 A U.S. Geological Survey team does some work on the surface of the Owens Dry Lake, where the Los Angeles Department of Water and Power is responsible for dust-suppression efforts on roughly 40 square miles of lake bed. Questions and concerns have been raised recently over the amount of water the city is using to meet its obligations. Photo courtesy USGS By Mike Bodine
Register Staff
11-20-2008 Top county officials dove into the details of dust mitigation at Owens Lake this week in response to concerns by local citizens, elected officials and business owners that water is possibly being over-used to control air pollution at the site.
A presentation to the Inyo County Board of Supervisors was scheduled for Tuesday at the request of the local Agriculture Resources Control Board to provide leaders with facts and figures related to the Los Angeles Department of Water and Power’s dust mitigation project. Great Basin Unified Air Pollution Control District Officer Ted Schade delivered the presentation.
Specific concerns about the project’s use of ponds to keep the dry lake bed wet enough to control dust had been brought to the forefront by Inyo County Agricultural Commissioner George Milovich at the urging of the Agriculture Resource Advisory Board, which recently toured the Owens Lake as part of its interest in ensuring more water than necessary is not diverted from agricultural purposes.
Schade told the supervisors that it is not the responsibility of his agency to tell LADWP how to fix the problem, but to tell them where to mitigate and what measures work effectively.
Schade added that since LADWP is in the water business, it has preferred to use water for much of the mitigation project, and it is also the most cost effective for LADWP, compared to managed vegetation or blanketing problem areas with gravel.
Schade described the shallow flooding techniques as a pipe coming up from the ground and flooding a certain area, and as water recedes and reaches a certain level, the area is flooded again.
Milovich said he was in favor of dust mitigation, and, within a reasonable regard, supporting wildlife at the lake, but he voiced concerns that perhaps the good of the whole valley is not being addressed. He said he wondered if the lake is being recharged for habitat and agriculture as well as dust mitigation.
At the Nov. 4 meeting Milovich said that when he had learned of the overuse of water, he also heard of the “moat and row” option that uses much less water than shallow flooding.
Schade explained that while the moat and row option is not currently one of Great Basin’s three BACMs, or Best Available Control Measures, the option is scheduled to be tried on a limited 3.5 square-mile area.
Moat and row is basically a windbreak consisting of trenches being dug and the dirt piled next to it with these long trenches crossing over each other in a grid pattern.
The completion and implementation of the moat and row measure is being delayed by requests for environmental impact reports from California State Lands Commission, which owns the land and leases it to LADWP, and the state Department of Fish and Game.
Currently, the City of Los Angeles uses about 65,000 acre-feet of water annually for shallow flooding and managed vegetation on the 30 square miles of controls, Schade said.
In 2010, when a total of 43 miles of controls are in place, L.A. will be using 95,000 acre-feet of water on the lake bed per year.
According to State Implementation Plans, or SIP, shallow flood areas on the lake bed should be at least 75 percent wet through the windiest months, October through June. Great Basin adopted SIPs in 1997, 1998, 2003 and 2008 that provided framework for solving the man-made particulate problem. Schade explained that updated satellite imagery comes in every nine days that shows how wet the shallow flood areas are. Schade said that so far, L.A. is keeping the ground wetter than the minimum.
Schade concluded his presentation by sharing some of the results of the mitigation project thus far.
“Dust control measures on Owens Lake work,” Schade said. He added that there have been dramatic reductions in both federal exceedance levels and annual particulate levels.
“Great Basin Air Pollution Control District is confident that within the next few years, the emissions from the Owens Lake bed will be reduced such that it no longer causes federal exceedances,” Schade said.
Annual particulate levels have deceased by more than 70 percent in Dirty Socks, east of Olancha.
Before dust control measures started to operate in 2001, Owens Lake was the largest single source of man-made particulate matter air pollution in the United States.
The newly created wet areas are also bringing the birds back to the lake.
On one day in April 2008, 49 birders from the Eastern Sierra Audubon Society and others identified 112 species of birds and counted more than 54,650 birds.
“Water for wildlife is not a waste,” said Owens Lake advocate and Sierra Club member Mike Prather, who noted he wanted the board to publicly recognize the lake as a valuable wildlife resource.
Prather suggested posting “wildlife viewing” signs as a way to “get people to slow down, and maybe even spend some money.” He also mentioned the large number of migratory ducks that frequent the lake – some 20,000 individuals were counted on one day, and this may someday appeal to hunters and bird watchers alike.
The project has brought revenue to the valley by creating 100 new jobs in the largest public works project ever constructed in Inyo County.
There has been more than $500 million in construction activity at the lake – that’s more work and money than it took to construct the aqueduct that diverted the lake water to L.A., according to Schade. But, Schade explained, the lake project is much more complicated as the aqueduct required simply digging hundreds of miles of trench through relatively open desert. The mitigation project contains more than 500 miles of pipelines and drains, 30 pumping and water treatment stations and 3,500 miles of drip irrigation tubing.
The entire mitigation project is mandated to be completed by 2017.
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