Knotweed Control & Restoration in the Stilly

Salmonid Habitat Restoration and Acquisition

Riparian Habitat
Project ID19-1151 R
Recovery DomainsPuget Sound
Start Date12/12/2019
End Date12/31/2023
Year2020
StatusOngoing
Last Edited04/19/2022
 
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Description    


Snohomish County proposes to restore riparian habitat by continuing knotweed control in first and second priority restoration areas along the SF and NF of the Stillaguamish River. The project goals include accelerate the natural recruitment and re-introduce native conifers along the South Fork Stillaguamish, and on the North Fork from the Oso slide and downstream by reducing knotweed infestations to a level where knotweed does not present an environmental threat.

Approximately 40 acres per year will be controlled. A total of 120 acres of knotweed on 42 river miles (does not count retreatment) will be controlled between Oso and Arlington. Knotweed control will be followed by conifer planting as needed. Knotweed control will open up understory areas allowing for five acres to be planted with 3,000 conifers. Approximately 0.5 river miles will be replanted providing a seed source for natural recruitment along with providing shade and large wood.

Knotweed degrades salmon habitat by reducing instream cover and food supply, elevating water temperature, and reducing future large woody debris recruitment. Knotweed stops juvenile tree development. If left untreated, in 50 to 100 years, there would be few trees in riparian areas forested by successional hardwoods. Knotweed control allows fishermen and other recreationists to reach the river and increased salmon runs of all species since cool water and stream complexity benefits all of the salmonid species and fishing. This project benefits Coho, Chinook, and Steelhead.
Project was partially funded for $40,000 in the 2019 grant round and fully funded in the 2020 grant round with the remaining $160,000. Project scope and metrics did not change. Match increased to 15% as appropriate for current funding level of $200,000.

Project Benefit    


Knotweed control on 42 river miles (does not count retreatment) between Oso and Arlington. Knotweed control will be followed by conifer planting as needed. Knotweed control will open up understory areas allowing for five acres to be planted with 3,000 conifers. This project benefits Coho, Chinook, Chum, and Cutthroat.

Accomplishments

Metric Completed Originally
Proposed
Riparian Habitat
  Stream Miles Treated 42.00
  Acres Treated 120.0

Funding Details

SourceFunds
PCSRF$200,000
Other$3,530
In-Kind Other$15,029
Report Total:$218,559


Project Map



Worksites

1-North and South Fork Stilla    


  • Worksite Identifier: 1-North and South Fork Stilla
  • Start Date:
  • End Date:
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Puget Sound
  • Subbasin:
  • Watershed:
  • Subwatershed:
  • State: Washington
  • Recovery Domain: Puget Sound
  • Latitude: 48.2748525
  • Longitude: -121.85304947

ESU

  • Puget Sound/Strait of Georgia Coho Salmon ESU
  • Puget Sound Steelhead DPS
  • Puget Sound Chinook Salmon ESU

Map

Photos

Metrics

Metrics
  • C.0 Salmonid Habitat Restoration and AcquisitionY (Y/N)
    •      . . C.0.a Habitat restoration and acquisition funding
    •      . . C.0.b Length of stream treated/protected
    •      . . C.0.c
      Project identified in a Plan or Watershed Assessment
    •      . . C.0.d.1 Project Monitoring (LOV)
    •      . . C.0.d.2 Monitoring Location (LOV)
    •      . . C.5 Riparian Habitat ProjectY (Y/N)
      •      . . . . C.5.a Riparian Habitat Funding
      •      . . . . C.5.b.1 Total riparian miles streambank treated
      •      . . . . C.5.b.2 Total Riparian Acres Treated
      •      . . . . C.5.c.1 Riparian plantingY (Y/N)
        •      . . . . . . C.5.c.2
          Species of plants planted in riparian
        •      . . . . . . C.5.c.3 Acres planted in riparian
        •      . . . . . . C.5.c.4 Miles of streambank treated with riparian planting
      •      . . . . C.5.h.1 Riparian plant removal/controlY (Y/N)
        •      . . . . . . C.5.h.2
          Species of plants treated/removed in riparian
        •      . . . . . . C.5.h.3 Acres of riparian treated for plant removal/control
        •      . . . . . . C.5.h.4 Miles of streambank treated for riparian plant removal/control