The City of Toronto has completed a study to address flooding issues at the Lower Simcoe Underpass to:

  • help prevent the combined sewage overflow in the area of the Lower Simcoe underpass during rainfall events
  • identify a location for a stormwater pumping station to drain rainwater from the underpass and
  • modify the existing Lower Simcoe sanitary pumping station.

Through the study, the City has explored alternative solutions for mitigating flooding in the Lower Simcoe underpass and is recommending a combination of sealing catch basins, the installation of a new Stormwater Pumping Station and redirecting the City’s drainage system in the area. View more details in the study’s Executive Summary and presentation.

Current studies, investigations and implementation projects in this area that will work in conjunction with the Lower Simcoe initiatives include:

Study Area Map, please contact Mae Lee (mae.lee@toronto.ca, 416-392-8210) for assistance reading

Since the Lower Simcoe underpass opened to the public in 2009, the area has experienced repeated flooding issues. A study completed by the City concluded that the flooding within Lower Simcoe area is due to:

  1. Combined Sewage Overflow (CSO) to the street from a pipe collecting the CSO and conveying to the Lake Ontario. Due to low point in the underpass, the pipe overflows in the underpass area.
  2. Storm water from the adjoining streets is collected in the Lower Simcoe underpass area but due to insufficient capacity in the storm pipe, the storm water cannot drain fast during high intensity rain causing flooding in the underpass.

The City has completed a few temporary works to mitigate the flood risk. The purpose of this Municipal Class Environmental Assessment (EA) study is to identify other alternatives for the above issues and determine preferred long-term solutions to help prevent flooding.