The California Air Resources Board on Monday ruled the city must obey last year's order by a regional air pollution agency to expand its efforts to cover nearly 3 more square miles of the lake.
The ruling is a blow to the city's powerful Department of Water and Power, which in 1913 began diverting water from the Eastern Sierra and the Owens River away from the shallow lake 200 miles north of Los Angeles.
The lakebed, sprawling across the starkly beautiful Owens Valley between Death Valley National Park and a sawblade wall of Sierra peaks, was once several dozen feet deep and was used by steamers in the 1800s.
However, it went dry in 1926 after its water source was diverted into the Los Angeles Aqueduct and the region has since been plagued with massive dust storms and poor air quality. Hard feelings persist in rural Owens Valley.
Beginning with a 1998 agreement, the DWP has spent $1.2 billion on the nation's largest dust mitigation project, mainly by putting water back into about a 40-square-mile area of the lake bed.
But the city challenged an order last year from the Great Basin Unified Air Pollution Control District to increase the mitigation area. The utility argued that the additional dust control project would cost it up to $400 million. The DWP argued that the city already uses 30 billion gallons of water each year to control dust and enough was enough.
"Billions of gallons of drinking water continue to be wasted every year controlling dust on Owens Lake, despite non-water, or low-water options that can control dust," DWP General Manager Ron Nichols said in a statement Tuesday.
The disputed mitigation orders extend into an area where dust problems weren't caused by Los Angeles water diversions and would "do nothing to save water," Nichols said.
The Great Basin district argues that air quality still doesn't meet federal standards and has accused the utility of trying to back out of previous agreements.
Monday's state ruling found no grounds for the DWP's claims that no additional dust controls are required, said a statement from Ted Schade, Great Basin's air pollution control officer.
"Having across-the-board support from the premier technical and legal air quality organization in the state is very gratifying," he said.
However, the water war is far from over. The DWP filed a federal lawsuit last month seeking to block the orders.
The suit, filed in U.S. District Court in Fresno, names the Great Basin air pollution district, the state Air Resources Board, the U.S. Environmental Protection Agency and the U.S. Bureau of Land Management. It asks the court for relief from the "systematic and unlawful issuance to the city of dust control orders and fee assessments."