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Rain Gardens
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One of the more intriguing new
landscape ideas to come along in recent years is the
rain garden. Unless you are a civil or city
engineer you probably don’t know that getting
rainwater from your home’s downspout to the nearest
river or stream is an important and costly aspect of
any city’s infrastructure. Roofs, streets,
sidewalks, parking lots, and driveways can’t absorb
water, so the rain that falls on all of these
impermeable city surfaces must be directed into big
underground pipes, called storm sewers, that carry
it to a nearby stream, river, or lake. |
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Previous Articles
It's
Finally Spring - March 13
Spring Garden Calendar-March 20
No
Garden Left Behind-March 27
Planting Trees for a Cooler Earth in a Warmer
WyoBraska-April 3
Viburnums - Shrubs for Wyobraska Springs-April 10
Want A Water Conserving Lawn? You might already have
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Creating Long
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Tree-lationships April 24
Bigger, Bolder, Brighter,
Better—and Back In The Landscape May 01 & 08
Hardy Shrub
Roses
May 15
Another Look
at Native Plants
May 22
No Child
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May 29
June
is Tree Care Month June 05
Summer Blooming Shrubs
June 12
Roses Are
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June 19
The Plants They will be Talking About Next Year at
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June 26
Busy Summertime Gardens
July 03
Cutting Your Lawn Down to Size
July 10
July 17
Insect Paranoia
If It Will Grow In Wyoming...
July 24
2007 Articles
2006 Articles |
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Storm water management has
become an increasing problem in most cities as
buildings and their related paving cover a greater
and greater proportion of the city’s surface area.
In response, cities have taken two approaches to
managing the growing volumes of stormwater that
accumulate during and immediately after a
rainstorm. The first was to require new
developments to build retention ponds on the
development site which accumulate the run off from
that particular development during and immediately
after the storm, and then release it slowly into the
city’s storm sewers. This keeps the city from
having to build larger storm sewer lines as the city
expands by allowing the accumulated run off to flow
into nearby streams over days after a rainstorm
rather than hours.
The other approach that many
cities are now taking is to stop some of the
stormwater from ever entering the city’s storm
sewers at all. The idea is to create mini-retention
ponds in residential and small commercial landscapes
that capture the rainwater from downspouts, and then
to plant these mini storm water storage areas with
plants that prefer the bog-like conditions that
these areas become. Any new idea that is going to
be widely accepted by the public has to have a
catchy name, and this one does—the rain garden.
Not surprisingly, interest in
rain gardens appears to be greatest in regions of
the country which receive quite a bit more annual
rainfall than Wyobraska. But in Wyobraska’s
semi-arid climate, rain gardens may still be an
option for the growing group of “green” homeowners.
That’s because in Wyobraska rain gardens may be a
way to provide sufficient natural precipitation to
xeriscape plantings to virtually eliminate the need
for any other supplemental irrigation.
The math of storm water runoff
is pretty surprising. The surface of an average
residential lot can be divided into three distinct
regions—roofs (from which rainwater can be captured
and directed into the landscape), sidewalks and
driveways (which tend to direct stormwater directly
into city streets), and landscape surfaces (which
absorb the rain as it falls). An average proportion
of these surfaces is landscape area--50%, roof--30%,
and sidewalks & driveways-- 20%.
If only that rain which falls
on the roofs is captured and kept within the
landscape it can have the effect of doubling the
annual precipitation for over half of the landscape
area. Twice the average annual Wyobraska
precipitation is more than enough annual
precipitation for any xeriscape plant, so adapting
the rain garden concept to Wyobraska would seem to
make it possible to create a xeriscape that is
irrigated entirely with natural precipitation—a
landscape doesn’t get much greener that that. |
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If the idea of creating a rain
garden in your landscape sounds like something you
want to put on your “to do” list, the place to begin
is the internet. There are risks to trapping
rainwater in your landscape, so you want to make
sure that you do it right. There is a wealth of
excellent how-to information about rain gardens on
the internet, so I suggest studying the information
from several of these sites before proceeding.
If the internet rain garden
information doesn’t scare you, the next step is to
go out into your landscape to get the answers to
three questions. The first question is-- Where does
all of the rain water that falls on my roof enter my
landscape? For most homeowners the answer is “at
the end of the home’s downspouts”. If your home
doesn’t have gutters, then the rain water enters
your landscape right beneath the lower edge of the
entire roof line.
The second question is—“Where
do I want to locate my rain garden?” Remember, in
Wyobraska, a rain garden may be nothing more than a
part of your landscape that you irrigate with the
water that runs off your roof. But you may also
elect to create a true rain garden that adds a
bog-like region to your landscape so that you can
add new a different plants to an area of your
landscape.
The second question is
important because it allows you to answer the third
important question, which is—“How will I capture
and/or redirect the rain water coming off my roofs
or out of my down spouts and get it to where I want
to water my landscape or to collect in my rain
garden?”
One of life’s often cited rules
comes into play here—namely that water (and anything
floating in it) runs downhill. The important point
being that you need to make sure that it is feasible
to get the rainwater from your roof to flow to where
you need it to end up in your landscape for your
rain garden (or natural xeriscape irrigation) to
work.
With the fall landscape project
season fast approaching, creating a Wyobraska rain
garden is a green landscape idea worth considering.
http://www.raingardens.org
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