Mono Lake Group Wins Round, Slows Diversion of Creek

Environmentalists have won another skirmish in the fight to protect Mono Lake by curtailing the Los Angeles Department of Water and Power’s ability to divert major Sierra Nevada stream flows into the Los Angeles Aqueduct for export to Southern California.

The Mono Lake Committee, an environmental group, filed suit in Mono County Superior Court on Wednesday charging that the DWP violated state laws July 13 when it shut off Lee Vining Creek flows into Mono Lake, located on the east side of the Sierra Nevada, 338 miles north of Los Angeles. The water is needed to preserve fish life and the aquatic ecosystems pending outcome of the litigation, they argued.

Judge Edward M. Denton issued a temporary restraining order requiring the department to open diversion gates and release at least 10 cubic feet of water per second, pending a full hearing on the issue. A Jan. 15, 1987, hearing date was set. This is the second court order forcing the DWP to let water flow into the lake. A similar order affecting nearby Rush Creek was issued two years ago.

Mono Lake is a large, brackish body of water that for nearly 50 years has been shrinking because four of the seven streams feeding it have been tapped to supply Los Angeles with 100,000 acre-feet of water annually. That amounts to a fifth of the city’s water needs.

The two most significant streams supplying the lake are Rush Creek and Lee Vining Creek. In dry years, when the Sierra snowpack is below normal, all water in the the creeks is diverted into the aqueduct, but in wet years the department allows the excess to flow into the lake. In those wet years, fish re-establish themselves in the streams.

Wednesday’s suit alleges that by shutting off Lee Vining Creek in July, after letting water flow into the lake for several months, the department immediately jeopardized fish life downstream. A biologist testifying for the Mono Lake Committee reported seeing 80 fish trapped in receding pools as the stream dried up, saying these and other aquatic life were doomed unless water was allowed to flow back into the stream course.

The plaintiffs cited both a 1937 state law that requires dam operators to maintain downstream flows that sustain fish and a 1983 U.S. Supreme Court decision holding that the department must strike an equitable balance between the needs of the local Mono Basin environment and Southern California urban needs when it determines how much water is to be diverted south out of the basin.

DWP attorneys contend that the department was granted exclusive diversion rights by the state in 1940, in compliance with existing laws, and that it has the right to block these streams to meet the needs of Los Angeles.

The Rush Creek suit was filed two years ago when the weather turned dry after several wet years. The DWP attempted to divert the total Rush Creek flow into the aqueduct, and angry fly fishermen filed a suit charging that the law required the department to maintain stream flows to keep about 30,000 fish alive in the lower reaches of the creek. An injunction was granted ordering the department to allow 19 cubic feet per second to flow downstream until the legal issues were resolved.

Trial in the Rush Creek case has been postponed pending the outcome of a joint study by the DWP and the California Department of Fish and Game to determine how much water must flow through the creek to sustain the aquatic environment. That study is to take two years or more, experts say.

If the City of Los Angeles ultimately loses the two cases, it will mean the loss of about 21,000 acre-feet of water--a fifth of the city’s total supply from Mono Basin. Department engineers calculate that the cost of replacing that water, plus the lost electrical energy revenues the water generates, will total $7.5 million a year.

While the loss of 21,000 acre-feet a year--enough to supply 105,000 people--would have little immediate impact on Los Angeles water users, DWP engineer LeVal Lund said such a loss would cause a “potential shortage” in dry years. He said the city would have to buy water from other sources to replace such a loss.