Case Studies of Fish Passage Improvement Projects in the Oregon Coast

Fish passage barriers constitute a significant limitation to native species, and in many cases barrier removal or replacement (e.g. increasing culvert size) is sufficient to address impacts to the aquatic biota.  Water diversions, either for drinking water, irrigation,  or aquaculture represent a unique class of barriers that cannot be easily removed, and whose structural modification is severely constrained by the services they  perform.  These structures are common throughout the Pacific Northwest and must be addressed as part of concerted watershed scale restoration efforts.  This presentation will cover strategies employed, planned, and proposed in the North Oregon Coast to modify these diversions with the goal of creating nature-like stream channels while maintaining their functionality.

Case studies of three planned and completed projects will be presented, including work in the Tillamook, Netarts, and Neskowin Watersheds. One of these case studies involves a water diversion on Fawcett Creek was identified as a barrier to fish passage in 2009. This diversion was prioritized at a basin level as critical for replacement and a new diversion was constructed to continue providing ponding for water withdraw and to allow for salmonid migration. This presentation will discuss the methods used for identifying priorities, the changes made to the structure, and the improvements with regards to fish passage that occurred as a result of these changes.