information from King County

King County’s inventive use of green infrastructure to keep polluted runoff out of Puget Sound earned honors from the Seattle chapter of the American Society of Civil Engineers. The organization recognized King County’s Barton Combined Sewer Overflow (CSO) Control Project as a 2017 Local Outstanding Civil Engineering Achievement in the water resources category.

The project entailed construction of 91 roadside rain gardens within a 15-block span of West Seattle’s Sunrise Heights and Westwood neighborhoods. The engineered rain gardens combine natural vegetation and technical design to control stormwater that used to enter the combined sewer system and cause overflows into Puget Sound near the Barton Pump Station during heavy rains.

Seattle-based firm SvR Design Company led the project design and engineering. Goodfellow Bros. Inc., led the construction. The project was successfully completed in 2015.

King County proceeded with the project after studies determined the neighborhoods’ topography, soil conditions and location within the service area were well-suited for green infrastructure. Like traditional gray infrastructure, the roadside rain gardens are inspected and maintained to ensure they function as designed and comply with regulatory requirements.

King County’s Wastewater Treatment Division is among many clean-water utilities nationwide that are exploring opportunities to include green infrastructure in long-term plans to control combined sewer overflows, reduce pollution, and improve water quality.

In additional to planned green infrastructure projects, King County has partnered with the City of Seattle on the RainWise Program, which offers rebates to voluntarily install rain gardens or cisterns on private property in neighborhood that are part of the combined sewer system.

More information about the Barton CSO Control project is online.