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Difficult decisions for the Colorado River are starting to be made.
In what will be a defining year for the struggling watershed, the federal agency that manages the basin’s dams took unprecedented actions on Friday to store more water in Lake Powell in order to preserve hydropower generation and protect water-delivery infrastructure at Glen Canyon Dam that the agency says is at risk of damage due to low reservoir levels.
The April 17 announcement from the Bureau of Reclamation will also set in motion events that could result in first-ever lawsuits from Arizona, California, or Nevada against their upstream neighbors over water supply from the shrinking Colorado River.
The Central Arizona Project, which delivers Colorado River water to Phoenix and Tucson, called Reclamation’s actions “a band-aid” and urged the agency to release even more water from upstream reservoirs into Powell. CAP, because it has lowest water-rights priority in the lower basin, is the most vulnerable to proposed water cuts that would attempt to align water supply with demand.
“There is no time to delay,” Patrick Dent, CAP’s assistant general manager for water policy, told Circle of Blue two days before the announcement.
The Bureau of Reclamation will make two moves to support Lake Powell, the huge reservoir formed by Glen Canyon Dam that is less than 25 percent full and shrinking.
Reclamation’s first move is to release more water from Flaming Gorge, an upstream reservoir that is 82 percent full. With the consent of the four upper basin states, between 660,000 acre-feet and 1 million acre-feet will flow from Flaming Gorge into Powell over the next 12 months.
Reclamation previously used upstream reservoirs to prop up Powell in 2022-23, when some 463,000 acre-feet were released. These extra releases are supposed to be recovered if water supply conditions turn favorable. If more dry years are ahead, then the upstream releases will have been a one-shot intervention.
The agency’s second move is to hold back more water in Powell. Using authority granted in a 2024 decision, the agency will cut Powell’s water releases from 7.48 million acre-feet to 6 million acre-feet. This is the first time that Reclamation has invoked its Section 6(E) authority.
Water supply conditions in the basin worsened each month this year as hot, dry weather drained a meager snowpack that is on a downward trend due to manmade climate change. A heat wave in late March was the most extreme on record in the Southwest for that time of year. Inflows into Lake Powell this year are projected to be the lowest ever measured, breaking a record set in 2002.
The water elevation at Powell currently sits at 3,526 feet. Reclamation has stated that it will do what it can to prevent the reservoir from dropping below 3,500 feet. Hydropower generation stops at 3,490 feet. Without Reclamation’s announced interventions, that level is expected to be breached by August.
With the two interventions, Powell is projected, with average weather conditions, to remain above 3,500 feet by April 2027, but just barely. If the next 12 months continue to be hot and dry, more emergency actions might be necessary.
If Powell were to drop below 3,490 feet, water would have to be released through a smaller set of pipes called the river outlet works. Reclamation has said that using these pipes for extended periods of time is untested and risks damaging them.
Reducing outflows from Powell will have two effects. One is that Lake Mead, located downstream, will shrink more quickly, as will its hydropower output. Boating access will be more difficult.
The other consequence is the specter of litigation. The 1922 Colorado River Compact requires the four upper basin states – Colorado, New Mexico, Utah, and Wyoming – to deliver 75 million acre-feet over 10 years. Add in the upper basin’s share of the water required for Mexico and the figure rises to roughly 82.5 million.
Cutting Powell outflows this year to 6 million acre-feet will likely push the 10-year total below the required threshold.
Reclamation is not focusing on the legal implications, says James Eklund, a partner at Taft Law.
“Reclamation is essentially telling the basin states, ‘We are going to protect our billions of dollars’ worth of infrastructure, including Glen Canyon Dam, and if you believe that violates your compact entitlement, you know where the courthouse is’,” Eklund, a former Colorado River commissioner for Colorado, wrote to Circle of Blue.
States in both upper and lower basins have already set aside money for potential litigation or are considering it.
Still, a legal right does not necessarily mean the water is available, Eklund cautions. “No court can conjure acre-feet that aren’t in the reservoir.”