Bureau of Reclamation takes drastic steps at Lake Powell to ensure hydropower generation

The US Bureau of Reclamation is invoking its authority to change annual operations at Glen Canyon Dam for the first time in order to protect hydropower generation as Lake Powell is at its lowest level since being filled in the 1960s, officials said during a press conference May 3.

The changes allow more water to flow into Lake Powell from upstream reservoirs, while releasing less water from Lake Powell downstream, said Tanya Trujillo, US Department of Interior assistant secretary for water and science. Lake Powell serves the Glen Canyon Powerplant, which has a generation capacity of 1.32 GW.

"We are taking extraordinary actions today," Trujillo said. "That is because now is the time to act. We do not have time to waste. ... We have unprecedented drought conditions not just in the Colorado River Basin, but all around the West."

About 500,000 acre-feet of water will be released from Flaming Gorge Reservoir, about 455 river miles upstream of Lake Powell. Meanwhile, 480 kaf will be held back in Lake Powell by reducing Glen Canyon Dam's annual release volume from 7.48 maf to 7.0 maf.

"We have never taken this step before in the Colorado River Basin," Trujillo said about the historic drought and low runoff conditions in the region. "We are taking these actions today because our climate is changing, and we are responsible for that."

The actions, which will last from May 2022 to April 2023, equate to about 16 feet of elevation increase for Lake Powell.

Lake Powell elevation

Lake Powell's water surface elevation is currently at 3,522 feet and will reach critical elevation at 3,490 feet, the lowest point at which Glen Canyon Dam can generate hydropower.

"We recognize the urgent need to protect operations at Glen Canyon," Lower Colorado Basin Regional Director Jaci Gould said. "The unprecedented conditions we are facing demand prompt actions."

This is not the first time actions have been taken to address lake elevation.

In 2021, 161 kaf of water was released from upstream initial units of the Colorado River Storage Project, and earlier this year Reclamation modified Glen Canyon Dam releases to temporarily hold back 350 kaf of water to slow the reservoir's decline in the months before spring runoff.

"Deterioration was common across the Southwest, with extreme to exceptional drought broadly expanding in New Mexico and moderate to severe drought increasing in coverage across parts of Arizona and Colorado," according to the US Drought Monitor's latest weekly summary.

The entire Western region has been in varying degrees of drought for years.

"The scientists tell use we're going to be seeing more dry hydrology," Trujillo said about the actions allowing more time for long-term measures.

Upstream changes

The 2022 Drought Response Operations Agreement, which is part of the Upper Basin Drought Contingency Plan approved by Reclamation, includes releasing an additional 500 kaf from upstream Flaming Gorge Reservoir. Additional water could also be released from Blue Mesa and Navajo reservoirs through a modified plan if those reservoirs meet their water contract obligations and have water available, which will be determined later this year, according to a statement May 3.

Flaming Gorge Reservoir, on the Green River in Utah and Wyoming, currently holds about 3 maf of water and is at 78% of its storage capacity. Operators will begin sending additional water to Lake Powell this month.

In addition to normal monthly releases, 81 kaf of supplemental water will be released through May. Additional supplemental releases will be made in varying levels each month to fulfill the 500 kaf total by the end of April 2023.

Flaming Gorge's contribution of 500 kaf of water is expected to drop its surface elevation by approximately 9 feet and could impact some of the reservoir's recreational amenities.

Downstream changes

To reduce the amount of water released from Glen Canyon Dam, Reclamation will hold back an additional 130 kaf before the end of the water year, which is Sept. 30, on top of the 350 kaf of water that was held back earlier this year. Reclamation will account for the temporary reduction so that it does not penalize either basin by triggering a new series of required releases or shortage determinations.

Water users in Arizona, California and Nevada will continue to make all required shortage reductions and water savings contributions in accordance with the basin's Drought Contingency Plan and 2007 Interim Guidelines, Gould said.

"We simply all need to do more, and we need to do more now," Gould said.