Citizen Discourse on Contaminated Water, Superfund Cleanups, and ...

the removal of existing dams. As advocates of dam removal projects, these groups found it helpful to focus on situations where federal water quality mandates called for the restoration of “impaired” or “impacted” waterways. In addition, under the edicts of the Endangered Species Act (1973), groups sometimes argued that threatened or endangered species would benefit from dam removal as a means of restoring habitats and migratory routes. Throughout Montana, groups began to rally public support for the protection and rehabilitation of rivers. The Clark Fork Coalition emerged in the 1980s when the ecologically healthier sections of the river (downstream from Milltown) were threatened by a pulp mill's request for relaxed pollution restrictions in its discharge permit. The Clark Fork Coalition became a strong political voice, adopting the river as a whole and advocating protection and remediation projects throughout the drainage system. The coalition brought together a variety of individuals and groups, including Trout Unlimited and Montana Audubon (to name only two), whose goals included the protection of fisheries, trout habitats, and riverine environments.

In 1993 groundwater contamination was recognized as the principal problem in need of remediation at the Milltown site (U.S. Environmental Protection Agency Region 8, 2004). Testing in the 1980s and 1990s showed that in addition to the first few contaminated wells, several other wells had become contaminated, and an expanding arsenic plume (see figure 5) was mapped and periodically updated (U.S. Environmental Protection Agency Region 8, 2004). Studies of the Milltown reservoir suggested that as much as 6.6 million cubic yards of contaminated sediment had been deposited behind the dam (see figure 6). Additionally, contaminants were migrating into the underground aquifer due to the weight and hydraulic pressure of the reservoir. Sediments in the reservoir included 2,100 tons of arsenic, 13,000 tons of copper, 19,000 tons of zinc, 143,900 tons of iron, and 9,200 tons of manganese (Missoula County Water Quality District, 2005a). ARCO, which had been identified as the Potentially Responsible Party (PRP), eventually became legally liable for remediation (U.S. Environmental Protection Agency Region 8, 2004).