Here’s the release from the Bureau of Reclamation (Patti Aaron):
The Bureau of Reclamation today released the Colorado River Basin August 2020 24-Month Study, which sets annual operations for Lake Mead and Lake Powell in 2021. Based on projections in the Study, Lake Mead will operate in the Normal Condition in Calendar Year 2021 and Lake Powell will operate in the Upper Elevation Balancing Tier in Water Year 2021 (October 1, 2020 through September 30, 2021).
The August 2020 24-Month Study projects:
– Lake Mead’s Jan. 1, 2021, elevation to be 1,085.28 feet, about 10 feet above the Lower Basin shortage determination trigger of 1,075 feet.
– Lake Powell’s Jan. 1, 2021, elevation to be 3,591.60 feet — 109 feet below full and 101 feet above minimum power pool.
Because Lake Mead is projected to begin the year below the Drought Contingency Plan elevation threshold of 1,090 feet, Arizona, Nevada and Mexico will make water savings contributions to Lake Mead in calendar year 2021. Those Drought Contingency Plans, adopted by the seven Basin States, the U.S. federal government and Mexico in 2019, continue to proactively reduce risk in the basin.
“After a promising start to the snow season last winter, spring and summer turned very dry,” said Reclamation Commissioner Brenda Burman. “Thankfully, our reservoirs continue to do what they were built to do and are providing reliable water by holding it over from wetter years.”
The Upper Basin experienced a dry spring in 2020, with April to July runoff into Lake Powell totaling just 52% of average. The projected water year 2020 unregulated inflow into Lake Powell—the amount that would flow to Lake Mead without the benefit of storage behind Glen Canyon Dam—is only 58% of average. Total Colorado River system storage today is 51% of capacity, down from 55% at this time last year. Drought contingency plans are proactively addressing risks to the system from the ongoing 21-year drought.
A key component of Reclamation’s Colorado River Basin activities is the integration of sophisticated modeling tools and scientific research to inform water management decisions. Through a decades-long partnership with the Center for Advanced Decision Support for Water and Environmental Systems at the University of Colorado in Boulder, Reclamation hydrologic engineers and hydrologists are actively collaborating with climate, hydrology and decision support scientists to provide advanced modeling tools.
“This scientific expertise is key,” Commissioner Burman continued. “It helps us understand what’s happening in the basin now and how changes to climate and demand are likely to impact the river in the future so we can best operate our reservoirs to protect water reliability for generations to come.”
Their work is helping Reclamation link advances in science to water resource management decisions in the face of greater uncertainty and increased hydrologic and operational risks. Reclamation’s modeling and operations teams further refine these tools, such as the 24-Month Study, to make annual operational determinations for Lake Powell and Lake Mead through close coordination with water and power customers throughout the basin.