Thompson Falls Dam is a seven-unit hydroelectric plant on the Clark Fork River in Thompson Falls. The units have a total generating capacity of 94 megawatts. (One megawatt can satisfy the average energy needs of 750 households.)
The dry-channel dam is a concrete gravity structure with an overflow spillway and an overall length of 289 feet. The structure has an average height of 17 feet above the riverbed. It is raised by flashboards and 8-foot drop panels. Thompson Falls is classified as a “run-of-river” project because it can generate electricity using the water that flows down the river, without the need to store additional water supplies.
Thompson Falls is one of two PPL Montana dams west of the Continental Divide. The Clark Fork River empties into the Columbia River, which in turn empties into the Pacific Ocean.
From PPL Montana
Historic Resources of Thompson Falls, Montana
(Page 2)
The Thompson Falls Multiple Resource Area nomination consists of one historic district and a variety of individual residential and commercial buildings constructed between 1900-1916. The Hydroelectric Dam Historic District is made up of five buildings and six structures, all of which date from 1910-1915 and are in good condition.
The six structures in the district consist of the concrete Dry Channel and Main Channel Dams (1915), the Dry Channel and Main Channel Bridges (1911), the masonry Powerhouse and the small, masonry Transformer House.
From the NRHP Nomination Form