RETURN TO USE INITIATIVE
2010 Demonstration Project
MILLTOWN RESERVOIR
SEDIMENTS
Milltown, Montana
THE SITE: The Milltown Reservoir Sediments Site
(Milltown Site) is an Operable Unit within a larger
Superfund site, the Milltown Reservoir Sediments/Clark
Fork River Superfund Site. The Milltown Site includes
approximately 120 miles of the Clark Fork River
upstream of the former Milltown Dam and Reservoir.
The Milltown Dam and Reservoir had been located at
the confluence of the Clark Fork and Blackfoot Rivers,
a few miles upstream of Missoula, in western Montana.
Approximately 6.6 million cubic yards of contaminated
sediments had accumulated behind the dam. Arsenic
in the sediments polluted the local drinking water
aquifer and the release of copper from the sediments
threatened downstream fish and other aquatic life.
These sediments were deposited over the past century,
the result of historical mining operations upstream in
Butte.
There are ongoing Superfund cleanup activities
throughout the Clark Fork Basin. EPA issued a Record
of Decision in December 2004, calling for removal of
the Milltown Dam and the most highly contaminated
sediments. There was broad public support for this
cleanup plan with approximately 98% of the nearly
15,000 public comments received favoring EPA's
proposed plans.
HE OPPOR1 JNI One of the main objectives
of the Milltown project is restoration of the Clark Fork
and Blackfoot river channels. By removing the dam
and restoring river flow in the area, the project aims
to restore the high quality of water from the Milltown
Aquifer, allow unrestricted fish passage, improve
native and recreational fisheries, provide high quality
habitat for fish and wildlife, and allow for expansion
of functional wetland and riparian communities. The
restored ecosystem will also provide safe recreational
opportunities including river boating, fishing and trail
access for hiking and bicycling.
PICTURED: View of tailwaters at the former Milltown Dam
(Source: EPA)
BARRIER: Competing ideas for what reuses would replace the
dam and surrounding area
SOLUTION: Extensive public involvement leading to a common
vision of future uses
PICTURED: View of the former reservoir area from Milltown
Bluff (Source: Sara Malo, U.S. Army Corps of Engineers)
BEFORE: Dam and reservoir that contaminated ground water
and downstream aquatic life
AFTER: Two free-flowing rivers with improving fish populations
and declining contaminant concentrations; wide community
acceptance of planned state park
SEPA
United States
Environmental Protection
Agency
Superfund Redevelopment Initiative
Updated: June 2010 1

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As currently envisioned, the lands presently owned by Northwestern Energy Corporation in the area
in and around the Milltown Reservoir Sediments Superfund Site would be converted to a publicly
owned park with trails, river access sites, bridges, interpretative signage, a viewing area on the bluff
overlooking the confluence of the Clark Fork and Blackfoot Rivers, and possibly an interpretative center.
Ideally, a trail system would link the Milltown Gateway, Confluence and former Reservoir areas along
the Blackfoot and Clark Fork Rivers as well as connect to Missoula's Riverfront Trail system, extending
the Kim Williams Trail along the Clark Fork River.
THE BARRIER: While there was clear consensus on the need for Site remediation, different
stakeholder groups at the federal, state and local levels had varying opinions on how cleanup should
be performed and what should happen to the Site once cleanup was completed. Many community
members wanted the property to be publicly owned, even though it was privately owned at the time.
There were concerns that the Site might be sold to private interests who might commercially develop
the Site and the community wanted the area to be a public resource. Stakeholders needed to work
together to develop a plan for the Site that would integrate remediation, restoration and redevelopment.
THE SOLUTION: Starting as a Superfund Redevelopment Pilot in 2002, EPA and state and local
stakeholders began a process of working closely together to develop a vision for the future of the Site
and surrounding area once contamination was gone and the river restored. This plan was created
in 2007 through a design workshop process in which the community worked with state and federal
agencies and volunteer landscape architects. That plan is now in the early stages of implementation.
THE SITE NOW: Removal of the Milltown Dam began in 2008 and was completed in January
2010. The reservoir area was dried out to allow for excavation and removal of sediments with the last
load of sediments being removed off site by train in September 2009. Off-site disposal of sediments
has removed the source of contamination and the removal of the dam has restored the fish passage
along the once again free-flowing Clark Fork and Blackfoot Rivers. Fish populations are increasing,
moving up river and recovering well, and contaminant concentrations downstream and in ground water
are declining. The State of Montana is presently planting native species to reestablish vegetation and
control erosion along the exposed floodplain that had previously been inundated by the former reservoir.
In 2010, EPA expects the Northwestern and the local Carpenter's Union to transfer their Site properties
to the State of Montana to be developed into a state park. Montana Governor Brian Schweitzer has
approved two Natural Resource Damage Program grants for the Milltown Project area: 1) a grant of
$2,663,749 awarded for the Milltown Two Rivers Recreational Facilities and Access; and 2) a grant
of $262,177 awarded to remove bridge piers and logs on the Blackfoot. The Governor also allocated
a five-year grant for operation and maintenance of the new park to the Montana Department of Fish,
Wildlife and Parks. "This site is just a great example of how state, federal and local groups can work
together," said Diana Hammer, EPA Project Manager for the Site. "Everyone has come together to
ensure integration of Site remediation, restoration and redevelopment. It has been a real pleasure to
work on this project."
FOR MORE INFORMATION, PLEASE CONTACT: Diana Hammer, Remedial Project
Manager, at (406) 457-5040 or hammer.diana@epa.aov: or Frances Costanzi, Region 8 Superfund
Redevelopment Coordinator, at (303) 312-6571 or costanzi.frances@epa.aov.
United States
Environmental Protection
i Agency
Superfund Redevelopment Initiative
Updated: June 2010 2

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