A rain garden is a popular technique of building a garden bed in a low area that accumulates water after a storm. It is planted with native plants that help to collect and filter rainwater and allow it to seep naturally into the ground. By installing a rain garden on your property, you can greatly increase your contribution to preserving clean rainwater, creating natural, native habitats, preventing local flooding and reducing water pollution.
What Is a Rain Garden?
Unlike specific points of pollution, such as some factory discharge pipes, nonpoint source pollution comes from many different spots. From farmlands to suburban lawns, people use the land in ways that cause nonpoint source pollution. And it is also more difficult to control nonpoint sources of pollution.
Why a Rain Garden?
A rain garden is a natural way for you to help solve our stormwater pollution problems, help recharge groundwater, and protect our water resources. A rain garden keeps rain on your property, where it naturally belongs. By creating a rain garden, you can help improve water quality in local streams, rivers, and lakes. You can use rain the way nature intended, instead of throwing this resource away. In addition, rain gardens are attractive landscaping features. They use native species of plants that are adapted to our region, and can be low-maintenance while providing habitat for native wildlife and butterflies.
What Makes a Rain Garden a Rain Garden?
A rain garden resembles a regular perennial garden in many ways. It is designed with deep-rooted plants that come back year after year; it is pretty to look at; it often has lovely flowers, grasses, trees and shrubs.
Differences From Other Perennial Gardens
There are certain qualities that make a rain garden unique.
- Rain Gardens have a ponding area, but they are not ponds. They often are planted with wetland plants, but they are not wetlands (although you can design a rain garden that mimics a wetland).
- The garden absorbs and filters rain that would otherwise run off your property and down the storm drain. This stormwater runoff usually comes from an impervious surface that rain cannot soak into, such as a roof or parking lot, or even a lawn.
- Many of the plants in the garden are native to the region, and have extensive deep roots that help the garden absorb rain. The native plants do not need special attention once they are established.
- There is a bowl-shaped dip in the garden, which holds the rain while it soaks into the soil.
- The garden bed is prepared or sometimes replaced to a depth of two feet in order to de-compact the soils and make the garden able to absorb water.
- A native plant garden that does not have rain directed into it from a hard surface of your property will still be a valuable asset, and will help absorb rain much better than a traditional landscape. But unless stormwater runoff is directed into the garden, it is not a rain garden.
Benefits of Rain Gardens
- Rain gardens are lovely landscaping features.
- Rain garden plants create wildlife habitat and attract butterflies, birds, and other wildlife.
- Rain gardens can save you money. They don't need to be fertilized or sprayed, only weeded and mulched. They reduce the amount of lawn you have to maintain. This makes your yard a healthier place for children and pets.
- A rain garden on your property makes you part of a solution to stormwater pollution. Rain gardens can potentially absorb hundreds of gallons of rain that would otherwise wash pollution down the street and into the nearest river, stream, or lake. Even small rain gardens can absorb a lot of rain.
- A rain garden can be part of a stormwater reduction plan to help solve problems of combined sewer overflows (CSOs).
- Rain gardens can actually remove many of the common pollutants in stormwater.
- Rain gardens are low maintenance. Once established, they require no fertilizer, watering, or mowing. A once-a-year cleanup, the addition of shredded hardwood mulch to keep the surface moist and tidy, and the removal of weeds and invasive species are all that are required.
- Rain gardens can contribute to groundwater recharge, a natural process that is interrupted by soil compaction and hard surfaces created during development and building.
- A rain garden project can educate the public about the problems that stormwater runoff creates, while giving people a beautiful solution.
- A rain garden project can be part of the educational toolbox used by a community stormwater education team.
There are many good resources on the internet and even at local nurseries and home improvement centers. If you download How to Build a Rain Garden (PDF), there are step-by-step instructions on how and where to build a rain garden and what type of plants to consider.
- Water flows in from slope, paved area, or pipe
- Wide, shallow basin with flat, level bottom and gently sloped sides
- 12 to 24 inches of fast-draining soil
- 2 inches of mulch
- 6 inches of ponding depth
- Berm or stones to stem or slow down overflow
- Perennial plants
Water is getting scarce in some areas, and water prices are rising. Many communities are rationing water. Droughts are causing much distress. A lot of your yards may be parching this year.
Well, here is some good news! There is a free resource you may not have thought of using to water your garden and lawn - rain. Consider some low-tech, old-fashioned technology for keeping your plants green and happy: rain barrels.
Does anybody remember rain barrels? The nice soft water is perfect to water your gardens. Rain barrels are making a comeback because they can save you money - and sometimes save your garden! The added advantage is that by using rain barrels, you can also help solve our stormwater pollution problems.
Have you ever wondered how much water runs off your roof? During a typical moderate storm of 1 inch of rain during a 24-hour period, over 700 gallons of water will run off the average roof, an impervious area of about 1,200 square feet. In one rainy day, your roof runoff could fill up fourteen bathtubs! Add up the many roofs in your city and we're talking a lot of water.
Stormwater from your roof is usually directed away from your yard and on down the street or road. On its way, it picks up pollutants; dirt, lawn clippings, pet waste, salt, lawn chemicals, gas and oil, and you name it (are you grossed out yet?). This water and the pollution load it carries generally goes to the nearest storm sewer, and from there to the nearest stream or river. Studies have determined that up to 70% of our surface water pollution is washed in there by stormwater. You can help solve this problem by keeping stormwater on your property and using it the way nature intended; to water the plants in your yard. A double benefit!
You can make a rain barrel, or buy one. Buying a ready-made rain barrel can be expensive. You can buy them from catalogs and on the internet (just do a search for "rain barrels"). Some garden centers carry them; call yours and check. Ready-made rain barrels range from about $70 to over $175, and shipping costs are additional. If you do buy a ready-made one, consider these safety features:
- Your barrel must be made of "food quality" materials, so the water you save will remain uncontaminated.
- Your rain barrel should not have a lid that easily comes off. This will insure that little creatures and little people will not be at risk of drowning in your rain barrel.
- Your barrel should be safely screened so it doesn't turn into a mosquito condo.
Just think: landscape watering consumes about 40% of your total water bill! Now think of how much money you will save with rain barrels - while you are protecting your local rivers, streams and lakes. Wouldn't it be great if everybody got a rain barrel? Be the first in your neighborhood.
Do your homework. Check with local nurseries or home centers or use internet resources. Many websites have planting tips and provide lists of available plants that are suitable for various soil types and microclimate conditions of rain gardens. Try our links section for some useful websites.