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Intensive Track-Down Work Benefits Water Quality in the Norwalk River
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in Connecticut's Norwalk River.
The small coastal stream in the Southwest Coast Watershed of Connecticut
has been degraded by urban runoff from residential and commercial sources affecting biological communities and
recreation. Because Norwalk River segment CT7300-00_G4 failed to meet the bacteria water quality standards
(WQS) for recreation, the Connecticut Department of Energy and Environmental Protection (DEEP) added it to the
state's Clean Water Act (CWA) section 303(d) list in 2002. Efforts to track down and address leaking septic systems
and other bacteria sources have led to improved water quality, allowing DEEP to remove Norwalk River segment 04
from the 2014 list of impaired waters for bacteria. Two other adjacent Norwalk River segments (7300-00_03a and
7300-00_05) were removed from the impaired waters list in 2012.
Problem
The 25-mile Norwalk River is influenced by commercial
and residential development. The river is heavily used
by recreational fishermen. Hydrology is influenced by
impervious cover, groundwater discharge and, and
discharges from two wastewater treatment plants
(WWTP). Both WWTP discharges are disinfected with
ultraviolet light from April 1 to October 1. Pollution
sources include WWTP discharges, impervious sur-
faces, septic systems, pet and animal waste, and lawn
care. Aquatic life use support is impacted by point and
nonpoint source (NPS) pollution, and by flashy flows and
elevated temperatures from runoff.
Data collected beginning in 1998 showed that Norwalk
River segment CT7300-00_04 often failed to meet WQS
for recreation, which require that the Escherichia coli
bacteria geometric mean values not exceed 126 colony-
forming units (cfu) per 100 milliliters (mL). As a result,
DEEP added this segment to the state's list of impaired
waters in 2002 (Figure 1). DEEP completed a total maxi-
mum daily load (TMDL) analysis in 2006, which estab-
lished that bacteria loads in segment 04 must be reduced
by 39 percent to meet WQS for recreational use.
Project Highlights
Harbor Watch at EarthPlace has conducted ambient
water quality monitoring and source track-down work
(pollution source investigation and identification)
throughout the Norwalk River watershed for 18 years.
Local municipalities (e.g., town of Wilton), nongovern-
mental organizations (NGOs) (e.g., Trout Unlimited),
and private foundations recognize the value of and
have contributed funding annually to sustain the
Norwalk River monitoring and track-down program.
Figure 1. Segment 04, in the headwaters of the the 64-square-
mile Norwalk River watershed, begins at the inlet of Factory
Pond in Wilton and extends upstream to Cooper Pond Brook,
which is downstream of Branchvilie Road in Ridgefield.
Norwalk River Watershed
Redding
;CT730(W)0_04
Sewage Treatment Plants
~ Municipal
A Private
CT7300-00_01
CT7300-00_02
CT7300-00_03a
CT7300-00_03b
CT7300-00_03c
CT7300-00_04
CT7300-00_05
CT7300-02_01
CT7300-02_02
New Ca'naan*
CT7300-07_01
CT7300-07_02
CT7301-00_01
CT7301-00_02
CT7302-00_01
Norwalk*
CT7302-00_02
Stamfo'rd
CT7302-13_trib_01

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Several sources of pathogens affecting this segment
have been identified and corrected. High E. coli counts
were detected in the river near the Branchville rail sta-
tion in 2012. Volunteer monitoring staff located a bac-
teria source near a residence on an upstream tributary
(Figure 2). The Ridgefield Inlands Wetlands Agent was
notified; their investigation revealed a cesspool leaking
into the brook The system was upgraded under orders
in 2013.
Detailed investigations indicated
that sources of E. coli were enter-
ing a ditch draining to Cooper Pond
Brook. Volunteer monitoring program
staff coordinated with the Ridgefield
Heaith Department, who worked with
property owners to improve their
septic system management practices.
Another intermittent discharge from
a septic system with an undersized
leaching field was also discovered and
was required to be corrected by the town of Wilton in
june 2013. Monitoring program data helped the town
locate and identify the illicit discharge.
Harbor Watch staff have reported on water quality
data at Norwalk River Watershed Initiative (NRWI)
meetings since the NRWI was organized in 1998. The
NRWI is an extensive collaboration of watershed stake-
holders, NGOs, municipalities, and state and federal
agencies. Timely updates on water quality provided
at those meetings results in a network of people who
are concerned with the river's health, act as good
stewards, and take timely action to address identified
problems and prevent new problems.
£. coli GeoMean Values for Norwalk River Segment
just above Factory Pond, Wilton/Ridgefield, CT
gure 2. Volunteers.
Results
Harbor Watch's volunteer monitoring program has been
Collecting ambient water quality data in the Norwalk
River since 2000. Data collected in 2015 showed a mean
E. coli level of 98 cfu/100 mL in segment 04, indicating
that the segment now meets WQS and the TMDL target
for E. coli bacteria, and is fully supporting its designated
use of contact recreation (Figure 3). As a result, DEEP
removed it from Connecticut's 2014 list of impaired
waters. This segment is between two other Norwalk
River segments that were removed from the impaired
waters list in 2012: segment CT7300-00_03a (near
Stonehenge Road) and segment CT7300-00_05 (near
Old Mill Road in Wilton).
350
300
250
^ 200
£ 150
100
50
2004 2005 2006	2008	2010 2011 2012 2013 2014 2015
	Geomean cfu/100 ml 	Fully Supporting below 126 cfu/100 mL
Figure 3. £ coli geomean values now meet WQS.
Partners and Funding
Collaboration by NRWI members has shown that
Increased awareness and behavioral change can solve
NPS pollution problems. Harbor Watch at EarthPlace
used CWA section 319 funding ($30,000) to conduct
extensive water quality monitoring and track-down
surveys for the program's first 3 years; since then,
other sources of funding have supported the program.
Local health and public works departments have
issued active abatement orders and other efforts when
NPS pollution sources are located, leading to source
reductions. Current collaborations include a project
with the Westport Weston Health District, Connecticut
Agricultural Experiment Station, and Yale University
to conduct a CWA section 319-funded genome source
tracking analysis for pathogens, using quantitative
polymerase chain reaction (qPCR) analyses alongside
conventional E. coli testing to determine pathogen
sources in three coastal streams.
The towns of Wilton and Ridgefield have been involved
with track-down work and follow-up with property
owners to remove pollution sources in areas found to
have high ambient E. coli counts. The Trout Unlimited
Mianus Chapter has funded additional track-down and
monitoring work.
CT DEEP has worked cooperatively with Harbor Watch
in the Norwalk Regional and other subregional basins,
providing CWA sections 319 and 604b funding for
ambient monitoring and track-down survey work, fol-
lowing up on reports of pollution, and attending NRWI
meetings to encourage other NRWI members to work
to correct identified sources of NPS pollution. The
U.S. Environmental Protection Agency has provided
funding support to NRWI partners through the Urban
Waters Program and the CWA sections 319 and 604(b)
programs.
^tDS7"X
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U.S. Environmental Protection Agency
Office of Water
Washington, DC
EPA 841-F-17-001Z
November 2017
For additional information contact:
Sarah Crosby, Harbor Watch at EarthPlace
203-557-4403 • s.crosby@earthplace.org
Christopher Malik, Connecticut Department of Energy
and Environmental Protection
860-424-3959 • christopher.malik@ct.gov

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