July 17, 2018

A changing climate at Mono Lake could mean more dust storms in the Eastern Sierra — or less water for L.A.

Louis Sahagun, LA Times

When dust storms began rising off the dry bed of Owens Lake, authorities in the Eastern Sierra blamed Los Angeles’ thirst. The city had, after all, drained the lake in the 1920s to serve its faucets.

Now, as dust kicks up from Mono Lake, authorities in the Eastern Sierra are once again blaming that water-craving metropolis about 350 miles to the south.

But this time, they’re also blaming climate change.

Since 1994, a landmark State Water Resources Control Board decision has capped L.A.’s diversions of the streams that feed Mono Lake, defusing for a time one of California’s most protracted environmental battles.

Scientists say climatic shifts, however, are bringing less snow to the Sierra Nevada and less snowmelt to Mono Lake. That means if Los Angeles keeps taking its allocated share, it will lead to a decline in lake levels and increased health risks for those exposed to windblown dust from the receding shoreline, according to the Great Basin Unified Air Pollution Control District.

To protect Mono Basin’s ecosystem and airshed, regulatory officials say, will require drafting new predictive models of precipitation, temperature and evaporation rates to control diversions into an aqueduct system that has transformed the ancient brine lake into the largest source of powder-fine air pollution in the United States.

Of particular concern are particulates of 10 microns or less, which are regulated by state and federal laws because they can lodge deep in the lungs, causing respiratory injuries. Dust storms at Mono Lake exceeded federal health standards 33 times in 2016, officials said.

The Los Angeles Department of Water and Power takes issue with the Great Basin district’s warning that more restrictive measures may be needed to meet clean air standards.

“We’re headed for a showdown with Los Angeles; no doubt about it,” said Phillip Kiddoo, air pollution control officer at Great Basin.

Mono Lake

Phillip Kiddoo, air pollution control officer for the Great Basin Unified Air Pollution Control District, walks across salt and fine white sand at Mono Lake's shoreline, which is prone to dust storms. Allen J. Schaben / Los Angeles Times

“The best way to control Mono’s airborne particulates is to raise the lake level, submerging exposed areas of lake bed prone to dust storms,” Kiddoo said. “To do that, however, L.A. has to agree to further reduce its annual exports of water, which isn’t likely.

“While we cannot interfere with L.A.’s water conveyance system, we could file a lawsuit,” he said. “And California health and safety codes give Great Basin authority to assess the city for our legal expenses.”

Rich Harasick, the DWP’s senior assistant general manager of the water system, said further reductions of its water exports aren’t needed. Since the water board’s 1994 decision, he said, the utility’s diversions have had “a very limited influence on Mono Lake’s elevation.”

Today, he said, the lake level is mainly influenced by weather conditions, which are affecting watersheds in which it operates throughout the Eastern Sierra.




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