How to Create Rain Gardens Final by loe13858

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									                                                                                                              Citizens protecting
                                                                                                                    and improving our
                                                                                                                            lakes & rivers

How to Create Rain Gardens
What are rain gardens?
A rain garden is a shallow, depressed garden planted with
vegetation designed to absorb stormwater or water runoff.
By collecting water that runs off from hard surfaces such
as roofs, driveways, sidewalks and other pavements, rain
gardens help prevent stormwater from running off directly
into lakes and rivers or indirectly by way of storm drains.
They help protect water quality by absorbing stormwater
and snowmelt that carry pollutants, sediment, grass clip-
pings and fertilizers.

A rain garden can be built in residential areas, in commer-
cial areas, near parking lots, along the lakeshore or gener-
ally anywhere stormwater runoff occurs. It is a water
quality tool you can implement in your own yard, not only                                    Rain garden photo courtesy of the
                                                                                             Crow Wing SWCD, Beth Hippert
helping prevent stormwater runoff but also adding beauty
to the landscape. Rain gardens require neither a lot of
space, money, nor professional landscaping expertise.                         How Do I Create a Rain Garden?
With the right instructions, plants and some expert re-                       The list below explains the main factors to consider when
sources you can build one yourself.                                           building a rain garden. Please see the “Want to Know
                                                                              More?” section of this factsheet for expert sources and
What Are the Benefits of a Rain Garden?                                       more detailed how-to information.
A rain garden …                                                               The most important factors in building a rain garden are
• filters runoff pollutants such as fertilizers, sediments                    location, type of soil, size and shape, suitable plants, and
    and pesticides                                                            maintenance.
• absorbs 30% more water than turf grass lawns
• recharges groundwater                                                       Location
• helps prevent flooding                                                      • Do not plant rain gardens in a wet area. There needs
• creates habitat for birds and butterflies                                      to be 3 feet of separation between the bottom of the
• reduces mosquito breeding.                                                     rain garden basin and the water table. If it is less than
                                                                                 that, move your rain garden to a different location.
                                                                              • Do not plant your rain garden over septic systems,
                                                                                 near walls, or over underground utilities. Before you
                                                                                 do anything, be sure to call Gopher State One Call at
                                                                                 (800) 252-1166 to check for underground utility ca-
                                                                                 bles, pipelines, or anything else that may be buried
                                                                                 underground.
                                                                              • Place your rain garden at least 10 feet away from a
                                                                                 house or other building.
                                                                              • Since the goal is to have your rain garden collect and
                                                                                 filter runoff, build it in a spot where it can catch the
                                                                                 water running downhill from roofs, gutters, down-
                                                                                 spouts, sump pump outlets, sidewalks, driveways or
                                                                                 other paved surfaces.
          Photo courtesy of the MN DNR, Heather Baird



Prepared by Minnesota Waters, a 5013(c) non-profit organization dedicated to promoting the responsible stewardship of our           Page 1 of 2
water resources. Minnesota Waters can be reached at 800-515–5253 or www.minnesotawaters.org. Revised April 2009.
How to Create Rain Gardens



 Soil compatibility                                             •   A mixture of flowers, sedges, rushes and grasses
 The soil in a rain garden must drain well so that water            can be used. Select plants that have different colors,
 does not stand on the surface or run off.                          textures, heights and blooming times to add interest
 • To determine the soil’s absorption rate in a potential           to your rain garden.
     rain garden area, do a percolation test: dig a hole six
     inches deep and about 12 inches across in the poten-       Maintenance
     tial rain garden area. Fill the hole with water. It        • Be vigilant about pulling weeds in the first year so
     should drain in 24 hours; if it doesn’t, the soil is not      that they do not compete with young plants.
     suitable for a rain garden.                                • Water the rain garden about two times a week if rain
 • Modify unsuitable soil by adding compost, which                 is not doing the job.
     works over time to loosen the soil and make it more        • Don’t use chemical herbicides in your rain garden.
     absorbent. If a soil is too wet, sand or gravel may           Instead, use untreated weed free mulch to help keep
     also be added.                                                weeds down and retain soil moisture.
 • A quicker option is to remove the soil and replace it        • Don't use any kind of fertilizers. Fertilizers increase
     with a rain garden soil mix. The ideal rain garden            competition between native and non-native plants.
     mix is 50 to 60 percent sand, 20 to 30 percent top-        • In the fall, cut back or mow down plants in the rain
     soil, and 20 to 30 percent compost.                           garden in order to help them re-start in the spring.
 • If you’re replacing unsuitable soil, dig out the soil
     down to one foot and replace with it with your new         Want to Know More?
     mix.                                                       Blue Thumb: Planting for Clean Water
                                                                (763)-398-3070
 Size and shape
                                                                http://bluethumb.org/raingardens/
 Generally, a rain garden should be one-third the size of
 the area from which it is receiving drainage. For exam-        University of Wisconsin Extension Water Resources
 ple, if the rain garden will be receiving runoff from your     Education, “Rain Gardens: A How-to Manual for
 backyard, and your backyard is 540 square feet, then the       Homeowners”
 rain garden should be approximately180 square feet or
                                                                http://clean-water.uwex.edu/pubs/pdf/
 10 feet by 18 feet.                                            home.rgmanual.pdf
 Rain gardens can be designed in any shape, but they
 should be twice as long as they are wide in order for the      University of Minnesota Extension, “How Can I Create
 water to spread evenly over the whole bottom. Typi-            a Rain Garden?”
 cally a kidney or oval shape is used. Design the rain          www.extension.umn.edu/distribution/naturalresources/
 garden so that it can be integrated into your home's           components/DD8241_4.pdf
 landscaping design.
                                                                Rain Gardens of West Michigan, “Rain Gardens: How
                                                                to Design and Construct a Successful Professional Rain
 Plant selection
                                                                Garden”
 • Select perennials to provide consistent ground               (616) 454-RAIN or (616) 451-3051
    cover, as opposed to annuals which need to be re-           www.raingardens.org/docs/rain_garden_factsheet.pdf
    planted every year.
 • Choose plants appropriate for your soil type that can
    tolerate both drought and wet conditions.
 • Place drought tolerant plants on the edges or berms
    of your rain garden and place plants that can tolerate
    the moisture closer to the middle of the rain garden.
    Native perennial plants are the best choices for rain
    gardens as they adapt to the climate. Recommended
    rain garden plants for Minnesota include blue flag
    iris, marsh milkweed, big bluestem, sedges, red
    twigged dogwood and buttonbush.

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