Mono Lake is a source of fine powder air pollution

For those who live near the brackish shores of Mono Lake in California, October can be a dreadful month. That’s when turbulent winds scour Mono’s exposed lake bed, or “tub ring,” and toss clouds of fine dust that blanket homes, ranch lands, and scenic trails.

For 50 years, the vast lake has been a source of so-called PM10 particles – a dust so fine that it can obstruct human airways, enter the lungs and worsen serious heart and lung diseases, such as asthma.

“We have a public health crisis in our hands,” grumbled Phil Kiddoo, enforcement officer for the Great Basin Unified Air Pollution Control District, who oversees a battery of monitoring devices that help chronicle the air pollution. dust storms hitting Mono Lake this time around. year.

Kiddoo and others have long blamed the city of Los Angeles for generating this risk of pollution. Since World War II, the city has diverted water from the streams that flow into the lake on the arid eastern side of the Sierra Nevada range. Without an adequate source of replenishment, critics say, the lake was allowed to slowly shrink, increasingly exposing its alkaline lake bed to the air.

Now, after two years of punitive drought, Mono County environmentalists, tribal leaders and air regulators have launched a campaign to raise the lake’s level. They hope to achieve this by preventing the Los Angeles Department of Water and Electricity from diverting water from the lake’s supply streams.

The campaign is based on the new argument that Los Angeles can afford to stop diverting water here because the Angelenos are now experts in water conservation.

Mill Creek runs through recent snowfall over Lundy Lake in Lee Vining, California. Mill Creek was the only one of the five main streams in the Mono Basin that was never diverted to the Los Angeles Aqueduct and still flows to Mono Lake.

(Brian van der Brug / Los Angeles Times)

For its part, the Water and Electricity Department said Mono County officials should first investigate whether the dust is coming from elsewhere before laying the blame.

Mono officials such as Kiddoo have often raised the possibility of legal action in the long-running dispute, but so far they have not gone to court. Recently, however, a coalition of 18 environmental groups and the Great Basin District wrote a correspondence to the DWP saying Los Angeles is conserving so much water it can afford to stop turning away from the lake’s supply streams. Mono.

They pointed out that water use in the DWP’s service area has decreased by 22% since fiscal year 2013-2014, according to the DWP’s water management plan. In addition, around 4 million Angelenos are currently using 40 gallons less per person per day than they were 15 years ago, even in drier conditions.

The DWP attributed these achievements to strategies such as stormwater capture, groundwater replenishment, recycling, low-flow toilets and $ 2 billion in court-ordered dust control projects Owens Lake, about 140 miles to the south. These projects use gravel, vegetation and other methods to reduce dust at Owens Lake, instead of using large amounts of water.

Mono County officials say the measures have saved the DWP more than double the 16,000 acre-feet of water the city typically exports from the Mono Basin in a year.

A man works with antennas.

Phillip Kiddoo of the Great Basin Unified Air Pollution Control District explains how an air monitoring device transmits data from the north shore of Mono Lake to Lee Vining.

(Brian van der Brug / Los Angeles Times)

“Now is the time for the city to share its conservation benefits,” said Wendy Schneider, executive director of the non-profit environmental group Friends of the Inyo. “Lives and ecosystems are at stake.”

Regional air quality officials, environmental groups and Native American tribal chiefs have called on the DWP and its commissioners to initiate discussions on reducing or even stopping the hijackings to minimize “exposure. potential of the city to liability and litigation that would most certainly ensue if an adversarial approach were taken.

Anselmo Collins, senior deputy general manager of the DWP’s water supply system, responded in a letter late last month, stating that the agency’s “ability to meaningfully engage” in such discussions is limited without further data and analysis of all possible sources of pollution that could affect air quality in the region.

With that goal in mind, Collins encouraged the Grand Basin District to investigate potential sources outside the lake, including “burn scars from forest fires, impacts from wild horses and the historic fluctuation” of water levels. lake “prior to the diversions of the LADWP”.

A road heads towards a lake.

Highway 120 runs along the south shore of Mono Lake in Lee Vining. Regulators hope to persuade the DWP to reduce water diversion from Mono Lake to help alleviate air pollution.

(Brian van der Brug / Los Angeles Times)

Famous for its towering craggy tuff formations, Mono Lake is a remnant of a vast inland sea, where the melting cool alpine snows cascading from the slopes of the Sierra combine with the salt water that is home to brine shrimp and swarms. alkaline flies that feed migrating birds, including about 50,000 California gulls.

The controversy over Los Angeles’ water diversions from Mono’s feeder streams is one of California’s oldest environmental battles.

By the late 1970s, the tributaries had dried up, causing the lake’s level to drop more than 40 feet and doubling the salinity of the water. Smelly salt marshes and choking dust storms followed.

The formal protests began with a lawsuit that a popular coalition of residents and environmental groups filed in Mono County Superior Court in 1979 against the DWP. The lawsuit alleged breaches of public confidence and the creation of public and private nuisance by exposing 14,700 acres of old lake bed.

The breeding cycles of western gulls became a delicate political drama for LA when a plummeting water level revealed a land bridge connecting an island colony to the shore, allowing coyotes to cross and feast on birds and their eggs. The Army Corps of Engineers attempted to detonate the land bridge with dynamite, but the mud only exploded high up, then fell back in place.

In 1983, the United States Supreme Court ruled that environmentalists had the right to challenge the amount of water LA exported from tributaries. A decade later, the National Water Board established rules for DWP’s water exports from the Mono Basin.

A person walks by a lake.

Phillip Kiddoo of the Great Basin Unified Air Pollution Control District walks along the north shore of Mono Lake.

(Brian van der Brug / Los Angeles Times)

When Mono Lake is between 6,380 and 6,392 feet above sea level, the DWP can export 16,000 acre-feet of water per year. If the lake drops to between 6,377 and 6,380 feet, DWP’s exports are reduced to 4,500 acre-feet of water per year. If the lake is less than 6,377 feet, the DWP cannot export water.

Once Mono Lake rises above a target level of 6,392 feet above sea level, the DWP will be authorized to export any water in excess of the required tributary flows of 89,000. acre feet.

Since 1994, the lake level has fluctuated between about 10 to 12 feet below this target level.

“The journey to raise the lake to a healthy level is not on time and the consequences are dire,” said Geoffrey McQuilkin, executive director of the Mono Lake Committee, a nonprofit that started out in the United States. 1970s in an attempt to prevent the death of the lake.

Recently, the National Water Board approved a 2013 voluntary agreement to repair damage to waterways caused by LA diversions.

The plan is to release pulses of water from an earthen dam along a seven-mile stretch of Rush Creek to mimic annual flood cycles, distribute willow seeds, and promote healthy trout populations.

But the agreement does not affect the water diversions, nor the height of the lake. Even now, declining water levels during the current drought exposes the lake bed more alkaline and threatens to once again discover a land bridge connecting the island colony to one of California’s three largest gull colonies. in the world.

An aqueduct

The Los Angeles Aqueduct crosses the Owens Valley near Lone Pine.

(Brian van der Brug / Los Angeles Times)

A mile southeast of the small mountain town of Lee Vining, the gateway to Yosemite National Park, there’s a stretch of crisp shoreline where Mono Lake committee members and DWP officials meet. every year in early April to read a lake level gauge at the start of the new year of runoff.

Maureen McGlinchy, hydrological modeling specialist for the committee, visits the site at least once a month to gather all the information with binoculars, water sample bottles, a notebook and a gadget that measures wind speed , ambient temperature and relative humidity.

On October 26, she reported that the lake’s surface altitude was 6,379.85 feet above sea level, or 12.15 feet below target level.

“If recent hydroclimatic trends continue into the future and LA continues to divert water from the region, the recovery of Mono Lake will remain at a standstill,” she said. “If, however, LA ceases its diversions, Mono Lake would hit the target level within 20 years.”


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