CROWN STREET Sustainable Streetscapes and Fish Habitat Enhancement Project

Building on the success of the award-winning Country Lanes project, the City of Vancouver has undertaken an exciting new approach to residential street design and stormwater management. Vancouver’s Crown Street has thus become the city’s first Sustainable Streetscape. The design of this street uses innovative ideas to integrate transportation into an environmentally sensitive setting. Located in the Southlands Community of Vancouver, the 5900-6200 blocks of Crown Street had a badly deteriorated road surface compounded by soft shoulder conditions. The local watershed contributes stormwater runoff to Musqueam and Cutthroat Creeks, two of the last salmon bearing streams in Vancouver. To date, the creek’s viability as salmon habitat has been precarious, prompting the Musqueam First Nation, David Suzuki Foundation and Musqueam Ecosystem Conservation Society to undertake projects to preserve and restore these salmon bearing streams. Given the sensitive setting of the street, the City understood that the old gutterless asphalt road could not be replaced with the standard residential street design. City of Vancouver’s Engineering Services responded to this challenge with an innovative design that would fit the overall character of the community, beautify the street, and nuture the salmon habitat of the adjacent streams. The Crown Street design features a narrow, meandering roadway flanked by vegetated swales and retention ponds. The road width was reduced from the standard 8.5m to 6.7m and is composed of 3.5m of asphalt flanked by 1m concrete bands and 0.6m of structurally reinforced grass on each side. The structural grass serves to separate the road surface from the swales and sidewalks, and also provides permeable parallel parking. A meandering street alignment provides traffic calming by breaking long sightlines. Stormwater runoff is facilitated by a network of swales and retention ponds. The swales are layered with 30cm of absorbent soil and vegetated with grasses and native plants. Pollutants are filtered by the vegetation and rainwater runoff infiltrates naturally into the ground. The system is designed for a 10-year storm, with overflow directed into a detention pond constructed in the adjacent park. As a result, the salmon-bearing streams are protected from rain-induced volume surges and the rainwater is filtered naturally versus the roadway runoff being directly discharged into the streams. Water quality and infiltration volume is being monitored in partnership with the University of British Columbia. Over the next five years, data will be collected and compared to a neighbourhood street which utilizes standard curb-and-gutter drainage. In 2006, Engineering Services will prepare a formal summary report for Vancouver City Council to review the potential for future residential street improvement options to be influenced by the Crown Street design.