Have you noticed the state of the Toronto harbour over the last few days? While it's starting to get better, it's been a brown mess since a powerful storm in the early morning on Tuesday dropped a month's worth of rainfall on the city in just a few hours.

If only this was just sediment shuttled into the lake from the Humber and Don Rivers, the harbour would just been an ugly site rather than a health risk, but that's not the whole story. According to Lake Ontario Waterkeeper, the Lake is also filled with sewage from bypasses that occur in the event of heavy rainfall.

"Big rains usually mean big sewage problems in Toronto," reads a recent blog post on the water quality watchdog's site. Both [the Humber and Ashbridges Bay] plants bypassed sewage with only partial treatment after the storm. You probably didn't hear about it because the city failed to issue any kind of public warning."

Krystyn Tully, Vice President at Lake Ontario Waterkeeper, tells me that there are hundreds of stormwater overflows spread along the Don Valley. These "combined sewer overflows release raw sewage directly into the harbour during heavy rains, like the ones earlier this week."

Six of Toronto's 11 beaches have been determined unsafe to swim in the wake of the storm, though no city-wide notification has been issued by the municipal government. The onus is very much on lake-users to ensure that they're informed about water quality. The Ministry of the Environment is currently conducting a review as to whether the city should have to inform the public when sewage bypasses occur.

In the meantime, be careful out on the water.

Photo by Jim Panou via Lake Ontario Waterkeeper