Study Urges Halving L.A.’s Mono Lake Ration : Environment: Report prepared for the state calls for letting lake level rise 8 1/2 feet to protect ecological balance.

A long-awaited environmental study on Mono Lake recommends that Los Angeles receive about half of its historic water deliveries from the ecologically imperiled lake basin near the eastern entrance to Yosemite National Park.

The report prepared for the State Water Resources Control Board calls for permitting the lake level to rise 8 1/2 feet beyond the current elevation of 6,375 feet above sea level to protect the scenic and environmental value of the ancient body of water.

Allowing more water to flow into the saline lake also will help restore fish populations in its Eastern Sierra feeder streams, the report concluded.

The report estimates that the city of Los Angeles, which for 50 years siphoned water from the streams and transported it 350 miles through the Los Angeles Aqueduct, would be able to draw about 44,000 acre-feet in an average year, a fraction of the 600,000 acre-feet of water consumed in the city each year.

Historically, Los Angeles has taken 85,000 acre-feet from Mono Lake streams, but in recent years has been barred under a court injunction from drawing any until the Mono basin’s complex ecological problems are worked out and the lake reaches 6,377 feet. An acre-foot is typically enough water to meet the needs of two families in Los Angeles for one year.

Environmentalists, who have been fighting the city Department of Water and Power for 15 years over the lake, welcomed the state water board’s recommendation as a step in the right direction, but said the recommended water elevation may still not be enough.

Martha Davis, executive director of the Mono Lake Committee, said the group prefers a second alternative discussed in the 1,800-page environmental report that would require a lake level of 6,390 feet--about 6 1/2 feet higher than the recommended elevation. The lake last reached that level in 1965.

“They recognize in their own report that the level they are recommending is not enough to address problems of expansive dust storms that exceed federal and state air quality standards or protect the brine shrimp, which is an important part of the food chain,” Davis said. “It is clear a higher level is necessary.”

The report, prepared by the consulting firm Jones & Stokes Associates, acknowledges the recommended level would “entail significant occurrence of dust storms and a significant reduction in brine shrimp productivity,” but concludes that the dust storms would occur over a small area and the shrimp losses would not seriously affect food supplies for foraging waterfowl, especially gulls that nest there.

Department of Water and Power officials said they were still studying the report, but in a statement issued late Friday said the recommended lake level could lead to higher water rates for city customers.

Henry R. Venegas, who oversees the DWP’s aqueduct division, disputed assertions that low lake levels have harmed the ecosystem.

“Even at an elevation two feet below the court-ordered level of 6,377 feet, the Mono Lake ecosystem has prospered,” Venegas said. “Since the court injunction . . . the gull population has increased. This supports our theory that there are other alternatives to raising the lake level that provide environmental benefits.”

The state water board will accept public comments on the environmental report for three months and hold hearings in October before deciding on the lake’s proper level. A Superior Court judge in El Dorado County overseeing litigation between environmental groups and the city has delayed his rulings until after the state board rules on the water level.