Colorado River managers looking to protect critical infrastructure at Lake Powell’s Glen Canyon Dam are seeking the ability to release less water from Powell next year as they work to rebalance demand on the troubled river.
“We are taking immediate steps now to revise the operating guidelines to protect the Colorado River System and stabilize rapidly declining reservoir storage elevations,” reclamation commissioner Camille Touton said late last week in a written statement.
The bureau currently operates the two reservoirs based on rules dictated in the 2007 Interim Guidelines and the 2019 Drought Contingency Plans. In seeking to change operations at Lake Powell and Lake Mead, the bureau must prepare a supplemental environmental impact statement, which it published a notice of intent to do on Friday. The 2007 guidelines expire at the end of 2025 and will be renegotiated in the coming years. The notice Friday makes clear this federal action is not intended to supersede those negotiations, but rather to address more immediate challenges.
“They are very worried about the infrastructure at the dam,” said Andy Mueller, general manager of the Colorado River District.
The current operating rules do not allow for the bureau to annually release less than 7 million acre-feet out of Glen Canyon Dam, Mueller said. “They don’t have the authority to go lower than that.”
However, after two dry decades and three particularly dry years in a row, Lake Powell is less than 25% full. The water level is low enough that another significantly dry year combined with a 7 million acre-foot release could lead to the Utah reservoir falling below a critical elevation, threatening the dam’s infrastructure and its ability to generate hydropower.
Mueller said he thinks it’s a smart move for the bureau to give itself more flexibility in how much water it releases out of Powell. “I’m happy to see the bureau seeking authorization to deal with the actual hydrology,” he said. “The key is to not let politics influence these decisions and make it on sound, reasonable science.”
The bureau is considering an annual release as low as 5.5 million acre-feet, Mueller said. “At some point, we have to operate those reservoirs as run-of-the-river structures,” he said. “We no longer have this buffer of storage and so if the inflow into Lake Powell is only 5.5 million acre-feet you shouldn’t release more than 5.5 million acre-feet.”
Scientists believe the Colorado River Basin is currently experiencing the driest 22-year stretch of the past 1,200 years. In recent years warmer temperatures have dried out soil conditions; those dry soils then suck up valuable runoff from streams.
James Prairie, a hydraulic engineer for the Upper Colorado Region of the Bureau of Reclamation, handles the modeling that top bureau officials rely on when planning for future scenarios at Powell. Prairie said he’s preaching preparedness for next year.
“This early I want them to think we have a lot of uncertainty in what we know right now and look at the lower end as a possibility that’s plausible and be ready for it,” Prairie said. “That’s why you saw the notice of intent go out.”
In the past two years, water managers have released a total of 661,000 acre-feet of water from Upper Basin reservoirs, including 36,000 acre-feet from Blue Mesa west of Gunnison, to try to keep the water level at Lake Powell from dropping too low. The lower water levels at Blue Mesa kept the reservoir’s marinas from opening this year.
Even with the extra water from Blue Mesa and Flaming Gorge reservoir on the Wyoming-Utah border, some bureau models predict the elevation at Powell could drop below 3,490 feet above sea level next year, the lowest elevation at which Glen Canyon Dam can generate hydropower.
One dire model that is based on the particularly dry year of 2002 shows Powell dropping below the 3,490 foot mark as early as July 2023, according to bureau projections.
“It’s a big deal that they’re trying to figure out how they can change operations in 2023 to release less than 7 million acre-feet from Powell. That’s never been done before,” said John Berggren, a water policy analyst with Western Resource Advocates. “It demonstrates how concerned they are.”
The bureau’s Touton indicated this summer that the states would need to come up with a plan to cut between 2 million and 4 million acre-feet of Colorado River water use by the end of 2023 to help balance the system. The Upper Basin states of Colorado, Wyoming, Utah, and New Mexico, released a plan in response to the commissioner’s call for cuts. The Lower Basin states of California, Arizona and Nevada did not release a combined plan. California recently said it would be willing to cut back its Colorado River water use by 400,000 acre-feet, about 9% of its total allotment.
In her call for water cuts, Touton also said the federal government would be willing to act unilaterally to make the necessary cuts if the states could not come to an agreement. Friday’s notice of intent from the Bureau of Reclamation lays the groundwork for that action, said Jennifer Gimbel, a senior water policy scholar at Colorado State University’s Colorado Water Center.
“It puts the states on alert that the bureau is considering other possible actions beyond what you all can agree to,” Gimbel said.
The 13-page notice signed by Tommy Beaudreau, the deputy secretary for the Department of the Interior, says the bureau will review a range of options for revised reservoir operations and publish a draft in spring 2023. The bureau said it anticipates proposing modifications for 2023 and 2024.
“In my mind it’s, ‘If you don’t agree, we’ll do something, and even if you do agree we still may do something,’” Gimbel said, describing the bureau’s notice of intent.
The notice also says the bureau will consider releasing less water to the Lower Basin out of Hoover Dam at Lake Mead.
“As this short-term crisis is addressed, we must not lose sight of the need to find durable, sustainable solutions for the Colorado River, which must include bringing uses downstream of Lake Mead and Lake Powell into alignment with available supplies,” Colorado River Commissioner Becky Mitchell said in a statement. “One critical step towards that, which would address both near and long-term needs, is to assess evaporation and transit losses in the Lower Basin, which is a step that can be taken immediately to conserve a significant amount of water.”
In recent weeks, top water officials in multiple basin states have called on the bureau to require California, Arizona and Nevada to account for water lost to evaporation and during transit in the Lower Basin. Upper Colorado River Commission director Chuck Cullom recently told The Colorado Sun that the bureau estimates that figure at about 1.2 million acre-feet annually. The Upper Basin states already account for evaporation losses in their Colorado River use.
The Colorado River Indian Tribes, which comprise four tribes in California and Arizona, the Fort Mojave, Chemehuevi, Hopi and Navajo, wrote a letter to the bureau last week contending that its water rights are not subject to the bureau assessing evaporation and transit losses.
“The CRIT water right is for diversion from the mainstream, it predates any reclamation projects on the river and the CRIT never entered a contract for delivery of water from storage in Lake Mead,” the letter reads. “Therefore, reclamation does not have the authority to assess system losses against the CRIT water right.”
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Less water potentially being released out of Powell has other implications for the Upper Basin states as well. The Colorado River Compact includes a provision that says the Upper Basin “will not cause” the flow of the river at a specific gauge, Lees Ferry in northern Arizona, to fall below an aggregate of 75 million acre-feet for any period of 10 consecutive years. In technical parlance, it’s referred to as a “nondepletion” requirement.
Dropping below the nondepletion requirement could trigger a “compact call,” meaning Upper Basin water use could be cut to meet downstream requirements.
“The states know that this is getting serious and everyone needs to take shortages,” Berggren said. “I haven’t heard any quibbling about a compact call yet.”