U.S. releases possible plans for managing Colorado River shortages

But it didn’t release alternatives submitted by the river’s Lower and Upper Basin states, which have been deadlocked for months. Instead, the Bureau of Reclamation chose to combine various parts of those alternatives with elements of an alternative submitted by 16 tribes, including eight tribes from Arizona, although not the Tohono O’Odham and Pascua-Yaqui tribes in Southern Arizona.

Most of the alternatives issued Wednesday offer different scenarios for reservoir levels that would lead to declarations of water shortages, how shortages would be apportioned among the states, how much water use would be curtailed during shortages, and how much water would be released from Glen Canyon Dam to Lake Mead at Hoover Dam. They’re aimed at creating a new operating regime for the river and its reservoirs to use after current operating rules expire at the end of 2026.

The amount of water released from Lake Powell at Glen Canyon Dam to Lake Mead is crucial for residents of Arizona, Nevada and California, the Lower Basin states. They rely on Mead to supply water for drinking, farming and industry.

in developing alternatives, the bureau combined elements of Upper and Lower Basin and tribal proposals into two alternatives, and based a third alternative on a proposal by conservation groups. A fourth alternative is based mainly on ideas from federal officials. A fifth is a “No Action” alternative that won’t be adopted but is required to be analyzed under federal law.

The bureau likely won’t propose a specific alternative until it releases a draft environmental impact statement. The Colorado Sun website reported this statement will be released in December, but Interior Department officials, who oversee the bureau, didn’t confirm a date when asked by the Arizona Daily Star.

The bureau didn’t propose alternatives reflecting the two basins’ positions because it hopes to reach compromise, said David Wegner, a retired bureau engineer who sits on a National Academy of Sciences advisory board.

“They’re hoping to nudge states to develop a collective, collaborative, basin-wide alternative,” Wegner said. “This is part of the chess game as to how you get to a solution. You have to force the issue.”

“Reclamation’s goal for the post-2026 process is to allow for the adoption of specific guidelines for the coordinated reservoir management of Lake Powell and Lake Mead through their full operating range and to provide for the sustainable management of the Colorado River system,” an Interior spokesman told the Star.

Here are specific alternatives:

Alternative 1: It’s designed to achieve what the bureau says is “robust protection of critical infrastructure.” Lake Powell releases would be determined based on elevations of water levels in Powell, unless what’s known as “equalization releases” are required to keep Powell and Mead at roughly equivalent elevations.

Annual releases from Powell to Mead would range from 5 million to 9.5 million acre-feet annually, compared to a historical average release of 8.23 million acre-feet and recent releases of 7.48 million. If necessary, releases to Mead could be cut below 5 million acre-feet and Powell could get additional water from upstream reservoirs to protect Glen Canyon Dam’s critical infrastructure.

The Lower Basin states may have to take cuts in deliveries of up to 3.5 million acre-feet annually. The cuts taken by each state would be based on their legal priorities for river water and would be triggered based strictly on water levels at Powell and Mead.

Alternative 2: It’s based on proposals submitted by both basins and the tribes. It would include unspecified “new delivery and storage mechanisms” for Powell and Mead, using both federal and non-federal water storage pools and “maximum flexibilities for all users.”

Lower Basin shortages would start at 1.5 million acre-feet and top out at 3.5 million acre-feet. Shortages would be triggered by the combined shortage in seven reservoirs — an idea proposed by the Lower Basin states — and “distributed pro-rata,” which typically means they would be split proportionally among users based on their existing use. Shortages currently are based on levels in Lake Mead.

Alternative 3: Based on a proposal submitted by a coalition of conservation groups. It sets a goal of stabilizing water storage for the entire river system, integrating “stewardship and mitigation strategies of Lakes Powell and Mead,” and maintaining opportunities for U.S.-Mexico cooperative measures and for water conservation.

Lake Powell releases would range from 5 million to 11 million acre-feet annually, and would be determined by total Upper Basin water storage, and Lower Basin shortages could reach 4 million acre-feet.

Alternative 4: Also combines proposals from the two basins and tribes. Under it, annual Lake Powell releases would range from 5 million to 12 million acre-feet, and based mainly on Powell’s water level with some scenarios also considering Mead’s elevation.

This alternative would have water cutbacks by both Upper and Lower Basins, with Upper Basin contributions stored in Powell and Lower Basin shortages limited to 2.1 million acre-feet annually and based on water levels in seven river reservoirs.

Arizona Department of Water Resources Director Tom Buschatzke said he’s disappointed and Central Arizona Project General Manager Brenda Burman said she’s surprised the Lower Basin alternative wasn’t studied as a whole.

“The Lower Basin’s alternative didn’t start at one extreme or the other, and it showed unequivocally that the Lower Basin was willing to take the first tranche of cuts,” he said.

“We believe any future consensus alternative will need to include both and believe that all the states that benefit from the river still need to share in the solution to protect its future,” said Burman, noting that CAP, ADWR and other Arizona water officials had discussed the benefits of this approach at a public meeting.

In a statement, Colorado River Commissioner Becky Mitchell of the state of Colorado said, “Colorado cannot speak directly to the contents of Reclamation’s matrix of potential alternatives at this time. Colorado continues to stand firmly behind the Upper Division States’ Alternative, which performs best according to Reclamation’s own modeling and directly meets the purpose and need of this federal action.

“The Upper Division States Alternative is supply-driven and is designed to help rebuild storage at our nation’s two largest reservoirs,” Mitchell said. The Upper Basin states are Colorado, New Mexico, Utah and Wyoming.