OCI was thrilled to partner with the City of Sammamish on this fish passage project where we managed the replacement of existing culverts under East Lake Sammamish Parkway (ELSP) that had caused barriers to kokanee salmon being able to spawn. The City of Sammamish, along with the Kokanee Work Group and Local Tribes, identified voluntary replacement of this fish passage barrier to support the goals established by the “Blueprint for the Restoration and Enhancement of Lake Sammamish Kokanee Tributaries,” a strategic plan of priority habitat restoration actions needed to move the native kokanee population closer to recovery. The successful replacement of the barrier now allows unimpeded access to over one mile of kokanee spawning habitat and restores natural sediment and flood transport processes to the watershed!
Several key elements to the project’s success included our long-standing partnership with the City of Sammamish, understanding their needs and goals on this project, and then putting our very best team forward to accomplish their objectives to deliver a successful project on time and on budget. It was imperative that we designed the new 14-FT wide by 9.4-FT rise precast box culvert to exact specifications in order to accommodate the placement of the existing sewer lines that penetrate the culvert walls. We transformed critical insight obtained from WSDOT into key project components by staying at the forefront of the evolving permitting agency and Tribal expectations, standards, and precedents being set by WSDOT’s projects through OCI’s recent and ongoing work developing WSDOT Fish Passage design. This not only helped us create a more permittable design, it was also more strategically aligned with the scope of the Brian Abbott Fish Barrier Removal Board Grant, for which we assisted the City (along with The Watershed Company) in preparing construction grant application materials, helping lead to successful construction funding. We also had to design a culvert that adhered to engineering design standards, but allowed to evolve over time as part of a bigger system.
OCI’s services encompassed designing the culvert replacement, developing preliminary engineering, alternatives analysis, performing hydraulic analysis using WDFW stream simulation, utility conflict resolution, coordinating acquisition of necessary permits from multiple authorities, assisting with the grant funding process and leading the review workshop, coordinating submittals such as a cultural assessment, biological evaluation, geotechnical investigation, and preparing final PS&E for construction. Completed summer 2021, it has been both exciting and rewarding to see kokanee move safely up stream!
