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Reclaim Your Rain: Rain Gardens for Home Landscapes

Have you ever been frustrated by having to water your lawn only days after a rainstorm? Where does all that water go? Add in the watering restrictions, and it makes maintaining that green lawn even more challenging. It may be time to consider replacing some of your grass with a rain garden.

Rain gardens are landscaped areas designed to collect and utilize rainwater. They are a great way to reclaim rainwater from a roof downspout or driveway. Rain gardens allow more water from rain to soak into the ground to water plants and create a beautiful, low-maintenance landscaped bed. Typically about 30 percent more water from a rain soaks into the ground in a rain garden than in an equivalent area of lawn.

Rain gardens reduce stormwater runoff that carries pollutants from fertilizers and pesticides and debris washing from lawns and driveways into nearby rivers, lakes or streams. They also prevent damage to stream banks and reduce the risk of local flooding. In addition to being beautiful, they can provide valuable habitat to many birds and butterflies.

How Do Rain Gardens Work?

A rain garden collects stormwater, filters it through soils and plants and allows it to soak into the ground. A rain garden receives runoff water from lawns as well as rooftops or other hard surfaces such as driveways. The rain garden holds the water on the landscape so that it can soak into the ground instead of flowing into a street and down a storm drain. The plants, mulch and soil in a rain garden combine natural physical, biological and chemical processes to remove pollutants from runoff. Many pollutants will be filtered out and break down in the soil over time.

Where Are the Best Places to Locate Rain Gardens in the Landscape

Rain gardens are best located in low areas if the yard where runoff tends to flow. While they should not be built next to a building’s foundations, rain gardens located near to impervious surface such as driveways, patios and sidewalks can easily capture the runoff from these areas.

A rain garden should be located at least 10 feet from the foundation of the house or other building. Sites with more than a 12 percent slope (an elevation change of 12 feet down per 100 feet in length) may not be suitable for rain gardens. Further, if you have a septic system, avoid planting a rain garden over top of the system.

What Plants Should You Use?

Finding plants for your rain garden is not difficult. Many native plants, available at your nearest Pike Family Nursery, are well-suited for your rain garden. Here are some suggested native plants:

Trees
Red Maple Acer rubrum
Black Gum Nyssa sylvatica
Willow Oak Quercus phellos
Bald Cypress Taxodium distichum
River Birch Betula nigra
Musclewood / American Hornbeam Carpinus caroliniana
Green Ash Fraxinus pennsylvanica
Sweetbay Magnolia Magnolia virginiana

Shrubs
Virginia Sweetspire Itea virginica
Summersweet Clethra Clethra alnifolia
Common Winterberry/Winterberry Holly Ilex verticillata
Buttonbush Cephalanthus occidentalis
River Birch Betula nigra
American Beautyberry Callicarpa americana
St. John’s Wort Hypericum fasciculatum

Perennials, Grasses and Groundcovers
New England Aster Aster novae-angliae
Broadleaf Uniola/Indian Woodoats Chasmanthium latifolium
Joe-Pye Weed Eupatorium fistulosum
Swamp Sunflower Helianthus angustifolius
Scarlet Rosemallow/Swamp Hibiscus Hibiscus coccineus
Cardinal Flower Lobelia cardinalis
Cinnamon Fern Osmunda cinnamomea
Royal Fern Osmunda regalis
Switchgrass Panicum virgatum
Golden Ragwort Packera aurea
Ironweed Vernonia noveboracensis
Yellow Stargrass Hypoxis spp.
Swamp Milkweed Asclepias incarnata
Asters Aster spp.
Violets Viola spp.
Broomsedge Andropogon virginicus
Narrowleaf Dragonhead Physotegia angustifolia
Blackeyed Susan Rudbeckia hirta
Loosestrife Lythrum spp.
Red Columbine Aquilegia canadensis
Clubed Begonia Begonia cucullata

How to Create a Rain Garden

1. Locate a rain garden in natural depressions in the landscape near a downspout of the home.

2. Use rope or garden hose to lay out the boundary of the rain garden in a curvy in shape with the longest length perpendicular to the slope of the land.

3. The rain garden should be designed to hold about 6” of water above the ground surface.

• Ideally, locate the rain garden in such a way that a low berm on the downhill side of the rain garden will hold back the appropriate amount of water. A berm is a small earthen dam, no more than 12” high.
• The bottom of the rain garden should be as level as possible, so some minor grading may be necessary.

4. A shallow swale or corrugated drain pipe (buried or above ground) will channel runoff from the roof downspout or paved surface to the rain garden.

5. The soil in the rain garden should be a loose, sandy organic soil that allows water to quickly soak into the ground to nourish plant roots and recharge the groundwater. A general rule-of-thumb is to have a soil that soaks in about one inch of water per hour. The following steps will help to achieve this:

• Mix organic matter into the soil within the rain garden by spreading 2 to 4 inches of compost over the area and mixing the organic matter in with the existing soil.
• If the soil is acidic (has a low pH), lime should also be added to neutralize the pH of the soil.
• For soils with high clay content, it may be beneficial to remove about 1-2 feet of the soil and replace it with a more porous “rain garden soil.” A soil mix suitable for rain gardens is a mix of 50-60 percent sand, 20-30 percent topsoil, and 20-30 percent compost. The clay content in the rain garden soil replacement mix should be no more than 10 percent.

6. Establish a grass or groundcover border along the upper edge of the rain garden to slow down the runoff water as it enters the rain garden. Do the same over the berm to stabilize it as a border of the rain garden.

7. Plant drought tolerant, wet tolerant, hardy plants. A mix of ornamental grasses, shrubs and self-seeding perennials are good choices. See list above.

8. Once plants are in place, cover the rain garden with a 3” layer of mulch. Shredded hardwood is a good choice since it is less likely to float away.

9. Remove weeds on a regular basis and replenish mulch as needed.

10. IMPORTANT NOTE: Plan on providing an “overflow” path for water to take if it keeps raining after the rain garden fills up. This path should be stabilized with a hardy grass or groundcover

A rain garden can be the beginning of a more natural landscape for a homeowner. A more natural landscape can combine beauty with less maintenance and less need for chemicals. There is also a great deal of satisfaction from knowing that the landscape is keeping pollutants out of streams and lakes close by. To learn more about rain gardens or to find photos of demonstration sites, visit www.cleanwatercampaign.com or call 404-463-3259.

(Special thanks to Dr. Rose Mary Seymour of the University of Georgia Cooperative Extension Service Griffin Office and Alfred Vick, Ecos Environmental Design, Inc..)

 
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