Capturing Storm Water in Ontario, Canada: A Guide to Storm Water Management Systems


Storm water management is a critical component of urban planning and environmental sustainability. In Ontario, Canada, where heavy rainfall and storms are common, managing storm water effectively is crucial to prevent flooding, protect water quality, and preserve natural habitats. In this blog, we'll explore the importance of capturing storm water and the various storm water management systems used in Ontario.

Why is Capturing Storm Water Important?


Storm water runoff occurs when rainwater flows over land, roads, and other surfaces, picking up pollutants such as sediment, oil, and chemicals along the way. Without proper management, this polluted runoff can contaminate rivers, lakes, and streams, harming aquatic life and affecting water quality for communities.


Additionally, in urban areas with large amounts of impervious surfaces like concrete and asphalt, storm water runoff can lead to increased flooding and erosion. Take a city like Toronto for instance which is approximately 630 km2 with an average annual rain fall of about 830mm that equates to 523,000,000 MILLION m3! Additionally, depending on specific areas of infrastructure, 20-40% of that is run-off. So Toronto alone could be repurposing approx. 157,000,000 m3 of water. By capturing and managing storm water, we can reduce these negative impacts and protect our environment and infrastructure.


Storm Water Management Systems for Ontario


  1. Green Roofs: Green roofs are vegetative layers on building rooftops that capture and absorb rainwater, reducing runoff and providing insulation. They can also improve air quality and create habitat for wildlife.


  1. Rain Gardens: Rain gardens are planted depressions that collect and absorb rainwater from roofs, driveways, and other surfaces. They help filter out pollutants and recharge groundwater.


  1. Permeable Paving: Permeable paving materials allow rainwater to seep through the surface and into the ground, reducing runoff and replenishing groundwater.


  1. Detention Basins: Detention basins are large, man-made ponds or reservoirs that temporarily hold storm water, allowing pollutants to settle out before slowly releasing the water into nearby water bodies.


  1. Vegetated Swales: Vegetated swales are shallow, vegetated channels that slow and filter storm water runoff, reducing erosion and improving water quality.


  1. Rainwater Harvesting Systems: Rainwater harvesting systems collect and store rainwater from roofs for later use, reducing demand on municipal water supplies and alleviating storm water runoff.


Regulations and Best Practices


In Ontario, storm water management is regulated under the Ontario Water Resources Act and the Environmental Protection Act. Municipalities often have their own storm water management guidelines and requirements, which developers and property owners must adhere to when planning and implementing storm water management systems.


Best practices for storm water management in Ontario include reducing impervious surfaces, preserving natural drainage features, and implementing green infrastructure wherever possible. By following these practices, communities can mitigate the impacts of storm water runoff and promote a more sustainable approach to water management.




Capturing storm water is essential for protecting water quality, reducing flooding, and preserving natural habitats in Ontario, Canada. Through the use of green infrastructure, rainwater harvesting systems, and other storm water management techniques, communities can effectively manage storm water runoff and promote environmental sustainability.

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