“EROSION IS NIBBLING AWAY AT ST. JOHNS LANDFILL”
[SUNRISE Edition] The Oregonian, Portland, Or., Aug 16, 1999
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Authors: JOE FITZGIBBON Special to The Oregonian
Dennis O’Neil is passionate about the St. Johns Landfill. When it closed in 1987, O’Neil supervised a team of engineers to cover the 230-acre city dump with a puncture-proof polyethylene cap, topped with about three feet of clean soil.
He installed pipes to collect and sell methane gas as it bubbled up from tons of decomposing debris.
Through the years, he hiked, poked and probed the landfill to keep contaminants from seeping into North Portland waterways.
“I feel really proud of what we’ve been able to accomplish,” said O’Neil, project director for Metro. “I’ll admit that I’m fond of the landfill — I guess that comes from spending so much time there.”
Now O’Neil faces one of his most serious challenges: erosion. The Columbia Slough wraps around the landfill like a giant moat. As water rises and falls, it washes away parts of the protective sand and silt dike that hold back toxic contaminants.
To add to the problem, the weight of thousands of tons of rubble and soil squeezes the garbage like a giant tube of toothpaste, pushing leachates toward the slough.
Thinking in long term
“There’s no immediate danger, but we always go with the worst-case scenario,” O’Neil said. “With something like this, you’ve got to think in the long term.”
Plans are under way to construct a series of sloped rock and plant walls around the most vulnerable areas of the landfill. Metro officials will add about 5,000 trees to the shore line to stabilize the eroding banks.
Engineers will construct a 1,000-foot slit trench near migrating ground water to capture contaminants before they reach the slough.
When the landfill opened on Columbia Boulevard in 1936, Portland officials promised residents that it would be used to dispose of ashes from the nearby city incinerator. But within three years, trucks were hauling in everything Portlanders threw away.
Garbage, refrigerators, old cars, industrial waste — from harmless to highly toxic — all found their way to the city dump and nearby wetlands.
Residents often complained about a pungent cloud of burning garbage wafting over the neighborhood.
After Metro took over operations in 1980, environmentalists and state agencies forced closure of the site.
When a study found toxic chemicals leaching into the Columbia Slough, and Smith and Bybee lakes, engineers constructed a protective dike around the perimeter. The entire site was capped to prevent rainfall from seeping in.
Costs about $36 million
Total costs to date for closing the landfill run about $36 million, paid mostly through garbage hauling fees and dumping charges at neighboring landfills. Metro also allocates about $1 million a year from the general budget for maintenance.
To reduce expenses, Metro officials are allowing some sheep farmers to graze stocks on the grassy covering each spring.
Engineers also have opened what is now the state’s largest landfill gas project. Nearly 100 wells collect about 880,000 British thermal units a minute, or enough fuel to heat 3,500 homes. The gas is piped nearly two miles away to Ash Grove Cement Co. to heat lime production kilns.
In the next 10 years, Ash Grove will pay Metro about $1.4 million for collection rights. “It makes better sense than flaring it off, where it adds to air pollution in the area,” O’Neil said.
Representatives from Poland, Russia and China have traveled to take a close look at the way Portland disposes of wastes and tour the St. Johns Landfill.
For the public, however, the North Marine Drive entrance remains closed. “It’s mostly to prevent vandalism,” O’Neil said. “I know that there are people who want to forget that it’s even out here, but we’re going to be managing it for a long, long time.”
