Lake Powell water levels continue to drop, and a new report released by the Bureau of Reclamation projects the possibility America’s second-biggest dam could be too low to produce electricity by July 2022.
Glen Canyon Dam can generate 5 billion kilowatt-hours per year at full capacity, enough to run about 470,000 average American homes. But if it sinks below 3,490 feet, that generation goes away.
The projections show a 25 to 35 % chance that will happen, but the reservoir has a 90 % chance of sinking below the threshold the Bureau likes to maintain to be safe. They mark that at 3,525 feet.
Lake Powell was at 3,546 feet above sea level on September 23. In July, the Bureau started releasing water from large reservoirs upstream, including Flaming Gorge and Navajo, in order to slow the losses in Powell.
The new long-term projections don’t show the lake sinking below the level known as “Dead Storage Pool,” or simply “Dead Pool,” which is 3,370 feet. At that point, the mechanisms allowing for the control of streamflow are no longer operative, meaning the reservoir ceases to serve its purpose for water storage and distribution.
As North America approaches the end of the 2021 water year, the two largest reservoirs in the United States stand at their lowest levels since they were first filled.
After two years of intense drought and two decades of long-term drought in the American Southwest, government water managers have been forced to reconsider how supplies will be portioned out in the 2022 water year.
Straddling the border of southeastern Utah and northeastern Arizona, Lake Powell is the second largest reservoir by capacity in the United States. In July 2021, water levels on the lake fell to the lowest point since 1969 and have continued dropping.
As of September 20, 2021, the water elevation at Glen Canyon Dam was 3,546.93 feet, more than 153 feet below “full pool” (elevation 3,700 feet). The lake held just 30 percent of its capacity.
To compensate, federal managers started releasing water from upstream reservoirs to help keep Lake Powell from dropping below a threshold that threatens hydropower equipment at the dam.