In 1998, one clump of the invasive knotweed (Polygonum cuspidatum s. lat.) was observed at the edge of the river's channel migration zone (CMZ) at river mile (RM) 29.75. In the winter of 1999 or 2000, this one plant was transported downstream during a winter storm event, giving rise to a population of knotweed that rapidly became widely distributed within the Hoh River CMZ to the river's mouth. Recognizing the potential threat to critical habitats, the Hoh Tribe initiated a restoration project in 2002, beginning the comprehensive river surveys, control, and effectiveness monitoring activities that continue today as a partnership between the non-profit 10,000 Years Institute, Hoh Tribe, Hoh River Trust, private landowners, Olympic National Park, and the U.S. Forest Service.