Arizona considers channeling water from Mexico as Colorado River recedes
A state board tasked with examining proposals to increase water supplies for Arizona approved a non-binding resolution Tuesday in support of a potentially massive seawater desalination plant in Mexico’s Sea of Cortez.
An association led by Israeli specialists in desalination IDE technologys presented the multimillion-dollar plan to the Arizona Water Infrastructure Finance Authority board, saying it could replace or supplement the diminishing Colorado River flowing through the channel from the Central Arizona Project. The plant would remove the salt from the seawater and pump it into the canal to the north, where it would flow through Maricopa, Pinal and Pima counties.
This is the first step toward evaluating a water project to which state lawmakers committed more than $1 billion this year, heeding Gov. Doug Ducey’s call to support desalination and other efforts. Some of the lawmakers who supported it balked at what they called the hasty nature of this resolution, since it was only presented to members last week. Ducey leaves office in January.
Board member Andy Tobin, a former House speaker and member of the Corporations Commission, said the biggest risk was moving too slowly. He noted that development that has relied on Scottsdale’s water could be cut off in January, in part because of the decline of the Colorado.
“We have people who are running out of water,” he said.
IDE representatives said they planned to submit the proposal for federal environmental review this week and hoped to show state support for that process. The project is substantial, potentially moving enough water to supply all of today’s 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 outgoing general manager, amended it to make it clear that the state was only committing to “discuss” the plan, not negotiate it.
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The proposal would also require the consent of Mexico. The company said it had discussed it with the governor of Sonora, who is interested in securing water for Hermosillo and Nogales. But most of the water would head to Arizona.
Proponents envision a seawater desalination plant near the resort town of Puerto Peñasco, Sonora. Once the reverse osmosis membranes separate the salt, fresh water would flow through a pipe 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 could receive direct access there, and then to two new reservoirs northwest of the county’s White Tank Mountains Regional Park. It could then enter the Central Arizona Project channel that flows into Phoenix, Pinal County and Tucson.
The consortium also envisions a smaller pipeline from the southern end of the CAP channel to Nogales, Mexico, where it would provide up to 10,000 acre-feet. Hermosillo, the capital of Sonora, would take its own share of water directly from the desalination plant. In all, Sonora would take 40,000 acre-feet. Each acre-foot equals 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 power a million or more Arizona homes, 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 combined with other sources, company officials say, it could increase homeowners’ bills by just a few dollars a month.
If Arizona commits to the project, residents in the served areas would ultimately pay for their water on their bills. The state would not pay for the construction of the plant, but would agree to pay for what it produces.
The plant could later be expanded 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 finance it privately, but would require a commitment from Arizona to purchase the water for 100 years. A final deal would likely require Arizona to pay even at times when it doesn’t need the plant’s water, as has been the case with desalination plants in California.
Environmentalists raised concerns about the project’s power requirements, the effects of brine returning to the sea, and the crossing of unique and sensitive habitats, including at Organ Pipe.
“I wonder if we are selling our environmental heritage because of a water disaster, if you will, a big disaster that we could be getting ourselves into,” Yuma Audubon Society conservation president Cary Meister told the board.
Others said there is no time to waste searching for new sources, as the receding Colorado River draws water from the CAP canal and threatens to empty it for years to come. A contingent representing Pinal County, whose farmers have so far borne the brunt of those losses, urged support for 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 could eventually provide enough water for every home in the state, leaving other sources for farms.
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IDE officials said that if the environmental review, permitting and financing proceed as expected, the project could be producing some water by 2027.
Sen. Lisa Otondo, D-Yuma, said she felt cheated by fast-tracking the proposal before the board. She supported the $1.4 billion commitment lawmakers gave Governor Ducey for water enhancement and conservation earlier this year. That bipartisan effort was approved with a guarantee that the money would not “seal” any particular project, she said.
“Sorry, but this reeks of backroom dealing,” he said.
Some public speakers and board members at the meeting said they had only heard about the proposal last week, and there should be no rush to pass a resolution supporting it. Doing so for such a large project could send the signal that there won’t be room for other proposals, they said, at a time when the board hasn’t even formulated its rules, hired a director or announced a request for proposals.
“Passage of this resolution will scare off competing proposals,” said Karl Flessa, a geoscientist at the University of Arizona and a 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 could end up paying for water but have unanswered questions about it, CEO Warren Tenney said. “You should wonder why they still have questions.”
Arizona has discussed the idea of a plant in the Sea of Cortez for years, and in 2020 joined partners from Mexico, California and Nevada in an initial feasibility study that also put the price per acre-foot at $2,000 or more. That idea, however, would not include a pipeline to northern Arizona, but would instead depend on a Colorado River water exchange with Mexico.
Some lawmakers warned of the potential cost to water ratepayers if Arizona agrees to insure a plant. House Minority Leader Reginald Bolding said he saw no reason to rush, when the board could take its time reviewing the resolution in the coming months. “Why is the need urgent at this time, today, this must 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. Anything the state does to increase its water supply will be expensive, Lewis said.
“You need to have a 100-year sustainable water supply for the state of Arizona,” he said, “and it’s going to take a sustainable money supply to do that.”