Rain Gardens in Calgary

Rain gardens protect our watershed by managing the amount of sediment and pollutants that reach our rivers from our stormwater system.

They also reduce river bank erosion, and localized flooding and runoff, by allowing for stormwater to soak into the ground.

In communities where there is not sufficient land for large-scale stormwater management like wet ponds, rain gardens are a great alternative.

In addition to protecting our watershed, rain gardens:

• Are planted with beautiful, hardy, low-maintenance, water-wise plants
• Attract birds, butterflies and mosquito-eating dragonflies
• Complement any landscape and enhance the beauty of the neighbourhood

How do rain gardens work?

A rain garden is a landscaped plant bed that captures and filters stormwater before it returns to our stormwater system, and eventually our rivers.

When it rains, stormwater from the surrounding area is directed into the rain garden. Plants, layers of soil and gravel filter and absorb the stormwater.

The silt and other natural solids, like leaves, are collected on top of the gardens. Other pollutants (chemicals and bacteria) are filtered out and used by the soil and plants.

Rain gardens can differ in both design and size, from small residential rain gardens, to large engineered rain gardens that work as part of the stormwater system.

Engineered rain gardens are large, landscaped features located in communities and on City of Calgary property. These rain gardens are designed to allow overflow in a large rain event and hold standing water for no more than 48 hours.

Engineered rain gardens are a low impact development practice and are a part of our Stormwater Management Strategy.

Excess water not absorbed by the plants, seeps into the native soil below or collects in the drainage pipe located under the drainage layers. This drainage pipe connects to the stormwater system and carries excess, filtered water back to the river.

Residential rain gardens

Rain gardens are a great landscaping feature when placed in a low lying area of your garden. Rain gardens are shallow depressions filled with loose soil and planted with beautiful, hardy low-maintenance water-wise plants.

When the downspout from your roof is directed toward the rain garden, the plants and soil naturally filter the runoff before it enters our stormwater system.

If you are using native plants, once established, your rain garden will require little to no water or no fertilization.

Looking for more details on how rain gardens work and can benefit your yard? See our YardSmart Rain Garden Brochure (Arabic, Hindi, Punjabi, Simplified Chinese, Traditional Chinese).

You can also visit Family Handyman for a guide on how to build a rain garden, select a site, amend your soil and improve stormwater management in your yard.