Have you ever looked closely at the mounds of snow trucked off city streets after a storm? Far from the pretty fluffy white stuff you marvel at while snowshoeing through the woods, snow-dump snow is laced with gravel, salt and hydrocarbons from oil and gas.
After receiving more than 450 centimetres of snow last winter, the snow “pile” at Moncton, N.B.’s snow dump (where the city literally dumps all of the snow trucked off the streets) was so enormous, it achieved a kind-of cult status. Aerial video footage shot by a drone flying over the snow mountain (in which giant snow blowers look like tiny worker ants) went viral, and Monctonians wondered what would happen when it all started to melt. (If it ever started to melt.)
The City of Moncton and Ducks Unlimited Canada (DUC) are working together on a solution that, by spring 2016, will see runoff from the dump flow from the enormous pile into nearby Jonathan Creek free of most nasty contaminants.
“We’ve constructed a shallow wetland below the dump to filter the run off—one of the many important things wetlands do,” says Adam Campbell, DUC’s head of Atlantic conservation programs. “The wetland will clean the water by slowing and capturing sediment, filtering particulate and absorbing excess nutrients.”
Currently, Moncton’s snow dump pile in Berry Mills, just outside the city, sits on a pad specially built for the purpose. When the city originally cleared the piece of land, they left tree roots and other vegetation in place to absorb some of the contaminants when the snow melted. The new wetland will do an even better job.
DUC is in the middle of constructing the 1.2 hectare (three-acre) wetland, which by spring 2016, will be complete with salt-resistant vegetation and ready to absorb most of the contaminants before the water flows into Jonathan Creek. Moncton city staff will test the water after it’s filtered to make sure the wetland is working as well as it should.
“There are no regulations specific to melting snow dumps at this point. This is something new for our region that we’re trying,” says City of Moncton engineer, Elaine Aucoin. “We hope that once we show how well the wetland works, other communities will learn from this approach.”