The Japanese Gulch Fish Passage Story
Presentation Abstract
The City of Mukilteo, Washington, needed to address fish passage and habitat restoration on Japanese Gulch Creek. This project was the first in-lieu-fee mitigation project authorized and processed by the Washington State Department of Fish and Wildlife. Funding was provided via an agreement with Snohomish County Airport, which had needs for habitat mitigation credits for development around the airport. The original concept of the project was to address fish passage in a concrete junction box between two culverts. Existing streamflow was spread over a concrete apron in a very thin layer that was a severe impediment to upstream adult fish passage. However, there were additional passage barriers upstream that would limit access to usable habitat should this initial barrier to passage be removed. The approach was based on an overall assessment of the conditions in the lower part of the watershed. This allowed the team to place the proposed project elements into context and to assess fish passage challenges in several locations in the lower creek as well as habitat conditions in the stream. The Confluence team developed a design using field engineered baffles and boulders to address the passage barrier in the junction box for a fraction of the initial cost projected by the City. This freed up project budget to address another upstream passage barrier in the form of a perched culvert. The team developed a conceptual design to move the stream from its existing heavily engineered channel (three concrete weirs and a concrete flume) back to its historical channel, thus bypassing three additional passage barriers and opening up more than twice the length of channel and habitat for future fish use. The original engineering estimate for the single junction box replacement was $650,000 and the Confluence team delivered a solution for four passage barriers and restoration of historical channel for $375,000. A future phase will daylight the creek and create a pocket estuary to enhance the connection between the creek and Puget Sound, thus providing juvenile fish habitat for salmonids and other species using the shoreline.
Session Title
Session S-08D: Salmon Recovery: Implementation and Progress I
Conference Track
Species and Food Webs
Conference Name
Salish Sea Ecosystem Conference (2014 : Seattle, Wash.)
Document Type
Event
Start Date
1-5-2014 5:00 PM
End Date
1-5-2014 6:30 PM
Location
Room 6C
Genre/Form
conference proceedings; presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Fishways--Washington (State)--Japanese Gulch Creek; Stream restoration--Washington (State)--Japanese Gulch Creek
Geographic Coverage
Salish Sea (B.C. and Wash.); Japanese Gulch Creek (Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
The Japanese Gulch Fish Passage Story
Room 6C
The City of Mukilteo, Washington, needed to address fish passage and habitat restoration on Japanese Gulch Creek. This project was the first in-lieu-fee mitigation project authorized and processed by the Washington State Department of Fish and Wildlife. Funding was provided via an agreement with Snohomish County Airport, which had needs for habitat mitigation credits for development around the airport. The original concept of the project was to address fish passage in a concrete junction box between two culverts. Existing streamflow was spread over a concrete apron in a very thin layer that was a severe impediment to upstream adult fish passage. However, there were additional passage barriers upstream that would limit access to usable habitat should this initial barrier to passage be removed. The approach was based on an overall assessment of the conditions in the lower part of the watershed. This allowed the team to place the proposed project elements into context and to assess fish passage challenges in several locations in the lower creek as well as habitat conditions in the stream. The Confluence team developed a design using field engineered baffles and boulders to address the passage barrier in the junction box for a fraction of the initial cost projected by the City. This freed up project budget to address another upstream passage barrier in the form of a perched culvert. The team developed a conceptual design to move the stream from its existing heavily engineered channel (three concrete weirs and a concrete flume) back to its historical channel, thus bypassing three additional passage barriers and opening up more than twice the length of channel and habitat for future fish use. The original engineering estimate for the single junction box replacement was $650,000 and the Confluence team delivered a solution for four passage barriers and restoration of historical channel for $375,000. A future phase will daylight the creek and create a pocket estuary to enhance the connection between the creek and Puget Sound, thus providing juvenile fish habitat for salmonids and other species using the shoreline.
