On December 16th 2010, Envirocon crews shifted the ever-patient Clark Fork River for 7th and final time. This breach marks one of the final stages of remediation work at the Milltown Reservoir Sediments Operable Unit Superfund Site near Missoula, Montana.

Envirocon has been the prime contractor on the site since 2003. However, this scope of work was performed under a contract with the State of Montana Natural Resource Damage Program, and was separate from the dam and sediment removal portion of the project.

Envirocon has spent the last two years constructing approximately three miles of new channel that would become the river’s final resting spot.

A crowd of people gathered on the bluff overlooking the former spillway in anticipation of the waters release into the new channel and its ultimate arrival at the new confluence of the Clark Fork and Blackfoot rivers.

Montana Governor Brian Schweitzer and other public officials were in attendance to inform onlookers of the historical and cultural significance of the river’s 100-year journey to its restored environment.

At 10:45 a.m., excavators operated by Envirocon’s Dave Kramer and Mike Achermann started removing the diversion dike that routed the water into the side channel. At this time, the crew downstream was finishing the log jam and starting on the vegetated soil lift that formed the right bank of the river.

GPS equipment was utilized to remove the dike to maintain the design shape of the river bottom as the excavation progressed from the left to right banks.

Water reached the access area at 12:00 p.m. just as the vegetated soil lifts were being backfilled.

Construction Manager, Rob Williams who was supervising the work at the access noticed the water level in the bypass channel starting to drop therefore signaling the day’s initial success. Yet the water still had another mile to travel before reaching the confluence.

Finally, at 1:00 p.m., flows were visible at the confluence amid cheers from the waiting crowd.

Upstream, the crew was opening up the last of the new channel and starting to shut off flows into the side channel. Long-time dozer operator, Dick Suomi closed off the flows into the side channel with a final push at about 3:00 p.m.

Over the next five or six months, Envirocon will reclaim the bypass channel and complete work in the surrounding floodplain. The State has plans to turn the restored area into a State park.

For more information and updates on the Milltown Reservoir Sediments Operable Unit Superfund visit http://www.epa.gov/region8/superfund/mt/milltowncfr/