Pent-Up Trouble 

ARCO’s proposed quick fix stirs up the Milltown Dam debate

The decision regarding the future of Milltown Dam inched toward a conclusion last week when Atlantic Richfield (ARCO) championed a report endorsing its own preferred alternative for handling one of the nation’s largest Superfund sites.

A quick review: Milltown Dam sits near the confluence of the Blackfoot and Clark Fork rivers eight miles upstream from Missoula. Due to a half-century of mine waste that was dumped into the Clark Fork upstream around Butte and Anaconda, the dam is currently the terminus for 8.8 million cubic yards of toxic sludge currently festering on the bottom of the reservoir formed behind the dam. These poisonous wastes create, according to local conservationists, a kind of double-edged sword of Damocles that hangs over the heads of downstream residents.

First, the toxic sediment has slowly percolated into the ground water aquifers around Bonner, rendering many wells in the area useless due to high concentrations of arsenic. Second, high-water events such as floods and ice floes inevitably stir up sediment that usually remains on the reservoir bottom, spiking the level of harmful metals in the Clark Fork to lethal levels. Such an event occurred in February 1996, when an ice jam broke loose on the Blackfoot, releasing a torrent of ice and water toward the dam. Officials initially feared the deluge might breach the dam, which didn’t happen, but the usually high flows created a dangerously high metals content, killing fish downstream from the dam. The flood cast both environmentalists and industrialists off in new legal directions to determine the extent of the clean-up.

ARCO, which as the owner is ultimately responsible for footing the bill for cleaning up the site, put its stamp of approval last week on a plan that would modify the dam by installing a giant inflatable rubber tube that would mitigate the affect of high-water events. According to the report, which runs some five inches thick and was prepared by a contractor hired by the petroleum conglomerate, the rubber retrofitting would cost $7.3 million and would prevent contaminated water from flowing downstream.

The biggest drawback to the plan, as Clark Fork Coalition spokesman Matt Clifford points out, is that it does nothing to address the ongoing leaching of metallic sludge into underground aquifers around Bonner. “Even if their [ARCO’s] plan prevents water from the Clark Fork from getting downstream, that stuff is sill getting into the groundwater,” says Clifford. “And that will be happening every day as far into the future as we can see.”

Those following the saga of Milltown Dam may be anxious to know what other options are available other than ARCO’s rubber tube plan. The whole process, according to Clifford, closely resembles the one that other federal land-managing agencies must follow in taking any action on public land. This stage is similar to the Environmental Impact Statements that accompany timber sales, species reintroductions, or other alterations in a specific area. The managing federal agency in this case is the Environmental Protection Agency (EPA). By law, the EPA must consider taking no further action as one possible option, though neither side at this stage sees this as a plausible outcome. For the record, according to ARCO’s own report, retrofitting the dam with rubber is the cheapest option next to doing nothing.

The other nine options listed in the report range from periodic removal of sludge laying to down some kind of protective barrier on the reservoir bottom. The whole notion of moving any accumulated muck carries a great deal of risk, both known and unknown, according to Bruce Hall, a spokesman for the Bonner Development Group, an organization advocating to leave the dam—and the contaminants behind it—in place.

“This isn’t the first time a conservative course of action has been recommended with Milltown,” Hall notes. “In 1995 the state found that doing nothing was probably as good as any other option. Of course, the flood in ’96 changed some opinions, but the reality is there’s a lot of inherent risk in moving any sediment at all. You can make the analogy of asbestos in an old house. The safest, most cost-effective thing to do is leave it undisturbed.”

The Clark Fork Coalition, according to Clifford, is throwing its weight behind one option that occupies a spot near the bottom of ARCO’s list of preferred actions. Their plan would remove the most toxic 5.5 million cubic yards of sludge and the dam, which would dramatically improve migrations of bull, cutthroat and rainbow trout in the Clark Fork. Clifford maintains that whatever risks might be inherent in moving the sentiment are temporary in comparison to the long-term health risks of leaving the hazardous material in place.

“It’s kind of bizarre,” Clifford says. “The EPA claims it has no jurisdiction to consider fish passage. They can work with wetland habitats and water quality and a host of other issues, but with fish, we have to move to FERC.”

He claims that is precisely what the Clark Fork coalition intends to do. FERC, or the Federal Energy Regulatory Commission, until a few years ago was as impenetrable to environmentalists as one of the concrete structures the commission is responsible for licensing. However, a decades-long precedent of unwavering re-licensing has ended in the past few years, most notably with the de-commissioning of Edwards Dam on the Kennebec River in Maine. Milltown Dam, while not quite the dinosaur that Edwards was, certainly fits the description of obsolete as a power-generating facility: Built in 1906, the dam currently employs two people and annually produces two megawatts of electricity.

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