An independent review panel supported by UC Santa Cruz recently completed its work evaluating restoration options for the Salton Sea, a shrinking lake in Southern California that has become one of the state’s most challenging environmental problems.
Within the last 2,000 years, the Salton Sea has fluctuated between two states—a lake or a dry desert basin, likely depending on the course of the Colorado River. But the current version of the lake was created in the early 1900s, when irrigation canals from the Colorado River broke temporarily, spilling a massive amount of water into the previously dry Salton Basin. Today, the Salton Sea is California’s largest lake. But it has been losing volume since the early 2000s, due to reduced agricultural runoff entering the sea as water is transferred to urban areas in coastal California.
This loss of water has increased the salinity of the sea to nearly twice that of ocean water, resulting in declining populations of fish and birds. The lake’s shrinking volume has also exposed formerly submerged portions of shoreline, called playa. Winds whipping across the dry playa uplift dust particles that may worsen local air quality and contribute to high rates of respiratory illnesses in primarily Latino surrounding communities.
The situation has continued to devolve over several decades, in part because appropriate restoration methods for the Salton Sea are difficult to identify and implement, and proposals are often both costly and contentious. In 2021, the State of California Salton Sea Management Program (SSMP) awarded a contract to the University of California, Santa Cruz to evaluate one particular form of restoration strategy: water importation concepts to refill the sea. Environmental Studies Professor Brent Haddad was the principal investigator on this project.
“I’ve been studying water management and water governance for most of my career and have been involved in many big projects, but none quite as complex and consequential as this one,” Haddad said. “The Salton Sea is a challenge that involves every aspect of water management, from engineering to governance to ecology to economy to public health.”
Assessing water-importation concepts
To tackle the specific question of whether it was feasible to import enough water from California’s Pacific coast, the Colorado River, or Mexico’s Sea of Cortez to refill the Salton Sea, Haddad established an Independent Review Panel to advise the state. The panel was chaired by Rominder Suri, Professor and Chair of Civil and Environmental Engineering at Temple University, and consisted of seven experts in different aspects of water-body restoration, including engineering, ecology, economics, biogeochemistry, and law.
Adina Paytan, a research scientist and lecturer for UCSC’s Institute of Marine Sciences served on the panel. Haddad himself was not a member of the panel. Instead, he oversaw the research and administrative team—including UCSC Professors Yihsu Chen and Michael Loik, graduate students Daniel Hastings, Hannah Newburn, Sepehr Ramyar, Prem Patel, Charlie Chesney, and Siyu Luo, project coordinator Azucena Beltran, and staff from the UC Santa Cruz Institute for Social Transformation—that supported the panel’s work.
The panel evaluated 18 specific ideas for water importation that were submitted by the public during two Requests for Information in 2018 and 2021. Of these, three approaches avoided a set of five “fatal flaws” that Panel members agreed no viable approach to water importation should have. The three approaches without fatal flaws, which all involved drawing water from the Sea of Cortez, were then combined into a Sea of Cortez Import Concept that underwent a detailed feasibility study, including cost, permitting, engineering, geotechnical, and benefits analyses.
This feasibility study showed that, while the Sea of Cortez concept was theoretically possible from an engineering perspective, it was extremely expensive, brought significant risk of environmental damage, would take decades to complete, and provided limited benefits to Mexico. As a result, there was a strong potential that desired benefits to the Salton Sea would either be long delayed or never realized. So ultimately, the panel’s final report did not recommend that the state proceed with any of the initially proposed water importation concepts. Haddad said he believes the panel made a sound, evidence-based decision on this matter.
“I think this gets us off of a potentially financially catastrophic track, where we could have been stuck trying to build a canal forever, without ever yielding a drop of water for the Salton Sea,” he explained. “And each year, the salinity in the lake grows and more playa is exposed, making the challenge that much more difficult. So speed is of the essence.”
Recommending alternatives
As the panel evaluated the feasibility of refilling the Salton Sea through the Sea of Cortez Import Concept, they also identified two other possible restoration approaches, which were both put through the same feasibility study. All three approaches proposed a large desalination facility at the Salton Sea. The excess salt produced in the process would be transported and disposed of in landfills off site via existing railroad lines. But the two additional concepts proposed water importation only at levels necessary to replace the amount of water lost in the desalination process. These concepts included plans to expand ongoing playa stabilization projects to minimize dust-related impacts on air quality.
These additional approaches were considered because the panel concluded there was strong research evidence to suggest that environmental, air quality, and economic goals for the region could be achieved while maintaining the Salton Sea at a lower volume than its mid- to late-20th century levels. Stabilizing the Salton Sea at a new smaller size would avoid the environmental damage and high cost that would result from attempting to totally refill the sea, and benefits could potentially be realized sooner and be more sustainable in the long term.
“This project really requires thinking about water in a very broad, holistic way, because we are in the midst of a drought that is likely to get worse, and any water that is going to the Salton Sea is water that will be missing elsewhere,” said panel member Adina Paytan. “So, if it’s possible to resolve air pollution issues and improve ecosystem health without having to maintain as large of a water body in the desert, that’s a win-win situation.”
One of the two approaches that the panel considered for restoring a smaller Salton Sea proposed replacing water lost to desalination with agricultural water from the Colorado River, via a voluntary transfer program. This plan, called the Colorado River Voluntary Transfer Concept, was based on recent successful programs undertaken by the Imperial Irrigation District (IID), in which California farmers were paid to fallow their fields, thereby freeing up water to flow to the Salton Sea. Converting agricultural practices to more water efficient crops and technologies or expanding the voluntary water program or water exchange programs to urban areas should also be studied, according to the panel’s recommendations.
Based on the findings of the feasibility study, the panel determined that the Colorado River Voluntary Transfer Concept, while challenging, was feasible overall. As a result, they’re recommending it to the state. The panel estimates that this plan would allow the Salton Sea’s salinity level to return to roughly ocean-level salinity as soon as 2051, and the eventual equilibrium water level of the Salton Sea would rest at roughly 258 feet below mean sea level.
Toward a healthier future for the Salton Sea
coordinator Azucena Beltran, and
UCSC Ph.D. students Siyu Luo and
Daniel Hastings on a site visit in Mexico.
The members of the UC Santa Cruz team that supported the panel’s work hope that the project’s recommendations will bring clarity and could help to spur progress on restoration.
“One of the big challenges with Salton Sea restoration is that there are a lot of ways to do it wrong, and the stakes are that local people have been waiting for decades to learn what will happen to this really important feature in their region,” Haddad said. “A feasible, cost-effective plan that could restore environmental benefits and minimize the Salton Sea’s contribution to air quality problems could really help the region move forward.”
Throughout the process, the panel and members of the research team sought input from local communities to better understand the issues facing the region and took field trips to visit the Salton Sea and northern Mexico. Project coordinator Azucena Beltran, a UCSC alumna who grew up in the Salton Sea region, helped to ensure that all public engagement processes were accessible to Spanish-speaking communities. Key project communications were translated into Spanish, and public meetings were structured as bilingual interpreted conversations, followed by question and answer sessions.
The team hopes that these practices might offer a model for future public engagement work around the Salton Sea, to ensure that voices from local communities are heard. Beltran said it will likely take communities some time to digest the Independent Review Panel’s latest reports, but the findings are already stimulating productive conversation.
“For so long, all we’ve heard as community members was that the sea was the reason for poor air quality, and the only solution talked about was water importation, so personally, I’m relieved to know that there are other options that could be less expensive and have the same effect,” she said. “It makes restoration feel more realistic and doable. To me, a successful Salton Sea restoration is one where both public health and ecological aspects are addressed in a way that is sustainable for years to come.”
