Glines Canyon Dam, also known as Upper Elwha Dam, built in 1927, was a high concrete

arch dam An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengthen ...

built on the

Elwha River The Elwha River is a river on the Olympic Peninsula in the U.S. state of Washington. From its source at Elwha snowfinger in the Olympic Mountains, it flows generally north to the Strait of Juan de Fuca. Most of the river's course is within the ...

within

Olympic National Park Olympic National Park is a United States national park located in the State of Washington, on the Olympic Peninsula. The park has four regions: the Pacific coastline, alpine areas, the west-side temperate rainforest, and the forests of the drier ...

Clallam County, Washington Clallam County is a county in the U.S. state of Washington. As of the 2020 census, the population was 77,155, with an estimated population of 78,209 in 2021. The county seat and largest city is Port Angeles; the county as a whole comprises ...

. It was located upstream from the mouth of the

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 historic district or heritage district is a section of a city which contains older buildings considered valuable for historical or architectural reasons. In some countries or jurisdictions, historic districts receive legal protection from ce ...

, a area comprising the dam, the powerhouse, and the water conveying system, was listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the United States federal government's official list of districts, sites, buildings, structures and objects deemed worthy of preservation for their historical significance or "great artistic ...

in 1988. and

Effects of dam on river habitat and area ecology

Lacking passage for migrating

salmon Salmon () is the common name for several commercially important species of euryhaline ray-finned fish from the family Salmonidae, which are native to tributaries of the North Atlantic (genus ''Salmo'') and North Pacific (genus ''Oncorhynchus' ...

, Glines Canyon Dam blocked access by

anadromous Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousa ...

salmonids Salmonidae is a family of ray-finned fish that constitutes the only currently extant family in the order Salmoniformes . It includes salmon (both Atlantic and Pacific species), trout (both ocean-going and landlocked), chars, freshwater whitefi ...

to the upper 38 miles (61 km) of mainstem habitat and more than of tributary habitat. The

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 The federal government of the United States (U.S. federal government or U.S. government) is the national government of the United States, a federal republic located primarily in North America, composed of 50 states, a city within a feder ...

to acquire the Elwha Dam and Glines Canyon Dam hydroelectric power projects for decommissioning and demolition for

habitat restoration Restoration ecology is the scientific study supporting the practice of ecological restoration, which is the practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human interrup ...

. The '' Elwha Ecosystem Restoration'' project started in September 2011 as work to demolish the nearby

Elwha Dam The Elwha Dam was a 108-ft (33 m) high dam located in the United States, in the state of Washington, on the Elwha River approximately upstream from the mouth of the river on the Strait of Juan de Fuca. The Elwha River Ecosystem and Fisheries Re ...

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.

Gallery

File:Lake Mills.jpg File:Glinescanyondam1.jpg File:Glines Canyon Dam (removed) from above, Oct 2014.JPG, Glines Canyon Dam (removed) from above, Oct 2014 File:Glines Canyon Dam (removed) from inside reservoir, Oct 2014.JPG, Glines Canyon Dam (removed) from inside reservoir, Oct 2014

References

Sources

* Grossman, Elizabeth (2002). ''Watershed: The Undamming of America'', Basic Books, . * Mapes, Lynda V. (2016). "Elway: Roaring Back to Life," The Seattle Times. http://projects.seattletimes.com/2016/elwha/

External links