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Map of the Upper Snoqualmie River Knotweed Control Project

Project Overview

The noxious weed program began working to control knotweed on the upper forks of the Snoqualmie River in response to concerns from citizens, landowners and public agencies.  In 2005, the program began working first on the Middle Fork due to the high level of habitat value and relatively low levels of knotweed infestation as well as an active cooperative weed management effort in the Middle Fork Valley.  The program expanded the project to the much more heavily infestated South Fork starting in 2007, inspired in large part by the interest and active participation of landowners on the river. Starting in 2014, the program further expanded the project area to include the uppermost stretch of the mainstem of the Snoqualmie River from Three Forks Park to Snoqualmie Falls.

Current Project Area (download project map)

  • Upper Snoqualmie River - from the confluence at Three Forks Park down to the Snoqualmie Trail Bridge
  • Middle Fork Snoqualmie River - from the uppermost infestation a little above the Mount Si trailhead, up Roaring Creek, and down to the confluence  
  • South Fork Snoqualmie River - from the uppermost infestation at Ollalie State Park/Exit 42 of I-90 down to the confluence  

Follow the links below for more information and photos of the knotweed control projects on the Middle Fork and South Fork Snoqualmie Rivers.

Middle Fork Snoqualmie

Middle Fork Snoqualmie River - click for information on knotweed control project

South Fork Snoqualmie

South Fork Snoqualmie River - click for information on knotweed control project