Marsh project revitalizes Oshawa wetland
By Joel Wittnebel/The Oshawa Express
A project to revitalize a key Oshawa wetland on the coast of Lake Ontario is being labelled an overwhelming success.
Starting last spring, the Friends of Second Marsh, along with Ducks Unlimited Canada and the Central Lake Ontario Conservation Authority (CLOCA), began pulling the water out of Oshawa’s Second Marsh to start the process fittingly labelled as a “draw down.”
The process works by pulling the dirty water from the marsh and allowing the sunlight to reach the mudflat at the bottom and seeds that have been laying dormant there, some having done so for decades.
Starting in April 2016, all the water was pulled from the marsh, yet it wasn’t until late July and August that the native seeds began to germinate, including cattails, bulrushes and smartweed.
Now, as the project begins the slow, tricky process of reflooding the marsh, things are looking healthy says Brian Brasier, the executive director of Friends of Second Marsh.
“It’s a bit of, I guess you call it a measure of science and art,” he says. “They’ve got a pretty good idea of how much water they want to put in this year at least for most of the season.”
The project also seems to have greatly impacted the invasive species directly responsible for the bad water quality in the first place.
“We’ve been able to, it looks like anyways, to severely reduce the carp. I don’t know if we’ve eliminated them, (but) that would be ideal, “
Feeding at the bottom of the marsh by stirring up the sediment, the invasive Asian carp have led to the decline in many marsh-dwelling plants that cannot survive when the sunlight they depend on to penetrate the water table is blocked by dirty water.
The last successful draw down occurred more than a decade ago in 2004. A 2015 attempt to aid the marsh through the same method was stympied by heavy rainfalls that June, with nearly an entire month’s worth of precipitation falling on a single day.
Brasier says this time around, things are looking the way they did back in 2004.
“That one turned out just fantastic results so we’re looking forward to sort of a similar thing,” he says.
The draw down not only benefits the plants that call the marsh home, but an array of other wildlife and shorebirds that depend on the vegetative cover during mating season.
The increase in plants is a good sign for the birds, Brasier says.
“It create a vegetation distribution that is much more conducive to waterfowl production,” he says.
If done successfully, the process only needs to be completed about once every 12 years.
The Friends of Second Marsh would like to remind residents to not assist carp attempting to enter the marsh. Dams and blockades are set up for a reason to keep the carp away and maintain the health of the wetland.