Herrera worked with the Snoqualmie Indian Tribe to design and install two floating wetlands in a large stormwater pond at the Snoqualmie Casino. The stormwater pond treats casino property runoff and discharges into Coal Creek, a salmon-bearing tributary of the Snoqualmie River. Due to the large, exposed surface area of the stormwater pond, water temperatures tend to climb during warm weather. The installation of floating wetlands is designed to shade some of this area and cool the pond discharge waters, improving water quality for migrating salmon in the stream.
The wetlands are planted with a mix of native shrubs and herbaceous species, such as twinberry (Lonicera involucrata), Sitka willow (Salix sitchensis), red osier dogwood (Cornus sericea), tule (Schoenoplectus acutus), and Pacific silverweed (Potentilla anserina). These plants will establish roots that grow into the water below the floating wetlands, on which a biofilm will develop. This biofilm is composed of microorganisms which uptake excess nutrients in the water, also contributing to improved water quality. These plants will provide habitat for wildlife above the water surface, improving a valuable habitat patch on the developed property.
On a sunny Saturday in November, a team of Herrerans joined volunteers organized by the Snoqualmie Indian Tribe to install the floating wetlands. We were thrilled to be a part of such a large volunteer event directly tied to improving wildlife habitat and water quality in our region.
We look forward to sharing more of our innovative water quality work in the coming months!
Contributors: Eliza Spear, Rob Zisette
