68th Avenue NW Extension

Client: City of Stanwood

68th Avenue NW Extension 2017-05-30T12:39:40+00:00

Project Description

The City of Stanwood’s 68th Avenue NW Roadway Extension project was one of 28 projects in the greater Puget Sound area awarded a Federal Stimulus Grant under the American Recovery and Reinvestment Act of 2009.  RH2 designed a 36-foot-wide paved roadway connecting the 68th Avenue and 279th Street intersection with the 68th Avenue and 280th Street intersection, establishing a new through-corridor connecting the two previously dead-end sections of 68th Avenue NW. The new roadway was designed to meet Stanwood’s standards for a neighborhood collector and included improvements to illumination, sidewalks, landscaping, and storm drainage.

The roadway corridor runs adjacent to Cedarhome Elementary School. Working closely with Stanwood and the school, RH2 relocated and reoriented the school’s primary entrance to meet Stanwood intersection requirements and provide sufficient crosswalks and sidewalks. The project required the school’s north driveway to be relocated and aligned with 280th Street NW, providing a safe intersection orientation for children to cross. Several iterations of review and comment by Stanwood Camano School District personnel resulted in a preliminary design of roadway and sidewalk improvements within the school property that meet the school district’s requirements for bus, vehicular, and pedestrian movements.

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.

The project also included acquisition of a new right‑of-way for the entire length of the corridor. Permitting elements of the project included SEPA/NEPA compliance, City Critical Areas compliance, a Hydraulic Project Approval from the Washington Department of Fish and Wildlife, an Army Corps Section 404 permit, and a Department of Ecology Section 401 Water Quality Certification.  RH2 assisted Stanwood in obtaining these permits in order to establish a safe route for children at Cedarhome Elementary.