Port must Fix Runoff at PDXby Alex Pulaski
The Oregonian, October 17, 2006
A new de-icing system will be built by 2012 to stem flows that harm fish
In November 2003, the Port of Portland began using a new $31 million system designed to collect runoff from de-icing fluid sprayed each winter on planes and runways at Portland International Airport.
The system itself has worked fine. But two faulty assumptions on which it was based have led to dozens of water-quality violations, an $82,500 state fine and an agreement signed this month that the Port will build a new treatment and discharge system by 2012.
The cost and details of beefing up the current system have yet to be determined. Although the Port is a public agency, airlines' usage fees ultimately pay the bills for such a system.
Discharges containing the de-icing fluid -- variations of glycol, similar to antifreeze -- are harmful to fish and other aquatic life. Bacteria break down the fluid, robbing fish of oxygen in the Columbia Slough, where the water is emptied.
As glycol-laden water passes into the lower portion of the slough, it encounters habitat for juvenile coho and chinook salmon, members of the Columbia Slough Watershed Council wrote the state Department of Environmental Quality in 2004.
The Port is looking at piping discharges directly into the Columbia River as part of enhancing its system. Current discharges eventually get there anyway, after passing from the slough to the Willamette River and then to the Columbia.
The Port began contacting advocacy groups in recent days to broach such a possibility.
"To its credit, the Port came to us, acknowledged a problem, and we're talking," said Brent Foster, executive director of Columbia Riverkeeper. "But I can tell you we're not excited about a new discharge into the Columbia."
Susan Aha, a Port water-quality and tenant environmental manager, said the chief problem with the current system was that it was based on modeling indicating that water flows in the slough ran 100 cubic feet per second.
"Since then we've come to realize that flows are much lower," Aha said, averaging 50 to 60 cubic feet per second.
Many days -- Monday, for example, despite heavy rain the day before -- there is no measurable flow at all.
The result of lower water flows is that the concentration of glycol in the slough is not sufficiently diluted.
The Port's modeling was based on pumping data in the slough from 1996 to 1998 -- exceptionally rainy years. At the time, estimates were revised downward slightly to account for heavy rains.
"It seemed to be a reasonable assumption," said Elliot Zais, a DEQ engineer. "But that turned out not to be the case."
The DEQ cited the Port for three violations of its permit with the department last winter and four times in 2003-04.
But in the winter of 2004-05, when harsh weather dictated greater use of de-icing material, the Port violated its permit on 44 days.
The Port de-ices runways on extremely cold days, and airlines spray down their planes to prevent ice buildup that can make them unsafe to fly.
A second flaw in the current system is that a holding tank was constructed to a capacity that, on most days, causes it to contain four times more biodegradable material than the city of Portland is willing to accept for treatment. That forces more de-icing material into a holding pond and later the slough.
Under the terms of the agreement with the DEQ, the Port can choose to commit 80 percent of the fine amount ($66,000) to an approved environmental project.
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