Map of Milltown Reservoir and Dam Location (PDF)

Milltown Dam

In April 2003, the U.S. Environmental Protection Agency (EPA) issued its proposed plan for the Milltown Reservoir and Dam site. In December 2004, the EPA issued the remediation plan, or Record of Decision, for the Milltown site. These plans called for removing the dam and portions of the contaminated sediments behind the dam.

In August 2005, federal, state and tribal governmental entities reached agreement on a settlement with ARCO and NorthWestern Corporation for the cleanup and restoration of the Milltown Reservoir area. The consent decree will allow the Milltown site to be returned to an attractive, ecologically healthy area. Since then, the state, in cooperation with the U.S. Fish and Wildlife Service and the Confederated Salish and Kootenai Tribes, has been working to combine the restoration and remediation work at the site.

The restoration plan's objectives are to:

• restore the river channels at the confluence to be naturally functioning and self-maintaining
• maintain water quality
• provide high quality habitat for fish and wildlife
• improve aesthetic values in the area by creating a diverse, natural setting
• provide functional wetland and riparian communities
• provide safe recreational opportunities such as river boating, fishing and trail access for hiking and bicycling

Related Documents

• Geomorphic Data Summary Report (PDF 18.7MB), December 2006 - A summary of geomorphic data collected 2004 through 2006 for Milltown restoration activities.
• Milltown Revegetation Data Summary Report (PDF 1.5MB), November 2006 - A summary of existing vegetation at the Milltown site.
• Stories of What is to Come at Milltown Dam (PDF 485KB), September 2006 - A six-page booklet containing three articles about future conditions at the confluence of the Clark Fork and Blackfoot Rivers.
• Summary of Restoration Plan for the Clark Fork River and Blackfoot River Near Milltown Dam (PDF 18.6MB), October 2005 - A 10-page booklet summarizing the revised plan.
• Restoration Plan for the Clark Fork River and Blackfoot River Near Milltown Dam, October 2005 - This document provides a refined vision of how these rivers might be restored once the EPA and Montana Department of Environmental Quality have removed the Milltown Dam and a large portion of the contaminated sediments. The new plan builds upon the previous restoration plan and provides new data, validates the previous design concepts, and includes recommendations and comments from four national experts who reviewed the April 2005 draft.
  • Plan (PDF 962KB), excluding Appendices
  • Appendices: A (PDF 53KB) | B (PDF 862KB) | C (PDF 689KB) | D (PDF 2.5MB) | E (PDF 88.7MB) | F (PDF 58KB) | G (PDF 666KB) | H (PDF 466KB) | I (PDF 64MB) | J (PDF 24.8MB) | K (PDF 1.5MB) | L (PDF 3.8MB) | M (PDF 42KB) | N (PDF 653KB)

  Copies of this document may be reviewed at the Missoula public library, the Bonner School library, the University of Montana library, the Missoula City County Health Department, and the Montana Fish, Wildlife and Parks office in Missoula.

  A compact disk containing the plan is available from the Natural Resource Damage Program at (406) 444-0205 or nrdp@mt.gov.
• Amendment to the Draft Conceptual Restoration Plan for the Clark Fork and Blackfoot River Near Milltown Dam (PDF), June 2004 – This four-page summary incorporates changes to EPA's proposed remediation plan, revised in May 2004, and public comment on the draft plan.

Status

Restoration

As part of Milltown Dam settlement, the state is implementing a comprehensive plan to restore the Clark Fork and Blackfoot Rivers at their confluence just upstream of Milltown Dam. This restoration plan is being integrated with the EPA remediation plan for the site, which is being implemented by Envirocon Corp. on behalf of the Atlantic Richfield Company (ARCO). Of the $11.5 million cost, $3.9 million is being paid by NorthWestern and the remaining $7.6 million is coming from the 1999 settlement recovery from ARCO.

All of the dam structures were removed in March 2009, allowing the Clark Fork River near Bonner to flow freely for the first time in 100 years. The State installed a submerged boulder grade-control structure at the location of the former dam spillway in February 2009 and, in the summer of 2009, plans to start channel and floodplain construction on a 2,500-foot reach of the Clark Fork River upstream of the remedial project area.

Restoration work will also remove approximately 500,000 cubic yards of sediment located upstream of where EPA is requiring sediment removal during the fall of 2009. This additional removal by the State will allow the Clark Fork River channel and floodplain to be re-established at the pre-dam elevation. In addition to the state-led restoration work, Envirocon, the Remedial Action contractor, will construct the Restoration designed floodplain and Clark Fork River channel through the area where 2.2 million cubic yards of sediment were removed and shipped to ARCO's upstream repository. The terms of the Consent Decree require Envirocon to complete this work for the State. The State hopes to have the restoration work near Milltown Dam completed by 2012.

Remediation

For updated information on remediation activities, see the Clark Fork River Technical Assistance Committee's website.

October 2005 Restoration Plan