Elbow Coulee Floodplain Restoration

Phase 1:  Reopening an Historic Side Channel 

Before: A constructed levy prevented the river from flowing into an important side channel in the floodplain

The ultimate goal of this multi-year project is to reconnect the Elbow Coulee flood plain and use natural stream processes to improve Twisp River rearing habitat for spring Chinook salmon and steelhead trout. 

In the construction phase of the project, completed in October 2008, we built a rock sill with a low-flow notch in the levy.  This action will restore river access to a primary side channel during the high flows that occur from about mid-April to mid-July, while lowering flows in the main channel.  In doing so, we will have greatly improved fish habitat where little has existed for more than half a century. Constructing a notch in the levy will allow flows to enter the side channel during the spring

A wood barb made of recycled fallen trees from construction will create habitat when water flows into the side channel We carefully obtained onsite many of the necessary materials for construction, placing large boulders to form a low-flow notch and recycling fallen trees to create cover for fish when high water overtops the rock sill and flows into the side channel in the spring.

 

 

 

 

 

 

 


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 After: A new rock sill in the levy will allow flows into the side channel during spring high water