Elbow Coulee Floodplain Restoration


Elbow Coulee Floodplain Restoration

Project Location:  Twisp River

Landowners:  Private, Washington Department of Fish and Wildlife, US Forest Service

Species Benefitted: Spring Chinook Salmon, Steelhead Trout

Project Status: 

  Phase 1
 
  • Construction completed October 2008
  •   Phase 2
     
  • Site restoration scheduled for Spring, 2009
  •   Phase 4
     
  • Monitoring and adaptive management will take place through 2012

  • Funding: Bonneville Power Administration

    Partners:
    • Bureau of Reclamation (Technical Assistance and Design)
    • US Forest Service  (Technical Assistance and Permitting)
    • Washington Department of Fish and Wildlife (Project Development and Construction Oversight)

    Project Description:

    The Elbow Coulee floodplain and project site lie on the north side of the Twisp River approximately 5 miles west of Twisp, Washington.  The floodplain contains a complex of beaver ponds and three historic side channels.  

     

    The Twisp River at the Elbow Coulee Floodplain project site

    In the decades following the historic 1948 flood, a manmade earth and boulder levy confined the Twisp River and separated it from two of the side channels in the Elbow Coulee floodplain.  This resulted in the loss of steelhead spawning habitat and rearing habitat for juvenile steelhead and spring Chinook salmon. The increased river velocities that resulted from confining the river’s energy into its main channel seriously limited fish spawning and rearing, which require slower flows. Furthermore, the resulting higher water velocities altered fish habitats by scouring spawning gravels, uprooting smaller plants, and flushing nutrients that, in an unconfined river, would support these endangered species.

     

     

    Post-1948 levy constructed at the head of an historic side channel in the Elbow Coulee floodplainWhen the Elbow Coulee levee was identified by biologists as an impediment to salmon recovery in the Twisp River, MSRF partnered with the US Forest Service and Washington Department of Fish and Wildlife to develop the Elbow Coulee Floodplain Restoration Project. Our goal was to improve the habitat available to endangered salmon and steelhead in this part of the Twisp River. 

    MSRF’s strategy for this multiyear project is to minimize the impact of construction while providing the greatest benefit to fish.  To accomplish this, the project began in 2008 with a small amount of construction to lower a section of the existing levy to reopen a historic side channel to spring high flows.  In 2009, MSRF and its partners will replant the disturbed areas and monitor the results of the construction.  If necessary, future work will further improve the site and address needs as they arise.






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