Arizona agencies take step to buying desalinated ocean water from California

Arizona agencies have taken a key step that could eventually allow the state to buy desalinated ocean water.

Central Arizona Project (CAP), Salt River Project and the Arizona Department of Water Resources – along with the Southern Nevada Water Authority — recently signed a memorandum of understanding with a desalination plant in Southern California.

CAP is a wholesaler of Colorado River water that provides water to roughly 80% of the state’s population.

“We’re facing a crisis on the Colorado River. The flow is way, way below any kind of average,” CAP President Terry Goddard told KTAR News 92.3 FM last week.

The operating agreement among the seven Colorado River basin states that share the natural resource expires this year. If the states can’t come to an agreement, the federal government will impose a settlement for how the water will be shared.

Arizona’s cuts could be as high as 77%, according to one U.S. Bureau of Reclamation proposal. Under this option, Arizona takes the brunt of the cuts because it has junior water rights on the river.

That’s why Grand Canyon State officials are looking at the possibility of buying desalinated water from the San Diego County Water Authority, which operates a seawater desalination plant in Carlsbad.

How would Arizona buy desalinated ocean water?

Arizona and Nevada would not actually import treated Pacific Ocean water if it gets to that point.

What would happen is that those states would be allowed to tap into part of California’s share of Colorado River water while paying for an equal portion of desalinated water that stays in California.

“Payment has yet to be determined,” Goddard said. “Then, Arizona entities would have the right to take part of the Colorado River allocation that would otherwise go to California.”

The Bureau of Reclamation would have to sign off on the deal, although Goddard said the agency has signaled it is supportive of the move.

The deal may also require additional state or federal legislation to make it possible.

“Legally, interstate transfers are not allowed. That’s been the tradition for 50 years on the Colorado River. This may be the exception,” Goddard said.

Desalination is expensive

Goddard said a desalination deal wouldn’t be a quick fix. It might be a more realistic option five to 10 years down the road because of the cost.

“Let me emphasize that desal is very expensive,” he said. “Desal is $3,000-$3,500 an acre-foot. Today, Arizona customers for the Central Arizona Project pay $300 an acre-foot.”

Goddard said San Diego is trying to “unload a loss on their desal program.”

“So, it’s not necessarily the case that we have to compensate them for every dime,” he said.

Central Arizona Project looking at other water supply options

However, Goddard said buying desalinated water from California isn’t Arizona’s most promising solution when it comes to acquiring new water sources.

He said groundwater and agricultural land exchanges within Arizona would be preferable.

Central Arizona Project is also talking to state tribes to see if they’d be willing to transfer some of their Colorado River water rights.

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