Arizona gets serious about piping water from Mexico in nonbinding desalination resolution

The CAP Canal heads towards a neighborhood in Phoenix as seen from the Deem Hills Recreation Area on December 12, 2018.


Brandon Loomis, Arizona Republic


A state board tasked with vetting water supply augmentation proposals for Arizona on Tuesday passed a nonbinding resolution in support of a potentially massive seawater desalination plant in Mexico’s Sea of Cortez.

A partnership led by Israeli desalination specialists IDE Technologies pitched the multibillion-dollar plan to the Water Infrastructure Finance Authority of Arizona’s board, saying it could replace or complement declining Colorado River water that flows through the Central Arizona Project’s canal. The plant would remove salt from seawater and pump it north into the canal, where it would flow through Maricopa, Pinal and Pima counties.

This is the first move toward evaluating a water project that state lawmakers this year committed more than $1 billion toward, heeding Gov. Doug Ducey’s call to support desalination and other efforts. Some of the lawmakers who supported it recoiled at what they called the rushed nature of this resolution, having only been sprung on members last week. Ducey leaves office in January.

Board member Andy Tobin, a former House speaker and Corporation Commission member, said the greater risk was acting too slowly. He noted that one development that has relied on Scottsdale’s water may be cut off in January, in part because of the Colorado’s decline.

“We’ve got folks running out of water,” he said.

IDE representatives said they planned to submit the proposal this week for federal environmental review, and hoped to show the state’s support for that process. The project is substantial, potentially moving enough water to supply all current Arizonans, while also requiring a parallel power line for pumping. The eight-member board unanimously approved the resolution after member Ted Cooke, the CAP’s retiring general manager, amended it to make clear that the state was only committing to “discuss” the plan, not negotiate it.


The proposal would also require Mexico’s consent. The company said it had discussed it with Sonora’s governor, who is interested in securing water from it for Hermosillo and Nogales. But the bulk of the water would head to Arizona.

Proponents envision a seawater desalination plant near the resort town of Puerto Peñasco, Sonora. Once reverse osmosis membranes separate the salt, the freshwater would flow through a pipeline north, crossing into the United States at Organ Pipe National Monument. From there the pipeline would follow State Route 85 to Arizona’s population center in Maricopa County. It would pass through Buckeye, which might receive direct access to it there, and then on to two new reservoirs northwest of the county’s White Tank Mountains Regional Park. It could then enter the Central Arizona Project’s canal flowing toward Phoenix, Pinal County and Tucson.

The consortium also envisions a smaller pipeline from the end of the CAP canal south to Nogales, Mexico, where it would provide up to 10,000 acre-feet. Hermosillo, Sonora’s capital, would take its own share of water directly from the desalination plant. In all, Sonora would take 40,000 acre-feet. Each acre-foot is about 326,000 gallons.

The initial plant would cost about $5.5 billion and supply 300,000 acre-feet, IDE representatives told the board. That would be enough to supply a million or more Arizona households, but at a cost of more than $2,500 per acre-foot. That would be a substantial price increase over CAP deliveries currently in the hundreds of dollars. But, if mixed with other sources, company officials say, it could raise homeowners’ bills by just a few dollars a month.

If Arizona commits to the project, residents in areas ultimately served by it would pay for the water on their bills. The state would not pay for the plant’s construction, but would rather agree to pay for what it produces.

The plant could later be scaled up to offer up to 1 million acre-feet, which would represent more than a third of Arizona’s share of the Colorado River. IDE would privately finance it, but would require a commitment from Arizona to purchase the water for 100 years. A final deal likely would require Arizona to pay even in times when it does not need the plant’s water, as has been the case with desalination plants in California.

Environmentalists raised concerns about the project’s energy requirements, the effects of brine returned to the sea, and crossing unique and sensitive habitats, including at Organ Pipe.

“I wonder if we’re selling our environmental birthright for a mess of water, so to speak, a big mess that we could be getting into,” Yuma Audubon Society Conservation Chair Cary Meister told the board.

Others said there’s no time to waste in seeking new sources as the Colorado River’s decline takes water out of the CAP canal and threatens to empty it in future years. A contingent representing Pinal County, whose farmers have so far borne the brunt of those losses, urged support of the desalination plan. Pinal Partnership CEO Tony Smith said the county’s farms generate more than $1 billion a year and are at risk of running out of groundwater. At 1 million acre-feet, he said, a desalination plant eventually could provide enough water for all of the state’s homes, leaving other sources for farms.

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IDE officials said if environmental review, permitting and financing move as hoped, the project could be producing some water by 2027.

Sen. Lisa Otondo, D-Yuma, said she felt deceived by the proposal’s fast track before the board. She had supported the $1.4 billion commitment that lawmakers granted Gov. Ducey for water augmentation and conservation earlier this year. That bipartisan effort passed with the assurances that the money would not “rubber stamp” any particular project, she said.

“I’m sorry, but this reeks of backroom deals,” she said.

Some public speakers and board members at the meeting said they had only heard of the proposal last week, and there should be no rush to pass a resolution supporting it. Doing so for such a huge project could send the signal that there will be no room for other proposals, they said, at a time when the board has not even formulated its rules, hired a director or announced a request for proposals.

“Approval of this resolution will scare away competing proposals,” said Karl Flessa, a University of Arizona geoscientist and Colorado River researcher who said he was speaking for himself and not the university.

The Arizona Municipal Water Users Association asked the board to slow down. Its Phoenix-area members include 3.7 million members who might end up paying for the water but have unanswered questions about it, Executive Director Warren Tenney said. “You should wonder why they still have questions.”

Arizona has for years discussed the idea of a Sea of Cortez plant, and in 2020 joined partners from Mexico, California and Nevada in an initial feasibility study that also placed the price per acre-foot at $2,000 or higher. That idea, though, would not include a pipeline north into Arizona, but would hinge on an exchange of Colorado River water with Mexico.

Some legislators cautioned about the potential cost to water ratepayers if Arizona agrees to lock in a plant. House Minority Leader Reginald Bolding said he saw no reason to rush, when the board could take its time to review the resolution in coming months. “Why is the need of urgency right now, today, this needs to happen?” he said.

But Mark Lewis, a retiring CAP board member, urged the board to act now. The resolution does not commit state funds, only a commitment to analyze and discuss. Whatever the state does to boost its water supply will be costly, Lewis said.


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