Momentum is building for a unique interstate deal that aims to transform wastewater from Southern California homes and business into relief for the stressed Colorado River. The collaborative effort to add resiliency to a river suffering from overuse, drought and climate change is being shaped across state lines by some of the West’s largest water agencies.  

Southern California’s giant wholesaler, Metropolitan Water District, claims a multi-billion-dollar water recycling proposal will not only create a new local source for its 19 million customers, but allow it to share part of its Colorado River supply with other parched river partners already facing their own cutbacks. To advance what would become the nation’s largest wastewater recycling facility, Metropolitan is securing financial aid from other major Colorado River users in Nevada and Arizona in return for giving them portions of its river supply. Amid critically low reservoir levels and the first-ever shortage declaration on the Colorado River, water managers and experts are touting the interstate deal as a prime example of the team effort required to safeguard the future of this iconic Southwestern river and the people who rely on it.

“It’s a really interesting and innovative approach around partnerships,” said Heather Cooley, research director with the Pacific Institute, an Oakland-based water policy center. “Something we haven’t yet seen.”

Thus far the project appears long on support, but there are some potential impediments, such as whether the next set of river operating guidelines due in place by 2026 will allow the partners’ proposed long-term interstate water exchanges. Additionally, California regulators must clear the way for Metropolitan and others in the state to put the recycled supply directly into the drinking water system.

Aid for the Struggling Colorado

Metropolitan pitched the ambitious wastewater recycling proposal more than a decade ago, but the project gained steam recently amid increasingly dry conditions across two of its key water sources in California’s Sierra Nevada and Colorado River Basin. Water interests along the lower Colorado River Basin have for several years discussed how they might augment the river’s shrinking flows. As it turned out, the Lower Basin’s next potential augmentation project is being hatched more than 200 miles away near the coast of California.

Southern Nevada Water Authority, the Central Arizona Project and the Arizona Department of Water Resources have agreed to spend up to a combined $12 million to assist Metropolitan with environmental review, almost half of the total planning cost. If the project isn’t built, or if operating agreements aren’t finalized, Metropolitan would refund the agencies’ contributions. However, if the Nevada and Arizona agencies stay on to help build the final project, they will gain to-be-determined slices of Metropolitan’s annual share of Colorado River water.

The partnering agencies are currently grappling with major cuts to their own Colorado River supply, and more are on the horizon.

“It’s not like we can go out and acquire more imported supply. Going forward, we really need to be looking here at home.”
~Deven Upadhyay, Metropolitan Water District assistant general manager

Last summer, the Bureau of Reclamation declared a first-ever shortage in the Lower Colorado Basin, requiring Arizona to slash its annual take of the river by 18 percent and Nevada by 7 percent in 2022. But the mandated cuts have done little to protect water levels at the river’s two main reservoirs, Lake Mead and Lake Powell, and now federal officials are on the verge of implementing a fresh round of unprecedented reductions that stand to affect supply for the Lower Basin states.

Metropolitan’s assistant general manager calls the deal a win-win for Southern California and the Southwest.

“The idea of the program is that in return for their co-investment to make this facility a reality, we would back off some of our Colorado supply,” Deven Upadhyay said. “It becomes one component of potential augmentation on the river to help others out.”

Boosting Water Security

At full capacity, Metropolitan’s wastewater recycling plant could produce up to 168,000 acre-feet a year. However, Upadhyay said Metropolitan doesn’t plan to make a corresponding amount of its river share available to the out-of-state investors.

But gaining even a sliver of Metropolitan’s Colorado River supply could boost water security for arid Arizona and Nevada. 

“We’re at a point in this Basin where we can’t afford to not look at reasonable ideas,” said Colby Pellegrino, deputy general manager of resources for the Southern Nevada Water Authority.

Contract details haven’t been finalized but Pellegrino estimates SNWA could secure between 25,000-35,000 additional acre-feet annually, or around 10 percent of its yearly river apportionment. In Las Vegas, one acre-foot of water is enough to serve two households for more than a year, though officials are continually striving to reduce per capita water use.

“We’re at a point in this Basin where we can’t afford to not look at reasonable ideas.”
~Colby Pellegrino, deputy general manager of resources for the Southern Nevada Water Authority.

Meanwhile SNWA, which relies heavily on Lake Mead to serve its more than 2 million customers in the fast-growing Las Vegas area, appears wholly interested in seeing the project through. It has already earmarked up to $750 million for Metropolitan’s proposal or other recycling projects. Such a major investment would require a long-term operating contract potentially in the 20- to 30-year range, Pellegrino said.

The partnership also figures to afford some long-term water security for Arizona, which takes the biggest hit of any state when shortages are declared on the Colorado River. Currently Arizona is grappling with how to cut 512,000 acre-feet and it faces further reductions if Lake Mead’s elevation drops below 1,045 feet and a Tier 2 shortage is triggered, a scenario the Bureau of Reclamation projects could happen by May 2023.

Gaining reliable access to Metropolitan’s river allotment could help Arizona address growing demand from municipal and industrial users, said Sarah Porter, director of the Kyl Center for Water Policy at Arizona State University. Porter applauded the multi-state collaboration, saying the recycling project and other augmentation ideas, like a proposed binational desalination plant along the Sea of Cortez in Mexico, could add flexibility to a system that serves 40 million people from Denver to San Diego and irrigates more than 4 million acres of farmland.

“It’s a huge amount of water,” Porter said of the potential yield of Metropolitan’s project for urban Southern California. “That’s one more community that relies on the Colorado River that has another degree of resilience.”

A Promising Leap in Reuse

California already has a rich legacy of turning wastewater into high-quality water suitable for a variety of uses including agricultural, groundwater recharge and outdoor irrigation. In 2020 the state used more than 700,000 acre-feet in recycled water, much of it going to golf courses, farms and some indirect potable uses. But experts say California can greatly expand the output through a recycling technology Metropolitan is currently ginning up support for.

Deemed “direct potable reuse,” the method treats wastewater through a three-step purification process involving membrane bioreactors, reverse osmosis and ultraviolet light disinfection. Unlike conventional systems where treated wastewater is put into underground basins until needed such as how Orange County handles it, direct potable reuse supplies could go straight into the drinking water system.

Direct potable reuse, however, is not currently permitted in California, but the State Water Resources Control Board is expected to finalize regulations by December 2023. To prove to regulators and the public that the process is safe and viable, Metropolitan has been compiling water quality data from a demonstration facility in Carson since 2019.

The technology is a great match with a county like Los Angeles where most of the treated wastewater currently goes into the ocean, said Cooley, with the Pacific Institute. With imported water becoming increasingly unreliable, she said it was critical for Southern California to pursue new recycling projects, noting the region currently reuses only 29 percent of its effluent.  

“There are lots of opportunities if we start thinking outside the box more and really look beyond individual agency service areas,” Cooley said. “We’re going to have to do more of that to address the challenges that we now face.”

Once California gives the green light, Metropolitan says it will build a facility near the demonstration facility in Carson that could produce up to 150 million gallons a day of potable water or enough to serve more than 500,000 households, using wastewater from a nearby plant operated by the Los Angeles County Sanitation Districts. Purified water from the new recycling plant would be delivered to four of the region’s groundwater basins for later use and two of Metropolitan’s existing treatment plants via approximately 60 miles of new pipelines for further distribution in its service area.

Overcoming Sticker Shock

Neither construction nor the new water will be cheap. 

In 2018 Metropolitan pegged construction costs at $3.4 billion, but inflation could spike the final price tag to $4 billion by the 2032 projected completion date. As for water prices, Metropolitan currently charges its member agencies around $1,100 per acre-foot of treated water; the new supply will likely run more than $1,800 per acre-foot.

Upadhyay, the Metropolitan official, downplayed the difference by saying cost concerns are relatively minor compared to the damaging effects climate change is having on the Colorado River and Sierra Nevada watersheds it relies on for imported water. He added the agency is hoping to reduce the impact on member agencies with contributions from the out-of-state partners. In addition, it has asked the California Legislature to contribute $500 million. Metropolitan also is exploring the possibility of similar partnerships with users of California’s State Water Project, but no contracts have been signed, Upadhyay said.

“It’s not like we can go out and acquire more imported supply,” Upadhyay said. “Going forward, we really need to be looking here at home.”

That sentiment is shared among some agricultural interests in the basin, including Bart Fisher, vice president of the Palo Verde Irrigation District Board of Trustees. Fisher, who farms on the west side of the Colorado River near Blythe, Calif., called urban water recycling efforts the “wave of the future” and noted Palo Verde farmers have been utilizing water reuse techniques for decades.

“These urban projects have major implications for the Lower Basin,” he said. “It will alleviate some of the pressure we are feeling.”

Finding Ways to Work Together

It’s unclear whether current operating guidelines for the river allow the sort of interstate exchange being proposed. But the partners say the concept shares ties with the intent of previously enacted conservation programs like the 2007 Intentionally Created Surplus, a water banking program intended to boost storage in Lake Mead. They hope guidance for interstate exchanges will be explicitly included in the next set of river operating guidelines that have to be finalized by 2026.

“It would behoove all of us to have a candid conversation in the renegotiations about that, make sure we have the rules spelled out,” said Pellegrino, SNWA deputy general manager. 

The 20-plus year megadrought is forcing all users in the Lower Basin to get creative in developing ways to stretch their shares of the Colorado River. And the clock is ticking.

Last month water levels at Lake Powell fell to a historic low and are still hovering near the minimum elevation level at which Glen Canyon Dam can generate electricity for more than 5 million homes and businesses across the West. The Bureau of Reclamation expects the combined storage at Lake Powell and Lake Mead to drop below 30 percent by late 2022 due to declining inflows of runoff.

Metropolitan’s wastewater recycling plant won’t cure all the Lower Basin’s myriad water troubles. But Colorado River veterans say the proposal is a welcome sign of progress, nonetheless.

“It’s good to see this multi-state collaboration and that’s what we do need,” said Porter, with Arizona State’s Kyl Center. “It’s better for everyone if we can find these ways to work together.”

---

Reach Writer Nick Cahill at ncahill@watereducation.org, and Editor Doug Beeman at dbeeman@watereducation.org.

 Know someone else who wants to stay connected with water in the West? Encourage them to sign up for Western Water, and follow us on Facebook , Twitter,  LinkedIn and Instagram.