Protection and enhancement of riparian buffers in WRIA 7 through restoration and stewardship

The final report on a knotweed removal and native plant project from grant PO-00J08401 to King County DNR for the grant entitled: Protection and enhancement of the riparian buffers in WRIA 7 through restoration and stewardship.

Appendix 5. Map of Skykomish/Tye River Control Locations 2014
Appendix 5. Skykomish/Tye River Control Locations 2014

Project abstract

This project addressed fundamental processes that were degrading water and habitat quality in the Snoqualmie River system. Invasive knotweeds (Polygonum spp.) had extensively invaded the Snoqualmie/Skykomish watershed, threatening water and habitat quality through their ability to spread rapidly and displace native riparian buffer vegetation. Resulting losses in shade, erosion control and buffering potential of riparian corridors adversely impacted water quality. This project aimed to restore and maintain healthy riparian ecosystem functioning through a comprehensive replacement of invasive knotweed with native vegetation. Environmental benefits included: a) enhanced native plant communities; b) reduced water temperature by increasing shade along key reaches, c) improved water quality through enhanced hydrogeomorphological functioning of riparian buffers; d) improved microclimate, cover, resting and feeding opportunities for native fauna; and e) improved long–term community stewardship capacity for these riparian environments. A framework was developed for similar landscape-scale projects elsewhere in the Puget Sound Region. 

Download the full report