Updated: April 6, 2009
With little fanfare on March 27, a contractor breached the cofferdam at the Milltown Reservoir Superfund Site allowing the Clark Fork River to flow through its final channel alignment where the Milltown Dam stood for more than a century.
The temporary cofferdam kept water from the area so crews could dismantle the dam’s spillway and divider block – the last pieces of infrastructure related to the company’s Milltown hydro-generation facility. Almost a year ago to the day, the same contractor had breached the initial cofferdam built to allow the demolition of the generation station’s powerhouse.
The second breach marked a milestone for Northwestern Energy ending a major piece of the company’s involvement in the project to dismantle the dam, remove about 2.2 million cubic yards of contaminated sediment and restore the river channel.
Bill Thompson, senior engineer – Safety, Health, and Environmental Services, has been responsible for ensuring the company complies with the Consent Decree concerning the site. He said that while much work remains at the reservoir, NorthWestern’s role now is limited primarily to paperwork needed to transfer land ownership and water rights to the state of Montana that will oversee the final reclamation of the area.
Looking north across the Clark Fork River is Bill Thompson who since 2000 has been responsible for managing the operations of the dam including during the initial stages of the remediation project and ensuring the company met its obligations as outlined in the legal documents directing the final settlement of the Milltown Superfund Site.
Pictured here is the Clark Fork River heading west toward Missoula from the site of the former powerhouse.
This video shows the site of the former Milltown Dam and powerhouse from the south bank of the river. Noted are the cofferdam and the breach site.
Geese fly pass an Envirocon excavator preparing the river channel for the cofferdam breach. The breach area is located in the bottom left corner of the photo.
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