‘Dream’ of desalinating water to boost Arizona’s supplies moves ahead with vote

• Proposals to desalinate seawater to help boost Arizona’s water supplies moved forward at a meeting of a state financing board.
• A desalination plant could be built in California or Mexico, allowing Arizona to trade for Colorado River water.
• The water financing board considered a long list of augmentation projects eligible for funding negotiated three years ago by then-Gov. Doug Ducey.

The long-held dream of boosting Arizona’s water supply by building seawater desalination plants in California or Mexico is now an official proposal with state backing, after a water financing board advanced several proposals for further review and investment.

The Water Infrastructure Finance Authority of Arizona drew 17 proposals for public-private partnerships and advanced four of them at a Nov. 19 board meeting. They include schemes to build desalination plants on the California coast or in the Gulf of California, to produce water that can be traded for shares of Colorado River water. Other proposals that will get further review include farm efficiency investments in upstream Colorado River states and a stake in Northern California underground water storage projects, either of which would also involve trades for Colorado River water.

“This is no longer a dream,” WIFA Director Chelsea McGuire said.

Any water augmentation — or even final approval for it — is still years away.

The partnerships would yield hundreds of thousands of acre-feet of water a year at a time when at least that much of the state’s existing Colorado River is at risk as drought drains the system. Next up, the state authority will determine how difficult it may be to permit and build these projects in other jurisdictions, and whether any or all are worthy of the hundreds of millions of dollars that lawmakers have approved for augmentation.

The goal is to have one or more of them flowing between 100,000 and 500,000 acre-feet of new water into the state yearly in the next 10 to 15 years.  For context, Arizona already has lost more than 500,000 of its 2.8 million-acre-foot allocation for the Colorado and stands to lose substantially more as seven states and the federal government haggle over how to divvy river water in the future.

An acre-foot is roughly 326,000 gallons and is about what it takes to supply three Arizona homes for a year.

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Bidders will try to prove their projects can work

The state has more than $300 million from the Legislature to put toward augmentation, and would likely need more to cover its share if these projects come online. A single existing desalination plant at Carlsbad, Calif., for instance, cost the San Diego area more than Arizona’s current fund. (Former Gov. Doug Ducey announced a $1 billion augmentation fund in 2022, but lawmakers have since chipped away at it to cover other expenses.)

The projects that WIFA accepted for further evaluation have no price tags attached yet, and the state’s cost share for any of them is yet to be negotiated. The bidders who will now seek to prove their projects can work include one partnership led by Spanish company ACCIONA and Canadian investment firm Fengate, and one led by EPCOR, a utility company that provides water to numerous Arizona communities and is owned by the city of Edmonton, Alberta.

Each of four proposals won 9-0 approval from the board. They include:

• A multi-pronged approach by the Acciona-Fengate Water Augmentation Alliance to desalinate seawater in Mexico for either importation or in trade for river water; desalinate seawater in Southern California and Baja California for use there in exchange for river water; upgrade farm irrigation systems in Mexico, California and Utah in exchange for river water; build advanced potable water recycling plants in Colorado and in Baja California in exchange for river water. If all of it happens, according to the proposal, Arizona would yield between 236,000 and 946,000 acre-feet a year by 2037.
• An EPCOR Water Innovation Partnership desalination plant in Baja California to pipe water to Mexico’s Colorado River area in exchange for river water. WIFA estimates this project could provide between 167,000 and 500,000 acre-feet by 2039.
• An EPCOR Water Innovation Partnership project investing in California groundwater storage and recovery in the Sacramento-San Joaquin Delta region in exchange for river water. It would store excess surface water underground, rather than depleting existing aquifers. This is estimated to provide between 10,000 and 100,000 acre-feet, with no listed timeline.
• An EPCOR Water Innovation Partnership treatment plant in Southern California to turn wastewater into potable water for the Tijuana area of Mexico in exchange for river water. This project could provide between14,000 and 95,000 acre-feet by 2043.

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Augmentation is needed ‘because our population continues to grow’

Desalination is a costly and energy-intensive process that leaves a concentrated brine that requires disposal. Costs per acre-foot range upward of $2,000 an acre-foot, compared to conservation and or irrigation upgrades that may cost hundreds less. McGuire said WIFA has not addressed how to deal with the brine or whether there may be a market for it, an assessment that would come in the next phase.

Arizona environmentalists have long favored water conservation over desalination, and after the project announcements the Sierra Club’s state chapter reiterated its positions.

“Yes, we have concerns about desalination and its environmental impacts, including the massive amounts of energy used and the disposal of the brine,” Grand Canyon Chapter Director Sandy Bahr said in an email. “We’re also concerned about giving private interests with a profit motive more control of water, something that is essential for life. They seem to be socializing the risks with the public and privatizing the profits.”

Bahr also questions the secrecy surrounding the proposals before the votes, and said tribes and others should be involved in the talks, “not just industry.” Board members at the meeting said they had been bound by procurement rules prioritizing business confidentiality up until now, but will review the projects transparently under state open meetings laws from this point on as they decide whether these project merit major state investment.

Several people, including representatives of the Sierra Club and the Chemehuevi Tribe, viewed the board’s meeting remotely and delivered pleas that the state not finance a plan to tap groundwater under the Mojave Desert in California. That concept, and long-proposed plan known as the Cadiz Project, has faced environmental resistance in California, and WIFA board members said they had rejected it as part of Arizona’s solution.

Arizona Water Resources Director Tom Buschatke said the state will work to “squeeze every drop” from its existing supply, but, “that’s not going to be enough to deal with our current and future situation.”

“We must augment because our population continues to grow,” WIFA board chairman Jonathan Lines said.

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Board member Ted Cooke, a former general manager of the Central Arizona Project that delivers Colorado River water to Phoenix and Tucson, said WIFA evaluated projects based both on their technical merits and on the ability of the contractors to attract outside investment. WIFA can’t design, finance, build and operate these projects alone, he said.

“This is a momentous milestone for all of us in Arizona who have been waiting for something like this to develop — and not for lack of trying — over a long period of time,” he said.

Still, Cooke warned, advancing these to the next phase is just a “warm up” for the real work to make one or more happen.

Brandon Loomis covers environmental and climate issues for The Arizona Republic and azcentral.com. Reach him at brandon.loomis@arizonarepublic.com.

Environmental coverage on azcentral.com and in The Arizona Republic is supported by a grant from the Nina Mason Pulliam Charitable Trust. 

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