Friday Harbor Town Council gives green light for pollution-filtering rain gardens on Spring Street
August 6, 2010 · 10:17 AM
The Friday Harbor Town Council gave the green light Thursday for the San Juan County Marine Resources Committee's proposed rain gardens on Spring Street, designed to filter stormwater before it reaches the harbor.
Development of the gardens is expected to begin in October, MRC member Johannes Krieger said. The project is being funded by a $35,000 grant from the state Department of Ecology and must be completed by June 2011. Susan Key, a hydrologist and Friday Harbor resident, said an additional $5,000 may be available in another grant.
Specifically, two rain gardens will be placed at First and Spring streets — on the corner of Herb’s Tavern and Coldwell Banker — and a tree well will be installed at Spring and Front streets. The project engineer is 2020 Engineering, a sustainable civil engineering company. 2020 is also the project engineer for the Sun Rise neighborhood being developed by the San Juan Community Home Trust. 2020 also did engineering work for Roche Harbor Village.
The gardens would be installed in place of pedestrian bulbs proposed on those corners, would not eliminate any parking spaces, and would be maintained by volunteers.
Krieger had presented the rain garden proposal to the council in July, and returned Thursday to satisfy council members' concerns about project costs and long-term maintenance. Mayor Carrie Lacher said she walked the sites with Krieger and was satisfied there would be no impact on parking.
Tests conducted by marine biologist Mike Kaill, who manages the Spring Street Landing Aquarium, detected a high level of surfactants in the aquarium after several long-lived aquarium animals died. The aquarium gets its water from the harbor.
The town has worked to identify surfactant sources, locating incorrectly plumbed sinks on Spring Street and advising businesses to not dump mop buckets into gutters. Kaill later tested oil that had accumulated on downtown parking spaces, and found them to contain surfactants as well.
According to Banyon Tree Design Studios, architect for a “deep-green” neighborhood on Bothell’s North Creek and designer of the Spring Street rain gardens, the rain gardens would capture at least 96 percent of total suspended solids, oil, grease and heavy metals from the street, as well as slow flows during large storm events.
“Even if we got 70 percent, it would be an improvement,” Krieger said at a council meeting in July.
A rain garden is a planted depression that allows rainwater runoff from impervious surfaces, like streets, to be absorbed. The water is filtered naturally, and then drains into the stormwater system.