68th Ave NW Reconstruction

The City of Stanwood proposed to extend an existing local collector, 68th Avenue NW to improve access to new residential developments and Cedarhome Elementary School. The existing roadway bisects a Category III depressional wetland and associated Type 5 stream. The improvements were designed to avoid and minimize impacts to these areas; however, fill of wetland and wetland buffer habitat and piping of additional Type Ns stream channel was necessary. Mitigation involving reestablishment and enhancement of existing critical areas was proposed to compensate for permanent sensitive areas impacts.

Wetland and stream habitat was delineated and characterized as palustrine emergent wetland by RH2’s Environmental Group. The mitigation concept developed in coordination with Washington Department of Fish and Wildlife, the US Army Corps of Engineers, and the Department of Ecology included removal of invasive vegetation and habitat enhancement. Mitigation was completed at a 2:1 ratio, resulting in reestablishment of 0.12 acres of wetland and enhancement of 0.7 acres of wetland and wetland buffer. Grading of the northern wetland piece expanded the hydrologic storage capacity and water quality functions of the wetland unit. Interpretive signage and permanent fencing help protect the wetland from human disturbance and teach students at adjacent Cedarhome Elementary about the importance of urban wetlands.

Depressional Wetland Habitat Northwest of 68th Avenue Roadway

Proposed Mitigation Design Southwest of 68th Avenue Roadway