Knotweed elimination is an important factor in preserving habitat for fish species. It is also important for elk and deer and other species that forage on the floodplain, where knotweed is out-competing native vegetation.

Although the Quillayute has the largest drainage area on the Peninsula (629 square miles) it is only 5 1/2 miles long and approximately half its length is in the coastal strip of the Olympic National Park.

In 2008 the Quileute Tribe treated knotweed on the Quillayute River for the first time. Most treatments were done in response to landowner requests but some were on land owned by the Tribe.

In 2009 the CCNWCB crew spent approximately 3 days treating knotweed on the Quillayute, at and around the Quillayute River Park, owned by Clallam County.

In 2010 the Quileutes did no work on the Quillayute River but they have funding for two more years of knotweed treatments and intend to continue work on the Quillayute River in 2011. The North Cascades Exotic Plant Management Team with the National Park Service treated 0.94 acres of knotweed on both the Quillayute and the Dickey, within the Olympic National Park.