The San Juan County Marine Resources Committee is proposing two rain gardens at First and Spring streets – on the corner of Herb’s Tavern and Coldwell Banker — and a tree well at Spring and Front streets to filter stormwater before it reaches the harbor.

MRC member Johannes Krieger presented the idea to the Town Council on July 15. He said the project would be paid for with a grant from the state Department of Ecology.

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.

Council members Steve Hushebeck and Noel Monin expressed interest in the project, but said they wanted a Plan B for garden maintenance if the plan to use volunteers falls through. Hushebeck was also concerned about the ongoing maintenance cost; Krieger said the gardens will be low-maintenance, but Hushebeck proposed a maintenance reserve fund be established with a portion of the grant.

Krieger is expected to report back to the council with responses to members’ concerns on Aug. 5.

Mayor Carrie Lacher questioned the “citizen science” that stormwater from town streets is contributing to pollution in the harbor. She questioned how effective a rain garden would be, and whether it would impinge traffic flow.

Tests conducted by marine biologist Mike Kaill, who manages the Spring Street Landing Aquarium, determined a high level of surfactants in the aquarium after several long-lived aquarium animals died. The aquarium gets its water from the harbor below.

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.

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.

Lacher later apologized for her harsh tone. “I just want it done well and done right, and to not be ugly in the long run.”

Councilman Felix Menjivar said he was “very impressed” by the proposal. “It will not cost us money or parking and will enhance the look of that area.”