Transcript Rain Gardens - NJIT Civic Engagement Computer Center

RAIN GARDENS
These educational materials are
the courtesy of
http://www.raingardens.org
http://www.rainkc.com
What is a rain garden?
A rain garden is an attractive
landscaping feature planted with
perennial native plants. It is a bowlshaped garden, designed to absorb
stormwater run-off from impervious
surfaces such as roofs and parking
lots.
Rain gardens can be small, formal,
home-owner style gardens, large
complex bioretention gardens, or
anywhere in between.
Why do we need rain gardens?
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Rain is natural; stormwater isn't.
Government studies have shown that up to 70% of the pollution in our
streams, rivers and lakes is carried there by stormwater.
Although most people never think about stormwater, about half of the
pollution that stormwater carries comes from things we do in our yards and
gardens!
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Planting a rain garden may seem like a small thing, but if you calculate the
amount of rain that runs off your roof, you would be very surprised. That rain
is supposed to soak into the ground, but instead heads down the street to
the storm drain, carrying pollution with it.
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Keeping rain where it falls, by putting it into a beautiful rain garden, is a
natural solution. You not only get a lovely garden out of it, you have the
added benefit of helping protect our rivers, streams and lakes from
stormwater pollution. You can be part of a beautiful solution!
What Makes a 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.
Qualities that make
a rain garden unique.
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Rain Gardens have a ponding area, but they are not ponds. They often are
planted with wetland plants, but they are not wetlands.
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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.
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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.
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There is a bowl-shaped dip in the garden, which holds the rain while it
soaks into the soil.
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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.
Benefits of Rain Gardens
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Rain gardens are lovely landscaping features.
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Rain garden plants create wildlife habitat and attract butterflies, birds, and
other wildlife.
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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.
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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.
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A rain garden can be part of a stormwater reduction plan to help solve
problems of combined sewer overflows (CSOs).
Benefits of Rain Gardens cont
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Rain gardens can actually remove many of the common pollutants in
stormwater. (fertilizers, pesticides, oil residue )
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Rain gardens are low maintenance. Once established, they require no
fertilizer, watering, or mowing. A once a year cleanup, addition of shredded
hardwood mulch to keep the surface moist and tidy, and removal of weeds
and invasive species are all that are required.
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Rain gardens can contribute to groundwater recharge, a natural process
that is interrupted by soil compaction and hard surfaces created during
development and building.
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A rain garden project can educate the public about the problems that
stormwater runoff creates, while giving people a beautiful solution.
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A rain garden project can be part of the educational toolbox used by a
community stormwater education team.
Benefits of Rain Gardens cont
• Reduce mowing
– Lawn mowing contributes greatly to the ozone
problem. Engines are inefficient at reducing
pollution. In fact, using a gasoline-powered
lawn mower for one hour generates the same
amount of air pollution as driving a car for
forty hours. A gasoline-powered weed eater
operated for one hour is even worse as it
generates pollution equivalent to driving a car
for sixty hours.
How much does it cost to build a
rain garden?
• Rain gardens cost no more than regular flower
gardens.
• The cost elements are the flowers, the peat
moss or compost that you add to the garden,
plus any edging or walls that you might build.
• Flower costs are a function of the size and
number of flowers that you choose.
• A do-it-yourself homeowner who starts with
mostly smaller plants might spend $ 2 to $4 per
square foot.
Before Starting
Choose The Right Place for Your
Rain Garden
• A rain garden is one type of “bioretention”—a system of
pond area, soil, plants and mulch that will retain water
and soak it up instead of letting it run off of your property
(even though your “pond” will be dry most of the
time). So the most basic things are the “pond,” or
depression into which water will flow, and the soils that
will absorb the water.
• Your property has an existing drainage pattern (even
though it may not be very noticeable), and it will usually
be easiest to take advantage of that. Note the direction
of runoff and low spots where water collects.
Hints for choosing a spot:
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Avoid creating a rain garden too close to building foundations; this
may lead to a leaky basement.
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Be aware of rights of way and underground service lines or utilities.
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Re-directing the rain--there are a number of creative and attractive
solutions if the rain doesn’t flow naturally to your chosen spot.
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If your land slopes, you can create a flat area for your rain garden in
several ways.
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Black walnut trees growing by the garden may spell trouble, due to
juglone, a chemical exuded from their roots.
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Don’t excavate an extensive rain garden under large trees.
Evaluate the Soil
• Soils vary greatly in fertility, drainage, and “pH” rating. Understand
what kind of soils you are working with, and put in a garden suitable
to the conditions you already have.
• Drainage is important
• Test your drainage!
• Design the Pond.
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• Compacted Soils
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• pH and Other Qualities
Prepare the Site
– Define the Borders
– How much soil is needed for replacement?
– Improve the Soil
– Grading the pond area
Develop a Design
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Tall Great Lakes Prairie Rain Garden For
Sun (6+ hours of sunlight) and clay soils.
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Short Great Lakes Prairie Rain Garden For
Sun (6+ hours of sunlight) and clay soils.
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Maplewood, Minnesota rain garden designs
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University of Wisconsin Extension Rain
Garden Manual.
Select the Plants:
Use native plants in rain gardens
• Native plants can tough it out
• Native plants attract beautiful creatures
• Native plants have deep roots
• Obtain native plants
• Do not take your plants from the wild.
• Plan Ahead for Plant Needs
Plant the Garden
& Rain Garden Care
• If it doesn't rain, water your plants until they
are established.
• Break strong water flow.
• Mulch your rain garden.
• Weed regularly.
• Don't park or drive on your rain garden.
• Don't let sediment, soil, sand, or debris flow
into your rain garden.
• Keep an eye on the plants.
Rain Barrels
Saving Rain for a Sunny Day
• During a typical moderate storm of 1” 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!
Rain Barrels
1) Your barrel must be made of “food quality”
materials, so the water you save will remain
uncontaminated.
2) 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.
3) Your barrel should be safely screened so it
doesn’t turn into a mosquito condo.