Aug 03, 2015

Seattle Releases Green Storm Water Pollution Reduction Strategy

The strategy sets course to manage 400 million gal of storm water runoff annually by 2020

Seattle green stormwater pollution reduction

Polluted storm water runoff is the leading water quality threat to Puget Sound, and Seattle Mayor Ed Murray released a draft citywide Green Stormwater Infrastructure Strategy, outlining plans to accelerate green approaches for preventing this type of water pollution.

“Green storm water infrastructure is a valuable tool for us, because it helps us prevent storm water pollution and greens our neighborhoods at the same time,” Murray said. “This win-win combination is critically important.”

Rainfall rushing off hard surfaces like roads and parking lots can overwhelm the piped drainage system and cause back-ups and combined sewer overflows. The runoff also carries pollution directly into creeks, lakes and other waterways. Green storm water infrastructure (GSI) prevents overflows and pollution much like a forest would – by slowing and cleaning the water, and either reusing it or allowing it to soak back through the soil. Examples of GSI include roadside bioretention swales and street trees that manage street runoff; raingardens and cisterns that manage roof runoff; and green roofs and permeable pavement that are self-managing.

In 2013, Seattle City Council Resolution 31459 challenged Seattle to rely on GSI to manage storm water runoff wherever possible and set an aggressive target to manage 700 million gal of storm water runoff annually with GSI by the year 2025 – a seven fold increase over Seattle’s 2012 baseline.

The draft strategy sets an interim goal of managing 400 million gallons of storm water runoff annually with GSI by the year 2020, summarizes progress to date, outlines a set of strategies and planned investments for accelerating the adoption of GSI in Seattle, and articulates a two-year work plan for city of Seattle departments.

The most significant increases are expected from projects led and funded by Seattle Public Utilities and King County Wastewater Treatment Div., voluntary retrofits on private property, and projects required by Stormwater Code. The Strategy also emphasizes promising opportunities for new partnerships to protect Seattle’s creeks, prevent combined sewer overflows into Puget Sound, and develop integrated transportation projects.

“Whether it’s a homeowner installing a rain garden, or a commercial property with a green roof and rain-absorbing pavement, there are steps we can all take to prevent polluted runoff and give Puget Sound a break,” said King County Executive Dow Constantine.

“While natural drainage approaches have been central to our work for nearly 15 years, this strategy guides us in redoubling our efforts to accelerate adoption,” said Ray Hoffman, director of Seattle Public Utilities. “For us, this means building innovative partnerships with sister agencies, community organizations, and project developers, and supporting Seattle residents’ efforts to manage their storm water on site.”

The draft five-year GSI Implementation Strategy is available for public comment through Aug. 26.