The Milltown Sediment Reservoir Superfund Site is a large Superfund site in Missoula County, Montana, seven miles east of Missoula. It was added to the National Priority List in 1983 when groundwater contamination was found in the Milltown area. The pollution caused by severe floods in 1908 that washes millions of tons of mine waste into the Clark Fork River, eventually ends behind the Milltown Dam.
Since 1992, the site has been part of the Clark Fork River Superfund Complex, which consists of three main locations (two others in Anaconda and Butte) along a 120-mile stretch of the Clark Fork River. The Complex is the largest and most expensive Superfund site in the United States.
Video Milltown Reservoir Superfund Site
Overview
The Milltown Dam ( 46Ã, Â ° 52? 18? N 113Ã, Â ° 53? 33? W ) is a gravity-type hydroelectric dam on the Clark Fork River in Missoula County, in western Montana. The dam is located about seven miles east of Missoula, Montana, at the Blackfoot River encounter with Clark Fork. Built in 1908 by William A. Clark copper mining tycoon, it was intended to supply hydroelectric power to its sawmill at Bonner, Montana nearby. Clark's sawmill supplied the giant logs used to support the mine tunnel wall in Butte. Since the 1870s, the Anaconda and Butte regions have been mined as one of the richest copper sulfate deposits ever found in North America. However, with the dam just months ago, the record flood at Clark Fork washes tons of downstream poisonous mining sediments, where it settles at the base of the dam to keep it until remediation begins, with a cumulative total of about 6.6 million cubic meters of contaminated sediment with arsenic, lead, zinc, copper, and other metals in the former reservoir bed. Maps Milltown Reservoir Superfund Site
Superfund establishment and study
In 1981, through a water quality study in the Missoula County area, four wells in Bonner serving 35 households were found to be contaminated with heavy metals. The Environmental Protection Agency and the Environmental Quality Department of Montana closed the well and started looking for the causes of groundwater contamination in the Milltown area. Two years later, in September 1983, it was determined that contamination was the result of heavy metal sediment buildup coming from intensive upstream mining by Anaconda Copper Mining Company. The findings resulted in the addition of the Milltown Dam Site to the initial National Priority List. Reviews are immediately initiated by the EPA to determine the Potential Responsible Party (PRP) and to develop plans to improve groundwater contamination problems. In 1977, Anaconda Copper was purchased by Atlantic Richfield Corporation (ARCO), which was responsible for the damage. In 2000, ARCO was purchased by British Petroleum.
In 1992, through the action of committed citizens in the Deer Valley, the EPA assigned the Clark Fork River upstream from the Milltown Dam to the Warm Springs Ponds section of the Superfund Site. In 1995, studies on site contamination rates were completed by EPA and ARCO. The next feasibility study seeks to determine how to restore Milltown groundwater. However, the study was discontinued because the wet winters of 1996 sent large ice jams on the Blackfoot River and into the Milltown Reservoir, causing severe scrubbing of contaminated sediments at the bottom of the reservoir and causing the fish to kill downstream.
Afraid of the uncontrolled release of water (and sediment), officials quickly lowered the reservoir level, breaking the ice pack before it could cause further damage. The EPA immediately began to check the extent of the damage, and after a debated public discussion it became clear that the threat of continued release of contaminated sediments into downstream fisheries should be addressed in the final remediation plan. More than 10,000 West Montana residents sent public comments to support the removal of the complete dam and full cleaning.
In 2003, the State of Montana, through its Natural Resources Damage Program, drew up a conceptual plan for the Milltown Dam site recovery. In December 2004, a final remediation plan was released by the EPA, calling for the removal of over two million cubic meters of contaminated sediment and removal of the Milltown Dam. In August 2005, an approval decision was signed by the parties, enabling the project to move out of the planning stage and into the ground. After more than 20 years of study and litigation, work began at Milltown Site on June 1, 2006 with the withdrawal of the Milltown Dam. Contaminated reservoirs are transported to an upstream warehouse near the city of Opportunity, a move that some locals oppose.
Three R from Superfund project
Remediation
Remediation is defined as the clearance of harmful substances to protect human health and the environment. Remediation on the Milltown/Clark Fork River Site is led by EPA and its main contractor, Envirocon. The remediation phase includes the removal of three million tons of contaminated sediment and Milltown Dam itself. Improvement goals include Milltown Aquifer recovery and downstream water quality as well as trout through the meeting area. Field work began in the summer of 2006 and the remediation phase had to end in December 2009, with project leadership shifting to the State of Montana for the restoration of the area.
Recovery Recovery in the Milltown context is the creation of natural rivers and floodplains after dismantling dams and sediments. With funds gained through the lawsuit of the Natural Resources Damage Program against ARCO, the State of Montana is leading the restoration of the meeting area to its natural state. Restoration work began in the summer of 2008 and increased as sediment removal approached the end. Restoration works include new river channel cultivation, fluvial wetland creation, bank strengthening, and rebuilding of natural vegetation cover. Restoration work is scheduled for completion in 2012.
Rebuilding Rebuilding is an attempt to restore the site of hazardous waste to productive use. Plans for rebuilding the Milltown area include the creation of a state park with a trail system that links the surrounding communities. In 2007, the conceptual design for the park was collaborated by Milltown Superfund Redevelopment Working Group and Montana Department of Fish, Wildlife, and Parks, National Park Service Rivers and Trails Program, the Idaho-Montana Chapter of the American Society of Landscape Architects. In 2009, a grant proposal for the initial park construction was submitted to the Natural Resources Damage Program.
See also
- Clark Fork River
- Anaconda Copper
- ARCO
- British Petroleum
- List of Superfund sites in Montana
References
External links
- Clark Fork River Technical Assistance Committee
- Clark Fork Coalition
- The History of Two Rivers
- EPA Region 8 Milltown Reservoir Sediment
- Historical American Engineering Record (HAER) no. MT-43, "Milltown Dam, Clark Fork River, 6 miles upstream from Missoula, Milltown, Missoula County, MT"
- HAER No. MT-43-A, "Milltown Dam, Powerhouse"
- HAER No. MT-43-B, "Milltown Dam, Spillway"
- Milltown Mouth History Project (University of Montana Archives)
Source of the article : Wikipedia
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