This project is assessing the capacity of a multi-functional water treatment feature to simultaneously reduce contamination and environmental degradation caused by stormwater runoff and provide high-quality public space. Initial plans were to test the prototype in Coupeville, located on Whidbey Island’s shellfish-rich Penn Cove. However, delays in construction have led to using an alternative location in Manchester, Kitsap County. The project will train residents and student researchers and deepen public understanding of shoreline and aquatic issues. If successful, this innovative design approach will help other coastal communities find ways to capture the economic, aesthetic, and environmental benefit of green shoreline infrastructure.
Washington Sea Grant-sponsored researchers are assessing waterfront GSI at Manchester Beach, Washington, where bioretention cells filled with Filterra soil media treat stormwater and a spiral raingarden treats lower base flows. The project sampled winter flows into and out of the system; state and county labs analyzed water quality in both. Researchers presented the park design directly to the public and in an online video.
Repeated testing found that the GSI system reduced dissolved metals in runoff by varying degrees and achieved dramatic reductions, ranging from 42 to 99 percent, in fecal coliform bacteria.