Thompson Falls Dam
First built in 1915, the Thompson Falls dam is a seven-unit hydroelectric plant on the Clark Fork River in Thompson Falls, Montana. NorthWestern Energy owns and operates the dam, along with 10 others across the state. The energy produced and collected at these dams allows us to provide clean, sustainable energy to meet our customers’ needs. NorthWestern Energy values being a good steward of the resources at our projects and works to protect and enhance the fish and wildlife resources around our sites.
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Fish Ladder
In partnership with Montana Fish, Wildlife and Parks, US Fish and Wildlife Service, and Confederated Salish and Kootenai Tribes, NorthWestern Energy operates a fish ladder at Thompson Falls dam which allows native fish, especially threatened bull trout and several other salmonid and non-salmonid species, to migrate above the dam. Once fish ascend the ladder, biologists collect and track important information including population health. Engineers and biologists worked together to design the ladder to be effective at catching and passing fish in a complex environment at multiple flow levels.
Providing fish passage allows access to important upstream habitats including areas used for reproduction. Access to these spawning and rearing areas help to maintain genetic diversity to support the health of fish populations.