The City’s Wet Weather Flow Master Plan

The Wet Weather Flow Master Plan is the City’s long-term strategy to reduce the impacts of stormwater on Toronto’s environment, rivers, streams, waterfront and Lake Ontario.

When rain falls or snow melts in Toronto, much of the water cannot soak into the ground because of hard surfaces such as roads, sidewalks, parking lots and rooftops. As stormwater flows across these surfaces, it can pick up pollutants such as:

• oil and grease
• litter and debris
• bacteria
• animal and pet waste
• garbage

Stormwater runoff can:

• reduce water quality in rivers, creeks, streams and Lake Ontario
• erode stream banks
• damage fish and wildlife habitat
• increase the risk of basement flooding

The plan sets out 13 objectives under four categories.

Water Quality

• Meet water and sediment quality guidelines.
• Prevent pollution and eliminate toxic substances at the source.
• Support safe recreational use of local waterways, including swimming.
• Improve the appearance of local waterways.

Water Quantity

• Restore and preserve the natural water cycle.
• Reduce erosion that can damage habitats and property.
• Reduce or eliminate risks to people and property from flooding.

Natural Areas & Wildlife

• Protect, restore and enhance natural features and ecosystems, including wetlands.
• Support healthy aquatic habitats and fish populations.
• Reduce contamination in fish.

Sewer System Performance

• Eliminate sanitary sewage discharges to the environment.
• Reduce the amount of groundwater and stormwater entering sanitary sewer systems.
• Reduce basement flooding.