Bio-what ? Bioswales used at University of Lethbridge to help filter stormwater runoff

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Lying in plain sight at the University of Lethbridge are six bioswales, or stormwater filtration systems.

The patches of grass and shrub gardens lining some of the U of L parking lots may look as though they’re just there for aesthetic value but they’re needed for much more.

“There’s sand and salt and anything that drips off of vehicles gets washed this way,” grounds manager at the University of Lethbridge, Phil Dyck, said.

Excess water filters through engineered land which is made up of compost and sand topped with plants that are salt-tolerant.

Bioswales keep pollutants out of the river, while also slowing down the flow of water to prevent downstream flooding.

“A lot of people don’t realize that the stormwater runoff from our cities, our sidewalks, our lawns, our parks, our parking lots all goes directly into the Oldman River untreated,” executive director of Oldman Watershed Council, Shannon Frank, said. “It does not go to the wastewater treatment plant.”

But one bioswale at the U of L has been damaged by foot traffic, becoming a non-functional “soggy ditch.”

“Traffic in there has compacted it so much that the water’s not percolating the way its supposed to,” Dyck said.

Most people walking by don’t know this specific patch of grass serves an important function and should “not” be walked on.

“No, not a clue,” University of Lethbridge student, Sophia Salamanca, said. “I didn’t think it had a purpose.”

University officials say they’re going to fix the damaged bioswale this fall, potentially adding a bridge and signage to help people to know they should stay off the grass.

“If we could get the message across to people to not cut through, that would be awesome,” Dyck said.

You too can help protect the river by making your own bioswale.

“It is possible to build a bioswale or rain garden even in a small place like people’s front yard,” Dyck said. “It does make a big difference on how fast the water runs off into the rivers.”

Frank says she believes more bioswales will be popping up around Lethbridge in the future.

“Because we’re typically now getting a lot of heavy storms at once instead of lesser rainfall events kind of spread out, this is becoming kind of a new problem with climate change,” Frank said. “We’re expecting we’ll see a lot more of these bioswales because of that.”

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global news

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