Storm drains in Calgary
Storm drains (or catch basins) are the main way stormwater gets into our underground pipes called the stormwater management system.
There are about 60,000 storm drains in Calgary which capture water off sidewalks, streets and roads.
The metal grates that can be seen at the edge of the road are only a portion of the catch basin structure.
Under the sidewalk is a barrel that collects the water. The barrel is attached to a pipe that allows the water to be whisked away into our rivers.
Remember, water entering our storm drains eventually travels to Calgary’s rivers and streams without water treatment. Never dump chemicals or use ice salt on storm drains.
Why is there water in the street after a heavy rainstorm?
To manage capacity of the stormwater system during heavy storms, many streets in Calgary are designed to have a low point(s) where rainwater is temporarily stored on the street until the storm drains can drain the water away. In some areas, we have also installed inlet control devices in the storm drains to manage how fast water flows into the pipes. Following intense rains, temporary ponding of water (roughly a half meter or less) is normal around many storm drains.
These measures are common practices for stormwater management. They’re designed to prevent overland flooding by keeping water away from houses, garages and businesses. They also help slow down the intense stormwater runoff to avoid overwhelming the stormwater sewer pipes and avoiding water backups into basements; however, this can be complicated when hail blocks the storm drains, increasing the duration of the ponding.
While our stormwater system manages the vast majority of rain and snow melt we experience in a year, the system has a limited capacity and may be overwhelmed during severe storms. With a changing climate, we know that intense rain and hail will happen more often, so we’re working to address this challenging problem as part of our updated Stormwater Management Strategy (pending Council approval) where improved drainage system design and improvement programs will be considered.
Protecting your home
There are many ways you can ensure your home is resilient during storm events:
- Maintain positive drainage on your lot - away from structures without adverse effect to neighbours or public property
- Conduct regular maintenance and clear debris in eavestroughs and downspouts.
- Ensure downspouts discharge a minimum of 2 metres from public infrastructure (sidewalks & pathways), 1-2 m from any building foundations, and are directed towards the street, lane or swale, while not impacting your neighbours or public property.
- Keep any grassed or concrete swales on your property free from debris, ice or obstructions.
- Regularly inspect grading around your foundation and fill any settling or depressions.
- Conduct regular maintenance on sump pumps. Ensure sump pumps discharge away from 1-2 m from building foundations, while not impacting your neighbour or public infrastructure.
- If necessary, clean leaves and yard waste away from the local storm drain or catchbasin.
Storm drain locations