.
The Upper Basin Hydrology Summary is available online at: https://www.usbr.gov/uc/water/crsp/studies/24Month_04_ucb.pdf.