2012 summer-silvermine river - NORWALK RIVER WATERSHED

Water Quality Data Report
For
The Silvermine River and Lower Norwalk River Storm Drains
May 2012 through August 2012
Silvermine River bank erosion at site SM4
Submitted by:
Richard Harris, Principal Investigator, Staff Scientist/Director of the Harbor Watch (HW) Program at
Earthplace, Westport, CT, Phone (203) 227-7253
Peter Fraboni, Associate Director & QA/QC Officer for the Harbor Watch Program at Earthplace,
Westport, CT
Nicole Cantatore, Quality Assurance Officer for the Harbor Watch Program at Earthplace, Westport, CT
Josh Cooper, Coastal Studies Technician for the Harbor Watch Program at Earthplace, Westport, CT
Toni Pawlowski and Amy Varga, Norwalk Mayor’s Water Quality Committee summer interns 2012
i
Table of Contents
Index of Figures and Tables
Acknowledgements
iii
iv
Abstract
Introduction
Research Zones
Methods and Procedures (Zones A, B, and C)
v
1
1
5
Section I
Introduction, Zone A (Upper Silvermine River)
Results, Zone A
Discussion, Zone A
6
6
9
Section II
Introduction, Zone B (Lower Silvermine River)
Results, Zone B
Discussion, Zone B
11
11
14
Section III
Introduction, Storm Drains (Lower Norwalk River)
Results, Storm Drains
Discussion, Zone Drains
16
16
19
Section IV
Keeler Brook
21
Final Conclusions
22
Appendix A References
Appendix B Photographs
A
B
ii
Index of Figures and Tables
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Table 1
Table 2
Table 3
Table 4
Map of Zone A for the Silvermine River from Borglum Road South to the Perry Avenue
Bridge, showing six monitoring sites on the Silvermine River and three sites on Belden
Hill Brook
Map of Zone B for the Silvermine River from the Silvermine Elementary School to James
Street showing nine monitoring sites on the Silvermine River
Map of five storm drains discharging to the lower Norwalk River and one site at the
Wall Street Bridge where the Norwalk River enters the Norwalk River Estuary
Map of four storm drains discharging to the Norwalk River Estuary
Map of three monitoring sites on the Silvermine River and two sites on Belden Hill
Brook around the margin of the Silvermine Sanctuary property
Observed maximum, geometric means, and minimum values for E. coli bacteria
concentrations at six monitoring sites in Zone A of the Silvermine River and three sites
on Belden Hill Brook from May to August 2012
Observed maximum, mean, and minimum values for dissolved oxygen (DO) at six
monitoring sites in Zone A of the Silvermine River and three sites on Belden Hill Brook
from May to August 2012
Observed maximum, mean, and minimum values for conductivity (µS) at six monitoring
sites in Zone A of the Silvermine River and three sites on Belden Hill Brook from May to
August 2012
Recorded rainfall for four months from the Norwalk Health Department
Observed maximum, geometric mean, and minimum values of E. coli bacteria
concentrations (CFU/100mls) at eight monitoring sites on the Silvermine River (Zone B)
from May through early August 2012
Observed maximum, mean, and minimum values for dissolved oxygen (DO) at eight
monitoring sites on the Silvermine River (Zone B) from May through early August 2012
Observed maximum, mean, and minimum values for conductivity (µS) at eight
monitoring sites on the Silvermine River (Zone B) from May through early August 2012
Observed maximum, geometric mean, and minimum values of E. coli bacteria
concentrations (CFU/100mLs) at nine storm drain outflows discharging into the lower
Norwalk River and Norwalk River Estuary from May through July 2012
Observed maximum, mean and minimum conductivity values (µS) at five storm drain
outflows discharging into the lower Norwalk River from June through July 2012
Observed maximum, mean and minimum salinity values (ppt) at four storm drain
outflows discharging into the Norwalk Estuary from May through July 2012
Map of Keeler Brook previously established and tested sites
CT DEEP criterion for E. coli bacteria levels as applied to recreational use effective
2/25/11
Observed E. coli bacteria concentrations, geometric means, and % frequency exceeding
576 CFU/100mLs at six monitoring sites in Zone A on the Silvermine River, and three
sites on Belden Hill Brook from May to August 2012
Observed conductivity (µS) maximum, mean, minimum at six monitoring sites in Zone A
of the Silvermine River and three sites on Belden Hill Brook from May to August 2012
Observed E. coli bacteria concentrations, geometric means, and % frequency exceeding
576 CFU/100mLs at eight monitoring sites on the Silvermine River, (Zone B) from May
through early August 2012
2
2
3
4
5
7
8
8
9
12
13
13
17
18
19
21
6
7
9
12
iii
Table 5
Table 6
Table 7
Table 8
Table C1
Table C2
Table C3
Table C4
Table C5
Observed conductivity (µS) maximum, mean, and minimum values plus individual site
ranges at eight monitoring sites on the Silvermine River (Zone B) from May through
early August 2012
Observed E. coli concentrations (CFU/100mLs) and geometric means at five storm drain
outflows discharging into the lower Norwalk River from June through July 2012
Observed E. coli concentrations (CFU/100mLs) and geometric means at four storm
drain outflows discharging into the Norwalk River Estuary from May through July 2012
Observed fecal coliform and E. coli (CFU/100mls) bacteria levels at 11 temporary
monitoring sites upstream and downstream of site KB2 on 7/16 and 7/31
Site Coordinates, GPS
Site numbers, descriptions and GPS coordinates for six monitoring sites on Silvermine
River and three sites on Belden Hill Brook
Site numbers, descriptions and GPS coordinates of eight sites in Zone B of the
Silvermine River
Site name, site description, and GPS Coordinates of five storm drains discharging to the
lower Norwalk River
Site name, site description and GPS Coordinates of four storm drains discharging into
the Norwalk River Estuary
GPS Coordinates of preliminary research sites on Keeler Brook
14
17
18
22
10
15
20
20
Acknowledgements
Harbor Watch (HW) wishes to thank the following individuals, departments and agencies for their help
with the summer-time investigation and research of the following areas: Norwalk’s storm drain systems,
the lower Norwalk River, the Norwalk Estuary, the Silvermine River and Keeler Brook. None of this would
have been possible without funding provided by the EPA, the CT DEEP, the NRG Power Plant, King
Industries, The Town of Wilton, The Town of Ridgefield, The City of Norwalk, Trout Unlimited (the
Mianus and Nutmeg Chapters), The Norwalk River Watershed Association, Inc., and the Sun Hill
Foundation. An additional employee, laboratory and dock space as well as technical help and fund
raising support were generously provided by Norman Bloom and Son Oysters and Clams.
Harbor Watch also wishes to thank the following departments and agencies for their help in the
investigation of storm drain systems and rivers for pollution sources. Areas studied during the summer
of 2012 included the Silvermine River, the lower end of the Norwalk River, the Norwalk River Estuary
and Keeler Brook thanks to funding provided by The Norwalk Shellfish Commission and the Norwalk
Health Department under the direction of the Mayor’s Water Quality Committee. A special thanks goes
to Jan Schaefer, Chair Person of the Mayor’s Water Quality Committee who arranged a grant from
Newman’s Own Foundation to assist HW in completing the large monitoring project on the Norwalk
River Watershed. HW was provided the use of two Norwalk summer interns, Amy Varga, a recent
graduate of UNH and, Toni Pawlowski, a junior at UConn to complete the field and lab work. Both
students, majoring in environmental sciences, turned in the enclosed assessment of the Lower
Silvermine River, the Lower Norwalk River and the major Norwalk River Storm drains discharging to the
lower Norwalk River and the Norwalk River Estuary as well as an initial bacteria survey of Keeler Brook.
The Norwalk Public Works and Conservation Departments helped by providing drawings of the storm
sewers and technical background. Mike Yeosock, Senior Civil Engineer, was particularly helpful in
providing maps on drainage systems and was quick to follow up on leads provided by HW on possible
sources of sewage infiltration.
iv
HW also wishes to thank the Norwalk Health Department for taking the time to survey areas where HW
felt that pollution problems existed after extensive testing turned up elevated bacteria counts. Tom
Closter, Director of Environmental Services, was always available to walk the suspected sites and help
HW gain access to monitoring sites located on private property. The Norwalk Public Health laboratory
has also been a great support in helping HW do inter lab work in cross checking samples to meet EPA
and CT DEEP quality assurance requirements.
It is also fitting to recognize Chris Malik of CT DEEP who has helped obtain EPA funding (319 and 604B)
on a total of eight storm drain systems to date which will allow HW to undertake a detailed analysis of
these systems and find sources of sewage infiltration and/or illegal cross connections. Chris has also
provided extensive background information on Keeler Brook and Tim Bridges of the EPA’s technical
group in Chelmsford Mass (EPA Region I) has helped with complimentary tests for pollution from
pharmaceuticals and other man-made products to further support the work of HW. All the support
mentioned above helped complete the work in a team effort. This research would not be successful or
completed without the people and resources mentioned above.
Richard Harris
Director Harbor Watch, a Program of Earthplace.
Abstract:
Harbor Watch (HW), the volunteer water quality program of Earthplace, the Nature Discovery Center,
has the overall mission of maintaining and improving the biological integrity of rivers and estuaries
within Fairfield County. HW works with the Norwalk Mayor’s water Quality Committee each summer to
monitor the Silvermine and Norwalk rivers, the Norwalk River Estuary and more recently Keeler Brook in
an effort to 1) locate sources of indicator bacteria impairment from numerous storm drain discharges to
both rivers; 2) protect the rivers from ill-advised residential management practices along the river
banks; and 3) assess the bacteria concentrations entering the Norwalk and Silvermine Rivers from
pollution sources upstream.
Dissolved oxygen (DO) levels, conductivity, temperatures, and water samples are taken weekly.
Membrane filtration is performed for fecal coliform and E. coli bacteria at the Earthplace laboratory. E.
coli input profiles affected by various weather patterns and stream flow are extrapolated from the data
to help find sources in the waterways of elevated bacteria counts. The result of this survey shows the
lower Silvermine and Norwalk rivers and numerous storm drain discharges to be moderately polluted
with E. coli bacteria. Keeler Brook and some of the storm drains discharging to the Norwalk River Estuary
are heavily polluted and will be further investigated by HW under a CT DEEP contract and a Connecticut
Department of Agriculture Grant during the fall of 2012 and spring of 2013.
v
Introduction:
Toni Pawlowski, a junior at University of Connecticut, and Amy Varga a graduate of University of New
Hampshire, were hired by the Norwalk Mayor’s Water Quality Committee under Jan Schaefer. Both
were assigned to HW and began monitoring water quality in late May and completed their work in
August of 2012. These interns worked with trained volunteers under the direction and oversight of the
HW program to investigate the health of the lower watershed of the Silvermine and Norwalk rivers as
well as monitoring nine continuously running storm drain discharges to the Norwalk River and the
Norwalk River Estuary. The objective of the water monitoring research was to discover sources of
bacterial (E. coli) pollution from point and non-point sources.
Research Zones
During the summer of 2012, the Silvermine workload focused on three zones indicated as A, B, and
storm drain discharges to the lower Norwalk River and the Norwalk River Estuary (Figure 1, Figure 2,
Figure 3, Figure 4). The first of these zones, running from Borglum Road to the Silvermine Tavern at
Perry Avenue, is referred to as Zone A. This section of the Silvermine River and Belden Hill Brook has
been studied over 6 years to monitor the effect of a large hobby farm on water quality. The farm
property is poorly located for housing farm animals on a property that is situated between the two
water bodies. The Silvermine River and Belden Hill Brook form a confluence at the southern end of the
farm property (Figure 5). Over the years, water quality has slowly improved as farm animals (including
two llamas) have been relocated by the owner to other locations. The original farm owners moved away
18 months ago along with the rest of the farm animals. The new owners show little interest in boarding
farm animals on the property. This change of ownership will prove to be very beneficial to water quality
of Belden Hill Brook.
Zone B, is located in the Silvermine River starting at the Silvermine elementary school property, which
borders the river and flows south to James Street (Figure 2). Zone B was first explored in detail by the
2008 Norwalk Mayor’s Water Quality Committee interns because of elevated E. coli bacteria counts
found at site SM3 (Figure 2). In addition, new sites were established in the slower moving ponds that
characterize the Silvermine River in that section south of the Merritt Parkway Bridge downstream
(south) to James Street (Figure 2). As with 2009, 2010 and 2011, the lower Silvermine River was found
to be moderately polluted with E. coli bacteria.
Nine large, continuously running storm drains are discharging fresh water to the lower Norwalk River
(Figure 3) and the Norwalk River Estuary (Figure 4). They are monitored every two weeks under a
variety of weather conditions to assess the extent of E. coli bacteria input and to rank the discharges in
order of priority for eventual repairs. Over the past few years elevated bacteria counts were recorded
from the discharge of these drains to the lower Norwalk River (Figure 3) which re-focused the research
the HW effort to include several marine drains discharging to the harbor waters (Figure 4). Continued
monitoring, research, and repairs to the infrastructure are essential to promote the health of the lower
Norwalk River and the estuary.
1
Figure 1 Map of Zone A for the Silvermine River from Borglum Road South to the Perry Avenue Bridge,
showing six monitoring sites on the Silvermine River and three sites on Belden Hill Brook
Figure 2 Map of Zone B for the Silvermine
River from the Silvermine Elementary
School to James Street showing nine
monitoring sites on the Silvermine River
2
Figure 3 Map of five storm drains discharging to the lower Norwalk River and one site at the Wall Street
Bridge where the Norwalk River enters the Norwalk River Estuary
3
Figure 4 Map of four storm drains discharging to the Norwalk River Estuary
4
Figure 5 Map of three monitoring sites on the Silvermine River and two sites on Belden Hill Brook
around the margin of the Silvermine Sanctuary property
Note: Monitoring site BH6.4D lies to the north on Musket Ridge Road.
Methods and Procedures:
Protocol established in the HW EPA approved Quality Assurance Project Plan (QAPP #10160, approved
9/16/2010) for the Norwalk River explains the methods used for water quality monitoring. Testing is
carried out on a daily basis. The interns leave Earthplace, located in Westport, CT, before 10 AM and
generally return in the early afternoon after testing the Silvermine River or storm drain discharges. The
testing of the Silvermine River centers on monitoring levels of E. coli bacteria because of swimming and
fishing safety issues (Table 1).
Conductivity (QAPP Appendix A3.8) and Dissolved Oxygen (QAPP Appendix A3.3) are run in situ with
meters. General observations, time, water temperature, and air temperature are recorded at each site,
with the information entered on a HW Data Sheet (QAPP Appendix A5.1). Water samples are also taken
at each site by inserting a sterilized bottle upside down and turning it underwater to prevent obtaining
surface films or disturbing the river bottom (QAPP Appendix A1.1).
Membrane filtration tests for fecal coliform and E. coli bacteria are performed after returning to the HW
state certified lab located at Earthplace (QAPP Appendix A3.13). These tests are analyzed following
Standard Methods, 21st edition (9222D, 9222G) and recorded in the HW Bacteria Log (QAPP Appendix
A5.1).
The Silvermine water quality is evaluated against the “all other recreational uses” bacteria geometric
mean of <126 CFUs/100 mLs, and a single sample maximum (SSM) of 576 CFUs/100 mLs.
5
Table 1 CT DEEP criterion for E. coli bacteria levels as applied to recreational use effective 2/25/11
Designated Use
Class
Indicator
Criteria
Recreation
Designated Swimming AA, A, B Escherichia coli Geometric Mean less than 126/100
CFU;*Single Sample Maximum 235/100
Non-designated
AA, A, B Escherichia coli Geometric Mean less than 126/100 CFU;
Swimming
Single Sample Maximum 410/100
All Other Recreational AA, A, B Escherichia coli Geometric Mean less than 126/100 CFU;
Uses
Single Sample Maximum 576/100
*Colony Forming Units, a single E. coli cell which grows to visible size under the proper food source
and incubation temperature as provided in the laboratory where it can be counted
Section I
Introduction, Zone A:
Zone A extends from Borglum Road to the Perry Avenue Bridge (Figure 1). The area is fully developed
along the river with mostly older homes on large properties of one or more acres. All properties depend
on septic systems for the disposal of human wastes. A new development of very large houses is on the
west bank of the river just north of the Silvermine Tavern (Perry Avenue Bridge). While the river banks
around the Borglum Road site SM9 (Figure 1) show adequate riparian buffer, some evidence of poor
property management at a few locations downstream exists along the river with yards mowed to the
water’s edge. All of this has taken a toll on water quality due to river bank erosion. Some of the
homeowners also have been overly aggressive with tree and riparian vegetation removal resulting in
partially degraded river banks. A major impact on the waterway over the years has been a small farm
built between the Silvermine River and Belden Hill Brook complete with a compliment of farm animals
(Figure 5). The original owner moved 18 months ago along with the remaining farm animals. The new
owner shows little interest in boarding farm animals.
Recent tests of Belden Hill Brook now show a slight increase in E. coli bacteria input to the brook
upstream (to the Northeast) of the Silvermine Sanctuary property at site BH6.4D (Table 2). It would
appear that other sources of E. coli bacteria are developing (Table 2). Another area of original concern
was the elevated bacteria counts observed at site SM6, the base of the dam at the Silvermine Tavern.
The closing of the Tavern’s restaurant is a possible cause of improvement to water quality at this
location (Table 2).
Results, Zone A:
Observed bacteria counts at all sites on the Silvermine River Watershed meet the CT DEEP geometric
mean criterion for a Class B river in concert with “all other recreational uses” of <126 CFU/100mLs
(Table 1, Figure 6). All sites also meet the CT DEEP secondary, single sample maximum (SSM) criterion of
having <10% of all samples taken at a single site being < 576 CFUs/100mLs (Table 1, Table 2, Figure 6).
Observed dissolved oxygen (DO) mean values and all individual DO concentrations meet the CT DEEP
criterion of 5 mg/L or greater for a Class B river (Figure7).
Observed conductivity means on most of the Silvermine River and Belden Hill Brook excluding the small
tributary at the Silvermine Tavern (site SM 6.1) fall into a range of a minimum of 200µS at site BH6.4A
and site BH6.4B and a maximum of 352µS at site SM6.1 (Table 3, Figure 8). Individual site ranges for
6
conductivity are a maximum of 539µS at tributary site SM6.1 to a minimum of 50µS at site BH6.4A
(Table 3, Figure 8).
Table 2 Observed E. coli bacteria concentrations, geometric means, and % frequency exceeding 576
CFU/100mLs at six monitoring sites in Zone A on the Silvermine River (SM), and three sites on Belden Hill
Brook (BHB) from May to August 2012
SM9
SM8
SM7
SM6.3
SM6.1
SM6
BH6.4D
BH6.4A
BH6.4B
Rain (in)
Days Prior
5/24/2012 6/6/2012
164
108
100
72
56
140
76
84
56
64
52
76
28
68
20
68
44
40
0.11
0.22
0
1
7/9/2012
68
28
52
48
320
76
196
56
96
0.05
5
% Frequency
Exceeding 576
8/2/2012 Geomean CFU/100mLs
36
81
0%
24
47
0%
20
53
0%
32
56
0%
148
114
0%
98
74
0%
156
87
0%
76
49
0%
104
65
0%
0.95
5
Figure 6 Observed maximum, geometric means, and minimum values for E. coli bacteria concentrations
at six monitoring sites in Zone A of the Silvermine River and three sites on Belden Hill Brook from May to
August 2012
E. coli (CFUs/100mLs)
1000
Max
Geomean
Min
a
100
10
1
SM9
SM8
SM7
SM6.3
SM6.1
SM6
BH6.4D
BH6.4A
BH6.4B
Sites
a CT DEEP geomean maximum for a Class B river
7
Figure 7 Observed maximum, mean, and minimum values for dissolved oxygen (DO) at six monitoring
sites in Zone A of the Silvermine River and three sites on Belden Hill Brook from May to August 2012
12.0
Max
Average
Min
Dissolved Oxygen (mg/L)
10.0
8.0
6.0
a
4.0
2.0
0.0
SM9
SM8
SM7
SM6.3
SM6.1
SM6
BH6.4D
BH6.4A
BH6.4B
Sites
a CT DEEP geomean minimum for a Class B river
Figure 8 Observed maximum, mean, and minimum values for conductivity (µS) at six monitoring sites in
Zone A of the Silvermine River and three sites on Belden Hill Brook from May to August 2012
800
Max
Average
Min
700
Conductivity (uS)
600
500
400
300
200
100
0
SM9
SM8
SM7
SM6.3
SM6.1
SM6
BH6.4D
BH6.4A
BH6.4B
Sites
8
Table 3 Observed conductivity (µS) maximum, mean, minimum at six monitoring sites in Zone A of the
Silvermine River and three sites on Belden Hill Brook from May to August 2012
SM9
258
224
198
60
Max
Average
Min
Range
SM8
254
223
197
57
SM7
258
224
198
60
SM6.3
252
222
199
54
SM6.1
728
352
190
539
SM6
254
219
191
63
BH6.4D
314
219
176
139
BH6.4A
224
200
174
50
BH6.4B
228
200
175
53
Figure 9 Recorded rainfall for four months from the Norwalk Health Department
8
7
Rainfall (in)
6
5
4
3
2
1
0
May
June
July
August
Average
Month
Discussion, Zone A:
This summer had an above average rate of precipitation. May received 6.99 inches, June received 6.92
inches, and July received 6.83 inches of rainfall (Figure 9). All of the observed E. coli data for the
Silvermine River and Belden Hill Brook are relatively constant and show stability with the exception of
site SM6.1 on 7/9 (Table 2, Figure 6). Site SM6.1 had an observed maximum bacteria count of 320
colonies/100 mL (Table 2, Figure 6). Even though this number is well above the average maximum
number of colonies found at all nine monitoring sites in the monitoring program for Zone A, it does not
exceed the CT DEEP SSM criterion for a Class B river. Since every monitoring site meets the CT DEEP E.
coli criteria on the four testing dates, storm water runoff from the Silvermine Sanctuary farm may not be
a source of impairment to Belden Hill Brook (Table 1, Table 2, Figure 6).
Observed DO means and daily concentrations of DO observed at each monitoring site all meet the CT
DEEP DO criteria for a Class B river of 5 mg/l or greater (Figure 7).
Observed conductivity means on the Silvermine River and Belden Hill Brook monitoring sites are fairly
uniform (Table 3, Figure 8). Based on observed conductivity values alone, the Silvermine River and
Belden Hill Brook in Zone A appear to be fairly stable with little increase in bacteria counts produced by
9
storm water runoff (Table 3, Figure 6, Figure 8). The wide ranges of conductivity values observed at site
SM6.1 (un-named tributary) and site BH6.D (northernmost site on Belden Hill Brook) of 538µS and
138µS respectively may possibly be due to storm water runoff and/or iron ions provided by a rusting
metal pipe (Figure 1, Table 3).
Table C1 Site numbers, descriptions and GPS coordinates for six monitoring sites on Silvermine River and
three sites on Belden Hill Brook
Site No.
Site Description
GPS Coordinates
Latitude:N41º09'34.7"
SM9
Borglum Road Bridge
Longitude: W073º 27' 09.5"
Latitude:N41º09'24.2"
Sm8
Silvermine Ave. Next to Red Barn
Longitude: W073º 26' 59.0"
Latitude:N41º09'14.2"
Sm7
Silvermine Ave.
Longitude: W073º 26' 55.2"
Latitude:N41º09'28"
BH6.4D
Musket Ridge Road Bridge
Longitude: W073º 26' 55.2"
11 Mail Coach Drive downstream from
Latitude:N41º09'12.7"
BH6.4B
Slivermine Sanctuary, upstream of BH6.4A
Longitude: W073º 26' 51.4"
11 Mail Coach Drive downstream from
Latitude:N41º09'11.9"
BH6.4A
Slivermine Sanctuary
Longitude: W073º 26' 52.1"
Confluence of Belden Hill Brook and the
Latitude:N41º09'10.8"
SM6.3
Silvermine River
Longitude: W073º 26' 51.6"
Latitude:N41º09'03.9"
SM6.1
Side Stream Next to the Silvermine Tavern
Longitude: W073º 26' 49.1"
Latitude:N41º09'05.0"
SM6
Perry Avenue Bridge
Longitude: W073º 26' 44.4"
10
Section II
Introduction Zone B:
The lower end of Silvermine River widens into a series of ponds and backwaters as the waterway
approaches its confluence with the Norwalk River at Deering Pond (Figure 2). Stream flow is reduced as
the river enters the ponds and the water deepens. This condition results in the deposition of fine silt
from land erosion upstream and the disposal of leaves, and yard waste into the river resulting in the loss
of hard river bottom in many places.
The lower Silvermine River, from site SM5 at the Silvermine School to site SM3 at James Street (Figure 1,
Figure 2) appears to be continually affected by poor property management, including the mowing of
lawns to the edge of the river, which results in erosion of the riverbank. A historical example of such an
occurrence can be seen behind the Silvermine Elementary School, where the Norwalk River Watershed
Initiative tried to stabilize the banks with “J hooks”, or large stone emplacements, to deflect the water
away from the west bank (Appendix B). A very large storm on April 15, 2007 accomplished just the
opposite. The J hooks were overridden, the west bank was severely eroded with the loss of trees, and
the river bed shifted twenty feel to the west (Appendix B). No effort, with the exception of the removal
of fallen trees by the city of Norwalk, was made to repair the damage. Another good example of stream
bank erosion is found at HW monitoring site SM4 (Figure 2, Appendix B). Trees continue to fall here as
the river undercuts the banks.
Three storm drain systems in Zone B that discharge into the Silvermine River were again monitored to
determine the volume of indicator bacteria (E. coli) in the discharge. Two sites, SM3.5 and SM4 Pipe,
showed light pollution levels (Table 1, Table 4, Figure 10, Appendix B). Site SM3.1 Pipe (a newly rebuilt
bypass pipeline to relieve the pressure of flood conditions at a dam upstream) was randomly tested in
an effort to assure that bacteria levels were substantially reduced after the failed septic system at #7
James Street was replaced during the fall months of 2010. Exploration of the lower end of Zone B of the
Silvermine River stopped at James Street, site SM3 (Figure 2).
Results, Zone B:
Sites SM3.5 and SM5 of Zone B meet the CT DEEP criterion for E. coli geometric mean of <126
CFUs/100mLs (Table 1, Table 4, Figure 10). Only sites SM3.5 and SM4 meet the secondary CT DEEP
criterion of a single sample maximum (SSM) of 576 CFU/100mLs for a Class B river (Table 1, Table 4).
Sites SM3, SM3.3, SM3.6, SM3.7, SM 4, SM4 Pipe, and SM5 exceed the both the CT DEEP geometric
mean and the SSM criterion (Table 4, Figure10).
All observed dissolved oxygen (DO) means meet the CT DEEP criterion of 5mg/L or greater for a Class B
river at eight monitoring sites in Zone B (Figure 11). Site SM4 Pipe fell below the CT DEEP criterion on
one individual sampling day (Figure 11). This site had a reading of 2.0 mg/L on 8/6.
Observed conductivity means range from a minimum of 222µS at site SM 4 to a maximum of 405µS
observed at site SM3.5 (Table 5, Figure 12). Site SM3.5 shows an elevated conductivity mean in
comparison to the other sites of Zone B (Table 5, Figure 12). Conductivity ranges at individual sites
varied from a minimum of 56µS at site SM3.5 to a maximum of 94uS at site SM3.3 (Table 5, Figure 12).
Site SM3.5, the site with the highest observed conductivity mean of 405µS also has the minimum site
range of 56µS of all sites tested (Table 5, Figure 12).
11
Table 4 Observed E. coli bacteria concentrations, geometric means, and % frequency exceeding 576
CFU/100mLs at eight monitoring sites on the Silvermine River, (Zone B) from May through early August
2012
SM3
SM3.3
SM3.5
SM3.6
SM3.7
SM4
SM4 Pipe
SM5
Rain (in)
Days Prior
6/4/2012 6/19/2012 6/26/2012 7/10/2012 7/24/2012 8/6/2012 Geomean
252
200
276
104
400
3000
347
156
108
400
252
500
1700
336
140
20
204
272
76
250
120
204
92
256
300
540
1900
338
252
72
212
440
400
1900
330
180
56
236
68
280
135
1560
104
660
156
280
5500
543
48
152
36
610
113
0.13
1.37
0.59
0.05
0.24
0.25
1
6
1
6
0
0
% Frequency
Exceeding 576
CFU/100mLs
17%
17%
0%
17%
17%
0%
50%
25%
Figure 10 Observed maximum, geometric mean, and minimum values of E. coli bacteria concentrations
(CFU/100mls) at eight monitoring sites on the Silvermine River (Zone B) from May through early August
2012
10000
Max
Geomean
Min
E. Coli (CFUs/100mLs)
1000
a
100
10
1
SM3
SM3.3
SM3.5
SM3.6
SM3.7
SM4
SM4 Pipe
SM5
Sites
a CT DEEP geomean maximum for a Class B river
12
Figure 11 Observed maximum, mean, and minimum values for dissolved oxygen (DO) at eight
monitoring sites on the Silvermine River (Zone B) from May through early August 2012
12.0
Max
Average
Min
Dissolved Oxygen (mg/L)
10.0
8.0
6.0
a
4.0
2.0
0.0
SM3
SM3.3
SM3.5
SM3.6
SM3.7
SM4
SM4 Pipe
SM5
Sites
a CT DEEP geomean minimum for a Class B river
Figure 12 Observed maximum, mean, and minimum values for conductivity (µS) at eight monitoring sites
on the Silvermine River (Zone B) from May through early August 2012
450
Max
Average
Min
400
Conductivity (uS)
350
300
250
200
150
100
50
0
SM3
SM3.3
SM3.5
SM3.6
SM3.7
SM4
SM4 Pipe
SM5
Sites
13
Table 5 Observed conductivity (µS) maximum, mean, and minimum values plus individual site ranges at
eight monitoring sites on the Silvermine River (Zone B) from May through early August 2012
Max
Average
Min
Range
SM3
285
244
200
85
SM3.3
290
242
196
94
SM3.5
426
405
370
56
SM3.6
267
227
186
81
SM3.7
267
228
186
82
SM4
249
222
183
65
SM4 Pipe
290
257
223
67
SM5
259
223
181
78
Discussion, Zone B:
The average rainfall from May to July, 2012, is 6.91 inches, slightly more than the monthly average of 4.5
inches (Figure 9). Three monitoring days, 6/26, 7/24, and 8/6, appeared to have bacteria counts
increased by rainfall (Table 4). In particular, all Zone B sites, with the exception of site SM3.5,
experienced marked increases in bacterial counts on 7/24.
Site SM3.3 is located near the Department of Social Services off of the entrance bridge to the parking lot
(Figure 2, Table C2). Storm water runoff could be the possible cause of elevated E. coli levels at site
SM3.3 or a polluted discharge from the adjoining pond from one or more of the Department of Social
Services (DDS) buildings on the pond’s shoreline could be the root cause of the problem (Figure 2).
Sites SM3.6 and SM3.7, which are both found north of the Merritt Parkway, are located on two adjacent
properties (Figure 2). Site SM3.6, located next to a home, has a rock wall along the riverbank. The
homeowner’s lawn extends up to the wall, making the yard a direct source of storm water runoff
contamination. Site SM3.7, located upstream of the home adjacent to site SM3.6, has very little riparian
buffer in the form of vegetation, and the river is level with the homeowner’s lawn which would allow
storm water runoff to flow from the lawn straight into the river. The homeowner’s two dogs have free
use of the yard, which is a likely source of E. coli contamination. There has also been a large amount of
erosion observed on the riverbank opposite of where testing is conducted at site SM3.7.
Site SM5 meets both the CT DEEP E. coli geometric mean but exceeds the Single Sample Maximum
(SSM) (Table 4, Figure 10). This particular site was processed in the HW lab on only three of the five
days, however, because the incoming sample bottles were accidentally misplaced due to high volume of
samples in the lab on both test days (Table 4). The geometric mean for site SM5 could possibly be
affected with the addition of two more samples.
With the exception of site SM4 Pipe on 8/6, all observed DO means and individual measurements meet
the CT DEEP criterion of 5 mg/L or greater at all sites (Figure 11). There are a number of factors that
could have caused a low reading at site SM4 Pipe such as high temperatures, organic products
undergoing biological decomposition in the effluent and/or reduced flow from the storm drain network.
The observed conductivity means for six of the eight monitoring sites ranges from a minimum of 222uS
at site SM4 to a maximum of 405uS at sites SM3.5 (Table 5, Figure 12). The six remaining sites are main
river locations and are fairly close in mean conductivity values which while elevated, point to a system
which has partial stability in the face of extreme weather conditions. The range of conductivity at each
of the six sites is somewhat wider than what exists at the monitoring sites in Zone A (Table 3, Table 4,
Figure 8, Figure 12). This is possibly due to the more developed nature of the river banks in Zone B which
lack riparian buffer in many instances and show many advanced cases of stream bank erosion (Appendix
B).
14
Site SM3.5 and site SM4 Pipe are both storm drain discharges and both were observed with elevated
conductivity values (Table 5, Figure 12, Appendix B). Site SM3.5 is a small continuously running storm
drain network along Silvermine Avenue on the west side of the river and is an anomaly with an elevated
conductivity mean of 405µS and a narrow conductivity range of only 56µS as observed over the duration
of the testing cycle (Figure 2, Table 5, Figure 12). Site SM4 Pipe is also a continuously running storm
drain discharge to a small pond which subsequently joins the Silvermine River just to the north of site
SM4 on the east bank of the Silvermine River (Figure 2). It also has an elevated conductivity mean of
257µS with a somewhat wider conductivity range of 67µS (Table 5, Figure 12). Of the two pipes only site
SM4 Pipe showed a significantly elevated bacteria count of 5500 CFU/100mls on 8/6 during a light
rainfall of 0.25 inches (Table 4, Figure 10). Conductivity values observed in Zone B reflect poor property
management practices. Many lawns are mowed to the water’s edge which allows storm water runoff to
carry fertilizers, pesticides, and pet waste directly to the river. An example of this practice is observed at
site SM 3 and others along the Silvermine River (Appendix B). Conductivity means for an undisturbed
stream in Fairfield County range from 100 to 125uS (HW records).
Removal of natural riparian buffer over time has accelerated stream bank erosion (Cover Photo,
Appendix B). This practice has exposed tree roots, which causes trees to eventually fall into the river.
Uprooted trees expose large pockets of open soil and gravel which are further eroded by rain storms
and rising river waters. Examples of this are seen at sites SM5 and SM4. The observed practice of
homeowners blowing leaving and grass clippings into the river in combination with silt from eroded
properties has turned the hard stony river bottom into a soft muck. This precludes fish and amphibians
from using the bottom for reproductive purposes. Home owners appear to be oblivious to the
consequences of their actions and it may now be too late to reverse the damage done to the river
banks. It is not too late, however, to replace poor property management with best management
practices. All it takes is homeowner education and understanding how they affect the river ecology with
poor property management. This has proven to be a tall order.
Table C2 Site numbers, descriptions and GPS coordinates of eight sites in Zone B of the Silvermine River
Site No.
Site Description
GPS Coordinates
Latitude:N41º08'09.8"
SM3
James Street
Longitude: W073º 26' 6.1"
Latitude:N41º08'15"
SM3.3
DMR Bridge
Longitude: W073º 26' 21.4"
Latitude:N41º08'17.3"
SM3.5
Silvermine Ave Drainage Pipe
Longitude: W073º 26' 25.9"
Latitude:N41º08'18.4"
SM3.6
North of the Merritt Parkway
Longitude: W073º 26' 23.8"
Latitude:N41º08'21.4"
SM3.7
North of the Merritt Parkway
Longitude: W073º 26' 27.2"
Latitude:N41º08'43.5"
SM4
Singing Woods Drive
Longitude: W073º 26' 31.6"
Latitude:N41º08'45.3"
SM4 Pipe
Singing Woods Drive Drainage Pipe
Longitude: W073º 26'28.2"
Latitude:N41º08'50.7"
SM5
Silvermine Elementary School
Longitude: W073º 26' 35.2"
15
Section III
Introduction, Fresh and Salt Water Storm Drains:
The storm drains section of the lower Norwalk River under investigation extends from the Linden Street
storm drain discharge to the Norwalk River south to the toe of the Norwalk estuary at Wall Street
(Figure 3, Figure 4). The lower end of the Norwalk River is characterized by the input from one hundred
storm drains. Several of these are quite large (up to 6 feet in diameter) with continually running
discharges, the result of piping away small streams so that the overlying land could be utilized for
structures. The subject of this section is the continued monitoring of nine storm drain discharges which
have been problematical over the past ten years in terms of elevated E. coli bacteria levels. The banks in
the lower section of the Norwalk River are characterized by an almost total loss of wetlands and most
riparian buffers. An exception to this characterization is the remaining tree line between New Canaan
Ave and Route 1 (Figure 3). Going downstream, the river banks are lined by light industry, a large
medical building, asphalt plants and marinas (Figure 3, Figure 4). The river has been dramatically
reshaped to mitigate flooding. Open space has been converted to parking lots all along the banks of the
area. The storm drains in the lower Norwalk River are a prime example of where protection of the
river’s ecology was given little thought during all the development that has occurred over the last 200
years. The unintentional cumulative effect of all this is the creation of a man-made waterway which has
lost most of its natural amenities, is unhealthy, has poor tidal flushing, and is visually unappealing. The
cost of remedial efforts at this point is unimaginable and not contemplated. Nevertheless, repair of the
large infrastructure (the largest polluter) is possible and should be undertaken and maintained as funds
become available1.
Storm drains discharging to the estuary (Figure 4) are partially flooded by marine water at high tide. This
necessitates taking bacteria samples at low tide to ensure mostly fresh water for the testing cycle.
Results:
Four storm drain outflows discharging into the lower Norwalk River, Linden St, New Canaan Ave,
Medical Center, and School St, exceed the CT DEEP criterion for E. coli bacteria for both the geometric
mean (<126 CFU/100mLs) and the single sample maximum (SSM) or less than 10% of all samples taken
at a single site may exceed 576 CFU/100mLs (Table 1, Table 6, Figure 13). Perry Ave passes the E. coli
bacteria geomean criterion, but exceeds the SSM (Table 6, Figure 13). All four major storm drain
outflows (Moody’s Lane, Washington St, Total Marine, and Calf Pasture) that discharge into the Norwalk
Estuary also exceed the CT DEEP E. coli criteria and SSM (Table 7, Figure 13).
Observed conductivity means range from a maximum of 1092µS at the Medical Center outflow to a
minimum of 328µS at the New Canaan Ave outflow for the five storm drain outflows discharging into
the lower Norwalk River. The widest conductivity range is observed at the Medical Center outflow with a
range of 1285µS while the narrowest conductivity range is observed at the Perry Ave outflow with a
range of 190µS.
Observed salinity means range from a maximum of 21.8ppt at the Total Marine outflow to a minimum
of 1.9ppt at the Moody’s Lane outflow for the four storm drain outflows discharging into the Norwalk
River Estuary. The widest salinity range is observed at the Calf Pasture Outflow with a range of 23.3ppt
while the narrowest salinity range is observed at the Moody’s Lane outflow with a range of 8.4ppt.
1
The large storm drain network at Moody’s Lane has been investigated by HW, the Norwalk Health Department and Public Works Department.
The degree of cooperation has led to finding a “hot spot” between Buckingham Place and Lockwood Lane (2009). As a large Norwalk Public
Works project replacing the existing storm sewer advanced up Lockwood Ave, construction workers discovered over 700 feet of failed sewer
pipes at the hot spot previously identified by HW. The 70 year old pipe was infiltrating sewage to the storm drain. The sewer pipe has been
replaced by Norwalk’s DPW.
16
Figure 13 Observed maximum, geometric mean, and minimum values of E. coli bacteria concentrations
(CFU/100mLs) at nine storm drain outflows discharging into the lower Norwalk River and Norwalk River
Estuary from May through July 2012
1000000
Max
Geomean
Min
E. coli (CFUs/100mLs)
100000
10000
1000
a
100
10
1
Sites
a CT DEEP geomean maximum for a Class B river
Table 6 Observed E. coli concentrations (CFU/100mLs) and geometric means at five storm drain outflows
discharging into the lower Norwalk River from June through July 2012
Linden St
Perry Ave
New Canaan Ave
Medical Center
School St
Rain (in)
Days Prior
6/1/2012 6/11/2012 6/27/2012 7/2/2012 7/18/2012 7/23/2012 8/1/2012 8/20/2012
1100
450
690
600
1600
21000
2900
700
1
10
150
100
110
10000
1
20
3000
120
3700
300
2300
29000
4200
520
60
160
110
1700
3100
13000
1000
1
2500
320
700
1500
2000
26000
340
320
0.36
0.24
0.59
0.2
0.19
0.52
0.18
0.87
3
6
2
3
0
0
3
2
Geomean
1391
37
1662
304
1215
% Frequency
over 576
CFU/100mLs
88%
13%
63%
50%
63%
17
Table 7 Observed E. coli concentrations (CFU/100mLs) and geometric means at four storm drain
outflows discharging into the Norwalk River Estuary from May through July 2012
% Frequency
over 576
5/14/2012 5/30/2012 6/13/2012 6/25/2012 7/11/2012 7/25/2012 8/9/2012 Geomean CFU/100mLs
Moody's Lane
2000
7000
11000
29000
53000
15000
28000
13883
100%
Washington St
200
2200
15000
17000
26000
2000
6000
4458
86%
Total Marine
1
15000
680000
140000
1300
7000
600
3597
86%
Calf Pasture Outflow
28
8000
3400
19000
10
1700
700
778
71%
Rain (in)
0.78
0.32
1.34
0.59
0.05
0.24
0.25
Days Prior
4
1
0
0
7
1
3
Figure 14 Observed maximum, mean and minimum conductivity values (µS) at five storm drain outflows
discharging into the lower Norwalk River from June through July 2012
1600
Max
Average
Min
1400
Conductivity (uS)
1200
1000
800
600
400
200
0
Linden St
Perry Ave
New Canaan Ave
Medical Center
School St
Sites
18
Figure 15 Observed maximum, mean and minimum salinity values (ppt) at four storm drain outflows
discharging into the Norwalk Estuary from May through July 2012
30.0
Max
Average
Min
25.0
Salinity (ppt)
20.0
15.0
10.0
5.0
0.0
Moody's Lane
Washington St
Total Marine
Calf Pasture Outflow
Sites
Discussion, storm drains:
Weather conditions specified in the discussion of Zone A tend to be fairly wet during the early summer
months of May and June with normal and 1.5 times normal rainfall respectively. In particular, on 6/13,
6/25 and 7/25 heavy rainfall affected the flow through storm water drainage networks and resulted in
elevated bacteria counts (Table 6, Table 7). Elevated E. coli bacteria levels were also observed
throughout the entire summer at Norwalk Estuary sites Moody’s Lane and Washington Street even
during dry weather (Table 7).
Bacteria samples collected during the summer of 2012 show an array of pollution inputs (Table 6, Figure
13). All five outflows discharging into the lower Norwalk River responded with greatly elevated bacteria
counts on 7/23 to a rain of 0.52 inches just prior to testing (Table 6). These sites are being contaminated
by a variety of sources to include infiltration from aged and failing sewer lines, illegal hookups and, in
some instances, an oversupply of waterfowl.
The outflows discharging into the Norwalk River Estuary were all greatly affected by rainfall on 6/13,
6/25, and 7/25 which resulted in dramatic increases in E. coli bacteria counts (Table 7). Most of this
infrastructure is old; some parts of these pipelines exceeding 70 years in age. Older pipeline materials
range from clay pipe to cast iron. All the sources of bacteria listed for the pipes discharging into the
lower Norwalk River also apply to the pipes discharging to the marine waters with one major difference;
salt water has access to many of these pipelines at high tide which complicates identification of input
sources and repairs. At Total Marine in South Norwalk, manholes over one hundred yards from the
harbor fill with salt water at high tide. With Harbor Watch acting as a bacteria screening source, the
Norwalk Public Works Department has made several repairs to Calf Pasture, Total Marine, and Moody’s
19
Lane to eliminate sources of sewage infiltrate. While the repairs greatly reduced the input of E. coli
bacteria to the harbor during calm weather, pollution problems persist in heavy rain (Table 7).
Wide conductivity ranges in the five storm drain outflows discharging into the lover Norwalk River point
to instability in the storm drain system. Wide salinity ranges in the four storm drain outflows discharging
into the Norwalk River Estuary are caused by salt water influence during periods of high tides. Harbor
Watch is still unclear how long it takes for each storm drain system to flush out the salt water in
between tides, but sampling only occurs at low tide to reduce the impact of the marine water. Moody’s
Lane is the only outflow discharge that sits high enough above the tide line to avoid impact from salt
water infiltration.
Harbor Watch has recently obtained funding from the Connecticut Department of Agriculture and the
EPA to resume pipeline screening analysis on several large pipelines to include Total Marine,
Washington Street, and School Street. With the support of the Norwalk Health, Conservation and Public
Works Departments, Harbor Watch will help identify more areas which may require repair. The EPA of
Region 1 (Chelmsford, MA) has helped HW in this task with pharmaceutical analysis and the loan of a
sophisticated pipeline camera. Hopefully the cumulative effect of this collaboration will be clean water
in Norwalk Harbor, and protection for the Norwalk shellfish industry.
Table C3 Site name, site description, and GPS Coordinates of five storm drains discharging to the lower
Norwalk River
Site Name
Site Description
GPS Coordinates
Dirt road parallel to railroad
N41º 08’ 12.3”
Linden
tracks off Perry Ave
W073º 25’ 34.3”
Discharge on East side of Perry N41º 08’ 8.1”
Perry
Ave bridge abatement
W073º 25’ 32.3”
Rear parking lot of Medical
N41º 07’ 09.7”
Medical
Center at 40 Cross St
W073º 25’ 10.7”
West across parking lot from
N41º 07’ 11.2”
School Street
Ash Creek Saloon
W073º 25’ 4.1”
Downstream on west bank
N41º 07’ 33.9”
New Canaan
from New Canaan Ave bridge
W073º 25’ 44.7”
Table C4 Site name, site description and GPS Coordinates of four storm drains discharging into the
Norwalk River Estuary
Site Name
Site Description
GPS Coordinates
Norwalk Rowing Association East of Moody’s N41º 06’ 55.1”
Moody’s
Lane draining into the Norwalk River
W073º 24’ 33.0”
N41º 05’ 01.3”
Calf Pasture Outflow Left side of pier at Calf Pasture Beach
W073º 23’ 34.6”
N41º 05’ 36.7”
Total
Total Marine boat launch
W073º 24’ 45.8”
N41º 05’ 56.9”
Washington
Maritime Aquarium Imax Theater parking lot
W073º 24’ 56.1”
20
Section IV
Preliminary research on Keeler Brook:
Seven sites were monitored on Keeler Brook, a tributary of the Five Mile River. Keeler Brook is located
entirely in Norwalk, CT. The sites on Keeler Brook are located primarily in residential areas though the
area does contain commercial properties. Research was initially focused around site KB2 located on
West Cedar Street in Norwalk (Figure 16). On 7/16 the monitoring team traveled downstream stopping
every 100m to take a sample and GPS coordinates. On 7/31 the team moved upstream from site KB2
using the same techniques.
As seen in Table 8, downstream sites have significantly higher E. coli counts than upstream sites. Site 2
(downstream) had the highest count of 31,000 while site 1 had the lowest count of 14,000 (Table 8). Site
7 was of most concern due to a foul odor present on the day of collection. This is likely to be due to
extremely heavy rainfall of 3.52 inches one day prior to our testing day.
Upstream sites were significantly drier due to only 0.17 inches of rain three days prior to testing. Site 2
had the lowest level of E. coli of 150 while site 1 had the highest level with 2,100 (Table 8).
Because these sites showed such elevated E. coli counts, future testing will be done in great detail under
varied weather conditions to determine sources of pollution. A CT DEEP contract has been offered to
HW, under 319 funding, to continue this research.
Figure 16 Map of Keeler Brook previously established and tested sites
21
Table 8 Observed fecal coliform and E. coli (CFU/100mls) bacteria levels at 11 temporary monitoring
sites upstream and downstream of site KB2 on 7/16 and 7/31
Site
1
2
3
4
5
6
7
Date
7/16/2012
7/16/2012
7/16/2012
7/16/2012
7/16/2012
7/16/2012
7/16/2012
1
2
3
4
7/31/2012
7/31/2012
7/31/2012
7/31/2012
Fecal Coliform.
E. coli
Amount of Days prior
CFU/100 mL CFU/100 mL rain (in) to sampling
27000
14000
3.52
1
49000
31000
3.52
1
52000
30000
3.52
1
44000
28000
3.52
1
52000
23000
3.52
1
46000
21000
3.52
1
37000
20000
3.52
1
3100
320
340
710
2100
150
270
590
0.17
0.17
0.17
0.17
3
3
3
3
Table C5 GPS Coordinates of preliminary research sites on Keeler Brook
Samples taken on 7-16-12
Samples taken on 7-3112
Site GPS Coordinates
Site GPS Coordinates
1
N 41º 06’ 10.7”
1
N 41º 06’ 13.0”
W 073º 26’ 29.1”
W 073º 26’ 26.9”
2
N 41º 06’ 09.5”
2
N 41º 06’ 13.2”
W 073º 26’ 29.2”
W 073º 26’ 32.4”
3
N 41º 06’ 08.4”
3
N 41º 06’ 14.5”
W 073º 26’ 29.7”
W 073º 26’ 29.3”
4
N 41º 06’ 07.9”
4
N 41º 06’ 16.3”
W 073º 26’ 30.3”
W 073º 26’ 28.7”
5
N 41º 06’ 06.7”
W 073º 26’ 30.9”
6
N 41º 06’ 06.4”
W 073º 26’ 35.6”
7
N 41º 06’ 03.2”
W 073º 26’ 34.1”
Final Conclusions for the Silvermine River and Norwalk Storm Drains:
Although the major discharge points for E. coli bacteria into Norwalk Harbor are now known, finding the
root cause of the inputs requires a detailed investigation of each storm drain network. The investigation
must be done manhole by manhole to isolate illegal hookups, and other possible sources of pollution.
Based on HW experiences, the process can take months and hundreds of tests for each system. We
again thank the Public Works, Conservation, and Health Departments of Norwalk for their support in this
effort. Each illegal hookup and cross connection found is another step forward in cleaning up Norwalk
Harbor.
22
Appendix A
References:
Harris, R. B. and P. J. Fraboni: Quality Assurance/Quality Control Plan for the Norwalk River Watershed
Monitoring Project (QA No. CT00162) (re-approved US Environmental Protection Agency. 1986.
Ambient Water Quality Criteria for Bacteria, US EPA 440/5-84-002, Washington, DC.
Harris, R. B and P.J. Fraboni: Water Quality Data Report for the Silvermine River and Lower Norwalk
River June 2010 through August 2010.
Harris, R. B and P.J. Fraboni: Water Quality Data Report for The Silvermine River and Lower Norwalk
River May 2011 through August 2011.
Eaton, A.D., Clesceri, L.S., Rice, E.W., and A.E. Greenberg. 2005. Standard Methods for the
Examination of Water and Wastewater, 21st Ed. American Public Health Association, American
Water Works Association, Water Environment Federation
A
Appendix B
Stream bank erosion at site SM3
SM4 Pipe located off Singing Woods
Rd.
Example of severe bank erosion and
fallen trees at site SM4
B
Alternate view of site SM4 showing
the number of fallen trees
Remaining pieces of J-hooks that
were installed in early 2000s at site
SM5. Stream bank erosion can be
seen in the background.
SM5, behind the Silvermine School,
showing the erosion caused by Jhooks installed in the early 2000s
C