Note to Reader:
Kitsap County is located in the center of the Puget Sound, Washington State, and has many small- to medium-sized communities located along more than 200 miles of marine shoreline. Kitsap’s shoreline and maritime context has created a special identity for the people living there and a strong connection to the surrounding environment.
One of these communities is Manchester, a small village of about 5,000 people that sits on the east-facing slope of a steep hill that rises 400 feet above the Puget Sound. The “downtown” commercial core of the community lies at the foot of this slope along the shoreline.
Manchester’s Stormwater Park: Retrofits to help the Puget Sound’s water quality
“The Manchester Stormwater Retrofit Project in Kitsap County will provide water quality treatment of stormwater for approximately 100 acres of the Manchester community. The goal of this project is to improve water in Puget Sound. Initially, the project was designed to replace an aging and undersized outfall. However, the County recognized a unique opportunity to remove stormwater pollutants. This park is Kitsap County’s first stormwater park,” wrote Chris May and his co-authors in an article published in the May 2016 issue of Stormwater Magazine.
Chris May js the Surface & Stormwater Division Director with Kitsap County Public Works.
“In 2012, as part of a countywide effort to identify and prioritize potential stormwater retrofit projects, KCPW initiated the Manchester Community Stormwater Retrofit Plan study.”
Kitsap County goal is “Integrated Solutions”
“The environmental impacts for population increase and resultant urbanization led Kitsap County Public Works (KCPW) to develop integrated solutions to manage stormwater runoff. One of the main components of the overall stormwater management strategy is the use of green stormwater solutions (GSS) in retrofitting existing development.”
“This project came about because an aging and undersized stormwater outfall pipe in Manchester needed to be replaced. Kitsap County took a holistic approach to the problem, and rather than just replace the outfall, sought a solution to address stormwater issues upland, improve water quality, alleviate flooding, and create a park for the community.”
Spiral Rain Garden is the Focal Point
“A spiral rain garden is the focal point of the park. Water that typically flows off the hillside is collected and treated through this facility. Then every half-hour, one cell of the three-cell spiral walls releases its water charge through rocks located on the sides of the figure. It then filters the water through the spiral, putting clean water back in to Puget Sound,” explained Andrew Nelson, Kitsap County Director of Public Works, in an interview on the day in November 2015 when the project was completed,
“By using a bio-retention soil mix for the plants that are in there, that spiral rain garden filters and treats the sediment that’s in the water as well as pollutants such as chemicals, oils and fuels that come out of our cars — and even pet waste that’s on the hillside.”
Stormwater Park Design
“The community voiced their desire for a ‘context-sensitive’ natural design that fit with the surrounding community’s character and took advantage of the Puget Sound views. An open-space ‘gathering’ area was also of high interest to the community that would connect to and complement the existing waterfront Pomeroy Park.”
“Education about stormwater, the Puget Sound, and how everyone can help improve environmental quality were also important messages the community wanted incorporated in interpretive signage for the stormwater facility.”
“Located on a site that once housed a gas station, the new park has enhanced the downtown area. It is now a public gathering space for the small community of Manchester.”
“It is not only a pleasant community space but also a workhorse to clean polluted stormwater runoff from roads, parking lots, commercial property, and residential areas using green stormwater solutions.”
To Learn More:
Read Manchester’s Stormwater Park: Retrofits to help the Puget Sound’s water quality for the complete story as published in the May 2016 issue of Stormwater Magazine.