Raingarden at
Friday Harbor High School. Bankful Nov
2008.
Rain gardens work like a native forest by capturing and infiltrating stormwater from rooftops, driveways, and other hard surfaces. A rain garden is a shallow depression in the landscape planted with flowers, shrubs and grasses that "don’t mind getting their feet wet." Rain gardens help soak up rainwater from downspouts, driveways, parking and sidewalks, while protecting our local waterways. When planted with certain types of plants, rain gardens also attract birds, butterflies and bees.
Rain gardens — reduce flooding by absorbing water from impervious surfaces; filters oil, grease and toxic materials before they can pollute streams, lakes and the marine environment; help to recharge the ground water supplies by increasing the quantity of water that soaks into the ground; and will provide beneficial wildlife habitat.
A typical rain garden profile.
How to build a rain garden
1. Determine how much impervious surface you have and how much of that water you want to manage
2. Decide where on the property you'd like to build a rain garden, ideally 30’ from foundations/hardscape
3. Do a percolation test to make sure the soils can soak up the water
4. Decide how big to make the rain garden based on the amount of water you are treating
5. Construct it!
6. Plant it!
7. Maintain it!
Use the online resources or contact the San Juan Islands Conservation District for more information to get your rain garden project going.
Rain Garden Web Resources
Rain Garden Handbook for Western Washington Homeowners
Rain Gardens - www.emswcd.org
Other Resources
Rain Gardens by Nigel Dunnett and Andy Clayden, 2007, Timber Press ISBN 978-0-88192-826-6
Soil doesn't drain well? Rain Garden alternatives
Bog gardens are areas where the soil is waterlogged either naturally or artificially, creating a suitable environment for growing plants that thrive in moist soil.
Bio-swales are landscape elements designed to remove silt and pollution from surface runoff water.