Broadview Green Grid Project

The Broadview Green Grid Project, involving 15 city blocks, manages stormwater flow from approximately 32 acres, and is almost an entire sub-basin of the Pipers Creek watershed. Seattle Public Utilities (SPU) partnered with Seattle Department of Transportation (SDOT) to provide neighborhood improvements as part of this project including integrating landscaping, calming traffic, and adding a sidewalk on each north-south street into the natural drainage system design.

Features and benefits of project 

Natural drainage features on the project include swales, stormwater cascades, small wetland ponds, larger landscaped areas and smaller paved areas. These features help reduce the quantity and speed of the runoff. This helps Pipers Creek by reducing the occurrence of large, fast flows of water that can damage the creek channel and habitat.

Slowing the water down also gives maximum opportunity for stormwater to infiltrate back into the soil and the water table, helping sustain the creek in the dry summer months.

Slower stormwater flows and infiltration improve water quality by preventing roadway pollutants and pesticides from being transported downstream into Pipers Creek and Puget Sound.

Location

The project area includes a "Cascade" system for N 107th St., from 4th Ave N. to Phinney Ave N, similar to the cascade constructed along N 110th St. in 2002.

Improvements similar to those of the "SEA Street" (Street Edge Alternatives) pilot project were constructed along Second and First Avenues Northwest, and along Palatine Ave N and Phinney Ave N, between N 107th St and N 110th St.

Construction Schedule

Construction began in late August 2003 and ended in the fall of 2004. Landscaping was completed in the spring of 2005.

Maintenance

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.