Rain garden built to help filter out polluted runoff

What some would see as just a portion of muddy lawn at City Park, Angie Flickinger saw as an opportunity to better the environment.

A couple years ago, Flickinger, who works on a part-time basis with the Southeast Alaska Watershed Coalition in Juneau, conducted a community watershed assessment to determine areas that would be ideal for a rain garden in Wrangell.

Rain gardens act as natural filtration for rainwater that empties into streams and other waterbodies.

"Basically, I went around on city and borough land, so I didn't do the whole island but kind of the city area," Flickinger said. "I cataloged streams, I looked at the state's catalog of anadromous fish streams and just walked and mapped them, looked at culverts, and assessed the state of the streams and waterways within the city."

Anadromous fish are those, like salmon, that swim upstream from saltwater to spawn. Playground Creek, which runs through City Park, is used by coho for spawning. Flickinger's assessment identified the area next to the creek as ideal for a rain garden.

"Previously, if you had come down here on a really rainy day or any day in the winter when it's been raining for months, you'd see that the rain accumulates, runs down the highway, then it would funnel right along this track," she said. That track runs from 1.5 Mile on Zimovia Highway, along the road to City Park, in front of the public restrooms and into Playground Creek, which drains into Zimovia Strait.

Runoff from the highway created a sort of ditch along the path, going into the stream.

"You would have all this sediment, all the junk from the highway, like you get oils and different pollutants, all kinds accumulate and dump into the stream," Flickinger said. "This seemed like easy, low-hanging fruit. Rain gardens are used to mitigate some of those stormwater issues."

A French drain was dug along the path down from the highway to funnel into the garden area, which is bowl-shaped to capture the water. A layer of drain rock is at the bottom, covered by topsoil, in which Flickinger is planting native vegetation. The garden will allow the water to filter down and enter the stream through groundwater.

Additionally, crushed rock was used to make a path from the road to the restrooms, so that Parks and Recreation trucks don't churn up soil or grass when they're trying to access the area for work.

Flickinger worked with the parks and recreation department to identify and eventually determine a location that would work for the garden.

"We are very pleased with the outcome of the rain garden project," said Kate Thomas, director of Parks and Recreation. "The practical application of a rain garden is perfect for that location with the runoff from the road, and the aesthetic improvement is fantastic."

Thomas said her department has been working incrementally to make improvements to all the areas they manage in the borough, and she believes the rain garden is a "great improvement to the site overall."

Grants from the state and Alaska Clean Water Advocacy funded the assessment and the design, materials and construction of the garden.

Flickinger is aware of similar projects throughout Southeast through the watershed coalition, one of which she oversaw in Juneau near the airport.

"They have a really big berm that we planted, and (we) installed a snow fence along Jordan Creek, which is super developed," she said. "That was meant to mitigate a lot of the snow that was being plowed right into the creek, where you get the same thing - all the crap you're digging up from the surface of the pavement."

As the native grasses and sedges that Flickinger planted in Wrangell continue to grow, she said she hopes it looks like a small wetland area. An educational sign will be put up to inform visitors about the purpose of the garden and how stormwater management impacts fisheries, and a cedar fence will be built to help people to walk around instead of through the spot.

Flickinger will conduct testing for turbidity and other parameters after the recent rains that have come through Wrangell. "We'll see what that looks like and if the rain garden is doing its thing. It's hard to tell, too, because we just planted it. It's got to settle in."

Controlled testing will be conducted in the stream above the garden and below it closer to the drainage area after the recent rains and again in the spring.

"It's such a visual project," Flickinger said. "Before we put it in, I'd come out here and there was a stream running across the lot. As long as that's not happening, we'll have a sense that it's working."