LOS ANGELES (AP) — Los Angeles could save billions of gallons of water under an agreement announced Friday that allows it to use waterless methods to control dust at Owens Lake.

The agreement with the Great Basin Unified Air Pollution Control District follows years of legal squabbling over responsibility for poor air quality at the Eastern Sierra lakebed, which was left dry after a growing Los Angeles began in 1913 to divert its waters 200 miles south.

Under the new agreement, the city expects to save nearly 3 billion gallons of water this year — or enough water for 43,000 people — by using less water-intensive and completely waterless measures, such as planting native grasses.

Mayor Eric Garcetti said in a statement that the deal was a “significant win for ratepayers and our environment” in both LA and the Owens Valley.

Since a 1998 agreement, LA has spent more than $1.3 billion on the nation’s largest dust mitigation project, mainly by putting water back into more than 45 square miles of lakebed. The Los Angeles Department of Water and Power said it uses about 25 billion gallons of water annually to limit dust on the lakebed and has eliminated more than 90 percent of excess blowing dust through its efforts.

It’s expected to take roughly three years for the city to ramp up new less water-intensive dust control methods, but once that occurs, the city expects to save roughly 10 billion gallons annually, said Joe Ramallo, a spokesman for the Department of Water and Power.

The size of the dust control area the city is responsible for has long been an issue of contention. State regulators ordered Los Angeles to expand efforts to control dust storms by an additional 3 square miles of the 110-square-mile lakebed in 2012.

The new agreement is the first to limit the city’s liability for dust mitigation to no more than 53.4 square miles, which accounts for most of the area that emits dust, Ramallo said.

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. It went dry in 1926 and has since been plagued with massive dust storms and poor air quality despite efforts by the city to keep dust down. Hard feelings persist in rural Owens Valley.

“The first rule of ecology is that everything is connected to everything else,” said Great Basin Board Chairman Ron Hames. “We know Los Angeles relies on that water, but we also need clean air, and it is Los Angeles’ responsibility to comply with the clean-air laws and protect public health. This agreement allows for both clean air for the families in the Owens Valley and clean water for Los Angeles.”

The agreement establishes an Owens Lake Scientific Advisory Panel that will be staffed by the National Academy of Sciences and will study the effectiveness of using waterless and low-water methods to control dust at the dry lake. Agreement terms also address the discovery of Native American artifacts on or around the lakebed. Dust control measures may be delayed without a penalty if more are discovered.

“The dust has settled on Owens Lake,” said the city’s utility commission president, Mel Levine. “We are gratified that today we continue to move forward in a renewed spirit of cooperation.”