A Piece of the Mono Lake Puzzle

The results of the latest scientific study of Mono Lake are valuable, but constitute no dramatic surprise: If the City of Los Angeles imports its full water-right entitlement from the Mono Basin, there will be a dramatic effect on the thriving ecosystem of the lake. A 30-foot drop in the lake level could kill off brine fly and brine shrimp populations and thus drive away many of the birds that use the lake for a seasonal stopover, as well as the California gulls that nest there.

The report by the National Research Council, an arm of the National Academy of Sciences, was applauded by both the Los Angeles Department of Water and Power and environmental groups led by the Mono Lake Committee. For the committee, the study confirmed its contention that a substantial lowering of the lake level would be environmentally devastating. The Department of Water and Power was pleased that the report, in the words of water system chief Duane Georgeson, “recognizes there is no threat to the ecosystem today.” At present export levels, it might be 20 to 30 years before such damage might occur, Georgeson said.

This was a strictly scientific effort that made no attempt to draw judgments about Los Angeles’ need for the water or to establish an optimum lake level. The lake now stands at about 6,380 feet above sea level--roughly 40 feet lower than it was in 1941, when the city began diverting water from the five Sierra Nevada streams that feed the lake 340 miles north of Los Angeles. In recent years, because of heavy snowpack runoff and a cutback in city diversions, the lake level has risen about eight feet.

As important as it is, the study is only one small piece of an exceedingly complex puzzle. The city now is under court injunctions to limit diversions from the Mono Basin, and thus is taking only about 80,000 acre-feet of water a year compared with its right to about 100,000 acre-feet. Another case is pending that could result, under California’s public-trust doctrine, in a court-established limit on Los Angeles’ right to water.

The research council’s study was ordered in the same federal law that created the Mono Basin National Forest Scenic Area in 1984. Now that the study is finished, the Forest Service will complete the drafting of a proposed management plan for Mono Lake. This, too, could affect the city’s water right. In December, Inyo National Forest Supervisor Dennis W. Martin said, “We have the option, and probably the responsibility, to identify a lake level that would best meet the overall management objectives of the Scenic Area.”

Furthermore, the City of Los Angeles is on record concerning the need to preserve Mono Lake. In 1986, Mayor Tom Bradley called the lake “a rare environmental jewel” that must be protected by letting more water flow into it. This could be done by restricting exports in wet years, when Owens Valley water is plentiful, and taking what the city needs in dry years.

Georgeson has been meeting for several years with representatives of the Mono Lake Committee and others in an effort to negotiate an acceptable compromise. Martin has said that he would prefer such a solution to any federally mandated lake level.

The problem for the city is to find alternative water supplies to compensate for the lost Mono Basin water, which also makes money for the city by generating electric power en route to Los Angeles. It seems certain that this is what the city will have to do. The scientific, legal and political odds are against the city’s ever again diverting its full 100,000 acre-feet--at least not year after year for any significant period.