Sixteen Arizona tribes, irrigation districts and cities plan to take less Colorado River water next year under a new agreement that was approved this week by three states and the federal government to help Lake Mead.

Tucson, which has rights to one of the largest municipal shares of Central Arizona Project water, won’t be one of them.

Officials from Arizona, Nevada and California and the Bureau of Reclamation on Wednesday held a ceremonial signing in Las Vegas of a plan committing them to spend $200 million to compensate these users for giving up the water in 2022 and 2023. The other 16 entities are listed by the state as participants in the new plan to leave a total of 500,000 acre-feet of river water in Lake Mead a year for at least the next two years.

While the Tucson Water utility has repeatedly said it could continue to adequately serve its customers even if it sustained large CAP cuts, it’s not giving up any water under this agreement for several reasons.

They include the city’s near-total dependence on river water and, said Assistant City Manager Tim Thomure, the fact that CAP officials told the utility it already had enough volunteers from other cities to save water. The short time the city had to decide on taking a water supply cut also may have been a factor.

Also, some sources outside the Tucson utility cite a little-known provision in decades-old CAP contracts that has led some officials outside the utility to be concerned that if they give up small amounts of CAP water for this agreements those cuts could under some circumstances become permanent. While Tucson Water officials say this issue wasn’t a factor, other sources told the Star they wouldn’t blame Tucson for maintaining its cut.

The purpose of this new plan is to bring short-term relief to Lake Mead. It’s in danger of falling to critically low levels as early as 2023 if arrangements aren’t made for water users to cut their take from the river, federal forecasters say.

It was put together in a few months after it became clear that the past two years of hot, dry weather in the Colorado River Basin was dropping Mead and Lake Powell much faster than expected.

Water agencies across Arizona, California and Nevada and the U.S. Department of Interior, were engaged in a “historic effort” to invest up to $200 million in projects over the next two years to get these and other entities to conserve water, the Arizona Department of Water Resources said in a news release. Water users will be paid $261 an acre-foot to give up supplies — a price more than double what Arizona cities paid last year for their CAP water (that price will rise to $144 next year).

The agreement, known as the 500+ Plan, would conserve enough water to serve about 1.5 million households a year. It would add about 16 feet total to the reservoir’s level.

So far, two tribes — the Gila River Indian Community in Sacaton and the Colorado River Indian Tribes in Parker — are the only Arizona entities to have signed formal agreements with authorities to conserve a specific amount of water.

The Gila River community is leaving behind 129,000 acre-feet a year in the lake. That comes on top of 200,000 acre-feet the tribe left in Lake Mead in 2019 and 2020 for the first Lake Mead-saving plan — the 2019 drought contingency plan. The Colorado River Indian Tribes will leave another 50,000 acre feet in the lake.

The rest of the participants in this agreement are still in negotiations, although many if not most of them sent representatives to Wednesday’s signing ceremony. The details of how much these entities will save and how much money they’ll receive may not be known for all of them for weeks or months.

In California, the Palo Verde Irrigation District in the Blythe area is the only entity to have formally signed onto an agreement to use less water, about 60,000 acre-feet a year. That will happen because the district’s farmers will let some of their farmland lie fallow over the next three years in return for $38 million in contributions from various water agencies including CAP.

That deal had already been approved before negotiations began gathering steam for this new water savings plan covering the entire Lower Basin. A much smaller deal, whose terms aren’t publicly known yet, was to be signed Thursday between Southern California’s Metropolitan Water District and the Quechan Tribe along the river west of Yuma.

Eight Arizona cities, all in the Phoenix area including Phoenix itself, have agreed to leave in Mead a total of somewhere between 22,000 and 30,000 acre-feet of CAP water to which they have rights, according to various estimates. The Arizona irrigation districts involved include three operating along the river, and two in Central Arizona.

“No need for Tucson to participate”

But Tucson decided not to participate because it, unlike those in the Phoenix area has no other source of water besides groundwater, said James MacAdam, a Tucson Water spokesman. Six of the eight Phoenix-area cities also have access to surface water served by the Salt River Project utility in that area, noted MacAdam. He added the City Council has voted to have the city take its entire, 144,000 acre-foot CAP allocation next year.

In 2021, Tucson got 94% of its drinking water supply — about 98,000 acre-feet annually — from Colorado River water that had been recharged into the aquifer and pumped back out, he said. The rest came from once-contaminated groundwater that had been cleaned up by the utility’s Tucson Airport Remediation Project treatment plant on the south side.

But next year, now that the city has recently stopped serving the treated water to its customers, all the city’s drinking water will come from CAP, MacAdam said Wednesday.

Thomure, however, said other factors aside, “there was no need for Tucson to participate” because plenty of other water utilities had agreed to conserve.

“It’s my undertanding that they have the volumes we need,” said Thomure, adding that city officials have been in regular contact with CAP officials on this, mostly CAP General Manager Ted Cooke.

“I let them know that if they were short from their other contractors, I would bring it to the mayor and council here” for their approval, he said.

Also, Thomure cited the fact the Phoenix-area cities are giving up water that they could well have lost anyway in the next couple years if Mead continued to fall. That water is classified as non-Indian agricultural water, NIA for short, that was due to be curtailed over the next few years under the 2019 Drought Contingency Plan.

Tucson’s CAP supply is municipal and industrial water. It has the highest priority of any non-Indian CAP supply and has equal priority to tribal supplies. Although the municipal supplies also will ultimately take cuts under the 2019 drought plan, they wouldn’t come as soon as the non-Indian agricultural water.

Tucson has the biggest single municipal and industrial CAP allocation in the state. Phoenix actually gets more CAP water annually than Tucson, at 159,000 acre-feet. But more than one-third of that is of the non-Indian agricultural variety, that will be cut off more quickly in future shortages.

It’s a “tough question” about whether Tucson Water should participate in the 500-plus plan, Catlow Shipek, an official with the Tucson-based Watershed Management Group, a conservation organization, acknowledged. But “my quick reaction is yes we should be collaborating and working in coorrdination with others to think about how to address the shortage on the Colorado River,” said Shipek, whose group has long pushed for water conservation in general and rainwater harvesting in particular.

“It’s tricky — short-term actions v. long-term actions,” Shipek said. “Being that Tucson Water is a municipal water provider, it may seem like a small drop in the bucket, but for them to participate may be like keeping our seat at the table and continuing collaboration across the region.”

MacAdam, however, said the utility wants to be clear that “We’re actively participating in the conversations at the state and bringing a collaborative approach.” Tucson Water demonstrated its commitment to collaboration during the 2019 drought plan negotiations, when it agreed to temporarily give up some of its CAP water to Pinal County farmers as a measure to mitigate federal cuts in CAP deliveries to those farmers — which also start next year, he said.

“We always value the water more than the money. But we will also make sure we do our part when it’s necessary,” Thomure said.

Tucson Water was one of many CAP users who were asked by officials of the project to consider taking up to 50,000 to 60,000 acre feet in cuts under the new plan. At an early December meeting, CAP officials said that response to their request for volunteers for those cuts had been “less than robust.”

Phoenix water utility official Cynthia Campbell said she thinks Tucson Water’s refusal to take cuts is “a very reasonable position.” She added she thinks the utility was concerned that it was given a short amount of time to make up its mind.

“You can’t play whiplash with people, where you tell them you need to do this and you tell them they need to do that,” Campbell said.

At the end of the day, asking cities to give up the volume of water that’s needed to make these enormous changes in lake levels is not realistic, because cities don’t have that volume to give, Campbell added.

Cities can do more to save water by partnering with large water users such as tribes and farmers to conserve water rather than doing it themselves, says Sarah Porter, a water researcher at Arizona State University.

“Cities have the ability to pay agriculture to use less water through various programs. That could be field fallowing or installing more efficient irrigation systems. Cities have less ability to contribute material amounts of water to keep Lake Mead up,” said Porter, director of ASU’s Kyl Center for Water Policy.


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Contact Tony Davis at 520-349-0350 or tdavis@tucson.com. Follow Davis on Twitter@tonydavis987.