Rain Gardens

A rain garden is a garden designed to temporarily hold and absorb rainwater and snowmelt run-off that flows from roofs, driveways, patios and lawns.

Rain gardens remove up to 90% of nutrients and chemicals and up to 80% of sediments from runoff. Compared to a conventional lawn, rain gardens allow for 30-40% more water to soak into the ground.

A rain garden is not a water garden, pond or wetland. It only holds water during and following rainfall or snow melt. And because it drains within 12-48 hours, it prevents the breeding of mosquitoes.

Rain gardens also help make neighbourhoods cleaner and more beautiful, and provide habitat for pollinators.

In Action

Ajax Ontario: Rain Garden Performance Monitoring. A recent study explored the effectiveness of different rain gardens installed near the waterfront. This project monitored the performance of three adjacent Rain Gardens with differing bio-medias and evaluated runoff reductions and water quality to assess the performance of the rain gardens.