Resources + Info – Basement Flooding Prevention

Last Saturday, I had great conversations with residents from across Etobicoke-Lakeshore about how they have been impacted by basement flooding.

At our Basement Flooding Prevention Drop-in, we had staff join us to share information and answer your questions about local City projects that are designed to reduce basement flooding and practical steps you can take to protect your property. If you missed the drop-in, it’s not too late to learn more!

What else can you do today?

1. Apply for the City’s Basement Flooding Protection Subsidy Program here
   Owners of a single-family, duplex, triplex or fourplex residential home can apply online for a subsidy of up to $3,400 per property to install flood protection devices. Eligible work includes:
   
   1. installation of a backwater valve,
   2. installation of a sump pump, and
   3. severance and capping of a home’s storm sewer or external weeping tile connection.
2. Sign up for Flood Messages at TRCA.ca/get-flood-messages
   Toronto and Region Conservation Authority (TRCA) runs a Flood Forecasting and Warning Program that operates 24 hours a day, 7 days a week to provides advice and warning for the forecasted timing and severity of potential flooding events from rivers and streams. Sign up today!
3. Learn more about the City’s Basement Flooding Protection Program (BFPP)!
   Find more information about the BFPP projects planned for Etobicoke-Lakeshore below.

What is the City responsible for, and what are you?

• The City is responsible for infrastructure within the public Right-of-Way.
• Homeowners are responsible for the operation and maintenance of drainage systems on their private property. This may include:
  • Lot grading
  • Front and rear yard or driveway drainage catchbasins
  • Foundation drains
  • Sump pumps and backwater valves
  • Private side sewer laterals and what you put down the drain (fats, oils, grease, etc.)
  • Disconnecting downspouts

What is the City doing to improve sewer and drainage systems?

The City’s sewer and drainage systems were not designed to handle the types of extreme rainfall events we are seeing more frequently today.

Following a storm on August 19, 2005, the City developed the Basement Flooding Protection Program (BFPP) and delineated the City into 67 Basement Flooding Study Areas. The studies for all 67 areas are now complete, as of the end of 2024, well in advance of the original 2030 timeline.

The BFPP consists of three major steps:

• Study the City’s sewer and drainage system – analyze the existing systems, determine where severe storms may result in surface and basement flooding, evaluate options and recommend solutions to mitigate flood risk.
• Design the recommended projects (preliminary and detailed design).
• Construct the recommended projects.

How are projects prioritized?

• Projects are prioritized based on a Council-adopted $68,000 cost-per-benefitting-property threshold. All City basement flooding projects must be prioritized to benefit the greatest number of properties and coordinated with other construction work.
• Projects meeting the threshold at the completion of preliminary design may proceed to construction. Projects that exceed the threshold are moved into the deferred project list for future consideration, when all projects under $68,000 that meet the threshold have been advanced for implementation.

Types of Basement Flooding Protection Projects

• High-Capacity Inlets – High-Capacity Inlets (HCIs) are catch basins designed to capture much more flow than standard catch basins and are typically installed to reduce excessive surface ponding at topographic low points.
• Inlet Control Devices – Inlet control devices (ICDs) are flow restrictors installed within catch basins to control the flow rate into the storm or combined sewer system.
• New Storm/Combined/Sanitary Sewers – These are new sewers proposed where a sewer does not currently exist or a secondary relief sewer where a sewer does currently exist. These projects can include several elements such as High-Capacity Inlets and Inlet Control Devices on the storm sewer system as well as sealing of maintenance hole covers on the sanitary sewer system. Pipes may be designed to provide temporary storage of excess storm or sanitary sewage.
• Storm/Combined/Sanitary Sewer Replacements – These are larger or deeper sewers that will replace already existing sewers. These projects can include several elements such as HCIs and ICDs on the storm and combined sewer system as well as the sealing of maintenance hole covers on the sanitary sewer system. Pipes may be designed to provide temporary storage of excess storm, combined or sanitary sewage.
• Road Re-grading – Re-grading a road involves adjusting the elevation of the road to improve overland drainage. This type of project can also include modifications including curb cuts to direct drainage to new outlets.
• Storm or Combined or Sanitary Sewer Storage Tanks – Storage tanks temporarily store excess storm, sanitary or combined sewage. These facilities are typically off-line from the sewer system and are drained via pumps.
• Dry Stormwater Pond/Wet Stormwater Pond/Engineered Wetland – Stormwater ponds/Engineered Wetlands temporarily store excess stormwater. Wet stormwater ponds and engineered wetlands always contain water whereas a dry stormwater pond is designed to fully drain between rainfall events. Each of these facilities also provide water quality treatment. Dry stormwater ponds are typically located within parks and the land within the pond can be used for recreational activities between rainfall events.
• Oil and Grit Separators – Oil and Grit Separators (OGS) are devices that are installed in maintenance holes to provide water quality treatment. These devices are typically installed in-line with the storm sewer system within the road right-of-way.
• Green Infrastructure – Green infrastructure utilizes soil, mulch and plants to remove pollutants from stormwater runoff. Green infrastructure can take a variety of forms such as swales or depressions where runoff from small storms is temporarily detained and treated. These units are typically installed within the road right-of-way.