Could desalinated ocean water fix the Colorado River from drying up?

This story is one part of a broader series about ways to save water from the drying Colorado River. See the full project here.

Desalination plants are already in use all over the world, drawing in ocean water and filtering out its dangerously high salt content, bacteria and other impurities to make it safe for use.

A dozen are in use in California, alongside more in Arizona, Mexico and other areas dotting North America.

One in Australia, the Victorian Desalination Plant, can provide up to a third of Melbourne’s water supply, according to the city’s water provider. And Israel is being hailed as a leader in the field with five desalination plants along its coasts providing tap water for nearly 9.2 million people.

But there are quite a few catches to the strategy.

First, Israel’s success with desalination wouldn’t translate the same way for the Colorado River Basin, according to Jay Famiglietti, director of the Global Institute for Water Security at the University of Saskatchewan. More than four times as many people depend on the Colorado River and, even then, human water consumption pales in comparison to the amount of water needed for agriculture in the basin, which feeds people across the world.

Agriculture only accounts for a small fraction of Israel’s economy.

Desalination can’t match the vast quantities of water the Colorado River provides, especially in a few short years, Dan Beard, a retired U.S. Bureau of Reclamation Commissioner told The Denver Post. And building a massive desalination plant could take up to a decade.

“This would be a long-term challenge,” Beard said. “You couldn’t just flip a switch and start a desalting plant.”

Desalinating water also requires huge amounts of energy, Beard said. Not only are the plants costly to run but that, in turn, makes the water they produce expensive as well.

One multi-billion-dollar proposal from Arizona Gov. Doug Ducey would build a desalination plant that could take water out of the Gulf of California and transform it into 200,000 acre-feet of usable water a year, but at an estimated price of $2,000 per acre-foot, a rate about ten times higher than current costs in the area.

Running the plant would cost tens of millions of dollars each year as well, KUNC reported.

“It works, but it’s expensive,” Beard said.

After all that, the desalination process has to do something with the byproduct of the filtration process, called brine, Famiglietti said. Wherever that brine is dumped will inevitably be damaged by its high salt content, potentially ruining entire ecosystems.

That environmental hazard alone could wreak havoc up and down the West Coast, Famiglietti said. But then if the brine begins slipping down toward Mexican waters, it could even create an international incident.

Desalination, like many of the other ideas, has a part to play in replacing some of the water lost by the Colorado River, Becky Mitchell, director of the Colorado Water Conservation Board, said. But it’s not a “silver bullet” solution.

“We have to consider all of the creative solutions and temper our expectations,” Mitchell said.

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