The federal government has started monthly adjustments to reduce the amount of water released from Lake Powell to keep the reservoir deep enough for power production from Glen Canyon Dam.
The Bureau of Reclamation stated in a Friday news release that dam operators will hold back 523,000 acre-feet in Lake Powell from now through April at a time when inflow to the reservoir is low.
Between June and September, after the spring runoff occurs, 523,000 acre-feet will be released downstream to Lake Mead. The amount could be adjusted, depending on updated levels and projections.
Only the monthly volumes are being adjusted, says the BOR. The annual release volume of 7 million acre-feet for water year 2023 (Oct. 1, 2022, through Sep. 30, 2023) will remain the same as laid out in prior agreements from 2007 and 2019.
“These monthly adjustments will boost Lake Powell’s elevation by nearly 10 feet by April 2023,” according to the BOR news release. “Latest projections show the reservoir dropping below the 3,525 feet target elevation as early as this month. The target elevation is a buffer that allows for response actions to prevent Lake Powell from dropping below elevation of 3,490 feet, the lowest elevation that Glen Canyon Dam can still release water through its eight penstocks and generate hydropower.”
Lake Powell’s surface was 3,527.89 feet above sea level as of Thursday afternoon, according to powell.uslakes.info, just 37 feet above the point where the dam would not be able to release water through its eight penstocks and generate power.
The BOR news release said the agency continues to “closely monitor the basin’s hydrology and will release updated projections later this month.”
The surface of Lake Mead was 1,042.96 feet above sea level as of noon Friday, a drop of just over 3 feet in the past month.
The minimum level for Hoover Dam to produce power is 950 feet in elevation. At 895 feet, or “dead pool,” the dam would no longer be able to release water downstream.