Dam repairs complete

Reservoir to be full by weekend

 

August 9, 2018

Jan Henry

HISTORY UNCOVERED - With the water level so low in Thompson Falls, an old railroad track could be seen along the river bank. The tracks were used when the dam was built.

School is just a few weeks away, but summer is just about started for boaters and other river enthusiasts in Thompson Falls.

Sanders County Historical Society photo

A LOOK BACK - Railroad tracks were an important part of the dam and powerhouse building process between 1913 and 1917. They were used to move rocks, concrete, iron and other heavy metal and equipment to the builders. A steam-powered jitney was used to pull the cars to and from the dam. After the dam was constructed, the rails were left in place and have been covered with water for more than 100 years.

Work to replace steel stanchions at NorthWestern Energy's Thompson Falls dam began earlier this summer. High flows from the spring runoff forced NorthWestern Energy to release steel spillway beams to allow for water, debris and logs to pass safetly through the dam, according to dam foreman Noel Jacobson. In order to replace those beams, the reservoir had to be drawn down. Work could not begin until the flow dropped below 20,000 cubic feet per second (cfs). At its peak this year, the Clark Fork River flows were more than 100,000 cfs.

Now that the steel stanchions have been replaced, work also has resumed on the two new radial spillway gates. According to NorthWestern Energy, the $5.6 million project will be completed by the end of the year.

The two new gates will replace four of the existing spillway gates. The advantage of the radial gates is that if river conditions change, NorthWestern can respond quicker. Instead of having to manually open gates, the radial gates open automatically.

The last time NorthWestern Energy had to draw down the reservoir to replace steel stanchions was in 2011.

 

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