Lower Simcoe Underpass Flood Protection Study

Updated June 2021

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

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 area (recommended under the sidewalk near the hotel)
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.

There are two other ongoing study and projects including the Basement Flooding Improvement Study (Area 62) and Don River and Central Waterfront & connected projects, that aim to improve water quality by reducing combined sewer overflows.

Lower Simcoe Underpass Flood Protection Study Completion Notice

Executive Summary – Please contact the staff listed should you require a full Project File

Recommendations Details

Study Overview

The purpose of the study is to address flooding issues at the Lower Simcoe Street Underpass, from Front Street to the Lake Ontario Shoreline, and to develop a plan to:

Prevent the combined sewage overflowing to the street in the Lower Simcoe Underpass area from the pipe during rainfall events
Identify a location of a storm pumping station to drain the rain water from the Underpass area.
Potential modifications to the existing Lower Simcoe Sewage Pumping Station

The City has completed a few temporary works to mitigate the flood risk. Additional infrastructure is required to manage the Combined Sewer and Storm Water. Purpose of this Class Environmental Assessment (EA) study is to identify alternatives for the two items identified above and determine preferred long term solutions to prevent flooding in the Underpass area.

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

Scott Street Pumping Station Inflow and Infiltration Investigation 2018-2019
Basement Flooding Remediation and Water Quality Improvement Study – Area 62 to commence later in 2019
Waterfront Sanitary Servicing Master Plan and Update 2018
Don River and Central Waterfront connected projects

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

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

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.
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. Additional infrastructure is required for the Combined Sewer and the Storm Water. Purpose of this Class Environmental Assessment (EA) study is to identify other alternatives for the two issues identified above and determine preferred long term solutions for the two issues and prevent flooding within the Underpass.

The Ontario Class Environmental Assessment process provides the public and interested parties with opportunities to provide input at key stages of the study.

The City is holding a virtual meeting to share information regarding recommended solutions to reduce the risk of flooding in the Lower Simcoe Underpass area.

Thursday, December 10, 2020 at 6:00 pm to 7:30 pm

We would like to hear from you. If you are interested in this study, would like to comment, attend the virtual public meeting or add to the project mailing list for notification, please contact: mae.lee@toronto.ca

Study Exclusions

Each building, unit owner(s) is responsible for the operation and maintenance of drainage systems on private property, which includes:

lot grading
underground parking
building maintenance
private driveway drainage and catchbasins
foundation drains

How to file a claim for flood or sewer back-up damages

What is a Class Environmental Assessment?

Ontario’s Environmental Assessment (EA) program promotes good environmental planning by determining and managing the potential effects of a project prior to implementation.

The EA program ensures that public concerns are heard. EA balances economic, social, cultural and natural environmental needs so that projects benefit Ontario.

This study is being carried out according to the Municipal Class Environmental Assessment process. This is an approved approach to satisfying requirements of the Environmental Assessment Act specifically tailored to municipal infrastructure. The process includes identifying the problem or opportunity to be addressed, developing and evaluating a range of alternative solutions, providing opportunities for public input and identifying a preferred solution.