Suquamish Culvert Fish Passage Analysis

The Suquamish Tribe engaged Tony to provide design and hydraulic review of two culvert projects and comment on fish passage issues and mitigation efforts. For the Provost culvert on Strawberry Creek, Tony reviewed the HEC-RAS modeling analysis, compared pre- and post-culvert replacement water levels to the locations of upstream mitigation plantings, and recommended restoration improvements. For the steep-gradient McDonald creek culvert, Tony determined the culvert design would increase the risk of downstream channel incision and bed mobilization that could compromise the planned downstream habitat improvement efforts. For both culverts, Tony evaluated the hydraulic feasibility of the WDFW’s stream simulation approach as an alternative to the proposed design, which would improve the creeks’ fish passage potential.

Services: Drainage Analysis, Stream Hydraulics