Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338
October 25, 1999
Answer to environmental problem blowing in the wind
A University of Guelph geography professor is replicating one of the most inhospitable places on Earth to see if he can stop the dirt from flying at North America's single largest source of dust.
Prof. Bill Nickling believes 400-metre square plots of salt grass will stop the formation of enormous dust clouds at Owens Lake in California, a 100-square- mile dried-out lakebed in the Great Basin Desert. Mimicking conditions in the desert, he tested his theories in a 15-metre-long wind tunnel he built at U of G. By doing so, Nickling and colleagues at the Desert Research Institute in Nevada hope to put an end to a years-long legal battle that has plagued the city of Los Angeles.
Winds from two surrounding mountain ranges drive sand across the lakebed surface which in turn kicks up dust into enormous feathered clouds that spiral as high as 15,000 feet, filling the valley. The dust is made up of corrosive salts containing traces of arsenic, which scatter over a wide area, posing an environmental and health hazard and clogging up the airways over the nearby China Lake Naval Air Station.
The problem began 75 years ago when a growing Los Angeles purchased large tracts of the Owens River watershed and promptly built a 233-mile aqueduct to take water to its thirsty citizens (the aqueduct project features in the 1974 film Chinatown). This soon drained Owens Lake, which had acted as the sink for the river, of every last drop of water. "In old photos, you see steamships plying the lake," says Nickling. "What remains now are huge dust clouds from the lake bed. On windy days, there's so much dust and salt flying, you can only see a few metres."
As Nickling explains it, the battle has been as much political as scientific. Because of the enormous potential costs involved, the city of Los Angeles, responsible for solving the problem, has delayed taking action, including taking several trips to court to stall proceedings. Finally, the EPA ordered the city to clean up the mess and assigned a deadline of 2006.
There have been other, less successful proposals on how to stop the dust flying, including refilling the lake with water or gravel or just paving it over. L.A. authorities decided both would be prohibitively expensive. There have also been creative proposals. One perhaps apocryphal story has it that the city of New York offered to send its garbage to cover the site. That offer was reportedly refused.
Nickling and colleagues proposed a much greener option than anything previously suggested. It would involve planting salt-tolerant vegetation to stabilize the surface. The idea is that a plant like salt grass slows wind speeds along the surface and stops the dust from becoming airborne. Wind tunnel trials Nickling conducted both at Owens Lake and in a campus lab sought to measure the aerodynamic properties of salt grass and to model potential planting densities and configurations to stop dust emissions.
Last year, authorities in California shipped several boxes of salt grass to Nickling at U of G, and he and his student team began experimenting with different placements in the wind tunnel to see which offered the most effective and cost-efficient natural windbreak.
Small circular patches of salt grass were placed in different formations in a 15-metre- long closed-circuit wind tunnel Nickling and his colleagues built themselves on campus. They've now come up with an optimal "floor plan" and will return to the desert this winter to set up 400-metre square patches at the north end of Owens Lake.
For field tests, Nickling can take on the road a 15-metre-long portable version that has already logged travel miles to Africa as well as Owens Lake, and which normally winds up on Nickling's driveway at home for modifications and repairs. "There are only three portable wind tunnels of this size in North America," he says. "You can't buy these off the shelf, and to have it custom-designed would be very expensive. So instead, we designed and built our own, with myself as the general foreman."
Contact: Prof. Bill Nickling, Department of Geography, 519-824-4120, Ext. 3529.