Two bioswales will go in the top two corners of Fort Seward this fall to help filter pollutants out of snowmelt. (Jillian Rogers)
Each winter, snow is piled up in the Fort Seward parade grounds from nearby roads. Pollutants scooped up with the snow eventually land in the storm drains and then flows into Portage Cove. Last week, Takshanuk Watershed Council unveiled its new plan for alleviating some of that runoff with a new bioswale project.
So, first of all, what is a bioswale?
“Basically, it’s this depression that has different layers,” says Takshanuk executive director Meredith Pochardt. She led an informal, informational session on Friday morning for about a dozen interested residents.
“The bottom layer will be drain rock, and then it will have some planting soil, and then this one will have mulch or bark, so that it doesn’t have be mowed,” she told the group. “We’ll have other plants within there, some other flowering plants, like a rose … something that looks pretty and is attractive.”
So, basically, bioswale is a fancy word for a filtration ditch. Runoff and snowmelt gets channeled into the bioswale, and then travels through the layers, cleaning the water that eventually ends up in the water table. Once covered with perennials, the system is inconspicuous, low-maintenance, and effective.
The project stems from a $10,000 snow removal grant awarded to the council a couple of years ago from the Alaska Department of Environmental Conservation. The goal with this money is to create two bioswales, and a snow storage area in the top two corners of the parade grounds this fall. The project will take up about 4,000 square feet of space on each corner of the privately-owned land.
“DEC in other communities has started to recognize these snow storage locations as potential storm water pollutants. When they melt, those snow piles are storing a bunch of pollutants – grease, dirt – which ends up being a lot of sediment that can end up in an anadromous stream, which can affect fish. And they usually have a lot of heavy metals and salt.”
Pochardt says the pollutants can also include antifreeze and oil – whatever the plows scoop up in the snow. Most winters, snow is piled up in the Fort area, so adding a couple of bioswales at the top is strategic. Also, the placement is such that snowmelt hits the filtering power of the bioswale before it can run into the storm drain. That’s why they’re not being created at the bottom of the grounds.
Another aspect of the project is to harden, or compact the ground above the bioswale so that there is a heartier surface where the snow gets piled. A firmer surface topped with gravel would see fewer impacts from the plow and diminish the muddy mess come springtime.
But the few Fort Seward residents that spoke out at the meeting didn’t like the idea of a gravel pad. Here’s Judy Heinmiller, who raised concerns about people mistaking the gravel surface for a parking pad.
“Once you start something, it’s hard to change it, so they will permitted in the future all four corners, so some sort of seasonal barrier. Perhaps an attractive fence, something that would keep someone from driving in and out.”
Haines Borough Public Facilities director Brad Ryan says it could be capped with something other than gravel, or not capped at all.
“It doesn’t have to be D1 if it’s hardened underneath and the snow’s just sitting on it. (The surface) doesn’t have to change much,” he says. “The important part is the swale that’s outside of it.”
He noted the borough is moving away from dumping snow into the ocean.
“Once of the focuses of the borough is to move away from dumping snow off the cruise ship dock,” Ryan says. “If you noticed, last year we didn’t do that. We’re putting it in the yard at the public safety building and the reason is, there are pollutants associated with that and DEC is giving little warning shots that they may come to halt, and we want to be ahead of the game.”
The plan is still a work in progress, and is scheduled for completion by the end of this month, with the bioswales in place by mid-November. After that, it’s just a matter of waiting for it to snow. And melt. The plants are scheduled to go in next spring.
