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IG A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS

WATER QUALITY
RESEARCH PROGRAM

Green Infrastructure Approaches to Urban Stormwater Management

Issue

Stormwater runoff is a major cause of
water pollution. In an undeveloped
environment, pervious ground surfaces
filter and absorb stormwater from rain
events as the runoff flows into nearby
waters. In an urban setting with large
amounts of impervious surfaces, much
more of the rainwater is directly
routed into engineered stormwater
collection systems.

In many older cities, the water
collection systems combine
stormwater with wastewater in
combined sewer overflows (CSOs)
before carrying it to wastewater
management systems for treatment.
Heavy-volume rain or snow events can
overburden the collection and
treatment systems, resulting in
overflows of untreated wastewater
(including chemical and microbial
pollutants) into nearby receiving
waters. This can result in unsafe
recreational and drinking water, as
well as potential harm to vegetation,
fish, and other aquatic life.

Research is needed to provide
information, methods, and tools that
will enable states and communities to

make more informed decisions on
cost-effective and more sustainable
ways to control stormwater runoff.

Application and Impact

EPA provides scientific and engineering
expertise to evaluate stormwater
control measures and to develop new
tools for decision making. EPA
stormwater management research
efforts focus on best management
practices (BMPs) to reduce the volume
of runoff and prevent discharge of
pollutants.

Traditionally, most BMPs for
stormwater control consist of "grey"
infrastructure (e.g., grate inlets) that
channel water through constructed
networks of drains and pipes. More
recently, "green" infrastructure
approaches (e.g., rain gardens, wet
ponds, swales, green roofs, porous
pavements, and constructed wetlands)
are being incorporated to restore more
natural water cycles to urban
environments. Onsite, green
approaches to stormwater
management are becoming more
preferred as they can be more cost
effective and provide additional

benefits such as pollutant removal and
ecosystem restoration.

Research Highlights

Modeling Tools

Storm Water Management Model
(SWMM)

The EPA SWMM model simulates the
quantity and quality of runoff
generated during rain or snowfall
events. SWMM is being used in
hundreds of projects throughout the
world to manage the impacts of
stormwater on wastewater treatment
facilities.

Current SWMM extensions are under
development to explicitly model green
infrastructure controls along with
traditional infrastructure approaches
such as stormwater collection systems.
The updated SWMM model will allow
engineers and planners to accurately
represent a combination of green
infrastructure controls within a study
area to determine their effectiveness
in managing stormwater and combined
sewer overflows.

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I U.S. Environmental Protection Agency

I Office of Research and Development


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System for Urban Stormwater
Treatment and Analysis INtegration
(SUSTAIN)

SUSTAIN is a decision support system
designed to facilitate the selection and
placement of optimal green
infrastructure techniques at strategic
locations in urban watersheds.

SUSTAIN is currently being applied to
various case studies to demonstrate
how the tool can identify the cost
effectiveness and hydrologic response
of various stormwater management
solutions.

Permeable Parking Lot and Rain
Garden Studies

In 2009, EPA completed construction
of an experimental, stormwater
management parking lot at its research
facility in Edison, N J. Researchers are
using the parking lot to demonstrate
and document the effectiveness of
three permeable pavement surfaces:
porous asphalt, porous concrete, and
interlocking concrete pavers. EPA will
study the performance capabilities of
the parking lot under various
conditions, and will evaluate water
quality.

An experimental rain garden has been
created alongside the parking lot,
which will allow EPA to measure the
ability of the rain garden to reduce
stormwater runoff from nearby roof
tops and the impermeable surfaces of
the lot.

Andrew W. Breidenbach (A HBERC)
Environmental Research Center
Green Infrastructure Demonstration

In collaboration with the University of
Cincinnati, and the Cincinnati
Metropolitan Sewer District (MSD),
EPA researchers will select and
implement green infrastructure best
management practices to manage wet
weather flow on the Cincinnati
AWBERC campus. Modeling will be
used to estimate the potential

effectiveness of various green
infrastructures to manage urban
stormwater.

Community-Scale Studies
EPA is conducting case studies in
several communities to evaluate the
effectiveness of green infrastructure in
managing stormwater and protecting
water quality.

Researchers are investigating the
impacts and benefits of best
management practices on runoff
volume, occurrence of overflows from
combined sewer treatment systems,
water quality, ecological integrity,
nutrient management, community
revitalization, and economic incentives
and benefits.

Study locations include communities
in:

•	Cincinnati, Ohio

•	Cleveland, Ohio

•	Baltimore, Maryland

•	Louisville, Kentucky

•	Kansas City, Missouri

These research projects will contribute
to a better understanding of how to
manage stormwater runoff and control
combined sewer overflows in urban
communities. They also demonstrate
how to enhance monitoring programs
for watershed management and
restoration efforts.

Resources:

Urban Watershed Management

http://www.epa.gov/ednnrmri/

Aging Water Infrastructure Research

http://www.epa.gov/awi/res concepts.html

SWMM (Version 5) and SUSTAIN

http://www.epa.gov/nrmrl/wswrd/mmd.html

Contacts:

Alice Gilliland, (513) 569-7852 or
giiiiiand.alice@epa.gov

Michelle Latham, (513) 569 -7601 or
iatham.micheile@epa.gov

U.S. Environmental Protection Agency

Office of Research and Development

JULY 2010


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