Elwha Watershed Information Resource

The Elwha River watershed is more than just a river and its tributaries--it also includes the ecosystems in and around the river and the fish and wildlife that use the river. All of these components are interconnected and problems in one area of the watershed can affect other areas significantly.

A volunteer back country ranger assists USGS scientists by sampling the algal communities growing on a piece of Elwha River cobble. Jeff Duda, U.S. Geological Survey

For over 90 years, the delicate balance of the watershed has been disrupted by two dams on the Elwha River, and many components have been affected. For example, the number of salmon in the river has declined significantly due to decreased habitat and increased water temperatures. This loss has been felt in many areas: by fisherman (sport, commercial, and tribal), by wildlife that have lost an important food source (salmon carcasses), and by ecosystems that benefited previously from marine-derived nutrients transported by salmon. As a result of the 1992 Elwha River Ecosystem and Fisheries Restoration Act, a major project is underway to remove the two dams and restore the watershed.

The Elwha dam removal and restoration project is one of the largest in U.S. history, and it provides a unique research opportunity. The watershed offers researchers nearly ideal study conditions, because over 80 percent of the watershed is protected in the Olympic National Park. Restoration efforts that succeed in the Elwha River watershed may be able to be applied successfully to other, less ideal watersheds.

However, before any restoration projects can be designed, it is essential to understand the current state of the Elwha River watershed. This baseline information will help researchers identify areas where restoration projects are needed. Additionally, researchers will be able to judge the effectiveness of restoration projects by comparing post dam removal observations against the pre dam removal baseline information. Researchers are currently working to identify and collect the necessary pre dam removal baseline information.

Learn more about the current state of the watershed and the ongoing research efforts by clicking on the links below:

Elwha Research Consortium: This group is dedicated to facilitating and coordinating a long-term program of research and education on the ecology and management of the Elwha River watershed.

Nearshore Consortium: This informal workgroup is dedicated to understanding and promoting the nearshore restoration associated with the Elwha dam removals.

Fisheries: Removing the dams is a critical component in restoring depleted fish populations in the Elwha River. Learn more about the fish in the river, including the current and historical status, the plan for restoring populations (post dam removal), and ongoing research efforts (including genetics studies).

Ecosystem: Many ecosystems in the watershed have been reduced or damaged by the Elwha dams. After the dams are removed, much of the area previously covered by the dams and reservoirs will be restored to its original condition. Learn more about the ecosystems in the Elwha River watershed, and find out about ongoing research efforts (for aquatic, riparian, terrestrial, nearshore, and wetlands habitats).

Water: Both the quality and quantity (that is, amount) of water in the Elwha River watershed are important to the people and wildlife that rely on that water. Dam removal is expected to affect the river water favorably in the long term; however, there may be short-term, adverse effects on the quality and quantity of the water.

Climate: Although removing the dams will decrease water temperatures in the river, climate change will also have a significant impact on the river.

Wildlife: Many species of wildlife live in the watershed. Dam removal will be beneficial to many of them (including northern spotted owls and other federally listed threatened species) because it will increase needed habitat. However, some wildlife (such as the trumpeter swan) that use the lake habitat provided by the reservoirs may be adversely affected by dam removal.

Research and Science Image Gallery: Efforts to establish baseline information about the state of the watershed (pre dam removal) are currently underway. Browse through this gallery to see some of the research efforts first hand.