Will California Stop Diverting Iconic Mono Lake Water to Los Angeles?
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As trickling snowmelt in the Sierra Nevada slowly raises Mono Lake — famed for its bird life and outlandish shoreline mineral spires — advocates are pressuring state water officials to halt diversions from the lake's tributaries to Los Angeles, which has used this clean mountain water source for decades.
Environmentalists and tribal representatives say such action is years overdue and would help the iconic lake's ecosystem, long plagued by low levels, high salinity and dust that wafts off the exposed lakebed. The city of Los Angeles, they argue, should simply use less water, and expand investments in more sustainable sources — especially recycled wastewater and uncaptured stormwater. This, they say, could help wean the city off Mono basin's water for good.
In December, the Mono Lake Committee, the basin's leading advocacy group, sent a letter to the State Water Resources Control Board requesting an emergency pause on water diversions from the lake. The water board hosted an online workshop to discuss the matter in February, and it is now considering further actions to restore the naturally saline lake.
Geoff McQuilkin, the Mono Lake Committee's executive director, said the lake will probably rise another four feet in 2023 — reason, as he sees it, to double down and halt exports.
"This is a year to take advantage of," he said. "We'd like to lock in these gains."
But the Los Angeles Department of Water and Power is pushing back. The agency began diverting the Mono basin's water in 1941, and officials say this supply, though a minute fraction of its overall demands, is a vital part of its portfolio, which includes water imported from the Sacramento-San Joaquin Delta and the Colorado River. The agency also has brushed away claims that the basin's wildlife — especially nesting birds — are threatened by the city's diversions. "The Mono Basin ecosystem remains healthy," the department recently stated. Moreover, the city has already cut exports from the lake's tributaries by 85%, starting in the early 1990s, when landmark hearings triggered tighter rules on sending the basin's water to Los Angeles.
"That's approximately 70,000 acre-feet per year," said Anselmo Collins, the city water department's assistant general manager of the water system, during the February workshop.
Historic diversions to Los Angeles amounted to between 80,000 and 100,000 acre-feet, and more, of the basin's water annually. Beginning in 1995, that was cut to between 4,500 and 16,000 acre-feet annually. Mono advocates say that's still too much.
The state water board has remained tight-lipped about how it may respond to the demands from Mono Lake's advocates. Samuel Boland-Brien, a supervising engineer with the board, said the agency plans to hold a hearing, though he couldn't say when, to discuss options for recovering Mono Lake.
Its surface elevation is currently around 6,380 feet, and in the past 30 years it has never risen much past 6,385 — still seven feet below a target recovery level of 6,392 feet,established in 1994.
"The need to reach that level isn't optional," Boland-Brien said.
While existing rules on Mono Lake diversions are designed to manage the basin's ecosystem — broadly categorized as public trust resources — they don't take into account the needs of the basin's indigenous residents, namely the Kutzadika'a tribe.
Dean Tonenna, a Kutzadika'a botanist, said his people were left out of the 1990s negotiations that led to the existing diversion rules. "The tribe has not been meaningfully engaged in any of the discussions or workshops that led to the decision," Tonenna said.
He said "a racist legacy" led to the lowering of the lake and still compromises his people's connection to the ecosystem. Now, he and other local tribal members want their interests considered.
That's the funny thing — it's such a drop in the bucket. I think the department recognizes they don’t need the water, but they just keep it because they have a right to it.Bruze Reznik, executive director of the environmental group Los Angeles Waterkeeper
Brian Gray, a senior fellow and water law expert with the nonprofit Public Policy Institute of California, said the dilemma over how to restore Mono Lake could prompt a review of the historical decisions that gave Los Angeles ownership of a share of the basin's water. If state officials conclude that the basin would benefit from having more water, he said, the water board "would have an obligation to reconsider its water rights decision, and specifically address the question of whether Los Angeles should be cut back, partially or completely."
The lake's defenders insist this would have almost no impact on the city's water supply. The city's 2023 Mono Lake diversions will amount to about 1% of the district's annual water use.
Sean Bothwell, executive director of the California Coastkeeper Alliance, said opportunities for water recycling and stormwater capture, as well as simply using less water in the first place, could more than make up for the relatively small amount of water the city draws from the Mono Lake basin.
"The Department of Water and Power really does not rely on this lake … so why continue to destroy Mono Lake when they have these other options available?" he said.
Boland-Brien noted that the 1994 decision called for "a hearing" if the target lake level wasn't reached by 2014. When that time came, the lake was 12 feet below the intended level, and dropping, for a severe drought had begun. Lake advocates agreed to give it more time.
Now, nine years later, the lake level is about the same as it was then, but there is still no firm date — or even an approximate one — for when that overdue hearing will occur.
"That's where a lot of the focus is now — when will that hearing be scheduled, and what will be determined in terms of whether additional actions are necessary?" Boland-Brien said.
The Legacy of Mono Lake
For decades, essentially the sky was the limit on exporting Mono basin water to Los Angeles. The legal cap, written into the city's water rights, was 167,800 acre-feet per year, with no considerations for the environment or local users. Exports ranged as high as 156,000 acre-feet — a peak recorded in 1978 — and in the 1970s and 1980s, exports averaged more than 80,000 acre-feet annually.
This rate of diversion put the lake on pace to eventually disappear — a fate met long ago by Owens Lake, 125 miles to the south of Mono and sucked dry by the same aqueduct system. By the 1980s, Mono Lake's surface had plunged 45 feet. Half the lake's volume was sacrificed for Los Angeles taps, toilets, lawns and pools, and its salinity level doubled, according to the Mono Lake Committee.
A landmark lawsuit challenged the city's diversions in 1979, and a court injunction halted exports in 1990. After weeks of hearings in 1993 and 1994, the state water board ordered the city's water department to reduce its diversions to a maximum of 16,000 acre-feet — deemed a sustainable level. The goal was to draw the lake over 20 years back to the target of 6,392 feet. Officials determined that this would protect native shrimp, flies, birds and geologic features, while preventing lakebed dust from endangering local communities.
The new rules included some key triggers: at a lake level below 6,380 feet, diversions are cut by 72%, and below 6,377 feet, diversions are banned.
But in the past 29 years, the lake level has only partially recovered.
"We've given it almost 30 years with the rules they established in 1994, and it hasn't worked," said Martha Davis, a board member of the Mono Lake Committee.
At the L.A. water department, Adam Perez, the Los Angeles Aqueduct manager, said "the lake level at Mono Lake continues to trend upwards."
Long-term lake level records, however, don't reflect this. The surface elevation has surged several times in the past three decades, usually in the year or so following wet periods. Each time, however, its surface level has dropped again — apparently a consequence of ramping diversions up to 16,000 acre-feet when the lake swells past 6,380 feet. Climate change is not helping either, causing decreased precipitation in the region and increased evaporation from streams and the lake itself.
McQuilkin said this rise-then-fall pattern will continue unless the water board steps in.
"Are we going to watch levels go up and then watch the lake drop again like it did in 2017?" McQuilkin said.
To L.A. water managers, the lake elevation is secondary. What matters, Collins explained at the February hearing, is that the basin's resources are sufficiently protected. Salinity levels, though variable with the lake's volume, have remained for decades within the acceptable range for the lake's invertebrate life, Collins said. He also pointed out that the land bridge that can form during low water periods, making nesting birds especially vulnerable to coyotes, has not fully emerged for many years.
"There is no emergency condition at Mono Lake," Collins said.
He added that the four main creeks that enter the lake "have been restored and are being protected," fish populations in these creeks are thriving and waterfowl habitat has been enhanced.
But Boland-Brien, at the water board, said achieving the 6,392-foot level is a clear mandate.
Tonenna, with the Kutzadika'a tribe, said proposed solutions to protect gulls nesting on the lake's islands from coyotes and prevent dust from lifting off the exposed lakebed — respectively, electric fences and sprinkler systems — are expensive and unworkable.
"All of this can be solved by putting water back into the lake," Tonenna said. "That's the most cost-effective way."
Why L.A. Clings to This Trickler
L.A.'s Department of Water and Power serves more than 4 million people. Its water comes from a variety of sources: As of 2020-21, about 41% was water purchased from Metropolitan Water District, which draws most of its water from the Sacramento-San Joaquin Delta and the Colorado River; 48% came from the Eastern Sierra, mostly the Owens Valley; 9% was pumped from local aquifers; and 2% was recycled water. In recent years, the Department of Water and Power's surface water diversions from the Mono Basin have amounted to between 1 and 3.5% of its total supplies.
There is momentum to restructure the city's water sources, with plans to greatly expand water recycling and stormwater capture programs, while continuing to improve on water conservation — already an area of deserved bragging rights for Los Angeles: In spite of a 25% increase in population since the 1980s, the city now uses almost 30% less water.
In 2019 former Los Angeles mayor Eric Garcetti set a goal of recycling 100% of the city's wastewater by 2035 — part of a broader plan to acquire 50% of the city's water from local sources by the same year. His vision aligns with that of Gov. Gavin Newsom, whose water strategy plan, released last summer, endorsed more water recycling, capturing stormwater and using less.
The progress prompts many to question why Los Angeles clings so tightly to the trickle it receives from the Mono basin.
"That's the funny thing — it's such a drop in the bucket," said Bruze Reznik, executive director of the environmental group Los Angeles Waterkeeper. "I think the department recognizes they don't need the water, but they just keep it because they have a right to it."
Gray suggested a practical reason Los Angeles isn't letting go: An appropriative water right holder who fails to put its water to beneficial use for five consecutive years can lose its water right permanently.
"By diverting this small amount now, they're protecting their entire water rights," he said.
The Natural Resources Defense Council's Mark Gold, who has been involved in the Mono Lake dispute since the 1990s, pointed out that Mono basin's water "is the cleanest water in the city by far" and said "it's also carbon-free, because it's 100% gravity fed once it's in the aqueduct."
Perez at the city’s water department said by email that purchasing the water currently diverted from the Mono basin from elsewhere would cost $44 million per year. And increasing reliance on other sources, he added, would just transfer impacts to other watersheds, "resulting in increased environmental pressure on those already-strained systems" of the Delta and the Colorado River.
"Imported supplies remain a vital source of the City's water resources," he wrote, "especially in consideration of the unpredictability and the unprecedented climate variability we continue to see in the desert southwest."
But environmentalists say there are better options. Andy Lipkis, the founder of the urban greening organization Tree People, told the water board at the February workshop that Los Angeles has a wealth of untapped opportunities to capture local rainwater and runoff, far beyond what Mono Lake provides.
"It's entirely possible for Los Angeles to conserve and capture well over the 4,500 acre-feet of water that the (water department) states it needs," he said.
Wastewater treatment facilities could create a torrent of recirculated water. Reznik said Los Angeles could be treating and pumping back into its supply system more than 300,000 acre-feet per year within two decades.
Imported supplies remain a vital source of the City's water resources, especially in consideration of the unpredictability and the unprecedented climate variability we continue to see in the desert southwest.Adam Perez, Los Angeles Aqueduct manager
Planned projects include Operation Next, sometimes referred to as Hyperion 2035, and a collaboration between the Metropolitan Water District of Southern California and the Los Angeles County Sanitation Districts, each of which aims to treat and reuse more than 150,000 acre-feet of water annually that is currently discharged into the ocean.
A window of opportunity for further developing California's water recycling programs will open wide later this year, when a new law takes effect requiring the state water board to adopt statewide rules on implementing direct potable reuse systems — considered the gold standard in water recycling.
Conservation is certainly the cheapest approach to reducing exports from impacted watersheds. Each resident of Los Angeles uses, on average, 70 to 80 gallons of water daily in and around the home.
"If every Angeleno could just drop one gallon, we'd get that 4 million gallons" diverted daily on average from Mono Lake, Reznik said, adding that even a 10-gallon per person reduction in daily use "is not a crazy number. There are places in the world doing 40, 50 gallons per day."
But to detach itself from its Mono basin water prematurely could be a risky gamble for Los Angeles, said Charley Wilson, executive director and CEO of the Southern California Water Coalition. He said that in water supply management, unlike the energy sector, there is little room for error or failure.
"You can't make a mistake — you can't go through rotating outages with water," he said. "You have to have the alternatives fully in place before you start eliminating or closing out these historic, embedded infrastructure projects."
Water Rights and Righting Wrongs
The city of Los Angeles defends its diversions from the Mono basin as though it has a right to take the water — which legally it does.
But water rights are not permanent fixtures of California law. They can be modified and, in extreme cases, revoked, if the water board determines such action is needed "to prevent waste, to ensure the reasonable and beneficial use of the available water, and to protect the public trust," Gray explained.
Already, the Los Angeles water department's capacity to exercise its water rights has been greatly diminished, with diversions limited to about 10% of historical levels. The question now is whether, and to what extent, the water board will further cut the city's privileges.
Perez said reduced diversions would compromise "the basic human right to water for the residents of Los Angeles."
But such equity considerations were not made of people living in the Mono basin in the 1940s.
"Since the day that settlers first came to our areas, we've been pushed off our lands, we've been robbed of our water," Tonenna said.
The state water board is now developing its Racial Equity Action Plan, which among other things considers "tribal beneficial uses and cultural resources, and related ecosystems when developing, implementing, and enforcing instream flow requirements."
"The board has committed itself to evaluate the water rights system because of the effects of historical and systemic racism that effectively precluded a number of groups from ever obtaining water rights, or that actually stripped certain groups of their ancestral aboriginal water rights," Gray said.
Jeffrey Mount, a water supply expert at the Public Policy Institute, is among the many who think Los Angeles could painlessly give up Mono Lake's water. He envisions an arrangement by which Los Angeles sells its water rights to a non-governmental organization better situated to steward the ecosystem. The lake could be managed back to something resembling its natural state. Equity and ecological issues associated with diversions would evaporate, while in times of plenty water could be offered to Los Angeles at market rates.
"You operate the facility with the environment as the priority objective, selling surplus water when you have it to fund improving the environment," Mount said.
Davis, with the Mono Lake Committee, would like to see a similar priority swap, with the lake basin's needs coming before those of Los Angeles. She said Mono Lake's plight reflects a statewide problem that ecosystems are often maintained at barely viable levels, which makes them especially vulnerable to drought and other climate change impacts.
"Imagine if Mono Lake had been at 6,392 at the beginning of this drought," she said. "If the lake is higher, then there is more flexibility for the lake to drop and not have all the ecological problems that we're seeing. But we're managing our ecosystems at the bottom."
This article was originally published by CalMatters.
