Jesus Ayala and his son, Josh, walk on a path at the edge of Mono Lake in 2022. Water diversions to Los Angeles dried the lake in the early 20th century.

Mono Lake stands out in the high desert of eastern California, a disc of blue amid a landscape of sagebrush and sandy soil. In 1872, Mark Twain called it “this lonely tenant of the loneliest spot on earth.”

Lonely as it may be, legal cases involving Mono have revolutionized environmental law in California, the American West and the U.S., bringing about important changes to water use and air quality regulations in recent decades and showing the way ahead for tribal resource rights today.

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In the early 20th century, the Los Angeles Department of Water and Power built the Los Angeles Aqueduct to capture snowmelt from the eastern face of the Sierra Nevada and channel water to the city. Within a decade, California’s Owens Lake, where the water had naturally flowed and collected for thousands of years, dried up. In 1941, the Los Angeles utility added an extension that allowed it to drain water from the nearby Mono Basin, tapping rivers and streams that had long fed Mono Lake.

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Mono was known for its abundant bird life, harboring up to 1 million birds of 300 different species. But by the 1970s, the lake’s plants were dying and dust storms clouded its shoreline. People who loved the lake were worried — including student researchers, who published “An Ecological Study of Mono Lake, California,” a 200-page report distributed by UC Davis’s Institute of Ecology.

Mono is a “triple water” lake, with three types of minerals (chlorides, carbonates, and sulfates) dissolved in it, making it two to three times saltier than the ocean. The students’ Mono Lake study, published in 1977, showed that as the lake’s water level dropped and its salts became more concentrated, its brine shrimp and alkali flies — tiny invertebrates that fed the lake’s birds by the millions — struggled to reproduce.

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“The present populations of these animals will not be able to withstand the increasing salinity predicted for Mono Lake,” the students wrote. That spelled doom for the lake’s abundant gulls, grebes and phalaropes.

Armed with these findings, in 1979, a group of environmental organizations sued the Los Angeles Department of Water and Power over the aqueduct’s effects on Mono, seeking to stop the utility from diverting so much water. They based their argument on the public trust doctrine, a legal principle that holds that certain natural resources are held in trust by the state for the benefit of the public. In 1983, the California Supreme Court ruled that protecting Mono Lake’s ecosystem fell under this doctrine. The court left the details to the state Water Resources Control Board, which implemented cutbacks to Los Angeles’ water diversions so that more water would reach Mono and the lake could eventually return to a healthy level.

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A decade later, Mono was the subject of more legal innovation — this time, a new application of the Clean Air Act, the federal law that regulates air emissions. The Great Basin Unified Air Quality Control District, responsible for regulating air pollution in Eastern California, sought to curb dust storms that billowed off the shorelines of Mono and Owens lakes — and to hold Los Angeles accountable for them. Caused by falling water levels from years of aqueduct siphoning, the storms were causing respiratory issues for local residents.

Yet this required the agency to convince the courts that the Clean Air Act could regulate not just refinery or factory smokestack emissions, but also those from natural sites altered by human impact. After a David-and-Goliath fight, the 9th U.S. Circuit Court of Appeals in San Francisco decided that Los Angeles had to bring the Mono and Owens lake beds into compliance with dust standards. Not only could they not divert as much water, but they had to clean up the damage that had already been done.

Now the Mono Basin could be part of making water history again. In 2017, California began using Tribal Beneficial Uses — water quality standards keyed to protecting traditional tribal fisheries and cultural practices — to incorporate long-ignored tribal needs into state environmental management. The first regional board to incorporate Tribal Beneficial Uses into a watershed management plan was the Mono Basin in 2020. The following year, the local Mono Lake Kootzaduka’a tribe requested Tribal Beneficial Uses for cultural practices and tribal subsistence fisheries, initiating a multi-year process of research and consultation.

“We’ve never been at the table to have conversations regarding Mono Lake or any of our traditional lands. This is … a long time coming,” said tribal chairperson Charlotte Lange at an April 2024 Lahontan Regional Water Quality Control Board hearing. The planned November 2024 adoption of the Mono Basin Tribal Beneficial Uses was delayed but remains on the near horizon, Daniel Sussman, a scientist for the California  Water Resources Control Board, told me.

Guest opinions in Open Forum and Insight are produced by writers with expertise, personal experience or original insights on a subject of interest to our readers. Their views do not necessarily reflect the opinion of The Chronicle editorial board, which is committed to providing a diversity of ideas to our readership.

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Mono’s legal impact continues to be felt across the country. Today, legal cases in process seek to apply the public trust doctrine to protect salt lakes in Utah and Nevada. Hawaii applies the public trust doctrine to groundwater, in accordance with Native Hawaiian values, and in 2018, a court held that the doctrine applies to California groundwater, too. And just last year, youth climate activists used the public trust doctrine in a complaint against the Wisconsin Public Service Commission.

As Geoff McQuilkin, director of the Mono Lake Committee, told me in a 2024 interview, “Mono is always the reference.”

Caroline Tracey is the author of “Salt Lakes: An Unnatural History.” She lives in Tucson, Ariz. This was written for Zócalo Public Square.

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