Massive Milltown Dam cleanup giving the Clark Fork, Blackfoot confluence a facelift
By KARL PUCKETT
Great Falls Tribune Staff Writer
October 26, 2008
MILLTOWN — In March, 1,000 onlookers cheered as workers breached the 102-year-old dam here. For more than a century, it blocked migrating fish and served as a backstop for toxic upstream mining waste.
One day last month, workers dug up polluted mud to much less fanfare.
"It's all got to come out," said Ben Johnson, project engineer for contractor Envirocon.
The dirty job of excavating toxic sediment doesn't draw crowds but it's no less important to the pollution cleanup at Milltown Dam, which is part of a massive Upper Clark Fork River federal Superfund complex in Western Montana.
About 1.6 million tons of pollution has been dug up at Milltown since last fall and carted away in railcars that run seven days a week.
It will take another year of digging and hauling to remove the remaining polluted sediment, but the project is on schedule for completion in late 2009 or early 2010, said Russ Forba of the federal Environmental Protection Agency.
Over the years, the waste, which came from upstream mining operations, piled up at the dam at the confluence of the Clark Fork and Blackfoot rivers. The accumulation fouled the area's drinking water and killed fish.
"It's in the wrong environment," Forba said.
Once the EPA's $108 million job is finished, the state will go to work on an $11 million plan to build a natural, self-sustaining river channel and floodplain, beginning at the dam site and ending three miles upstream, said Doug Martin, Milltown restoration manager for the Natural Resources Damage Program in the state attorney general's office.
Major construction should be completed by 2012.
As part of the restoration project, native species such as willows, water birch and cottonwoods will be planted, Martin said.
"Instead of it being just an industrial area for a relatively few Montanans — basically the Anaconda Company — this site is going to be a publicly used area," said David Schmetterling, a fisheries research biologist with Montana Fish, Wildlife & Parks, who studies fish near the dam.
The state is negotiating a land transfer with NorthWestern Energy, which owns much of the dam site property, and the entire area could be turned into state park, Martin said.
The dam was constructed in 1906, by copper king William Clark, to produce electricity for a lumber mill in Bonner.
In 1908, a flood washed hundreds of thousands of tons of waste from mining and smelting activity in Butte and Anaconda downstream via the Clark Fork, and periodic slugs of waste followed in ensuing years, Forba said.
It all came to rest at the dam.
"It helped build this state," Kustudia said of mining. "But it left some consequences."
Anaconda Mining Company owned the mining operations but Atlantic Richfield Company and British Petroleum, along with dam owner NorthWestern, are responsible for funding the EPA's cleanup.
The Milltown site is one of four polluted areas along a 120-mile stretch of the Upper Clark Fork River from Butte and Anaconda to Milltown that, in sheer size, comprise the nation's largest Superfund cleanup area, said Diana Hammer, an EPA spokeswoman.
"In other parts of the country, there are Superfund sites the size of a block," she said.
The cost of cleaning up the entire Upper Clark Fork will be in the neighborhood of $1 billion, she said.
The waste at Milltown, which is laced with heavy metals and arsenic, polluted drinking water supplies in an aquifer. That landed the site on the federal Superfund list in 1983.
"Already the project is well on its way of achieving its goal of restoring the drinking water supply and getting the cancer-causing agent out of it," said Peter Nielsen of the Missoula City-County Health Department.
Initial testing showed arsenic levels in the aquifer were 200 parts per billion. The standard for drinking water is 10 ppb. Since the cleanup began, levels have dramatically dropped, Nielsen said.
Thirty to 40 homes in the area use water from a well drilled outside the pollution plume.
"This isn't just putting a Band-Aid over a problem," said Schmetterling, the FWP fisheries biologist. "This is really fixing it."
On April 9, a rainbow trout became the first fish on record in 100 years to pass upstream through the newly opened dam.
Additional upstream movement has followed, Schmetterling said. Previously, the dam blocked the migration of hundreds of thousands of fish returning to upstream spawning grounds in both rivers, isolating and reducing populations, he said.
Schmetterling predicts fish density will increase once the pollution is removed from the site.
"I think it's way, way premature to evaluate the success of this project," said Bruce Hall, executive director of the Bonner Development Group.
Many residents opposed the dam's removal because of the loss of revenue from the hydroelectric dam as well as the recreational and aesthetic appeal of the reservoir, he said.
"Right now, it's an eyesore," he said.
Hall said he supported an alternative cleanup method that would have left the sediment in place and rehabilitated the dam, as did many others.
Mike Kustudia of Missoula, a member of the Clark Fork Technical Assistance Committee, which is monitoring the cleanup, acknowledges the short-term negative impacts of the project, including the release of toxic sediments downstream.
However, the long-term benefits will outweigh the short-term negatives, he said. To Kustudia, whose great-grandfather worked in the Butte copper mines that contributed to the pollution, the cleanup is the best thing to ever happen to the Clark Fork River.
"Those generations lived off copper," Kustudia said. "Our economy is evolving."
To get at the pollution at Milltown, workers were forced to "dewater" the reservoir, which involved gradually lowering it before breaching the dam March 28.
The tricky part was removing the dam without sending too much toxic waste into the Clark Fork toward Missoula and other downstream communities, Forba said.
"That's a reality of removing a dam," he added.
A bypass channel was constructed to reduce the amount of escaping sediment.
To date, the 527,000 tons of sediment that has washed downstream since 2006 is less than the 603,000 tons the EPA anticipated over the four years of the project, Forba said.
However, this year's to-date release of 371,000 tons is higher than expected, and the influx reduced aquatic insects by 70 percent as far away as the Bitterroot River, which is 13 miles downstream, Nielsen said.
EPA and health officials say the influx of polluted sediment isn't posing health threats to downstream communities or people recreating.
"The demise of the river is greatly exaggerated," Nielsen said.
Water-quality standards in the river for suspended sediments and arsenic each were exceeded once since the breaching of the dam, Forba said. And arsenic levels in riverbank soils are far below removal levels, he added.
Between Milltown and the Bitterroot River, arsenic in the soil has ranged from 6 parts per million to 20.5 ppm, and less than 5 ppm from the Bitterroot to Thompson Falls.
"Let's put it this way, soils in Butte are a lot higher," Forba said.
For a heavily used recreational park, the action level to remove arsenic-contaminated soil is 680 ppm, Forba said.
Six giant cells have been carved out of the floodplain at Milltown, where workers have dug up the nastiest soil. In one, stumps — remnants of trees cut down when the dam was built and later covered by the reservoir — are now visible.
The site covers 540 acres, but only the 185 acres containing the worst pollution is being excavated.
"Everything you see here, the roads, the train tracks, were put in," Forba said at the cleanup site Sept. 30.
The tracks allow access by a 45-car train. Each car can carry 100 tons of pollution, which is transported to a five-square-mile waste repository near Anaconda.
About 1.4 million tons of sediment still needs to be transported, Forba said. Sediment transports will continue for another year.
"We're to the point now (where) we have to start removing haul roads to start accessing the rest of the material," Envirocon's Johnson said.
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