2015 was a much drier year for most of us in Mount Dennis, but we can’t lose track of the real problems we face living beside Black Creek and at the bottom of the 15km Black Creek Sanitary Trunk Sewer. But no matter where in Mount Dennis you live, your toilets flush into that sewer, and when it is overloaded, your sewage either ends up either in your basement, or in the Black Creek!
This intolerable situation is finally getting some attention. In the words of Toronto Water “The Black Creek STS has experienced capacity issues during some rainfalls, which have caused flooding due to the surcharging of the trunk sewer. Over the next few decades, a significant population increase is expected to occur within the Black Creek sanitary drainage area, which will result in an increase in capacity constraints on the trunk sewer. In addition, during some storms, combined sewer overflow discharges to Black Creek occur from three combined trunk sewers that flow into the Black Creek STS.”

In other words, don’t expect the basement flooding to get any better until after major upgrades!

Soon we will be seeing notices about public consultations for another environmental assessment. This will be the third EA dealing with our problems. The Conservation Authority started the EA ball rolling in 2008, with the first meeting public in January 2009. That study confirmed that the culvert where the Black Creek passes under Jane Street was inadequate and predicted that a severe storm would flood hundreds of homes. This was clearly demonstrated in 2013! City of Toronto topographical maps show water levels east of Jane Street several meters deep during severe storms, and flooding extending from Jane Street to Weston Road.

In 2012, the City of Toronto defined Study Area 4 along Humber Boulevard and Alliance Avenue and launched another EA studying local sanitary and storm sewers, declaring that they were inadequate, and that holding tanks should be provided. This study also stated that these local fixes assumed the trunk sewer and Jane Street culvert were upgraded. Now a third EA will look at the trunk sanitary sewer that regularly spews sewage ONTO local streets. Mount Dennis residents and property owners are encouraged to visit, attend the meetings, and press to make sure permanent solutions are put in place.

We know that as far back as 1986, the problems had been identified by the City of York, leading among other things to the construction of the holding tank on Hyde Avenue. This past summer, Toronto Water installed flow gauges in the Black Creek sewer on Cordella Avenue, and also in the sewer under Rockcliffe Court. These gauges use cell phone technology to monitor and report flow and pressure in the trunk sewers, and should quantify the extent of the problems. Unfortunately, these devices seem to need service after storm events, demonstrated by the presence of maintenance crews on a regular basis.

There is very little we can do other than attend the public meetings. We can however insist that all downspouts in Mount Dennis are disconnected since they increase local issues during storms, and put hundreds of homes at risk. As more homes in the low lying areas install backwater valves, homes at higher elevation will experience basement flooding. Reducing the entry of downspout flow will help all of us.

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