Clark Fork drawdown a necessity

I have been fielding a number of questions from local folks about the drawdown of the reservoir behind our dam here in Thompson Falls. I fully understand the concern and the questions so I wanted to explain how we managed the high flows this spring and what we have planned for the near future.

In May, with extremely high flows and large amounts of debris and logs coming down the Clark Fork, we were forced to release a number of steel spillway beams to allow the larger volume of water, debris and logs to pass safely through the dam. With flows now receding, we need to replace those beams and have begun to draw down the reservoir, which will eventually allow us to safely and efficiently do the work.

How long the draw down will take is uncertain and is directly tied to how much water continues to come down the river. Our work cannot begin until the flow drops below 20,000 cubic feet per second. Our flows are currently still above 50,000 cubic feet, but are slowly trending down. Once we start, we expect this repair work to take about three weeks to complete.

We are aware that many of our friends and neighbors use the reservoir for boating and summer recreation. The draw down will affect how we all will be able to use the reservoir until this work is complete. We apologize for the disruption and will do our best to get the repairs done as quickly as possible.

We currently have two new spill gates under construction on the main dam. These new gates will allow us to safely pass more water, debris and logs during high flows and may lessen the probability of future steel beam removal. Completion of these new gates is expected by year end.

We are asking boaters to use extra caution on the reservoir during our current high flows and as the reservoir continues to drop. In fact, we would prefer that boaters avoid using the reservoir until everything is restored. We were forced to also remove the boat restraint, a safety device above the dam due to the high volume of water, debris and logs in the river. It is important to remember that boating between the dam and a point 1,020 feet upstream is prohibited year-round for safety reasons by the Montana Fish, Wildlife and Parks commission.

We appreciate your patience as we continue the drawdown and work to make the needed repairs.

Thank you,

Noel Jacobson, Foreman

Thompson Falls Dam, NorthWestern Energy