Glines Canyon Dam


Glines Canyon Dam, also known as Upper Elwha Dam, built in 1927, was a high concrete arch dam built on the Elwha River within Olympic National Park, Clallam County, Washington.
It was located upstream from the mouth of the Elwha River at the Strait of Juan de Fuca, and about 8 miles upriver from the Elwha Dam. It impounded Lake Mills reservoir. The dam was demolished in 2014 as part of the Elwha River ecosystem restoration project; as of 2015 it is the tallest dam ever to be intentionally breached. The Glines Canyon Dam was the largest dam removal ever.

History

The dam was built privately to generate electricity for industries and major military installations on the Olympic Peninsula, including lumber and paper mills in Port Angeles.
The Glines Canyon Hydroelectric Power Plant historic district, a area comprising the dam, the powerhouse, and the water conveying system, was listed on the National Register of Historic Places in 1988.

Effects of dam on river habitat and area ecology

Lacking passage for migrating salmon, Glines Canyon Dam blocked access by anadromous salmonids to the upper 38 miles of mainstem habitat and more than of tributary habitat. The Elwha River watershed once supported salmon runs of more than 400,000 adult returns on more than of river habitat. By the early 21st-century, fewer than 4,000 adult salmon returned each year.

Habitat restoration

Numerous groups lobbied Congress to remove the two dams on the river and restore the habitat of the river and its valley. The Elwha River Ecosystem and Fisheries Restoration Act of 1992 authorized the US Federal Government to acquire the Elwha Dam and Glines Canyon Dam hydroelectric power projects for decommissioning and demolition for habitat restoration.
The Elwha Ecosystem Restoration project started in September 2011 as work to demolish the nearby Elwha Dam began downstream. The final piece of the Glines Canyon Dam was removed August 26, 2014. Now that the dam has been removed, the area that was under Lake Mills is being revegetated and its banks secured to prevent erosion and to speed up ecological restoration.

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