Milltown Reservoir Sediments
National Priorities List (NPL) History
May 2013 - The Milltown Reservoir Sediments Superfund Site is currently in a monitoring phase:
Monitoring the recovery of the groundwater (from arsenic contamination)
Groundwater Compliance Monitoring Well Results
- Monitoring a network of wells in the area around the Superfund Site (EPA in conjunction with Missoula County) Public Health Groundwater Results
- Monitoring the recovery of the local fishery (Montana Department of Fish, Wildlife, and Parks; funded by EPA) Milltown Fisheries Report
- Monitoring the restoration and revegetation of the area (Montana Natural Resource Damages Program with Geum Environmental Consulting and the University of Montana; EPA Oversight) Revegetation Report 2009-2012; 2011 Monitoring Vegetation Monitoring Report; and 2012 Monitoring Vegetation Monitoring Report.
- Final Monitoring Plan: Post-Construction Remediation Action Construction Monitoring Plan (March 2013)
- Annual Maintenance and Monitoring Report (2013)
May 1, 2013 – Clark Fork River: open to recreation/bank closed (”dock on the rocks”) to allow fragile vegetation to establish in the floodplain. Blackfoot River: banks are open to recreation/river is closed in the project area – boaters still must exit the river at Weigh Station. (Montana Fish, Wildlife and Parks Commission Order)
In September 2012, EPA and the State of Montana marked another project milestone – the end of the end of the Remediation and Restoration phases and the beginning of the Monitoring and Redevelopment phases. View the press release. For more information about Redevelopment, please visit the Milltown State Park website.
October 2011 - EPA releases the Report of its First Five-Year Review of the Water Supply and Milltown Reservoir Sediments Operable Units of the Milltown Reservoir Sediments/Clark Fork River Superfund Site.
Under Superfund law, EPA is required to conduct a review of the remedial action no less frequently than every five years. The timing of this, the first five-year review for the Milltown site, was triggered by the permanent draw-down of the Milltown Reservoir, commencing remedial action in 2006. There are three Operable Units (OUs) at the Milltown Reservoir/Clark Fork River Superfund Site. OU 1 is the Milltown Water Supply, OU2 is the Milltown Reservoir Sediments, and OU3 is the Clark Fork River. This five-year review examined the remedial action for OU1 (water supply) and OU2 (reservoir sediments). OU3 (the Clark Fork River) will be examined separately in a five-year review due in 2015.
Five-year reviews seek to answer three basic questions:
- Is the remedy functioning as intended?
- Are the remedy assumptions still valid?
- Has other information come to light that would call the remedy into question?
The focus of the Milltown five-year review is the remedial action—namely removal of the Milltown dam and reservoir sediments—and the remedial action goals and objectives. This five-year review was conducted between January and August 2011. The review found "The remedy at the Milltown Reservoir Sediments Operable Unit (including the Drinking Water Operable Unit) is expected to be protective of human health and the environment upon completion, and in the interim, exposure pathways that could result in unacceptable risks are being controlled." The second Milltown five-year review is due in September 2016.
The complete report and an executive summary are available in the Site Documents section below.
EPA's Superfund Redevelopment Initiative selected the Milltown Reservoir Sediments Superfund Site for a national case study to highlight the cooperation and collaboration that has gone into turning this Superfund Site into a restored river/flood plain and new Montana State Park. The Milltown project was initially selected as a national SRI highlight and then expanded for a more in-depth case study. As we have often said, it is not every day we have the opportunity to turn a Superfund hazardous waste site into a state park. The restored flood plain and river system will be an asset for generations to enjoy. Read more about the story in this fact sheet: Integrating the '3Rs': Remediation, Restoration, and Redevelopment (PDF) (14 pp, 2.3MB, about PDF).
- Milltown Return to Reuse Initiative 2010 Demonstration Project (PDF) (2 pp, 485K, about PDF)
- Transformation of the Milltown Reservoir: Superfund Site to State Park (PDF) (88 pp, 9.6MB, about PDF)
December 16, 2010 – Two major project milestones: 1) Clark Fork River diverted to its "new original" channel; and 2) NorthWestern Energy’s Milltown property transferred to the State of Montana
At noon on Thursday, December 16, 2010, a crowd gathered (WMV video) (3:45, 43MB) as state, federal, tribal, and local officials watched as the Clark Fork River slowly made its way down its newly constructed channel in the site of the former Milltown Reservoir. The Clark Fork River was diverted earlier that morning about two miles upstream and slowly worked its way downstream to the confluence with the Blackfoot River. This event was the culmination of years of Restoration work at the Milltown Reservoir Superfund Site, work that was closely integrated with on-going remediation.
These are two of the "3Rs", the third being Redevelopment. The Redevelopment Plan for the Milltown Reservoir Superfund Site was developed by the Milltown Redevelopment Working Group in collaboration with state, federal and local agencies and organizations as well as members of the public.
A key part of the Redevelopment Plan is the land transfer that also occurred on December 16, 2010. The crowd welcomed the announcement of the transfer of 415 acres of NorthWestern Energy property to the State of Montana. This land is slated to eventually become part of the planned Milltown State Park.
Read about the event in the Missoulian: Clark Fork River flows into new channel in life after Milltown Dam
September 24, 2009 - The last trainload of contaminated sediments leaves the Milltown site
This important project milestone comes nearly two years after the first trainload left the site (October 2, 2007). Since that time, almost every day a trainload of 45 cars—each carrying approximately 100 tons of sediment—has carried the sediments some 90 miles to the Anaconda Smelter Superfund Site for disposal. At that site, the material can be used in establishing vegetation for site reclamation. EPA had estimated it would take between 200 and 2000 years to naturally deplete this source of arsenic in the sediments. Once the source of arsenic is removed, EPA estimates the local drinking water supply will be safe to drink within a decade. Read the September 24, 2009 press release.
The 2004 Milltown Record of Decision called for removing the Milltown Dam and 2.2 million cubic yards (over 3 million tons) of contaminated reservoir sediments. The dam is now gone and so are the sediments. Removing these contaminants removes the source of pollution—arsenic—that polluted the local drinking water wells years ago. Removing these sediments also means that copper from the sediments can no longer periodically scour from the reservoir and kill or chronically impair the fishery below the former Milltown Dam. Completing this removal is a necessary step to permanently address the public health and ecological risks posed by the reservoir sediments.
As significant as this milestone is, much work remains to be done. This project integrates the “3Rs”: Remediation, Restoration, and Redevelopment. The focus of this project is now shifting from Remediation to Restoration and Redevelopment.
The State of Montana's Restoration program—led by the Montana Natural Resource Damages Program—is well underway to return the Clark Fork and Blackfoot rivers to naturally-functioning systems. More information is found on the Milltown Dam Restoration Program website.
The objectives of the Milltown Restoration Plan 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
Redevelopment efforts are led by the Milltown Redevelopment Working Group. The working group is working closely with EPA, the State of Montana – particularly the Department of Fish, Wildlife and Parks, Missoula County, and the community to turn the Superfund site into a State Park.
What's happening with the 3Rs: Remediation, Restoration, and Redevelopment at the Milltown Site?
- March 27, 2009: Breached the Spillway Coffer Dam; Began Stage 3 of the ceanup
- February 2009: Reached the 2,000,000 ton mark of sediments excavated, loaded and hauled off-site for disposal.
- Sediment excavation and removal is about three-quarters complete!
- January 2009: Removed the Milltown Dam spillway.
- October 2008: One-year anniversary of contaminated sediment excavation, loading and hauling off-site
- November 2008: State of Montana removed 5,000 logs from the Blackfoot River
- November 2008: State of Montana completed the Highway 200 Bridge over the Blackfoot River
- November 2008: Missoula County completed the new pedestrian bridge over the Blackfoot River
- November 2008: Missoula County completed additional recreational trails along Highway 210 E
- July 2008: The Milltown Redevelopment Working Group revised its Conceptual Redevelopment Plan for the project area.
March 27, 2009 -The Milltown Spillway Coffer Dam is Breached – Stage 3 begins!
The Spillway Coffer Dam (located just upstream of the former Milltown Dam spillway) was successfully breached on Friday, March 27, 2009. This event was "more historic and less dramatic" than last year's breach of the Milltown Dam. "More historic" in that the river was redirected closer to the base of the Milltown bluff—thought to be the original river channel; "less dramatic" because the river elevation l only dropped about two feet below the project area. Initially, only about 20 percent of the combined Blackfoot and Clark Fork River flows were captured by the new channel but by the following Monday, about 70 percent of the flow was in the new channel at the base of the Milltown bluff. Crews are hoping to divert the entire flow into the new channel so soil stockpiled between the two channels (old and new Clark Fork River channels) can be recovered for later use in site restoration.
The Spillway Coffer Dam (located just upstream of the former Milltown Dam spillway) was successfully breached on Friday, March 27, 2009. This event was "more historic and less dramatic" than last year's breach of the Milltown Dam. "More historic" in that the river was re-directed closer to the base of the Milltown bluff—thought to be the original river channel; "less dramatic" because the river elevation l only dropped about two feet below the project area. Initially, only about 20 percent of the combined Blackfoot and Clark Fork River flows were captured by the new channel but by the following Monday, about 70 percent of the flow was in the new channel at the base of the Milltown bluff. Crews are hoping to divert the entire flow into the new channel so soil stockpiled between the two channels (old and new Clark Fork River channels) can be recovered for later use in site restoration.
To see before and after pictures of the breach of the spillway coffer dam, see the photo/video gallery section of this page.
Clark Fork Coalition hosts the live "Dam Cam": Milltown Reservoir Web cam
March 28, 2008 – The Milltown Dam is breached!
The Milltown Dam was completed in 1908 and around noon on Friday, March 28, 2008, a century later, the Milltown Dam was officially breached. This was an historical moment in both the cleanup of the Milltown Reservoir Sediments Superfund Site and in the rich cultural and natural history of the Milltown-Bonner area.
Approximately 1,000 people, including Montana Governor Schweitzer, Senators Baucus and Tester, local legislators, city council members, tribal, state, federal, and local officials, community groups, and members of the public, gathered on the bluff overlooking the reservoir and near the dam. Everyone anxiously watched and waited as an excavator scooped out the last bit of soil and the dam was officially breached. Water trickled through slowly at first, gathering speed as more and more of the river flows were captured. The chasm deepened as more and more of the coffer dam eroded away. Then, just before dark Friday night, the Blackfoot River flows had been completely captured. Now the Clark Fork and Blackfoot Rivers are flowing freely downstream for the first time in over a century.
While much as been accomplished, more remains to be done. For the next year and a half, work crews will continue to excavate and load contaminated sediments onto rail cars (45 cars/day) en route to the Anaconda Smelter Superfund site nearly 100 miles away. Later this summer, when river flows drop, workers will begin removing the rest of the Milltown Dam (divider block, radial gate and spillway). As the cleanup (remediation) continues, restoration and redevelopment of the site are beginning. The remediation should be done in 2010 and restoration should be completed by 2012. Redevelopment is ongoing. Hopefully, this Superfund site will one day become a state park.
This innovative cleanup integrates remediation, restoration, and redevelopment and plans to:
- Remove the Milltown Dam and Powerhouse.
- Excavate approximately 2.2 million cubic yards of the most highly contaminated sediments in the Milltown Reservoir.
- Restore the Milltown drinking water supply in as little as a decade.
- Allow unrestricted fish passage.
- Return the Clark Fork and Blackfoot rivers to a more natural and free-flowing state.
Cleanup is underway!
Public Involvement the Cleanup Design
EPA has convened a Design Review Team to to work on the remedial design. The Design Review Team has been meeting periodically since the fall of 2005. Along with EPA, the State of Montana, the US Fish and Wildlife Service, and the Confederated Salish and Kootenai Tribes, Missoula County and the Clark Fork River Technical Assistance Committee are representing the public in design discussions. The Design Review Team continues to meet regularly to review and discuss site cleanup plans.
A number of new design documents and other site-related documents are available to the public. You can download the documents from the Clark Fork River Technical Assistance Committee.
Background and Cleanup Goals
In December 2004, EPA, with the concurrence of the Montana Department of Environmental Quality, issued the Milltown Reservoir Sediments Record of Decision (ROD). ROD summary fact sheet (PDF) (4 pp, 83K, about PDF)
The ROD contains three parts: Part One: The Declaration (eight-page legal summary which EPA and DEQ signed), Part Two: Decision Summary (fully describes the selected remedy, including information leading to this decision), and Part Three: Responsiveness Summary (public comments and responses to those comments). The U.S. Department of Interior/Fish and Wildlife Service and the Confederated Salish and Kootenai Tribes also concur with the Milltown Reservoir Record of Decision. There is no public comment on the Record of Decision. It is a final document.
Consent Decree (PDF) (187 pp, 478K, about PDF) negotiations (to determine who pays for and performs the work) were completed in the summer of 2005. Consent Decree fact sheet (PDF) (4 pp, 347K, about PDF)
The 3 Rs: Remediation. Restoration. Redevelopment. The Milltown Reservoir Sediments cleanup (remediation) is being carefully planned and coordinated with the State of Montana's Natural Resource Damages Program , integrating remediation and restoration activities.
Redevelopment: Envisioning the Future
The Superfund cleanup (remediation) portion should be complete in 2009. The restoration work should be completed about 2 years later (2011). What will the area look like once the remediation and restoration are complete? What do we want to see in 5, 10, 20, or 50 years?
This is the question the commuity-based Milltown Redevelopment Working Group seeks to answer. This group of citizens was appointed by the Missoula County Commissioners in 2003 to work with their neighbors and other community members to examine possible land re-use and redevelopment options for the Milltown Superfund Site. In early 2005, after many meetings, public outreach and public comment, the Milltown Redevelopment Working Group presented a Conceptual Redevelopment Plan to the Missoula County Commissioners for consideration. The redevelopment plan (PDF) (58 pp, 8MB, about PDF ) was adopted by the county in March 2005. Highlights of this plan include walking, biking, and equestrian trails in the Bonner-Milltown area, upgrading the Bonner pedestrian bridge over the Blackfoot River, and looking at ways to tell the stories of the area's rich history through historic preservation activities.
There are currently three workgroup subcommittees:
- Recreation and Trails (chaired by Sue Furey, Piltzville). Current focus: Planning for a possible public park
- History and Culture (chaired by Judy Matson, West Riverside). Current focus: Preserving local historic photos and items from the Powerhouse.
- Outreach (chaired by Gary Matson, West Riverside). Current focus: Outreach about planning for a possible public park.
Over the past couple of years, the Redevelopment Working Group has been raising funds to implement parts of the Conceptual Plan. The Working Group currently has about $4 million for various redevelopment projects. Recent examples include:
- Safety trail for school children and other pedestrians along Highway 210 East from the Bonner School to the Piltzville Fire Station (EPA funded).
- New pedestrian "hybrid" bridge over the Blackfoot River in Bonner (funding from EPA, Montana Natural Resources Damage Program, and the federal highway bill for alternative transportation projects).
During the summer of 2007, the Working Group made presentations to various area groups and neighbors about the Conceptual Plan and gathered some ideas about how to refine the "concepts" and move more towards designing what may one day become a state park or other state-managed property (e.g., fishing access site or wildlife management area). In September 2007, the Working Group hosted a "Design Workshop" where 30 participants (community members, experts from agencies, and volunteer landscape architects) spent two days talking and dreaming and ultimately coming up with designs for three potential park areas::
- Milltown Gateway: low intensity design ; higher intensity design
- Confluence Area (Clark Fork and Blackfoot Rivers) lower intensity design
- Former Milltown Resevoir Area: larger area: more detailed design; bluff overlook
As currently envisioned, the lands 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, 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 connecting to Missoula's Riverfront Trail system, extending the Kim Williams Trail along the Clark Fork River.
An interpretative center/signage is also envisioned, describing the history of the area from Glacial Lake Missoula to the Native Americans' road to the buffalo, Lewis and Clark's voyage of discovery, the mining and logging history, the construction of the Milltown Dam and Powerhouse, area poets and artists, to the present-day Superfund cleanup, river restoration and area redevelopment.
The Redevelopment Group meets the fourth Tuesday of each month at Our Saviour's Lutheran Church in Bonner. Meetings run from 6:30-9:00 p.m., are free and open to the public. For more information, please contact Peter Nielsen, Missoula City-County Health Department, at 406-258-4968 or Diana Hammer, EPA, at 406-457-5040. Read the Redevelopment Working Group newsletter (PDF) (6 pp, 1.9MB, about PDF ).
EPA strives to keep the community involved and informed about site activities through on-going community outreach and education efforts.
- Updates about the cleanup progress - EPA publishes two-page updates every two weeks describing cleanup progress, upcoming events and other site-related issues. Click here to subscribe.
- Informational kiosks - these provide an overview of the cleanup (remediation), restoration, and redevelopment activities, including the weekly updates. Kiosks are located at: the Milltown Community Office, start of the Kim Williams Trail along the Clark Fork River, the Missoula Public Library, the Missoula County Court House, the Weigh Station River Access on the Blackfoot River and one will soon be located in the parking lot for the bluff overlook.
Bluff overlook - the best place from which to view the on-going cleanup of the Milltown Resevoir is from the bluff overlooking the site. Through the generous donation of land from the Plum Creek Timber Company (donated), NorthWestern Energy (in progress) and a private landowner (in progress) and the public service spirit of the Carpernters' Union Local #28, the bluff overlook should remain a public asset for years to come! The bluff is open to the public—please respect posted signs and neighboring private property. Directions to the overlook.
In the near future: EPA is partnering with others to design and build a handicap-accessible trail leading to a fenced area on the bluff. There will be a small parking lot and interpretataive signage on the bluff and at the parking lot. EPA is currently working with the State of Montana and Burlington Northern Railroad to (hopefully!) aquire additional land on the bluff and along the south side of the Clark Fork River.
- Tours can be arranged by calling Diana Hammer, EPA, 406-457-5040.
- EPA allows hosts periodic public meetings, publishes site fact sheets, and makes presentations to area organizations and community groups.
The Milltown Reservoir Sediments site is an Operable Unit within a larger Superfund site, the Milltown Reservoir Sediments/Clark Fork River Superfund Site. This site includes approximately 120 miles of the Clark Fork River upstream of the Milltown Dam and Reservoir. The Milltown Dam and Reservoir are located at the confluence of the Clark Fork and Blackfoot Rivers, a few miles upstream of Missoula, in western Montana.
Behind the Dam are approximately 6.6 million cubic yards of contaminated sediments. Arsenic in the sediments has polluted the local drinking water aquifer and release of copper in the sediments threatens 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 Superfund cleanup activities on-going 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 some 98 percent of the nearly 5,000 comments received during the public comment periods supported EPA's proposed plans.
The Milltown site is located adjacent to the unincorporated communities of Milltown and Bonner. Other nearby unincorporated communities in the "Two Rivers Area" are Piltzville, West Riverside, Pine Grove, and East Missoula. Missoula, the county seat is six miles west of the site. There are approximately 60,000 people in Missoula and 95,000 people in Missoula County.
Immediate risks to public health from a contaminated drinking water supply have been temporarily addressed. With the implementation of the Milltown Reservoir Sediments Record of Decision, EPA expects the Milltown drinking water supply to be cleaned up permanently. The groundwater should be clean within a decade following removal of the source of pollution (reservoir sediments contaminated with arsenic) and the Milltown Dam (which provides hydraulic pressure, driving the pollution into the Milltown groundwater).
|Media Affected||Contaminants||Source of Contamination|
|groundwater, reservoir sediments||arsenic, copper||historic mining activity|
It's been 16 years since residents of Milltown received official notice their arsenic-contaminated aquifer might be purified someday. Now well water test results indicate that process may have finally begun. Read more.
You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.
To keep the public up to date about cleanup activities at the Milltown Reservoir Superfund Site, EPA produces weekly updates and maintains a site photo gallery.
cleanup activities. To plan and carryout the cleanup, EPA produces a number of technical documents such as the Record of Decision (ROD), monitoring plans, design work plans, etc.
First Five-Year Review Report, September 23, 2011 (59 pp, 12.7MB)
Arsenic levels drop in Milltown water
Milltown Reservoir/Clark Fork River Contacts
U.S. Environmental Protection Agency, Region 8
10 West 15th Street, Suite 3200
Helena, MT 59626
866-457-2690 (toll free)
Montana Department of Environmental Quality
1100 North Last Chance Gulch
P.O. Box 200901
Helena, MT 59620-0901
800-246-8198 (toll free in-state only)
View Documents at:
U.S. EPA, Montana Office
10 West 15th Street, Suite 3200
Helena, MT 59626
EPA Butte Office
400 N Main St, Room 339
Butte, MT 59701
Mansfield Library, University of Montana
Missoula, MT 59812
Missoula Public Library
301 East Main
Missoula, MT 59802
Hearst Free Library
3rd and Main
Anaconda, MT 59711
Montana Tech Library
Butte, MT 59701
Grant-Kohrs Ranch, National Historic Site
National Park Service
266 Warren Lane
Deer Lodge, MT 59722
Powell County Courthouse
Deer Lodge, MT 59722
Technical Assistance Grant Group
Clark Fork River Technical Assistance Committee
P.O. Box 9086
Missoula, MT 59807