Owens Lake is a dry lake at the terminus of the Owens River just west of Death Valley and on the eastern side of the Sierra Nevada. For at least 800,000 years, the lake had a continuous flow of water, until 1913 when the Los Angeles Department of Water and Power (LADWP) completed the 233-mile Los Angeles Aqueduct to supplement the budding metropolis’ increasing water demands. With this secure water supply, Los Angeles grew as populous as San Francisco by 1920 with more than 500,000 inhabitants. Six years later, the diversions from the river left Owens Lake nearly completely dry.

Physical Consequences of Dryness 

The lake’s bed covers around 110 square miles, and when filled with water before the diversions was between 23 to 50 feet deep. Since its depletion of water and exacerbated by its arid surroundings, Owens Lake has produced alkaline (of high pH) dust containing trace metals. The dust can be picked up in windblown storms and cause respiratory distress in humans and otherwise contaminate its surroundings. It is considered one of the largest sources of “PM10″ (dust) pollution in the nation. 

Occasionally, the dry bed of the lake – which has essentially become a salt flat – appears pink from halobacteria, named for their affinity for saline environments. 

Controlling the Dust

A series of agreements between LADWP and Inyo County have reduced emissions by 99 percent since 1997. LADWP uses 25 billion gallons of water each year and has spent more than $2.5 billion since 2000 (some coming from ratepayers) to flood the area in an effort to mitigate the dust problem. Shallow flooding accounts for about 60 percent of the control measures. Other measures include planted native vegetation, tillage to improve resistance to wind erosion and gravel cover.

LADWP, the Great Basin Unified Air Pollution Control District, residents and environmental justice advocates frequently debate the cost-benefit of the LADWP’s measures.