What is a Rain Garden?

Rain gardens are attractive landscaped areas planted with perennial native plants which don’t mind getting “wet feet”. Built in a depression, rain gardens are designed to increase infiltration allowing rain and snowmelt to seep naturally into the ground. Benefits of rain gardens are multiple: they recharge groundwater supply, prevent water quality problems, provide habitat for birds and butterflies, and are great looking landscape features.

History of the Rain Garden

Rain gardens were first used in Maryland in the early 1990s to address pollution that was threatening the Chesapeake Bay. The rain garden was modeled after the bioretention basin. Bioretention basins were initially designed as a Best Management Practice to minimize the impacts of development and stormwater runoff. Bioretention basins are depressions which collect and hold stormwater runoff. They reduce pollution by slowing the flow of surface runoff, allowing time for pollution to settle out before it continues its flow to the nearest river or lake. While detention basins are primarily used to contain water from a large drainage area, rain gardens are designed for use on residential lots, giving the homeowner the ability to reduce the amount of stormwater runoff that flows from their yard.

Rain gardens help our communities “bloom”, making them more attractive places to live while maintaining watershed health.

Why do we need Rain Gardens?

As development increases, the ability of our environment to perform its natural processes decreases. This is because the natural landscape that was once able to absorb and clean stormwater is covered by impervious surfaces. Impervious surfaces are simply surfaces that water is unable to penetrate. Rooftops, driveways and roads are all examples of impervious surfaces. Increased impervious surfaces result in an increased amount of stormwater runoff and an increased chance for pollution to enter our waterways through our storm sewer systems. This type of pollution that results from stormwater runoff is called nonpoint source pollution. Studies have shown that up to 70% of the pollution inour streams, rivers and lakes is carried there by runoff from practices we carry out in our own yards and gardens!

Some of the common “nonpoint source pollutants” from our yards that end up in our local waterways include soil, fertilizers, pesticides, pet wastes, grass clippings and other yard debris. Rain gardens capture the rain that would usually runoff your property and allow it to soak into the ground. This helps minimize runoff and helps reduce the amount of pollution that enters our waterways.

Additional rain garden links.