‘Sludge’ shows up on Lake Simcoe shoreline

By Chris Simon Innisfil Scope May 16 2012

When the ice receded from Cathy Hampshire’s Lake Simcoe shoreline, a thick dark ‘sludge’ rolled in.

The Lefroy resident has owned lakefront property in Innisfil for over 40 years. But she’s seen the quality of the lake water drop in that time, and has serious concerns for the watershed’s overall health. So when the thick matter started showing up a few weeks ago, she was prompted to take action.

“This spring, we have been very concerned by the amount of debris that is washing up on shore,” she said. “It is quite obvious that people are dumping their lawn clippings and tree leaves directly into the lake. This is not a good situation for the fish, fowl or people who live on the lake.”

The ‘sludge’ is actually a mix of plant residue — mostly leaves, twigs, grass clipping and other natural decay — which likely comes from the Holland River. The combination can form muddy mats or rafts, and can be blown ashore, depending on wind direction. While it’s unsightly, the substance is safe, said Lake Simcoe Region Conservation Authority limnologist Brian Ginn.

“It’s mud, probably from the Holland River, which works its way into Cook’s Bay,” he said, noting visiting another Lefroy site to investigate similar matter in the fall. “It consists of material from the sides of the river, and bits of plant matter. It’s non-toxic, more of an aesthetic issue. People are driving their boats too fast, and taking chunks off the side. With more people around the lake, and larger interest (in boating), this is going to happen.”

Ginn says the matter has likely been kicked up by boats travelling along the river at excessive speeds. Residents can remove the matter from their shorelines, using a pool skimmer, rake or a similar device, or they can simply wait for it to dissipate.

“It’s a natural process, but if they don’t like the look of it, they can just scrape it off and dispose of it,” he said. “The only thing we can do (to prevent the spread) is observe the posted speed limits when boating.

“That will reduce the erosion. (The LSRCA) also has stewardship programs to prevent erosion using natural vegetation to modify the shoreline and slow the process.”

But Hampshire says the material highlights broader issues within the watershed.

“People need to be educated on caring for our lake,” she said. “This is decay, a whole layer of sludge. Now it’s at the public beaches, where kids go and play. It can’t be good for kids to be swimming in. The lake keeps changing, but it’s getting worse. My concern is all the stuff that’s being put into this lake; it’s something we have to address.”