SR 167 Completion Project/Hylebos Riparian Restoration Program

Herrera assisted WSDOT in design and permitting of this project, which involves approximately 6 miles of new state highway (for State Route 167) amid a flat and wet landscape extending from the Tacoma tideflats to the City of Puyallup. Herrera prepared design plans for relocation and restoration of over 2 miles of Hylebos Creek and tributary streams, and wetland restoration within the creek’s enhanced floodplain (known as the Hylebos Riparian Restoration Program [RRP]) which will mitigate for stream channel impacts, increased highway runoff flows, floodplain capacity losses, and wetland impacts as a result of constructing the new highway. The Hylebos RRP represents an innovative and holistic approach to mitigating project impacts on streams and wetlands. Herrera biologists, engineers, geomorphologists, hydraulic modelers, landscape architects and permitting specialists collaborated in developing the design.

Herrera’s site assessment work that informed RRP design included delineating over 60 wetlands in the project area, stream surveys to characterize instream and riparian habitat conditions, geomorphic analysis of historical and current channel conditions and sediment transport and deposition, and comprehensive hydraulic modeling including analysis of future sea level rise potential in the downstream end of the project area. The RRP approach will effectively restore stream habitat and floodplain habitats and connectivity to achieve multiple objectives, offsetting the need for conventional stormwater flow control facilities in the new highway right of way and any need for offsite mitigation. Herrera staff led coordination of permit applications with the Puyallup Tribe of Indians and local, state, and federal agencies.