Elwha Watershed Information Resource

As part of the Elwha River Watershed restoration, the two dams on the river will be removed and various restoration projects will be carried out to try to return the watershed to its pre dam condition. River restoration projects fall into two major categories: revegetation and engineered log jams.

Elwha River channel with woody debris. Gary Thayer, National Park Service

Revegetation projects will help restore native plants to the areas around the dams. Currently, the dams and their reservoirs cover about 715 acres of land that was covered historically with native plants. After the dams are removed and the reservoirs are drained, 684 of those acres will be exposed and available for replanting.

In addition to blocking the passage of salmon upriver, the dams block downriver transport of large woody debris (trees, branches, and root wads). In healthy rivers and streams, large woody debris accumulates naturally and provides habitat for fish. The depletion of this debris from the lower Elwha River has resulted in limited spawning and rearing habitat for salmon. In an effort to restore large woody debris (pre dam removal), engineers and biologists have constructed man-made versions of these debris collections called engineered log jams.

Learn more about the Elwha River restoration by clicking on the links below:

Revegetation: Restoration projects will focus on replanting the land behind the dams with native plants and preventing non-native plants from growing there. Ongoing research studies consider seedbanks, sediments, seed transport, invasive species, and methods for revegetation.

Engineered Log Jams: Since 1999, more than 20 engineered log jams have been installed in the Lower Elwha River to restore critical salmon habitat.