Q
CANOPY TREES
GREEN ALLEYS
Louisville Metropolitan Sewer District
(MSD) installed multiple green
infrastructure projects in the watershed,
including:
•	Planting more than 115 canopy
trees,
•	Installing green alleys with infiltration
trenches and permeable pavers at
Magnolia Alley and Ormsby Alley,
respectively.
These installations include nearly
$788,000 for a green roof and
infiltration practices at the Business
School; the Grawemeyer Oval; Speed
Museum; and, the Ekstrom Library.
Favorable sandy soils in the area
contributed to the application of
infiltration practices and maximized the
volume of stormwater removed from
the combined sewer system.
http://www.msdlouky.org/aboutmsd/streaml
ine/2015/StreamLine 08-2015.pdf
PROJECT PARTNERS
MSD has met extensively with the Old Louisville
Neighborhood Association and Park Hill
neighborhood residents as well as University
stakeholders to discuss green infrastructure and
flood mitigation opportunities. After the 2009 flood
event, the University of Louisville included green
infrastructure as part of its master plan, which
spurred the density of green infrastructure on its
campus.
CENTRAL LOUISVILLE GREEN
INFRASTRUCTURE PARTNERSHIP
LOUISVILLE, KENTUCKY
The Partnership is an innovative approach to addressing stormwater and
regulatory compliance while enhancing the life of its urban residents
PROJECT DESCRIPTION
Pursuant to the federal consent
decree issued In 2005, Louisville
and Jefferson County MSD
developed an Integrated Overflow
Abatement Plan (IOAP) to correct
violations of the Clean Water Act
(CWA). The IOAP proposed a suite
of projects, the majority of which
were gray infrastructure such as
storage basins, to provide
additional system capacity to
reduce combined sewer overflows
(CSOs). MSD, with the assistance
of Heritage Engineering, modeled
sewersheds using the InfoWorks
Collection Systems platform.
In some basins, model results
supported strategic placement of
green infrastructure practices to
replace proposed gray
infrastructure storage basins and
reduce CSOs to the regulated level
of control. MSD developed a green
infrastructure financial Incentive
program based on model results
from the targeted sewersheds to
encourage the use of green
infrastructure and thereby improve
water quality and reduce the
frequency and volume of combined
sewer overflows.
This 1,400-acre urban watershed—
located in central Louisville—
includes the University of Louisville
Belknap Campus; residential,
commercial and industrial land
uses; and major rail and highway
transportation	corridors.
Historically, the area drained to a
tributary/slough of Mill Creek,
before area surface streams were
piped to carry combined
stormwater and wastewater. In the
early to mid-1800s, nearly 26 miles
of streams were piped, and 560
miles of combined sewer system
were installed. This area now
drains to the combined sewer
system, which discharges to the
Ohio River.
Since the piping removed surface
streams from sight, over time,
developments were built in flood-
prone areas. This includes
sections of the University of
Louisville Campus and the Park
Hill neighborhood, which
experienced severe flooding in
1997, 2006, 2009 and 2011.
Floodwaters caused more than $25
million in damages at the
University alone during the August
4, 2009 event (7.5 inches in less
than 1 hour).

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GREEN STREETS SUCCESS STORIES
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PURPOSE/OBJECTIVE
The Central Louisville Green Infrastructure Partnership is the result of
MSD's forward thinking desire to simultaneously achieve regulatory
compliance while reducing flooding and enhancing the quality of life for
Louisville's urban residents. The goals of the Central Louisville Green
Infrastructure Partnership include reducing the number and volume of
CSOs; reducing flooding around the University of Louisville campus;
reducing cost of CSO controls to ratepayers; and, increasing project
benefits to the community.
APPROACH
In light of repeated flooding—and the availability of MSD's green
infrastructure financial incentives program—the University of Louisville and
other area property owners partnered with MSD to install green
infrastructure.
LESSONS LEARNED
The project has demonstrated a significant positive impact on the
environment and community. With no surface streams in the area, green
infrastructure is used to reduce impervious area, increase tree canopy,
provide open space, and capture and infiltrate stormwater that would
otherwise travel through gray infrastructure and treatment plant effluent to
the Ohio River, or overflow through combined sewer overflows. The green
infrastructure projects treat the first flush of stormwater and reduce the
volume and frequency of these combined sewer overflows, thereby
lowering levels of bacteria that pollute the Ohio River.
Project information transfer within the clean water industry has included
both local partners and national researchers. Leveraging partnerships
with the University of Louisville and EPA Office of Research and
Development (ORD), the project research, including planning, SUSTAIN
water quality modeling, design, construction and post-construction
monitoring have been documented and disseminated to national peers.
Project impacts have been supported by the EPA, who provided peer
review and also recognized Louisville's work with green infrastructure in a
memo titled "Protecting Water Quality with Green Infrastructure in EPA
Water Permitting and Enforcement Programs" as a benchmark example of
meeting regulatory requirements with the use of green infrastructure. The
green infrastructure knowledge gained from this project is now a key
component of a new graduate-level class, as well as a capstone design
class that MSD staff teaches at the University of Louisville, focusing on
effective design and implementation of green infrastructure.
POINT OF CONTACT
Wes Sydnor, MS4 Program Manager
700 W. Liberty St.
Louisville, KY 40203
502-540-6274
For more information, please visit www.epa.gov/g3
to
msd
RESULTS/OUTCOMES
This project enabled
successful implementation of
key portions of the Phase I
stormwater quality MS4
permit program including
requiring green infrastructure
on new development,
demonstrating viability of
green	infrastructure,
outreach and education. The
project is a successful
component of MSD's
implementation of a consent
decree for combined sewer
overflows.
These projects have
combined to remove more
than 123,000,000 gallons of
stormwater, and nearly
300,000 gallons of Combined
Sewer Overflow in a typical
year. In addition to infiltrating
stormwater,	reducing
flooding and combined sewer
overflows, the project also
provided ancillary aesthetic
benefits to the project area
cityscape— including open
space, tree cover and paver
blocks to revitalize and
support	underserved
communities in this area.
Per U.S. Census data
estimates for 2013, the
area's median household
income (zip code 40208) was
$25,760. The data also
revealed income for nearly
29 percent of households
below $15,000 annually.
The green infrastructure
projects reduce the
magnitude and frequency of
combined sewer overflows.
Offloading the system
mitigates flooding and
combined sewer overflows
and basement backups,
thereby improving the quality
of life for area residents.

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