Download Rain Gardens as a Means to Control Stormwater

Rain Gardens as a means to control stormwater run-off at the
Galloway Municipal Complex
Elizabeth
1
Asher ,
Lee
1Richard
1
Smith ,
Tait
1
Chirenje ,
Patrick
1
Hossay
and Barbara
2
Fiedler
Stockton College of New Jersey, 2Municipality of Galloway, NJ
The Galloway Project
What is a rain garden?
A rain garden (bio-filter) is an
on-lot retention of stormwater
through the use of vegetated
depressions designed to
collect, store, and infiltrate
runoff. It is often planted with
deep-rooted native plants
and grasses, and located
optimally to receive runoff
from hard surfaces such as a
roof via a downspout,
sidewalk or driveway.
Advantages of using rain gardens
A Rain Garden will:
• filter runoff pollution and improve water quality
• conserve water while recharging local groundwater and protecting rivers / streams
• remove standing water from yard and reduce mosquito breeding
• create habitat for birds and butterflies as well as increase beneficial insects that
eliminate pest insects
• reduce garden maintenance, increase garden enjoyment and enhance curb appeal
Through the Sustainable Communities Initiative led by Drs. Hossay and Chirenje, the
Richard Stockton College participates in workshops and projects that help
communities improve their energy efficiency and other areas of sustainability.
Two classes taught by Drs. Chirenje and Hossay conducted an environmental audit
of Galloway township from January to May 2007. A recommendation from the water
group was to reduce stormwater flow from the complex (flows into Patriot Lake).
The objective of the Galloway Project was to build a rain garden that would intercept
run-off from the front parking lot of the municipal building before it reached the storm
drains and proceeded to Patriot Lake.
www.urbanwaterquality.org/RainGardens/LIDRG1.jpg
Why use rain gardens?
http://www.apwa.net/Images/Publications/Reporter/Maplewood1.JPG
Understanding the importance
of rain gardens is vital to not
only our homes, businesses,
and towns, but also to the
ecosystem. Through decades
of development, we have
covered our once lush and
permeable land with
impervious roofs, driveways,
parking lots, and roads, thereby
reducing the site’s predeveloped evapotranspiration
and infiltration rates.
Clearing and grading can remove surface depressions that store rainfall.
Construction activities also compact the soil and diminish its infiltration rate,
resulting in increased rates and volumes of stormwater runoff from the
development site. This causes not only flooding, but also lowers the vital
water tables below ground. Water tables rely on the infiltration of water over
long periods of time.
Adopted from : http://www.nashville.gov/stormwater/images/raingarden_BarrExample2.jpg
Rain gardens generally slow down the rush of water from hard surfaces (including
lawns), holding water and allowing it to naturally infiltrate into the ground. Other
important features include:
• Filtration of runoff from roofs, driveways and lawns.
• Conservation of water resources by reducing the need for irrigation.
• They are an aesthetic way for homeowners, businesses and
municipalities to help ease storm water problems.
• Restoration of the functions of wooded wetlands removed by land
development
• More efficient absorption of runoff – 40% more than a standard lawn control.
• Construction of a rain garden is cost efficient, requires less technical
experience – often, no permits or heavy equipment required to install.
Dr. Hossay’s Municipal Policies and Dr. Chirenje’s Intro to Pollution classes
and volunteers have been working on the site since 08/30/07.
Above: The crew spreads the organic top soil, and Ecomat (to reduce soil
erosion) and rocks to slow down the flow of the runoff into the garden
Seven months later
Eight months later
These underground water storage “facilities” act as natural filtration systems
for pollution such as metals, suspended solids, hydrocarbons, pathogens,
and nutrients. They feed our rivers and streams which not only provide
homes for innumerable species, but also perform other ecological functions.
Precipitation catchment areas
Rain garden schematic
Six months later
http://www.carlson-art.com/lifescience/water-runoff_lg.jpg
Flow channels
designed to
reduce erosion
Native or low
maintenance
non-native
plants
Choice of plants
depends on soil
type, amount of
shade and water
reaching garden
http://www.montgomerycountymd.gov/Content/DEP/Rainscapes/images/garden_head.jpg
Infiltration basin, must allow drainage of excess
water not absorbed by plants
Berm to hold
water in basin
and prevent
overflow
New Jersey Stormwater Rules
Rain gardens are especially useful now, given the urgency to treat stormwater as a
significant contributor of non-point source pollution. The Stormwater Management
rules, N.J.A.C. 7:8 specify stormwater management standards that are mandatory
for new major development. The New Jersey Stormwater BMP manual provides
guidance for these rules. They establish that stormwater needs to be retained and
treated on site for all new major developments, whereas in the past stormwater
flowed directly into sewers and subsequently sent to treatment plants.
Challenges
Some local homeowner’s rules are not flexible enough to allow rain gardens
in front yard; the cultural aesthetic of “lawn appeal” is difficult to change, and
rain gardens not widely promoted by developers and municipal governments.
Acknowledgements
The authors would like to thank Mr. Conover and Berenato from the Atlantic County
Utility Authority for their ecosoil donation and student volunteers who donated their
time on this project. Funding for the project came from the Richard Stockton College
Day of Service Committee to whom we are grateful.