The Case for Removing the Milltown Dam

by Karen Knudsen, Clark Fork Coalition

The case for removing the toxic sediments at Milltown, and the dam that keeps most of them there, is far stronger than the case for leaving them in place. The people of the Clark Fork River basin now have an unprecedented opportunity that they should seize.

The roughly eight million cubic yards of mining waste piled up behind the dam are more than enough reason to take action. These sediments contain metals that are poisonous to both people and aquatic life and are the reason the reservoir is a Superfund site. They leach arsenic, a powerful cancer-causing agent, into the surrounding groundwater, rendering the water in some Milltown wells unsafe to drink. To make matters worse, arsenic has turned out to be even more carcinogenic than previously thought, so even more wells are likely to be declared unsafe in the near future.

The Blackfoot River, on the left, the Clark Fork River, and the Milltown Dam. Photo courtesy of the Clark Fork Coalition.

The sediments also contain huge amounts of copper, which is deadly to fish. Almost every spring at high water, and during winter ice scours like the one in 1996, sediments are scoured from the bottom of the reservoir and washed over the dam. The same thing often happens when the reservoir is lowered, as it was in 1996 for safety reasons. In either case, the result is often a deadly pulse of copper that far exceeds the State water quality standards that are in place to protect fish.

Make no mistake: the dam remains in Milltown not because it is economically viable, but because it abuts a Superfund site. It generates only 1.4 megawatts—a tiny fraction of the power that a single customer, Smurfit-Stone Container, uses. Montana Power at one point tried to give the dam away. Though it is now being sold to NorthWestern Corp. as part of a larger energy sales package, the dam would probably have been decommissioned by now if not for MPC’s fear of Superfund liability.

ARCO, the company that already is liable for Superfund cleanup, promotes the fallacy that the dam is useful for keeping most of the reservoir sediments from washing downstream. It favors cleanup options that call for “managing” the sediments in place, which could reduce downstream copper pollution to some degree. But those options assume that someone with the necessary expertise and financial resources will be around, forever, to conduct the finely tuned dam operations that are necessary to prevent disaster.

With millions of cubic yards of poisons hanging over our heads, is it wise to stake the future of our river on the chance that some corporate entity will be around to “manage” the sediments forever? And even if we were willing to take such a gamble, none of those options would do anything about the arsenic plume that is contaminating Milltown’s groundwater.

Leaving the pollution in place is the path of least resistance. It is the weak and, for ARCO, cheap solution. It is also the one that fails to consider the costs borne by current and future generations of Clark Fork Valley residents.

As if all the pollution problems weren’t enough, another compelling reason exists for removing the dam: it blocks fish, keeping trout populations in the Clark Fork and Blackfoot Rivers well below what they ought to be. Before the dam was built, cutthroat and bull trout grew large and fat in the main Clark Fork below Missoula and then moved upstream to spawn in smaller streams such as Rock Creek and various tributaries of the Blackfoot. Every spring, thousands of trout still congregate below the dam, trying unsuccessfully to migrate past it. The dam also creates ideal habitat for northern pike, an exotic species that eats young trout. Several years ago, Governor Racicot’s Bull Trout Scientific Group found Milltown Dam was the main reason that the bull trout is almost extinct in the middle Clark Fork River.

What about the local economy? Certainly, letting 8 million cubic yards of toxic-laden sediments sit next to a town isn’t very good economic development. Sure, the artificial warm water fishery in the reservoir may provide some small benefits, but they are trifling when compared to the economic boon that would come if the native trout fishery were to return to its historic levels.

Moreover, no one should underestimate the economic benefits of having a free-flowing, clean river running through a town. Just ask the people of Butte, who are working hard to develop a greenway along the restored Silver Bow Creek. They are doing so because they understand the economic and social benefits that a clean, free-flowing river can provide. Or ask the people of Missoula, who know that the Clark Fork is one of their town’s biggest economic assets.

At some point we must ask ourselves whether the marginal benefits provided by the dam can possibly justify giving up what may be our best chance to truly restore the Clark Fork. To an ever-widening circle of concerned citizens, the answer is clear: the best future for the river is one with clean water and no dam.

For more information, contact Matt Clifford at the Clark Fork Coalition, 406/542-0539 or matt@clarkfork.org