Owens River Valley began to dry up, Los Angeles investigated the Mono Basin area. In the 1930s, Los Angeles purchased of land in the Mono Basin. Over the next decade, Los Angeles took water from creeks and streams in the area. In 1919, Mono Lake had a water surface elevation of above mean sea level. In 1955, the elevation of the lake was reduced to 6,405 and still dropping. The decrease in water volume of the lake subsequently increased lake salinity, adversely affecting the local food chain. In 1980, there was a documented fifty percent reduction in the resident shrimp population, and by the spring of 1981, this reduction reached ninety five percent. Also, as the water level of Mono Lake dropped, an island within the lake that was key nesting habitat for bird species became accessible from shore (effectively becoming a peninsula), allowing coyotes access to the nesting habitat. The subsequent predation on nesting birds significantly reduced population numbers. As the level of the lake continued to drop, shoreline area increased, resulting in airborne dust and sediment transport that covered the lake with very fine silt and impacted water quality. In 1976, a group of students from the University of California began to study the Mono Lake environment. Their research concluded that the lake's reduction in water level caused environmental damage, including the loss of the lake's brine shrimp, loss of migrating and nesting birds, and the destruction of the Mono Lake's natural beauty. In 1979, the National Audubon Society, Mono Lake Committee, Friends of the Earth, and four Mono Lake landowners filed suit against the DWP. Plaintiffs claimed that the waters of Mono Lake were protected from the DWP diversions by the public trust doctrine. The Supreme Court held that the state has an obligation to protect Mono Lake once the diversions begin to harm public trust interests. The court also held that California water law permitted the State Water Resources Control Board (SWRCB) to objectively study Mono Lake water rights after the agency granted the rights. Audubon claimed that air pollution in the form of alkali dust storms were caused by Mono Lake's dropping water level. On October 6, 1988, the United States Court of Appeals, Ninth Circuit, held that Audubon could not claim a federal common law nuisance based on air pollution. In 1984, when DWP threatened to once again dry the creek, a trout fisherman,