Elwha River Restoration Frequently Asked Questions

Elwha River


What is this project all about?
Removing the Elwha and Glines Canyon dams will free the Elwha River after nearly 100 years. Salmon populations will swell, from 3,000 to more than 300,000 as all five species of Pacific salmon return to more than 70 miles of river and stream.

The returning salmon and restored river will renew the culture of the Lower Elwha Klallam Tribe, who have lived along the river since time immemorial. Tribal members will have access to sacred sites now inundated by water, and cultural traditions can be reborn.

Elwha River Restoration creates a living laboratory where people can watch and learn what happens when salmon return to a still wild and protected ecosystem. The return of fish will benefit bears, eagles and other animals that have been deprived of a vital food source for nearly a century.

Just as the dams and their hydroelectric power played a vital role in the history and development of the state of Washington's Olympic Peninsula, removing them will create new opportunities for growth and regional vitality. Removing the dams will reestablish the river's natural flow of sediment from the mountains to the coast—rebuilding wetlands, beaches and the estuary at the river's mouth.

Why remove the dams?
Removal of the dams on the Elwha River will restore the river to its natural free-flowing state, allowing all five species of Pacific salmon and other anadromous fish to once again reach spawning and rearing habitat.

The dams were built in the early 1900s and have provided hydroelectric power to a mill for most of that time. However, neither dam was built to include any method of fish passage: the loss of more than 70 miles of salmon spawning and rearing habitat led to a dramatic decrease in fish populations and wide-ranging effects on the entire Elwha Valley ecosystem.

In the early 1990s, extensive environmental review showed that dam removal was the only way to restore native anadromous fish stocks and the river's ecosystem.


How was the decision made?
The 1992 passage of the Elwha River Ecosystem and Fisheries Restoration Act mandated full restoration, and directed the Department of the Interior to evaluate a range of alternatives and determine the best manner by which to restore the river's ecosystem and native anadromous fisheries.

The Elwha Report, released as a draft for public review in September 1993 and submitted to Congress in January 1994, studied four alternatives: removing both dams, removing Elwha Dam and installing fish passage at Glines Canyon Dam, removing Glines Canyon Dam and installing fish passage at Elwha Dam, providing fish passage at both dams, and compared them to the no action alternative (retaining both dams without fish passage).

Two Environmental Impact Statements were also released. The Final Programmatic EIS, released in June 1995, concluded that removal of both dams was the only way to achieve full restoration of the Elwha River ecosystem and fisheries. The Final Implementation EIS, released in November 1996, studied sediment management and concluded that sediment accumulated within the two reservoirs should be allowed to erode downstream naturally.

A detailed timeline of the process is also available.

How long will it take to remove the dams?

Dam removal will begin in 2011 and is expected to last 2.5-3 years. The dam removal process is just one step in a multi-year plan for complete restoration of the Elwha River and ecosystem.

Elwha Dam powerhouse and surge tank as viewed from just north of the dam and Lake Aldwell.
The Elwha Dam, impounding Lake Aldwell.


How will the dams be removed?
An overview and animations of proposed removal plans for both Elwha Dam and Glines Canyon Dam can be found here. Different removal strategies will be used for each dam as they are removed simultaneously.

How much will the removal cost?

The $26.9 million dam removal contract was awarded to Barnard Construction of Bozeman, Mont. in August 2010.

The total cost of Elwha River Restoration is approximately $324.7 million, which includes purchase of the two dams and hydroelectric plants from their previous owner, construction of two water treatment plants and other facilities to protect water users, construction of flood protection facilities, a fish hatchery and a greenhouse to propagate native plants for revegetation.

Will any electricity be lost as a result of dam removal? Why get rid of dams that are making money and creating cheap energy?
The amount of electricity generated by the dams is minimal compared to both the region's needs and its power production capacity. The dams provide power equal to about one half the energy needs of just one local company, the Nippon Paper Industries mill. The mill is currently receiving all of its power from the City of Port Angeles via the regional electrical grid. The mill is currently seeking to construct a power facility at the mill that would exceed the amount of power the two dams produce on average.

Bald eagles in flight over forest
The return of salmon to the Elwha Valley ecosystem will benefit an array of lifeforms, from insects to eagles.


How will dam removal affect wildlife?
Revegetated areas will provide wildlife habitat, and the restoration of salmon will provide food and nutrients that the upper Elwha ecosystem has been deprived of for nearly a century. Pacific salmon die following reproduction, or spawning. As adult salmon return to their freshwater natal streams to spawn, they bring with them marine-derived nutrients including carbon, nitrogen and phosphorous. Decomposing salmon carcasses provide not only a food source for other fish and wildlife, but also "a gift from the sea" in the form of nutrients that link the marine and terrestrial ecosystems. Often referred to as a keystone species, salmon are known to benefit more than 100 other species.

Will any species be affected by loss of the Lake Aldwell and Lake Mills reservoirs as available habitats?
Yes. Migratory trumpeter swans (Cygnus buccinator) have used both reservoirs as feeding and resting habitat in the fdall and winter. The loss of this habitat has been addressed through the purchase of a 53-acre conservation easement in the Chehalis River Valley in Grays Harbor County, Washington that has been identified as important trumpeter swan habitat. The easement was acquired with funding from the National Park Foundation.

The Chehalis River Valley, located south of the Olympic Peninsula features wetlands and river channels which provide for secure night roosting. Every winter, between 300-600 trumpeter swans use parts of the valley, many reaching the area by migrating south through the Elwha River valley. More information can be found in the environmental impact statement.

What effect will construction, increased traffic and noise have on habitats and the species that use them?
Wildlife and fish may be impacted in the short term by dam removal activities including noise, traffic and high sediment flows. The long-term benefits of Elwha River Restoration—including the return of salmon, natural downstream sediment flow and an increase in upland forest habitat—will outweigh any temporary adverse impact.

lake mills delta aerial north
Aerial view of the Lake Mills delta.


What will happen to all the sediment once the dams are removed?
Approximately 13 million cubic yards of sediment have built up in the Lake Mills reservoir behind Glines Canyon Dam since 1927, while approximately five million cubic yards of sediment currently remain in the Lake Aldwell reservoir. Much of this sediment will be released in a slow, controlled manner.

To allow for a gradual release of sediment, plans call for a lowering of the water level in Lake Mills prior to the start of dam removal in 2011. A drawdown experiment was conducted in 1994, in which the reservoir was drawn down 18 feet over the course of one week, then allowed to remain stable for one week. As the water level dropped, the river began to cut into the existing delta, creating a deep and narrow channel. A new delta began to form at the new, lowered lake level and the river channel moved laterally along the existing delta. The test indicated that the gradual lowering of the water level would allow for efficient erosion and movement of the delta sediment load downstream.

Based on those findings, the water level in Lake Mills will be lowered in 2011 in preparation for dam removal. After the dam removal period (approximately two-and-a-half to three years), the river will begin to restore itself to natural conditions. Sediment transport will return to natural levels, resulting in restored and rejuvenated habitats downstream from the dams.

Will dam removal affect area beaches?
Yes. The two dams have blocked the river's natural sediment flow for nearly a century and over 18 million cubic yards of sediment now lie on the bottom of the two reservoirs. Removing the dams will reestablish the natural flow of sediment from the Olympic Mountains down to the Strait of San Juan de Fuca, restoring the estuary, beaches and shellfish beds along the mouth of the river.


Last updated: February 28, 2015

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