The City of Shoreline, WA is undertaking some massive public works projects, including a renovation of the Aurora Corridor. This project covers redesign and redevelopment of three miles of Aurora Avenue North that are a part of Shoreline.
Otak, the design firm for the project, created a sidewalk tree median that is a rain garden. They specified the Silva Cell in order to ensure the trees in the median got the required soil volumes and to create additional space for the rain garden soil mix to extend under the sidewalk (which is topped with permeable pavers). By using this technique they were able to increase the soil volume for tree growth and enlarge the natural storm water treatment area for the water. The tree medians are similar to tree lawns, but rather than turf they containnative plants and grasses in addition to Maples, Ginkos, Ash, Pear and Dogwood trees that will be planted.
In addition to the permeable pavers, curb cuts allow stormwater to come in off the street and in to the rain garden (it is filtered through a catch basin first). The trees planted will each have access to about 500 cubic feet (close to 600 – 750 cubic feet with soil sharing).
The beginning of the excavation along Aurora Avenue:
Silva Cells go in:
Hopefully we’ll have some finished images of the site before too long.
Thanks, Otak, for these photos!