Street Edge Alternatives


Seattle's pilot Street Edge Alternatives Project (SEA Streets) was completed in the spring of 2001. It is designed to provide drainage that more closely mimics the natural landscape prior to development than traditional piped systems.

To accomplish this, we reduced impervious surfaces to 11 percent less than a traditional street, provided surface detention in swales, and added over 100 evergreen trees and 1100 shrubs.

Two years of monitoring show that SEA Street has reduced the total volume of stormwater leaving the street by 99 percent.


The project is located on 2nd Ave NW, between NW 117th and 120th Streets. 
View vicinity map (pdf).

Community Benefits

Learn more about how the SEA Streets project benefited the community:


The bioretention cells in the project are maintained by SPU Operations and Maintenance to ensure stormwater functionality at a service level B. Residents are welcome to provide additional maintenance to improve curb aesthetics.

Project Resources