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Specific Site Information

Milltown Dam | Milltown Dam Webcam | SilverBow Creek

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

Restoration Status

As part of Milltown Dam settlement, the State of Montana implemented a comprehensive plan to restore the Clark Fork and Blackfoot Rivers at their confluence just upstream of the former Milltown Dam. This restoration plan was integrated with the EPA remediation plan for the site, which was implemented by Envirocon Corp. on behalf of the Atlantic Richfield Company (ARCO). Of the $13.5 million cost to implement the Restoration plan, $3.9 million was paid by NorthWestern and the remaining $9.6 million came 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 by 2012 implemented the restoration plan for the project site that included approximately 17,000 feet of new river channel and over 500 acres of new floodplain.

In addition to the state-led restoration work, Envirocon, the Remedial Action contractor, constructed the state’s Restoration designed floodplain and Clark Fork River channel through the area where 2.2 million cubic yards of contaminated 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 through restoration contracts also removed approximately 400,000 cubic yards of sediment from the floodplain in additional to the 2.2 million cubic yards EPA removed.  This additional removal by the State allowed the Clark Fork River channel and floodplain to be re-established near the pre-dam elevations.

The major Restoration construction work was finished by fall of 2010, after which, in the spring of 2011the 5th largest flood event occurred (see photo #4).  After an evaluation of the flood effects, areas where change occurred that would hamper the project from meeting the Restoration goals (see 1st page) were reconstructed.  The final Restoration construction was completed in spring of 2012.  The site is now owned by the State of Montana and is being developed into a State park by Fish, Wildlife and Parks .

A monitoring program is being followed to assess whether the restoration actions that were implemented are meeting to goals established for the project by the site Trustees.  Monitoring reports are available through this webpage, see document section.


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

2012 as built
2012 As built condition of the Milltown Restoration project area.
August 2006
August 2006
July 2008 Spillway Removed
July 2008 Spillway Removed
june 14 flood

June 14, 2011,  5th largest flood event in monitoring history of Clark Fork River near Milltown.

2012 Bank construction

2012 Bank construction

milltown site in 2012 after restoration

Milltown site in 2012 after Restoration Completion

Upper Clark River Cleanup and Restoration

The Montana Department of Environmental Quality (DEQ) and the Natural Resource Damage Program (NRDP) are commencing the cleanup and restoration of the Clark Fork River Operable Unit in 2013.  For details about the cleanup and restoration activities please refer to the following DEQ link.   

clark for clean up crew

clark fork picture

Silver Bow Creek

Remediation and Restoration

The cleanup of the Silver Bow Creek Superfund site near Butte is one of the largest stream and floodplain remediation and restoration projects undertaken in the United States. Since remediation began in 1999, the Department of Environmental Quality (DEQ) has:

  • removed over four million cubic yards of contaminated tailings in the floodplain (see Silver Bow Creek Corridor map (PDF))
  • reconstructed the stream channel for the first 10 miles of the creek and partially reconstructed another five miles

When complete, over 23 miles of stream channel and floodplain will have been restored and approximately five million cubic yards of tailings and soils laden with heavy metals removed.

Under restoration activities funded by NRDP, aquatic and riparian resources are being restored and a variety of recreational opportunities created, including a 22-mile greenway trail system. These combined remediation and restoration efforts will result in a restored floodplain ecosystem, slated for completion in 2014 or 2015.

The 2012 Silver Bow Creek Fact Sheet provides further information on remediation and restoration activities along Silver Bow Creek.

For further information on Silver Bow Creek developments, upcoming activities and list of remedial  documents see

Photo of Silver Bow Creek Stream Reconstruction
Stream Reconstruction
Floodplain Revegetation
first mile of sbc
Mile 1 of Silver Bow Creek Project
end of Subarea 2
Subarea 2
ramsey flats transformed
Ramsey Flats Transformed
Related Documents