Other parts of the world remove salt from water to make it drinkable. Is that possible in Colorado?

The Dolores River near Bedrock just upstream of the Bureau of Reclamation’s Paradox Valley Unit. (Corey Robinson, Special to The Colorado Sun)

State Sen. Kevin Priola traveled to Israel in 2022 and came away with an idea: If the arid country can produce drinking water by taking the salt out of saltwater, the same technology could potentially help Colorado with its water concerns.

The next year, Priola sponsored a bill directing the state to study desalination.

“Thinking of the Colorado River Basin, the northern states and the southern states are basically all in the same boat when it comes to water,” said Priola, a Democrat from Henderson. “I was trying to get people thinking and talking and looking at desalination as being part of the solution.”

The bill was an attempt to explore all options in response to near-crisis conditions on the Colorado River, the water supply for 40 million people, and future water supply gaps in Colorado. But while some uses of desalination — also called desalinization — are technically feasible, the hurdles are so big, lawmakers and experts have said it isn’t worth the investment for Colorado, even as a study topic. Priola’s bill failed, but people are still talking about the concept.

“There’s an idea that, ‘Hey, this is an easy solution. Why don’t we just do this?’” said Gregor MacGregor, a water law expert at the University of Colorado. “It’s like, well, we don’t ‘just do it’ for many reasons.”

The Colorado River Basin, which includes western Colorado, has been stressed by drought, climate change and overuse for years, resulting in a near crisis in 2021 and 2022.

Colorado is facing future water shortfalls of up to 740,000 acre-feet for cities and industries, and up to 200,000 acre-feet for farms and ranches by 2050, according to the state’s 2023 water plan. One acre-foot roughly equals the annual water used by two to three households.

Colorado is already gearing up water projects focused on conservation, drought planning, efficiency and infrastructure upgrades. Priola wanted to explore desalination as one of the possible solutions. 

Desalination involves sucking saltwater out of the ocean — or another salty source of water — and pushing it through a series of membranes to remove dirt, sand, heavy metals and salt, using a process called reverse osmosis to produce drinkable water.

Some cities in Colorado, like Brighton, already use reverse osmosis to treat water. And a federal plant in Montrose County’s Paradox Valley extracts naturally occurring briny groundwater to keep it from over-salting the Dolores River.

But experts are quick to list the challenges: The price tag is high, the process is energy intensive and the byproduct could be environmentally harmful. 

Sen. Cleave Simpson, a Republican from Alamosa, is one of the lawmakers who voted against the 2023 desalination bill. He said he’d rather spend money to improve efficiency than search for new water supplies — and he’s not alone.

When asked if he’d want to invest in desalination between now and 2050, Simpson simply said, “No.” 

Israel is doing it. Why can’t we?

California communities already have facilities, like the Carlsbad Desalination Plant that provides about 10% of the San Diego region’s water demand. The entire Carlsbad project cost about $1 billion.

Arizona has for decades flirted with the idea of building a desalination plant on the coast of Mexico to draw seawater from the Gulf of California to help augment its water supplies.

Israel gets most — 80%-85% according to some estimates — of its drinking water from desalinated seawater. 

But Israel has different water supply limits or demands from farms and cities. Its population of 10 million — a quarter of the population served by the Colorado River — lives in an arid, Mediterranean climate. 

It is about 28 times smaller than the sprawling Colorado River Basin. It has fewer rivers, lakes, groundwater aquifers and mountains to feed its water systems, which means there’s more political momentum to spend money on expensive options, like desalination, to preserve naturally occurring supplies.

“Look at the landmass and the population of Israel versus the Colorado River Basin. It’s kind of apples to oranges there,” MacGregor said. “We could take that money and invest in on-farm improvements that would probably be a much easier and tried-and-true method.”

But … what about a pipeline to Colorado from the Pacific?

Sen. Kyle Mullica, D-Thornton, who also sponsored the 2023 bill, said his goal was to look at all options to address water stress in Colorado. When it comes to building pipelines to transport desalinated seawater from the Pacific Ocean to the state — it makes a certain amount of sense, he said.

“If we want to talk about pipelines … we’ve had businesses invest in pipelines transporting other materials similar distances, when you think about oil,” Mullica said. “I don’t think it’s out of the question.”

That idea is not a viable source of water for Colorado that the state is considering, said State Engineer Jason Ullmann, Colorado’s top water cop.

Building the plant and the pipeline would be pricey. Then there are energy expenses related to pumping water over 1,000 miles and thousands of feet up in elevation. The total cost would likely be in the tens of billions of dollars, he said in an email.

“Colorado is focused on more feasible solutions to solve our water supply programs,” Ullmann said.

If not seawater, what about groundwater?

If hurdles accessing ocean water are too high, Coloradans might be tempted to consider the water below their feet.

California announced future projects to desalinate brackish groundwater, which is slightly less salty than seawater. The federal government has a research facility in Alamogordo, New Mexico, looking into de-salting groundwater in inland states. Nearby, the city of Alamogordo is planning a $54 million groundwater desalination facility.

Becky Mitchell, Colorado’s top negotiator for Colorado River issues, questioned where the state could put the byproduct, called brine — a mix of water, concentrated salt, heavy metals and more.

“It’s the brine disposal that is part of the piece that we have to address,” Mitchell said.

Coastal communities can release it into the ocean, raising concerns about negative impacts on fish populations and coral reefs. Colorado’s options would be more limited, but could include pumping the brine underground or spreading it in ponds to evaporate. 

Both come with baggage. Evaporation ponds raise questions about economic impacts and harm to wildlife. At the Paradox Valley Unit, injecting brine deep underground has been linked to thousands of small earthquakes and a 4.5 magnitude earthquake in 2019.

Then there is the question of whether there is any unclaimed brackish groundwater available in the first place, Simpson said. In his region, Colorado courts have already declared deep, confined groundwater aquifers to be over-appropriated. 

“Unless we change course somehow, tapping more water, deeper — that needed to go through desalination to be used — it’s just not an option,” he said.

Could more facilities around the basin help Colorado?

Water experts and lawmakers want other basin states to invest more in desalination to add to their water supplies in hopes that it could reduce demand for Colorado’s water. 

“We’re talking about a way to have our neighbors to the southwest and west rely more on desalinated water, and Colorado benefiting from having to send marginally less water downstream going forward,” Priola said.

It’s not that simple, water experts said. 

Colorado River Basin states would need dozens of facilities to make a dent in the basin’s multimillion acre-foot supply gap. (The Carlsbad Desalination Plant in California provides up to 56,000 acre-feet of desalinated seawater per year, and it’s the largest in the U.S.)

Even if Lower Basin states — Arizona, California and Nevada — had ample water supplies coming from desalination, they would still have the right to use their full legal allotment of Colorado River water.

And Colorado’s obligations to ensure water flows downstream are founded in century-old water law. More desalination would not change those obligations.

Theoretically, Colorado could pay to build and operate a coastal facility, and the treated water could be piped to a nearby community in California. In exchange, Colorado could keep an equal amount of water.

But the hurdles are sky-high, experts said. Colorado River law requires Colorado to work in tandem with other Upper Basin states to share water and send it downstream. That means New Mexico, Utah and Wyoming would need to OK a new deal.

If the water accounting and legal gymnastics worked out, the politics might not. To even suggest transferring water between the Lower Basin and the Upper Basin would be politically toxic, said Anne Castle, a water expert and federal representative on the Upper Colorado River Commission.

“We have historically been adamantly opposed to transbasin transfers. We don’t want the Lower Basin coming up and buying up water rights in the Upper Basin,” Castle said. “The same would be true for theoretically freed-up supplies in the Lower Basin from desalination. … I don’t see it.”

This story is part of a series on water myths and misconceptions, produced by KUNC, The Colorado Sun, Aspen Journalism, Fresh Water News and The Water Desk at the University of Colorado Boulder. 

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