If you had traveled north through the Owens Valley before 1924, just past the hamlet of Olancha, you would have come upon an amazing site: a large blue lake in the middle of a high desert landscape. Wedged between the snowcapped escarpment of the Sierra Nevada on the west and the equally imposing mass of the Inyo Mountains to the east, Owens Lake was 15 miles long, 10 miles wide and 30 feet deep. Its saline waters contrasted strikingly with the rugged peaks and arid hills, and supported a large population of waterfowl. The Los Angeles Department of Water and Power (DWP) erased that lake with hardly a thought. Starting in 1913, when the agency's 233-mile-long Owens Valley aqueduct began siphoning off the snow-fed streams that tumbled down the east side of the Sierra, the 800,000-year-old lake dwindled rapidly, its shoreline receding year by year until all that remained by the late 1920s was a salt-encrusted playa. Overshadowed by other aspects of Los Angeles' bold colonization of the Owens Valley, the desiccation of Owens Lake attracted little attention for most of the 20th century. Reporters, novelists and screenwriters found it far more dramatic and entertaining to focus instead on the great human struggle between the valley's doomed homesteaders and the big-city power brokers far away. After all, that conflict involved guns and explosives, intrigue and betrayal —themes much sexier than evaporation. In the end, though, the indignant ghost of Owens Lake proved a more formidable adversary for the DWP than desperate ranchers with rifles and dynamite. Now, work has begun on an expensive and controversial project to put some of the city's water back into Owens Lake. It will not appear as it did before 1924, in the days when ducks thronged its marshes and Cartago was a bustling port instead of a memory. But the lake bed will be wet again and sprout vegetation, thanks to tiny particles of dust. When a lake evaporates, it leaves behind its minerals — the salts and other substances leached from rocks and soil over which feeder streams pass. The water becomes brackish and then briny, and a crust of mineral deposits forms as the lake bed dries. That is what happened when Los Angeles began diverting the Owens River into the aqueduct. And when the wind blew down from the mountains, a frequent occurrence, it whipped the dry lake bed's mineral deposits into stinging, alkaline dust clouds. Although residents of the valley pleaded for help, they were ignored for decades. In 1975, the Navy also began complaining, saying that the huge dust storms were interfering with operations at its China Lake Naval Warfare Center. The complaints led to a 1983 state law directing Los Angeles to study the issue and take reasonable measures to control the dust. Monitoring revealed that Owens Lake was the largest single source of particulate pollution in the nation. At least 300,000 tons of dust blow off the lake bed each year (some estimates put the figure as high as 8 million metric tons). Inhalation of tiny dust and soot particles is linked to premature death and serious illness, especially among the elderly and people with respiratory conditions such as asthma. Analysis showed that the Owens Lake deposits contained such carcinogens as nickel, cadmium and arsenic, as well as sodium, chlorine, iron, calcium, potassium, sulfur, aluminum and magnesium. About 40,000 people living from Big Pine to Ridgecrest were put at risk by the dust clouds. In January 1993, the Environmental Protection Agency classified the Owens Valley as a "serious nonattainment area" under the Clean Air Act's PM-10 standard, referring to particulate matter less than 10 microns in diameter (about one-seventh the thickness of a human hair). The EPA ordered the California Air Resources Board to demonstrate how the standard would be met by early 1997. The board missed the deadline, and residents of the Owens Valley filed a notice of intent to sue. The State Implementation Plan was late because of disagreement between the Great Basin Unified Air Pollution Control District and the DWP. The pollution board wanted Los Angeles to control the dust by flooding 35 square miles of the lake bed with enough water to serve 100,000 families; the city balked at the cost and promised a legal challenge. Litigation was avoided with a compromise plan released in July 1998 and approved by the EPA the following month. Work is now under way on a $62 million contract the city signed in July to carry out that plan The first stage is construction of a 5-foot-wide pipeline that will take water from DWP's aqueduct to the upper end of the lake, where it will be allowed to spread several inches deep across 10 square miles of the dusty playa — essentially turning it into a quagmire. The city has agreed to treat another 3.5 square miles in 2002, 3 square miles in 2003, and a minimum of 2 square miles every year thereafter until the air pollution district determines that the PM-10 standards have been met. Besides flooding, the city intends to plant some of the lake bed in 4- to 20-acre "farms" of saltgrass to bind the loose surface, and cover with gravel any areas that still generate dust. The flooding is expected to use about 25,000 acre-feet of water a year. Irrigation for the saltgrass may require another 15,000 acre-feet, meaning the entire project could use 40,000 acre-feet of water a year — as much water as 80,000 Southern California households would use annually. Where DWP will get the water for the long term is uncertain. The city would prefer not to continue tapping its aqueduct. Buying replacement water from the State Water Project and the Colorado River will cost an estimated $13 million a year. "It's going to come from where it needs to come from," said David Freeman, DWP general manager, who is less interested in discussing water supply details than the "warm and positive" relationship he says has developed between the city and the Owens Valley. "A whole new attitude was born with the settlement," he said. Perhaps. But many Owens Valley residents believe the city eventually will pump more local ground water to compensate for water lost to dust control, further withering the valley's vegetation — an issue that in the past has prompted litigation, not to mention gunplay and decades of bitterness. The DWP's expensive dust control experiment might finally put the ghost of Owens Lake to rest, but it is unlikely to close the book on one of the West's most enduring hydraulic dramas. Contacts: David Freeman, Los Angeles Department of Water and Power: (213) 367-1338. Great Basin Unified Air Pollution Control District: (760) 872-8211. Environmental Protection Agency's Owens Lake PM-10 information: www.epa.gov/region09/air/owens/index.html