California water regulators are reevaluating why Mono Lake hasn’t stabilized

More than three decades after a landmark decision requiring Los Angeles to limit its water intake to raise the level of Mono Lake, California regulators are reassessing why the lake hasn’t recovered and what to do about it.

At the request of state water officials, UCLA climate scientists developed a new model to analyze why the lake remains well below state-mandated target levels. In a new report, they say that without LA’s use of water from the streams that feed the lake, its water level would be 4 meters high – close to that required limit.

“The way exports are regulated, meeting lake level goals is impossible,” Alex Hall, a climate scientist at UCLA, told members of the California State Water Resources Control Board at a meeting Tuesday.

Although his UCLA team estimates that climate change also played a role, keeping Mono Lake 2.6 meters lower than it would otherwise be, the researchers concluded that stopping LA’s water shipment would almost double the chances of the lake reaching its target level within the next 20 years.

In a 1994 decision, state water regulators required the LA Department of Water and Power to limit the diversion and take steps to raise the lake level by 17 feet. Mono Lake is now higher than it was then, but still about 9 feet below the required level.

DWP officials said they had questions and wanted to review UCLA’s analysis.

Eric Tillemans, interim DWP administrator, told the state board that city studies have found that Mono Lake levels are “more dependent on rainfall, evaporation and runoff than any other factors.”

“It’s a high-tech and novel scientific modeling effort, but it wasn’t developed through a simple process or expert peer review,” Tillemans said, adding that “more time is needed to complete a comprehensive review.”

Anselmo Collins, DWP chief operating officer and senior assistant general manager, said the analysis conducted by UCLA researchers should be fully evaluated before federal officials consider whether it should be used to guide policy decisions.

In 1994, the State Water Resources Control Board set a target level of 6,392 feet above sea level for Mono Lake. The level is still about 9 feet below that.

(Myung J. Chun / Los Angeles Times)

In recent years, LA has received about 2% of its water from Eastern Sierra streams in the Mono Basin. Environmental advocates have urged the city to take less water to help the lake reach a healthy level and supports an ecosystem important to migratory birds.

Richard Katz, former president of the Board of Water and Power Commissioners of Los Angeles, proposed at a book to the federal board that the DWP should freeze its use of water from the Mono Basin. He wrote that doing this would be the “fastest and least expensive way” to raise the level of the lake.

Katz also said the city’s latest decision twice the size of the water restoration project provides a “unique opportunity” to increase the local water supply while Mono Lake recovers.

Others spoke on Tuesday meeting in Sacramento has asked the state water board to step in and require LA to take less water to keep up with the lake, or stop taking water altogether.

“It’s been too long that this has been allowed to happen,” said Noah Williams, a member of the Bishop Paiute Tribe, adding that the focus should be on “really fixing the lake elevation issue.”

Former LA City Councilwoman Ruth Galanter, who helped broker the deal that laid the groundwork for the 1994 decision, urged the state board to insist that the DWP fulfill its commitment.

“This kind of delay is what gives the law a bad name, and makes people lose faith in the idea that the government is here to serve you,” Galanter said. “So it’s not just Mono Lake that’s at stake here. It’s the integrity of our legal system and our regulatory system.”

Geoffrey McQuilkin, executive director of the nonprofit Mono Lake Committee, urged the state water board to take action, saying over three decades the DWP “has shown that it will not willingly turn this national treasure over.” He agreed with Katz that the city should freeze its use of local water until Mono Lake rises.

Geoffrey McQuilkin, executive director of the Mono Lake Committee, looks through binoculars at Mono Lake’s South Tufa on Aug. 1, 2025.

(Myung J. Chun / Los Angeles Times)

Janisse Quiñones, DWP’s leaving the chief executivehe did not agree. He told the state water board on March 13 a book that Los Angeles has reduced its use of water from the Mono Basin since 1994, but that further reductions will not significantly accelerate the lake’s rise.

Quiñones also said that the protections put in place by the state water board, as well as additional measures by the DWP, “have been successful.”

“Mono Lake is very different from all the other salt lakes of the West – including the Salton Sea and the Great Salt Lake – which are decreasing in elevation and facing serious environmental problems,” he wrote.

Quiñones told the board that reducing or stopping the city’s use of Mono Basin water would be “unreasonable, foolish, and would place an unnecessary financial burden on LADWP ratepayers.”

It is not clear when the water board may call another meeting on the matter.