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The Center for Sustainable Infrastructure Blog

Kitsap County Combines Innovative Stormwater Infrastructure with Beautiful New Community Gathering Space

August 7th, 2016 · No Comments · Water

Check out this amazing video featuring the time-lapse construction process for a Puget Sound community’s innovative new stormwater park! The park features an eye-catching spiral “nautilus” design, 4 interconnected green stormwater solution (GSS) treatment cells, and 18 distribution channels to uniformly distribute incoming water to the 4 cells. The GSS cells are made up of engineered treatment material as well as a mix of extremely rain-tolerant plants. The proprietary filtration media working in combination with these plants should keep the park functioning for many years before media replacement will be necessary.

Urban stormwater runoff is a major source of pollution affecting sensitive aquatic ecosystems in Western Washington. Puget Sound Partnership (PSP), a regional agency that coordinates local water quality restoration projects has identified urban stormwater as one of the top priorities in our region that needs to be addressed. Washington’s Department of Ecology recently implemented new stormwater management regulations under the National Pollutant Discharge Elimination System (NPDES) permit. These regulations focus on low-impact development (LID) and green stormwater infrastructure.

Since these regulations focus mostly on new development, they do not address issues with already built infrastructure. Through retrofitting it is possible to implement flow-control and water treatment measures within the footprint of an already developed space. Retrofitting can be more expensive than building new stormwater infrastructure, so it requires high levels of engineering expertise and a willingness to experiment with new techniques.

Many communities in Western Washington have very limited existing stormwater infrastructure. Manchester in Kitsap County, founded in the early to mid 1800s, is one such example. In 2012 Kitsap County Public Works identified downtown Manchester as a good candidate for retrofitting during a countywide effort to identify and prioritize potential projects. A wide range of options were explored, with the top three highest-ranking sites all associated with the Main Street-Colchester drainage basin that empties directly into Puget Sound.

The goal of the project was to be in full compliance with stormwater water-quality treatment standards with regard to total suspended solids, metals, PAHs, and etc. 91% of pollutants must be removed in order to fully comply with Dept. of Ecology regulations.

Throughout the technical design and development process, the project team met with members of the Manchester community to solicit public feedback. Community members expressed interest in a design that fit with the local character and showcased views of Puget Sound. A “gathering” area that complemented an existing nearby park and included educational material about stormwater and the Sound’s ecology was of particular interest to many people.

Funding for this project came from Kitsap County as well as a $1,000,000 grant from Washington’s Department of Ecology. To learn more about the innovative design of Manchester’s Stormwater Park, watch the above video or visit Kitsap County’s website for additional resources.*

*Follow the link to Kitsap County’s website and look under “Additional Information” to access the May 2016 issue of  Stormwater: The Journal for Surface Water Quality Professionals ( You will find an excellent article that provides many additional details about this project. Information for this blog post was sourced from that article.


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