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Types of flooding

There are many types of flooding that can have a significant impact on Calgary.

Overland flooding

Overland flooding happens when water overflows from the banks of creeks, streams, rivers or lakes.

Depending on how severe the flooding is water can slowly creep up into backyards or it can rapidly spread throughout the streets with little warning.

In winter, frozen catch basins, storm drains or piled snow, combined with quick thawing and/or rain, can also cause overland flooding, which can enter basements or garages.

Basement seepage

Basement seepage occurs when water is absorbed by the soil and raises the level of the underground water table. Water seeps through the soil and eventually reaches the foundation of your home.

The water works its way into your basement through cracks and holes, or through joints in the home's foundation. Basement seepage can also happen in homes near rivers because of elevated river levels due to either spring or summer high-water levels or winter ice jams.

Sewage backup

Water on flooded streets or high groundwater may drain into the sanitary sewer system. This overloads the sanitary sewer pipes and can force sewage back through the sewer line and into your basement.

If you are having a backup, contact 311. To help our crews before arrival, view oursewage backup guide.

Stormwater backup

The City of Calgary's stormwater system empties into the Bow and Elbow rivers through large pipes. When the rivers rise, or there is excessive rainfall, water can flow back into the stormwater pipe system and spill back onto streets through stormwater drains.