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The American Recovery and Reinvestment Act (ARRA), Green Reserve of 2009, through the State Revolving Fund,
provides funding for a wide variety of qualifying projects in the categories of: green infrastructure, energy efficiency,
water efficiency, and other innovative projects. For more information on ARRA, to find out if your current or future
planned project meets the necessary criteria, and how to apply, visit www.Recovery.gov.
Green Street designs provide better environmental
performance while creating attractive, safer environments.
A Green Street
is a street that uses
natural processes
to manage
stormwater runoff
at its source.
Streets comprise a significant percentage of
publicly owned land in most communities, and
thus offer a unique opportunity to manage for
environmental outcomes. A Green Street uses a
natural systems approach to reduce stormwater
flow, improve water quality, reduce urban
heating, enhance pedestrian safety, reduce
carbon footprints, and beautify neighborhoods.
Through various combinations of plants and
soils, these objectives—and several others—
can be met on different types of streets in
many settings. Green Street features include
vegetated curb extensions, sidewalk planters,
landscaped medians, vegetated swales,
permeable paving, and street trees. This guide
provides an overview of different strategies that
can be employed in transportation rights-of-
way at the local or neighborhood scale.
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Green Streets
www.Recovery.gov
Residential
Streets
STORMWATER CURB EXTENSIONS
PERMEABLE PAVING
VEGETATED SWALES
Residential streets offer the greatest potential for
building Green Streets in new neighborhoods or
retrofitting existing streets because the streets
are typically slower, less trafficked, and likely to
already have some landscape elements.
These days, it is fairly common for homes to have
rain gardens incorporated into their landscaping to
collect and store stormwater runoff from rooftops,
driveways, and patios. "Rain garden'ls the general
term used to describe stormwater strategies that
use plants and soils to filter, absorb, and slow
rainwater on the landscape surface.
Similar types of rain gardens can take various forms
within the street right-of-way itself—the edges of
the street can be built to allow stormwater to flow
into a landscape area, or space within the paved
area of the street can be converted to landscape,
increasing permeability. Additionally, permeable
paving that is durable, load-bearing, and built with
an underlying reservoir can temporarily store water
prior to infiltration.
In new construction situations, Green Streets
can be designed to handle significant volumes
of water. In retrofit situations, they can typically
handle all of the rain from small storms, while
excess water from large storms can overflow into
existing storm sewer systems.
Rain gardens are beautiful
landscape features that
naturally filter runoff and
require less maintenance
than turf grass.
STORMWATER CURB EXTENSIONS
Conventional curb extensions
(also known as curb bulb outs,
chokers, or chicanes) have
been used for decades to
enhance pedestrian safety and
help in traffic calming.
A stormwater curb extension
simply incorporates a rain
garden into which runoff flows.
TYPICAL STREET
OPPORTUNITY
IMPLEMENTATION
Optional: Existing curb and planting
strip can Be retained as is or
incorporated into curb extension
Street tree —\
Vegetated
curb extension
Conventional landscape—, \
r \ \
On-street parking—\
^Two-way car travel
20' minimum
through zone
&EPA
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Green Streets
www.Recovery.gov
I PERMEABLE PAVING
Permeable paving (pavers,
or porous asphalt and
pervious concrete) in the
parking lane converts
impervious surfaces to allow
stormwater to absorb into the
ground, which reduces the
amount of runoff without any
loss of parking on the street.
The aesthetics of permeable
paving can also give the
illusion of a narrower street
and therefore help calm traffic.
EXISTING
Existing driveway—\
Conventional
landscape—\
OPPORTUNITY
\
-On-street parking
IMPLEMENTATION
^Pervious pavers
/
/ ^Concrete band,
/ / flush with pavers
\
-*. i r
^Travel lane allows one
/ car to pass while the car
traveling in the opposite
direction waits in the
parking zone
VEGETATED SWALES
Swales are long, shallow
vegetated depressions, with
a slight longitudinal slope.
As water flows through the
swale, it is slowed by the
interaction with plants and
soil, allowing sediments
and pollutants to settle out.
Water soaks into the soil and
is taken up by plants, and
may infiltrate further into
the ground if the soil is well-
drained.
EXISTING
Sidewalk
Street tree
OPPORTUNITY
IMPLEMENTATION
^Vegetated swale on one
' side of the street
fc- Two-way car travel
On-street parking on one
/ side of the street only
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Green Streets
www.Recovery.gov
Commercial
Streets
STORMWATER PLANTERS
STORMWATER CURB EXTENSIONS
PERMEABLE PAVING
Commercial streets in most urban areas need to
accommodate a wide range of users and uses
including pedestrians, drivers, bikers, transit
riders, on-street parking, outdoor seating,
lighting, trees, etc. Because of all these demands,
finding space to collect and manage stormwater
can at first appear challenging. There are,
however, several design options that towns and
cities can consider when integrating stormwater
mangement into even their most active streets.
The key is thinking creatively in finding space
that can accommodate multiple purposes in one
space, such as a street tree pit designed to collect
runoff, or the curb extensions (also known as
"pedestrian bulb outs") at the corners designed
to reducing crossing distances for pedestrians
that can also contain a rain garden. These design
options are more easily accommodated in new
streets where the location of underground
utilities is considered from the start. More
strategic design is necessary for streets with
existing utilities. The pay-off of these efforts,
though, is a more attractive, walkable street
that considerably reduces polluted runoff.
A community's identity is
often most evident on its
commercial streets.
Green Street techniques not
only achieve environmental
goals but can greatly
improve the look and feel
of a community.
STORMWATER PLANTERS
Planters are long, narrow land-
scaped areas with vertical walls
and flat bottoms, typically open
to the underlying soil.They
allow for more storage volume
than a swale in less space.
Water flows into the planter,
absorbs into the plants and
topsoil, fills to a predetermined
level, and then, if necessary,
overflows into a storm sewer
system. If desired, planters can
accommodate street trees.
TYPICAL STREET
Sidewalk—\
On-steet parking—A
Bicycle lane—A\
OPPORTUNITY
—Stormwater planter
IMPLEMENTATION
Building frontage
/- Conventional landscape
Two-way
car travel
^Reduced
r Stormwater entry/exit r Pedestrian egress zone / pedestrian
/ curb cut ' ' / : -
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Green Streets
www.Recovery.gov
ISTORMWATER CURB EXTENSIONS
Stormwater curb extensions
on commercial streets are
similar to those on residential
streets.They are rain gardens
typically located near the
corners that can also provide
the pedestrian with a more
comfortable crossing.
Curb extensions can also
be located mid-block by
converting one or more
parking spaces.
EXISTING
OPPORTUNITY
Sidewalk—\
Angled parking A
\\
Street tree —\ \\
IMPLEMENTATION
^Building frontage
^Pervious paving /^Stormwat r curb extensio
PERMEABLE PAVING
Permeable paving on
commercial streets can be
incorporated into sidewalks
and parking lanes.
Recent advances in permeable
paving technologies now
make many appropriate for
higher speeds or where large,
heavy vehicles are expected
to be parked—areas such as
loading zones and bus stops.
EXISTING
Sidewalk—,
On-steet parking—A
Bicycle lane—\\\
_^~- \\\
OPPORTUNITY
IMPLEMENTATION
r~Stormwater curb extension/—Pervious pavers
** roA
v>EPA
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Green Streets
www.Recovery.gov
Arterial
Streets
VEGETATED SWALES
Arterial streets in towns and cites are
often characterized by wide expanses of
pavement, little greenery, and little to address
pedestrian needs. Should an arterial street
already have landscape areas adjacent to
the roadway or within grassy medians, then
retrofitting these areas to accommodate
rainwater will significantly reduce runoff
and help protect water quality.
Where adjacent landscape space does not
exist, a process of "road dieting" can be
undertaken. This involves determining just
how much paved surface is necessary to
safely manage travel, and how much can
be converted to green space. In addition to
managing runoff, this is also an opportunity
to retrofit the functionality of arterial
streets, making them more "multi-modal" by
incorporating sidewalks, on-street bike lanes,
or landscape-separated bike green ways.
Again, as with residential and commercial streets,
though it is easier to plan and design all of these
uses into a roadway from the beginning, most
arterials present opportunities to incorporate
Green Street features, and can be highly successful.
Busy arterials need
not only be a conduit
for traffic. They have
the potential to be
attractive, green
boulevards that reduce
runoff and reinforce a
community's identity.
VEGETATED SWALES
Like residential streets, arterial
roadways are good street
types for swales because they
typically have long, linear
stretches of uninterrupted
space that can be used
to manage stormwater.
Some arterials may not have
landscape space in place
but do have travel lanes or
paved shoulders that can be
narrowed to create space for
swales.
TYPICAL STREET
Street trees
Side swale
OPPORTUNITY
IMPLEMENTATION
Sidewalk
•ccrj
\ f
L/IV JZ
a
ArteriaI Streets
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Green Streets
www.Recovery.gov
Alleys
PERMEABLE PAVING
VEGETATED SWALES
In many towns and cities, alleys comprise a
significant amount of impervious surface and
are sometimes prone to flooding because they
are often not connected to the sewer system.
Green Street techniques like vegetated swales
and permeable paving effectively reduce and
treat runoff, alleviate flooding, and are far less
expensive than installing connections to sewers.
Alleys are the "low-hanging
fruit" of Green Street
design—a good starting
point for towns and cities
to begin incorporating
stormwater management.
PERMEABLE PAVING
Alleys are typically low-speed
and low-trafficked streets and
therefore suitable locations
for using permeable paving.
The entire surface could be
permeable, or if heavier vehicles
are anticipated for loading
and u nloading, or the alley is
"reversed crowned" (sloping
toward the center line), then
only the middle section needs
to be permeable.
TYPICAL ALLEY
OPPORTUNITY
IMPLEMENTATION
I VEGETATED SWALES
If the alley is crowned in such
a way that water flows to the
side, then stormwater can be
accommodated by simply
greening edges of the alley
with swales and planters.
If necessary, water can
flow through pipes or
covered trenches to allow
vehicle access to garages
and driveways.
TYPICAL ALLEY
OPPORTUNITY
IMPLEMENTATION
Illustrations and photographs used in this brochure are from the EPA publication
Stormwater Management Handbook-Implementing Green Infrastructure in Northern Kentucky
Communities and were created by Nevue Ngan Associations of Portland, Oregon.
This handbook, as well as other valuable resources, are available at both
www.epa.gov/smartgrowth andwww.epa.gov/greeninfrastructure.
EPA-833-F-09-002 August 2009 www.epa.gov/greeninfrastructure
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