The EE Sampler - Jefferson County Public Schools

Rain Gardens: What, Why, and How?
Kristen Barnes
Why are rain gardens important? As impervious surfaces increase throughout many
neighborhoods, storm water runoff is becoming a growing problem. Pesticides and yard
waste, coupled with oil and gasoline from cars, are washed into storm drains. As pipes
reach capacity, contaminated water often ends up in local streams or rivers, where the
aforementioned chemicals are a big concern. Creating a rain garden can help relieve
several of these problems, lessening the amount of water flooding storm drains, as well as
filtering the run-off , decreasing pollution reaching streams by up to 30%.
What exactly is a rain garden? Many homeowner's can set aside areas of their lawns
for a rain garden, which is a garden designed to collect rainwater from gutters and
downspouts. An area of ground is dug out, which allows water to be absorbed into the
ground--instead of quickly running into storm drains. The plants used in rain gardens
have complex, deep root systems, which allow excess water to be both absorbed and
filtered by the plants. Grass possesses only a simple root system, therefore can't absorb
water from storm runoff.
How can I make my own rain garden?
When planning the location of your rain garden, you should consider how storm water
will be directed toward it. Downspouts should be easily accessible or directable to the
garden.
You must also consider the quality of the soil. It needs to allow the water to drain
properly, otherwise pooling will occur, likely leading to continued runoff and
flooding. Most gardens will be dug several inches deep, and drainage quality can be
tested by whether or not water can drain within a 24 hour period. If this isn't the case,
the soil at the bottom of the garden can be replaced with a mix of compost, sand, and
topsoil.
The plants used in your garden are your choice, but there are some general guidelines
that are helpful to follow. You should consider the location of your garden, and how
much sunlight it will receive daily. Some plants need direct sun to flourish, while
others prefer more shaded areas. Choosing local, native species is also helpful when
trying to establish your garden, as they will be in the proper climate, and will likely
possess the complex root systems necessary to properly filter rain water.
For Further Information on why and how rain gardens can help you, consult:
www.msdlouky.org -Louisville Metro Sewer District guideline for rain gardens
http://raingardens.org/docs/Create_A_Rain_Garden.pdf -A Michigan based
publication, with good general information on rain garden design and maintenance.
16