Willapa Hills Trail Bridges Lewis County, Washington
After being washed out during an extreme weather event, replacements for the Dryad and Spooner bridges were needed for the two lone Chehalis River crossings on the Willapa Hills Trail, while a dangerous intersection would be eliminated with the addition of the Littell bridge. Together, all three structures provide safer, accessible, and more complete crossings as part of the local trail system in this Washington State Park.
Replacing Structures to Create Safe Trail Crossings
During the weather event that compromised the existing structures, floodwaters swept the truss spans downstream and removed most, if not all of the approach span structure. The resulting bridge debris removal occurred two years later. The Dryad and Spooner bridge structures are single span 300-foot-long post-tensioned steel trusses with precast concrete deck panels. Adding the Littell bridge near the Adna trailhead provides users a safe overhead crossing over SR 6. Previously trail-goers had to cross the road to continue their journey along the 56-mile Willapa Hills Trail that connects Chehalis in Lewis County with South Bend in Pacific County. Otak designed the replacement structures for each crossing, as well as provided information on baseline river, geomorphic, and riparian habitat conditions and facilitated the permitting processes necessary for the project. This included SEPA documentation and compliance, impacts analysis, and aquatic permitting applications and support documentation (HPA, Lewis County critical areas compliance, etc.).