Tumwater Dam
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HISTORIC TUMWATER DAM (text from above picture appears below)

Also visit Father Dale Peterka's Tumwater Canyon story for additional information.

The Tumwater Hydroelectric Project was constructed from 1907 to 1909. At that time, the hydroelectric project was the largest west of Niagara Falls. The project was constructed by the Great Northern Railway Company to produce power for electric locomotives traveling through the old Cascade Tunnel on the Stevens Pass route.

Electrification of the three miles of line brought an end to the serious smoke and gas conditions in the tunnel resulting from the coal burning locomotives. Four 100 ton electric locomotives were in service on the trolley line to pull passenger and freight trains through the tunnel which was abandoned in 1929 upon completion of a new eight-mile long Cascade Tunnel. The locomotives were the first in the United States to utilize the principle of regenerative braking, returning power to the lines on the downhill grade.

From the Tumwater Dam, water was delivered through a penstock to a powerhouse over two miles downstream. A bridge was constructed across the river to allow railroad access to the dam construction site. The bridge was then utilized to carry the penstock to the powerhouse. The bridge still stands and serves as a link to the old penstock route. The powerhouse was a concrete and brick structure that housed three waterwheels and three 2,000 kilowatt generators.

The Tumwater Hydroelectric Project was closed in 1956. By that time, the railroad had converted to diesel engines. The project was purchased by Chelan County Public Utility District in 1957. The powerhouse and related generating facilities were subsequently removed.

The Tumwater Dam is now equipped with modern fish passage facilities to assist adult salmon and steelhead returning to their spawning grounds.


Groundbreaking - July 6, 1907
Length - 400 Feet
Height - 23 Feet
Construction Cost - $100,000
Fishway - Newly Constructed in 1987

Head: - 200 Feet

Material - Wood & Steel
Length - 11,654 Feet
Diameter - 8.5 Feet

Surge Tank:
Height - 210 Feet
Capacity - One Million Gallons

Power House:
Generators - Three, 2,000 Kilowatts each 25 Cycle AC
Turbines - Three, Francis type 4,000 horsepower each