Fairfield County River Report

Harbor Watch | 2020

Fairfield County River Report: 2020

Sarah C. Crosby Mary K. Donato Peter J. Fraboni Devan S. Healy Nicole C. Spiller Kasey E. Tietz

Harbor Watch, Earthplace Inc., Westport, CT 06880

This report includes data on: Ash Creek Watershed, Aspetuck River, Byram River, Comstock Brook, Deadman’s Brook, Little River, Noroton River, Norwalk River, Rippowam River, Saugatuck River, Silvermine River, and Stony Brook.

This report should be cited as: S.C. Crosby, M.K. Donato, P.J. Fraboni, D.S. Healy, N.C. Spiller, and K.E. Tietz. 2020. Fairfield County River Report 2020. Harbor Watch, Earthplace, Inc. 1-52 p.

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About Harbor Watch

The mission of Harbor Watch is to improve water quality and ecosystem health in Connecticut.

Each day we strive to reach this goal through research in the lab and field, collaboration with our partners, and education of students and the public. Harbor Watch addresses pollution threats to Long Island Sound and educates the next generation of scientists through hands-on research and experiential learning. As part of the larger organization of Earthplace, the work performed by Harbor Watch also supports the mission of Earthplace to build a passion in our community for nature and the environment through education, experience, and action.

Since its inception, Harbor Watch has trained over 1,000 high school students, college interns, and adult volunteers in the work of protecting and improving the biological integrity of Long Island Sound and has monitored hundreds of sites for a variety of physical and biological parameters.

In 2020, Harbor Watch: • Studied over 200 field sites in Fairfield County, CT • Conducted biweekly, May-September monitoring of 12 rivers in 15 towns • Trained 35 high school and college students • Processed over 1300 water samples for bacteria concentration analysis in our laboratory

Visit www.harborwatch.org for more information!

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Acknowledgements

The authors would like to thank Ben Archer, Shane Behler, Ryan Burns, Doug Donato, Gina Donato, Brian Healy, and Sarah Sherts for their assistance with data collection and laboratory analysis. Funding for the research presented here was generously provided by City of Norwalk, Connecticut Department of Energy and Environmental Protection, Copps Island Oysters, Elizabeth Raymond Ambler Trust, Greens Farms Garden Club, The Jeniam Foundation, King Industries, New Canaan Community Foundation, Norwalk Cove Marina, Norwalk Mayor’s Water Quality Committee, Norwalk River Watershed Association, NRG – Devon, Outdoor Sports Center of Wilton, Patagonia of Westport, The Petterson Family Fund, Rex Marine, Tauck Ritzau Innovative Philanthropy Inc., Town of New Canaan (Conservation Commission), Town of Ridgefield, Town of Westport, Town of Wilton, and Upwell Coffee. Additional support was provided by the generosity of individual donors. We thank our funders for their generous support, without which this work would not be possible!

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Key Terms and Information

Acronyms: • CT DEEP: Connecticut Department of Energy and Environmental Protection • CFU/100 mL: Colony forming units per 100 mL. This is a unit of measurement for bacteria concentrations. A colony is raised from a single bacterium to a visible colony for counting by providing the preferred heat range and media for the required incubation period. These units are appropriate for direct comparison to those in MPN/100mL. • MPN/100 mL: Most probable number per 100 mL. This is a unit of measurement for bacteria concentrations based on statistics rather than direct counts of specific colonies. These units are appropriate for direct comparison to those in CFU/100mL.

Study Site Naming: • Sites are numbered with the lowest number being closest to the mouth of the river where it meets a larger body of water (e.g., Long Island Sound). Sites with the highest numbers are located furthest upstream. • Site names that include “SD” indicate that the sample location is a storm drain outfall rather than an instream location. These sites are not held to the same pass/fail assessment standards as instream sites and were not included in the pass or fail assessments.

Terms/Symbols in Tables: • “N/A” - Indicates that a sample was not taken at that time for reasons including broken or lost sample bag, stagnant water, inaccessibility due to construction, dry river bed, or other factors. • “>” – Indicates that the results exceeded the reporting limit. • “Wet” - Rainfall is indicated as “Wet” if ≥ 0.1 inches of rain fell within 2 days prior to sampling. • “Dry” - Rainfall is indicated as “Dry” if ≤ 0.1 inches of rain fell within 2 days prior to sampling.

Disclaimer: Every effort has been made to ensure the accuracy of the information presented in this report. If you notice anything in this report that you believe may be an error, we welcome that or any other feedback. Please contact us by email at [email protected].

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Introduction

Harbor Watch is a research and education program based out of Earthplace in Westport, CT. Our mission is to improve water quality and ecosystem health in Connecticut. In this report, we present a study of water quality in rivers throughout Fairfield County conducted in 2020. The goal of this monitoring was to assess the health of each river and to identify areas where sources of sewage pollution may be present using Escherichia coli (E. coli) or Enterococci as indicators.

Since 1986, Harbor Watch has been monitoring water quality throughout Fairfield County. Testing has been conducted both instream and in stormwater systems flowing into Long Island Sound and its tributaries. Due to the COVID-19 pandemic, more limited stormwater testing was conducted during the 2020 monitoring season than in years past. This report contains data summaries for the 12 rivers we monitored in 15 towns in Fairfield County from May through September.

This report includes data on 5 water quality parameters: E. coli, Enterococci, dissolved oxygen, conductivity, and temperature. E. coli and Enterococci were selected for study because they are the indicator bacteria of choice for the Environmental Protection Agency (EPA) and Connecticut Department of Energy and Environmental Protection (CT DEEP) for sewage pollution in freshwater systems and saltwater systems, respectively. Their presence in high concentrations suggests that there are likely also more harmful pathogens present. Dissolved oxygen is an important water quality indicator because many aquatic species rely on it for survival, similarly to how land animals rely on oxygen in the air. When dissolved oxygen is not available, species like fish and macroinvertebrates will relocate to higher quality waters or die due to the lack of oxygen. Conductivity is a measure of how easily the water can carry an electrical current by measuring the ionic strength of the water. It can quantify the intrusion of salt water or other sources of salts and other compounds into a waterway. Temperature is also an important parameter for aquatic species, which can be excluded from a given location if the temperature is too high or too low.

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Methods

Each river was visited approximately twice per month from May through September for a total of 10 sampling days per river. Sites were selected based on access and representativeness of the river, with effort made to space sites evenly throughout the length of the river. Monitoring was carried out under a Quality Assurance Project Plan approved by the CT DEEP on 2/18/2020 (RFA #17057). Due to the Covid-19 pandemic, some sampling sites listed in the QAPP were dropped from monitoring for safety.

Monitoring teams left Earthplace in Westport, CT in the morning to begin sampling and would return within 2-3 hours. Each team was comprised of fully trained Harbor Watch staff, sometimes accompanied by volunteers. At each site, a water sample was collected and kept on ice. Water temperature, dissolved oxygen, and conductivity were measured at each site using a YSI Pro2030 meter.

Upon return to the Harbor Watch laboratory, the water samples were analyzed for total coliform and E. coli or Enterococci using enzyme substrate methods set forth in Standard Methods (SM9223B). E. coli concentrations were evaluated using the criteria published in the CT DEEP Surface Water Quality Standards on 10/10/13 (Table 1). Because the rivers we tested do not contain designated swim areas, the “all other recreational uses” criteria will apply.

Table 1. CT DEEP criteria for E. coli and Enterococci levels as applied to recreational use, effective 10/10/13. Highlighted cells represent criteria used by Harbor Watch in this report. Designated Use Class Indicator Criteria Geomean less than Designated AA, A, B Escherichia coli 126/100 mL; Single Sample Swimming Maximum 235/100 mL Geomean less than Non-designated AA, A, B Escherichia coli 126/100 mL; Single Sample Swimming Maximum 410/100 mL Geomean less than All Other AA, A, B Escherichia coli 126/100 mL; Single Sample Recreational Uses Maximum 576/100 mL Geomean less than Designated SA, SB Enterococci 35/100 mL; Single Sample Swimming Maximum 104/100 mL Geomean less than All Other SA, SB Enterococci 35/100 mL; Single Sample Recreational Uses Maximum 500/100 mL

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Results and Discussion

Fairfield County Summary

From May through September 2020, 12 rivers were monitored by Harbor Watch across 15 towns in Fairfield County, CT (Table 2). There were 104 unique sampling locations that were monitored a minimum of 8 times each. Many of these rivers did not meet state criteria for bacteria concentrations (Table 3, Figure 1) and are acting as a pathway for sewage pollution to enter Long Island Sound. Fifty-five percent of sites exceeded either the CT DEEP geometric mean criterion (< 126 MPN/100 mL for freshwater sites or < 35 MPN/100 mL for estuarine sites) (Figure 2), the secondary single sample maximum criterion of < 15% of indicator bacteria samples at each site (> 576 MPN/100 mL for freshwater sites or >500 MPN/100 mL for estuarine sites) (Figure 3), or both. The Little River had the fewest exceedances of the CT DEEP criteria for bacteria. There was a 2-way tie for the most exceedances, with 100% of the sites studied on Stony Brook and in the Ash Creek Watershed failing either one or both CT DEEP criteria for bacteria (Table 3).

Table 2. Percentage of sites studied in each town that failed one or both state criteria for allowable levels of bacteria. Number Failing Town of sites Bacteria River Bridgeport 3 100% Ash Creek Watershed Darien 2 100% Noroton River Easton 4 50% Aspetuck River Fairfield 7 86% Ash Creek Watershed, Aspetuck River Greenwich 7 43% Byram River New Canaan 13 23% Noroton River, Rippowam River, Silvermine River Newtown 2 0% Aspetuck River Norwalk 4 75% Norwalk River, Silvermine River, Stony Brook Redding 8 13% Aspetuck River, Little River, Saugatuck River Ridgefield 5 40% Norwalk River Stamford 6 100% Noroton River, Rippowam River Trumbull 2 100% Ash Creek Watershed Weston 8 13% Aspetuck River, Saugatuck River Westport 22 73% Aspetuck River, Deadman's Brook, Saugatuck River, Stony Brook Wilton 11 64% Comstock Brook, Norwalk River, Saugatuck River, Silvermine River

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Table 3. Percentage of sites studied in each river that failed one or both state criteria for allowable levels of bacteria. Number Failing River of sites Bacteria Towns Ash Creek Watershed 11 100% Bridgeport, Fairfield, Trumbull Aspetuck River 14 21% Easton, Fairfield, Newtown, Redding, Weston, Westport Byram River 7 43% Greenwich Comstock Brook 5 80% Wilton Deadman's Brook 9 89% Westport Little River 4 0% Redding Noroton River 7 71% Darien, New Canaan, Stamford Norwalk River 10 50% Norwalk, Ridgefield, Wilton Rippowam River 9 67% New Canaan, Stamford Saugatuck River 14 29% Redding, Weston, Westport, Wilton Silvermine River 8 25% New Canaan, Norwalk, Wilton Stony Brook 6 100% Norwalk, Westport

Figure 1. Map of 2020 sampling locations that met both of the CT DEEP indicator bacteria criteria (green) or exceeded one or both of the criteria (red).

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Figure 2. Map of 2020 sampling locations and E. coli and Enterococci concentrations for each site. The bacteria concentrations for each site were compared to the state criteria for recreational waters (Table 1). Passing sites (green) had a geometric mean less than 126/100 mL for E. coli or 35/100 mL for Enterococci.

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Figure 3. Map of 2020 sampling locations and percentage of E. coli and Enterococci samples failing the CT DEEP single sample maximum criterion for recreational waters at each site. Passing sites (green) had less than 15% of their samples exceeding 576/100 mL for E. coli and 500/100 mL for Enterococci.

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The state criterion for acceptable dissolved oxygen levels is set at a minimum of 5 mg/L for freshwater. Eight percent of all observed dissolved oxygen readings were below 5 mg/L in 2020. Deadman’s Brook had the highest frequency of low dissolved oxygen readings with 26% of observed readings below 5 mg/L. Prolonged periods of low dissolved oxygen can be harmful to marine and aquatic organisms. Factors during the monitoring season such as low flow, precipitation (Figure 5), decomposition of organic matter, and warm water temperatures may have impacted the observed dissolved oxygen values.

Figure 4. Map of 2020 river sampling locations and percentage of individual dissolved oxygen readings less than the CT DEEP minimum criterion of 5 mg/L.

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Figure 5. Monthly rainfall totals for 2020 (Norwalk Health Department Rain Gauge).

Data were collected on these Fairfield County waterways for multiple reasons. Harbor Watch aims to better understand the ecological health of our watersheds by monitoring dissolved oxygen, conductivity, water temperature, and bacteria levels, and to make these data available for use by interested stakeholders. A secondary objective is to use the data collected to assess where sewage pollution sources may be located so that we can perform further investigation. Once sources are identified, Harbor Watch works with our municipal partners to fix the problem. Out of an abundance of caution, pollution track-down was put on hold during the majority of the 2020 monitoring season due to the unknown survival and transmission rates of COVID-19 in sewage (which we would be searching for in stormwater systems). Beginning in September 2020, track-down surveys were resumed on projects in Bridgeport, Fairfield, Norwalk, Stamford, Stratford, and Westport. Track-down surveys are ongoing and will continue year-round as conditions allow. Our process of repetitive bacteria testing has a history of success in identifying point sources of pollution such as leaking sanitary sewer lines, broken sewer laterals, and pipes illegally hooked into the storm water system. By partnering with municipalities to fix these problems, we have been able to calculate as much as 99% reductions in bacteria concentrations entering our waterways from a single source location. The frequent incidence of failing bacteria concentrations observed over this monitoring season (Figure 1, Table 1) indicates that there is still much work to be done to improve the overall water quality of the Long Island Sound watershed. We look forward to tackling these issues head on with our partners.

In the chapters to follow, we present a data summary of each of the 12 rivers monitored by Harbor Watch this summer. Additional data for each river can be found in an appendix at the end of this report.

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1. Ash Creek Watershed (Ash Creek, Rooster River, Horse Tavern Brook, and Londons Brook)

The Ash Creek Watershed encompasses portions of Fairfield, Bridgeport, Trumbull, and Easton, CT. The watershed is approximately 9,800 acres or 15.3 square miles. There are multiple tributaries which discharge to Ash Creek including Rooster River, Horse Tavern Brook, Londons Brook, and Ox Brook. Harbor Watch began monitoring the Ash Creek Watershed annually in 2016. After taking a break from monitoring in 2019, the watershed was added back into the sampling rotation in 2020. Changes to monitoring included site name changes to be more representative of the specific river within the watershed on which they were located as well as a site was added to include the Londons Brook tributary. Ash 1 was originally dropped because of safety concerns due to COVID-19, but was added back halfway through the season. The Ash Creek Watershed tied for the highest frequency of exceeding the state bacteria criteria of all watersheds monitored in 2020. All sites failed one or both CT DEEP criteria for bacteria. Dissolved oxygen readings were observed below 5 mg/L at sites Rooster 4.6 on 9/21 and 9/28, Rooster 4.5 on 6/8, 6/18, 8/18, and 9/28, and Ash 1 on 8/18 and 9/28. Track-down work was conducted on Londons Brook, Horse Tavern Brook, and Ox Brook to attempt to identify sources of elevated bacteria concentrations, but no sources have been isolated at this time. This work will continue in conjunction with municipal partners to locate sources of pollution. See Appendix 1 for additional data.

Figure 1.1. 2020 geometric mean of E. coli concentrations at each site.

Figure 1.2. Mean of freshwater site geometric means from 2016-2020 (black bars) and total rainfall from May through September each year (grey squares and line). Fairfield County River Report 2020, Harbor Watch | 13

2. Aspetuck River

The Aspetuck River is a major tributary to the Saugatuck River, meeting the river just downstream of Harbor Watch site Saugatuck 2 (see chapter 10 for Saugatuck River). The watershed includes parts of Bethel, Newtown, Redding, Easton, Fairfield, and Westport. Harbor Watch had previously monitored the Aspetuck River in 2003 and 2004 and again from 2007-2011. The river was added to the sampling regime in 2020 to assess how water quality may have changed over the last 9 years. In 2020, 3 sites (Aspetuck 7, Aspetuck 8, and Aspetuck 12) exceeded one or both CT DEEP bacteria criteria. Dissolved oxygen values were observed to be above 5 mg/L at all sites on all sampling days except for Aspetuck 14 on 8/20. See Appendix 2 for additional data.

Figure 2.1. (Left) 2020 geometric mean of E. coli concentrations at each site. Unlabeled sites were located on Saugatuck River (chapter 10) and Deadman’s Brook (chapter 5). Figure 2.2. (Above) Mean of site geometric means from 2003-2020 (black bars) and total rainfall from May through September each year (grey squares and line).

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3. Byram River

The Byram River watershed encompasses portions of 4 communities whose political boundaries fall within Connecticut and New York, but the river is located primarily in Greenwich, CT and Port Chester, NY. The watershed is approximately 12,000 acres or 18.7 square miles and is defined by two main drainage basins, the Byram River and the East Branch of the Byram River. The main stem of the Byram River is approximately 14 miles long. The river begins at the Byram River reservoir and flows south, ultimately discharging to Long Island Sound through Port Chester Harbor. The land use in the watershed is predominantly residential.

2020 marked the 4th year that Harbor Watch collected data on the Byram River since 2016. Due to COVID-19, sampling was not conducted at sites Byram 1, Byram 2, and Byram 4 for safety reasons in 2020. Of the sites tested, 3 sites (Byram 3, Byram 7, and East Byram 1) exceeded one or both CT DEEP bacteria criteria. Dissolved oxygen values were observed to be above 5 mg/L at all sites on all sampling days except for East Byram 3 on 9/29. See Appendix 3 for additional data. 2016 2017 2018 2019 Geometric Geometric Geometric Geometric Site mean mean mean mean East Byram 3 99 49 51 69 East Byram 2 162 86 72 56 East Byram 1 421 194 178 274 Byram 7 232 105 202 205 Byram 6 126 51 124 53 Byram 5 76 53 N/A 68 Figure 3.1. (Top) 2020 geometric mean Byram 4 171 159 141 N/A of E. coli concentrations at each site. Byram 3 114 88 150 104 Table 3.1. (Bottom) Comparison of Byram 2 528 266 455 N/A geometric mean by site from 2016 to 2020. Byram 1 339 152 299 N/A

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4. Comstock Brook

Comstock Brook is a tributary of the Norwalk River located in Wilton, CT. It meets the Norwalk River between Harbor Watch monitoring locations Norwalk 9 and Norwalk 6 (see chapter 8 for Norwalk River). The watershed is primarily residential. Four of the 5 sites studied failed one or both state criteria for allowable levels of bacteria, indicating that this brook is a potential conduit for sewage pollution to the Norwalk River and ultimately Long Island Sound. Dissolved oxygen readings were observed to be below 5 mg/L at East Comstock 2 on 6/23, 7/29, and 9/1, Comstock 2 and Comstock 1 on 7/29, 8/12, 8/17, and 9/1. East Comstock 2 was impacted by the lack of rainfall in 2020, with the brook drying up at the end of the monitoring season. Low precipitation accumulation throughout the monitoring season also impacted Comstock 2, which is downstream of the South Norwalk Electric and Water diversion and dam, causing low or no flow on many of the monitoring days. See Appendix 4 for additional data.

2018 2019 2020 Geometric Geometric Geometric mean mean mean East Comstock 2 79 110 178 East Comstock 1 72 119 137 Comstock 3 226 198 88 Comstock 2 533 415 393 Comstock 1 315 244 203 Table 4.1. Comparison of geometric mean by site from 2018 to 2020.

Figure 4.1. 2020 geometric mean of E. coli concentrations at each site. Unlabeled site is located on the Norwalk River (Chapter 8).

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5. Deadman’s Brook

Deadman’s Brook is a tributary to the Saugatuck River located in Westport, CT. It meets the Saugatuck River between Harbor Watch study sites Saugatuck 0.5 and Saugatuck 0.25 in downtown Westport. While Harbor Watch has done intermittent studies of Deadman’s Brook over the past several years as part of our student education programs, 2018 was the first year in which a comprehensive study was conducted during the summer monitoring season. Sampling was suspended in 2019 and reinstated in 2020. Unfortunately, in 2020, all but the northernmost site failed either one or both state bacteria criteria, indicating that Deadman’s Brook may be contributing to the elevated bacteria levels observed in the lower Saugatuck River. The Figure 5.1. 2020 geometric mean of E. coli concentrations at each site. watershed was greatly impacted by the low precipitation over the monitoring season, leading to 26% of individual dissolved oxygen readings dropping below 5 mg/L and sites drying up. Track-down work to locate sources of pollution was conducted at the mouth of the river as well as higher up in the watershed. This work will continue in conjunction with our municipal partners in the Town of Westport. See Appendix 5 for additional data.

2018 2020 Geometric Geometric mean mean Deadman 9 20 30 Deadman 8 82 189 Deadman 7 462 390 Deadman 5 369 255 Deadman 4 240 161 Deadman 3.5 176 400 Deadman 3 378 490 Deadman 2 339 515 Table 5.1. Comparison of geometric mean by site for 2018 and 2020. Deadman 1 427 366

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6. Little River

Little River is a tributary to the Saugatuck River located in Bethel and Redding, CT. Little River meets the Saugatuck River at the northeastern corner of the Saugatuck Reservoir. Three of the sites studied in 2020 were located on the main stem of the river and the fourth site, Little 2A, was located on an unnamed tributary. 2020 was the first year in which a comprehensive study was conducted during the summer monitoring season. All sites met both state criteria for bacteria. Dissolved oxygen readings were observed to be below 5 mg/L at Little 4 on 7/16, 8/13 and Little 2A on 6/9, 7/28. Low precipitation accumulation during the monitoring season greatly impacted site Little 2A, which was dry on numerous monitoring days. See Appendix 6 for additional data.

Figure 6.1. 2020 geometric mean of E. coli concentrations at each site.

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7. Noroton River

The Noroton River watershed encompasses portions of Stamford, Darien, and New Canaan, CT. The watershed is approximately 7,000 acres (11 mi2). The river begins in New Canaan and flows south along the border of Stamford and Darien. The river discharges into Long Island Sound through Holly Pond. The land use along the river is a mixture of residential and light commercial. This is the 5th consecutive year during which Harbor Watch has monitored the Noroton River. Bacteria concentrations at 5 sites (Noroton 1.5, Noroton 2, Noroton, 3, Noroton 4, Noroton 8) failed one or both CT DEEP bacteria criteria. Dissolved oxygen readings were observed to be below 5 mg/L at Noroton 8 on 5/27, 6/2, 8/31, 9/17, and 9/28, Noroton 7 on 6/18, Noroton 2 on 8/31, and Noroton 1.5 on 7/30. See Appendix 7 for additional data.

Figure 7 .1. (Left) 2020 geometric mean of in dicator bacteria concentrations at each site. Figure 7.2. (Right) Mean of freshwater site geometric means from 2016-2020 (black bars) and total rainfall from May through September each year (grey squares and line).

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8. Norwalk River

The Norwalk River watershed includes New Canaan, Norwalk, Redding, Ridgefield, Weston and Wilton, CT, as well as Lewisboro, NY. The watershed is roughly 40,000 acres (64.1 mi2), which is developed by commercial/light industry uses and residential neighborhoods (NRWI, 1998). The main stem of the Norwalk River is approximately 20 miles in length, beginning in the Great Swamp in Ridgefield, ultimately discharging in Norwalk Harbor where the last 3 miles are a tidal estuary (NRWI, 1998). Harbor Watch has monitored the Norwalk River year-round for 25 years. In 2020, 5 sites (Norwalk 4, Norwalk 6, Norwalk 9, Norwalk 21, and Norwalk 23) exceeded one or both CT DEEP criteria for E. coli. Dissolved oxygen readings were observed to be below 5 mg/L at Norwalk 21 on 7/14, 8/27, and 9/9. In addition to instream monitoring, we partnered with the Town of Wilton to add water level loggers at 4 sites. These loggers will allow us to track river flow throughout the monitoring season in the future. See Appendix 8 for additional data.

Figure 8.1. (Right) 2020 geometric mean of E. coli concentrations at each site. Unlabeled sites were Saugatuck River (chapter 10), Comstock Brook (chapter 4), Silvermine River (chapter 11), and Belden Hill Brook. Figure 8.2. (Left) Mean of site geometric means from 2011-2020 (black bars) and total rainfall from May through September each year (grey squares and line).

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9. Rippowam River

The Rippowam River, also known as the Mill River, watershed covers 37.5 square miles from the NY State border, through parts of New Canaan, Ridgefield, and Stamford, where it discharges into Stamford Harbor. The southern portion of the basin is commercial, industrial, and residential and the northern portion is largely residential, forested, and agricultural (CT DEEP). 2017 was the first year during which Harbor Watch monitored the Rippowam River. Due to COVID-19, sites Rippowam 8, Rippowam 5, and Rippowam 3 were skipped in 2020 for safety reasons. The water quality in the river did not meet CT DEEP criteria for bacteria at 6 sites (Rippowam 0.5, Rippowam 2, Rippowam 4, Rippowam 7, Rippowam 10, Rippowam 12) in 2020. Dissolved oxygen readings were observed to be below 5 mg/L at Rippowam 12 on 9/29, Rippowam 11 and Rippowam 10 on 8/17, 9/1, and 9/29, and Rippowam 0.5 on 8/17. See Appendix 9 for additional data.

2018 2019 2020 Geometric Geometric Geometric Site mean mean mean Rippowam 12 102 252 197 Rippowam 11.5 85 96 49 Rippowam 11 51 113 59 Rippowam 10 130 144 151 Rippowam 9 89 114 108 Rippowam 8 177 197 N/A Rippowam 7 317 548 404 Rippowam 5 767 568 N/A Rippowam 4 373 327 213 Rippowam 3 323 434 N/A Rippowam 2 569 443 278 Rippowam 0.5 2023 158 331 Figure 9.1. 2020 geometric mean of indicator bacteria concentrations at each site. Unlabeled sites were located on Noroton River (Chapter 7). Table 9.1. Geometric mean by site from 2018-2020. Please note that the indicator bacteria tested at Rippowam 0.5 in 2018 was E. coli but in 2019 it was switched to Enterococci.

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10. Saugatuck River

The Saugatuck River watershed is located in Danbury, Ridgefield, Bethel, Redding, Wilton, Weston, Easton, Westport, and Norwalk, CT. The watershed is approximately 38,704 acres (60.5 mi2) and is defined by 2 main drainage basins: the Saugatuck River and the West Branch of the Saugatuck River. The land use is a combination of protected preserve around the Saugatuck Reservoir, residential, and light commercial. The Saugatuck River discharges into Long Island Sound at Saugatuck Harbor. Harbor Watch has monitored the Saugatuck River for over 10 years. Due to COVID-19, sites West Saug 3 and Saugatuck 6 were not sampled for safety reasons in 2020. Four sites (Saugatuck 0.25, Saugatuck 0.5, Saugatuck 0.75, West Saug 1) failed one or both CT DEEP bacteria criteria. Dissolved oxygen readings were observed to be below 5 mg/L at West Saug 5 on 6/24, 8/13, and 9/15, and Saugatuck 0.5 on 7/20. See Appendix 10 for additional data.

Figure 10.1. (Left) 2020 geometric mean of indicator bacteria concentrations at each site. Unlabeled sites were located on Little River (chapter 6), Deadman’s Brook (chapter 5), and Stony Brook (chapter 12). Figure 10.2 (Above) Mean of freshwater site geometric means (black bars) and brackish site geometric means (striped bars) from 2016-2020 and total rainfall from May through September each year (grey squares and line).

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11. Silvermine River

The Silvermine River is a tributary to the Norwalk River and flows from Lewisboro, NY into New Canaan, CT, through Wilton, and into Norwalk. It meets the Norwalk River between our monitoring locations Norwalk 4 and Norwalk 1 (see chapter 8 for Norwalk River). The watershed is primarily residential with a few reservoirs located in the upper reaches of the watershed. Due to COVID-19, Silvermine 3 was skipped for safety reasons, as was Silvermine 2 periodically when team members were sampling alone. Two sites (Silvermine 1.5 and Silvermine 4) failed either one or both state criteria for bacteria. Dissolved oxygen readings were observed to be below 5 mg/L on 8/13 at sites Silvermine 10, Silvermine 9, and Silvermine 4 and on 9/8 at sites Silvermine 9 and Silvermine 8. See Appendix 11 for additional data.

2019 2020 Geometric Geometric mean mean Silvermine 10 6 30 Silvermine 9 59 28 Silvermine 8 76 80 Silvermine 7 137 94 Silvermine 6 62 42 Silvermine 5 132 90 Silvermine 4 107 146 Silvermine 3 83 N/A Silvermine 2 104 356 Silvermine 1.5 379 268 Table 11.1. Geometric mean by site from 2019 and 2020.

Figure 11.1. 2020 geometric mean of indicator bacteria concentrations at each site. Unlabeled site was located on Comstock Brook (chapter 4).

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12. Stony Brook

Stony Brook is a tributary to the Saugatuck River located in Westport, CT. The brook meets the river on the west bank of Saugatuck Harbor between Harbor Watch sites Saugatuck 0.5 and Saugatuck 0.25 (see chapter 10 for Saugatuck River). The watershed is residential at its headwaters and shifts to commercial as it flows towards Saugatuck Harbor. Part of the river flows through a nature sanctuary. While Harbor Watch has done intermittent studies of Stony Brook in the past as part of our student education programs, 2020 was the first year in which a comprehensive study was conducted during the summer monitoring season. All 6 sites exceeded one or both state criteria for allowable levels of bacteria. Dissolved oxygen readings were observed to be below 5 mg/L on 9/2 at sites Stony 6 and Stony 5.

Figure 12.1. 2020 geometric mean of indicator bacteria concentrations at each site.

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Appendix 1: Ash Creek Watershed

Table A1.1. GPS coordinates and site locations for the Ash Creek Watershed. Sites Rooster 8 and Horse Tavern 3.5 were added mid- way through the season as track-down sites Site Name Latitude Longitude Site location notes River Name Horse Tavern 5 41.24438 -73.23205 Revere Lane Horse Tavern Brook Horse Tavern 4 41.23572 -73.22811 Chestnut Hill Road Horse Tavern Brook Rooster 8 41.22641 -73.22206 Old Town Road Horse Tavern Brook Horse Tavern 3.5 41.21851 -73.21785 Anton Street Horse Tavern Brook Horse Tavern 3 41.21243 -73.22382 Vincellette Street Horse Tavern Brook Horse Tavern 2 41.20316 -73.22940 Wilson Street Horse Tavern Brook Horse Tavern 1 41.19585 -73.23199 Stratfield Road Horse Tavern Brook Londons 1 41.19538 -73.23540 Montauk Street Londons Brook Rooster 4.7 41.19260 -73.22850 Cornell Road Rooster River Rooster 4.6 41.18858 -73.22064 Brooklawn Avenue Rooster River Rooster 4.5 41.18807 -73.21872 Capitol Avenue Rooster River Rooster 3.5 41.18283 -73.21771 Brooklawn Avenue Rooster River Rooster 2.5 41.17648 -73.22304 North Avenue (Route 1) Rooster River Ash 1 41.16745 -73.22369 Commerce Drive/State Street Ext Ash Creek

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Table A1.2. Ash Creek Watershed E. coli and Enterococci concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: Weather Underground – Tweed New Haven Regional Airport, October 16, 2020). Note: Sites Rooster 8, Horse Tavern 3.5, and Ash 1 have geometric means calculated with fewer than the requisite 8 values. These sites were added mid-way through the season Indicator % exceeding Bacteria 5/5/20 5/19/20 6/8/20 6/18/20 7/7/20 7/22/2020 8/18/2020 9/10/2020 9/21/2020 9/28/2020 Geomean SSM Horse Tavern 5 E. coli 411 172 437 615 922 2240 1633 >4839 130 225 625 50% Horse Tavern 4 E. coli 44 55 192 521 449 821 >4839 996 114 65 282 30% Rooster 8 E. coli N/A N/A N/A N/A N/A >9678 >4839 9678 292 >4839 3641 80% Horse Tavern 3.5 E. coli N/A N/A N/A N/A N/A 3448 >4839 5654 262 1961 2173 80% Horse Tavern 3 E. coli 649 488 1034 1540 722 4106 >4839 7945 1041 4839 1763 90% Horse Tavern 2 E. coli 214 326 977 >4839 4352 11199 4352 9678 260 3466 1899 70% Horse Tavern 1 E. coli 219 921 1961 3106 865 17329 4611 >9678 1106 4479 2296 90% Londons 1 E. coli 228 613 651 1159 922 615 3106 >4839 1633 >4839 1217 90% Rooster 4.7 E. coli 153 579 1454 1034 690 >9678 2595 >9678 538 1733 1355 80% Rooster 4.6 E. coli 144 214 1095 821 857 7945 4185 >9678 63 2069 1000 70% Rooster 4.5 E. coli 1414 N/A >4839 6131 14136 6488 1274 >9678 717 2595 3544 100% Rooster 3.5 E. coli 2420 >2420 1633 1842 7945 >24196 3255 >24196 >24196 >48392 7070 100% Rooster 2.5 E. coli 727 770 2092 3466 5475 >24196 5475 >24196 >24196 >48392 6196 100% Ash 1 Enterococci N/A N/A N/A N/A N/A 9208 >24196 8164 2755 323 4382 80% Weather Dry Dry Dry Dry Dry Wet Wet Wet Dry Dry

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Table A1.3. Ash Creek Watershed mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Horse Tavern 5 16.6 8.94 251 Horse Tavern 4 17.7 8.54 273 Horse Tavern 3 17.1 8.60 427 Horse Tavern 2 17.0 8.47 429 Horse Tavern 1 17.6 9.80 433 Londons 1 17.8 7.83 323 Rooster 4.7 18.5 10.57 384 Rooster 4.6 17.8 8.10 352 Rooster 4.5 18.9 5.64 520 Rooster 3.5 17.2 8.61 392 Rooster 2.5 17.7 8.49 384 Ash 1 20.4 5.00 11600

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Appendix 2: Aspetuck River

Table A2.1. GPS coordinates and site locations for the Aspetuck River Site Name Latitude Longitude Site location notes River Name Aspetuck 14 41.35429 -73.33885 Equestrian Ridge Aspetuck River Aspetuck 13 41.33470 -73.33758 Poverty Hollow Road Aspetuck River Aspetuck 12 41.31704 -73.34166 Church Hill Road Aspetuck River Aspetuck 11 41.31303 -73.33631 Meeker Hill Road Aspetuck River Aspetuck 10 41.30770 -73.33206 Stepney Road Aspetuck River Aspetuck 9 41.28625 -73.33289 Rock House Road Aspetuck River Aspetuck 8 41.27396 -73.32518 Valley Road Aspetuck River Aspetuck 7 41.25933 -73.32469 Silver Hill Road Aspetuck River Aspetuck 6 41.22881 -73.32407 Wells Hill Road Aspetuck River Aspetuck 5 41.21346 -73.32895 Judges Hollow Road Aspetuck River Aspetuck 4 41.19807 -73.33502 20 Aspetuck Glenn Aspetuck River Aspetuck 3 41.18664 -73.34276 Bayberry Lane Aspetuck River Aspetuck 2 41.17682 -73.35817 Lyons Plains Road Aspetuck River Aspetuck 1 41.17486 -73.36151 Weston Road (Route 57) Aspetuck River

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Table A2.2. Aspetuck River E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020) % exceeding 5/6/2020 5/18/2020 6/4/2020 6/15/2020 7/15/2020 7/27/2020 8/20/2020 9/9/2020 9/23/2020 9/30/2020 Geomean SSM Aspetuck 14 20 41 60 166 201 186 66 49 53 >2420 102 10% Aspetuck 13 50 52 242 178 35 179 22 30 13 >2420 82 10% Aspetuck 12 48 36 172 260 163 148 248 117 99 >2420 163 10% Aspetuck 11 69 35 172 21 24 46 2 <2 1 116 18 0% Aspetuck 10 39 19 84 81 63 78 11 30 5 384 42 0% Aspetuck 9 34 19 35 56 31 91 18 60 17 >2420 53 10% Aspetuck 8 45 185 192 142 140 210 82 83 108 2420 161 10% Aspetuck 7 38 88 156 116 70 105 178 687 50 1414 144 20% Aspetuck 6 9 40 148 42 260 86 186 29 127 816 88 10% Aspetuck 5 19 24 64 6 72 35 20 12 11 2407 35 10% Aspetuck 4 8 14 111 20 48 23 16 21 16 816 32 10% Aspetuck 3 12 21 145 70 46 39 23 34 30 >2420 55 10% Aspetuck 2 10 20 96 57 123 102 135 10 50 687 60 10% Aspetuck 1 19 33 93 79 155 141 148 41 52 921 88 10% Weather Dry Dry Wet Dry Dry Dry Wet Dry Dry Wet

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Table A2.3. Aspetuck River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Aspetuck 14 19.3 9.11 169 Aspetuck 13 18.0 8.72 150 Aspetuck 12 17.3 7.25 162 Aspetuck 11 19.1 8.30 159 Aspetuck 10 18.3 9.20 152 Aspetuck 9 17.2 9.34 130 Aspetuck 8 16.8 9.44 130 Aspetuck 7 16.7 9.76 129 Aspetuck 6 17.6 8.26 177 Aspetuck 5 18.9 9.29 182 Aspetuck 4 19.1 9.30 182 Aspetuck 3 19.0 8.75 187 Aspetuck 2 18.3 9.41 195 Aspetuck 1 18.0 9.32 202

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Appendix 3: Byram River

Table A3.1. GPS coordinates and site locations for the Byram River Site Name Latitude Longitude Site location notes River Name East Byram 3 41.09915 -73.68308 88 John Street East Branch of Byram River East Byram 2 41.07998 -73.67743 105 Porchuck Road East Branch of Byram River East Byram 1 41.06051 -73.67454 329 Riversville Road East Branch of Byram River Byram 7 41.09460 -73.70437 111 Bedford Road Byram River Byram 6 41.06092 -73.67760 Sherwood Avenue Byram River Byram 5 41.04627 -73.66265 7 Bailiwick Road Byram River Byram 4 41.03858 -73.66530 Glenville Street Byram River Byram 3 41.02740 -73.66169 Comly Avenue and Pemberwick Road Byram River Byram 2 41.02383 -73.65859 2 Upland Street E. Byram River Byram 1 41.01649 -73.65623 Den Lane Byram River

Table A3.2. Byram River E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: M. Long, personal communication, October 15, 2020) 5/14/2020 5/18/2020 6/9/2020 6/17/2020 7/16/2020 7/29/2020 8/18/2020 8/31/2020 9/17/2020 9/29/2020 Geomean % exceeding SSM East Byram 3 17 16 57 74 61 88 315 228 73 75 69 0% East Byram 2 42 41 54 46 166 49 272 72 26 16 56 0% East Byram 1 61 461 225 276 N/A 1226 1203 133 126 205 274 22% Byram 7 84 120 236 548 185 66 2420 75 119 387 205 10% Byram 6 28 46 43 43 43 37 488 35 22 119 53 0% Byram 5 35 45 33 88 78 101 435 29 62 76 68 0% Byram 3 20 53 125 61 613 1046 >2420 47 19 13 104 30% Weather Dry Dry Dry Dry Dry Dry Wet Dry Dry Dry

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Table A3.3. Byram River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) East Byram 3 18.4 8.32 236 East Byram 2 18.2 8.38 274 East Byram 1 20.0 8.27 278 Byram 7 19.3 7.95 841 Byram 6 19.1 9.45 629 Byram 5 21.2 8.84 429 Byram 3 20.7 9.26 437

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Appendix 4: Comstock Brook

Table A4.1. GPS coordinates and site locations for Comstock Brook Site Name Latitude Longitude Site location notes River Name East Comstock 2 41.23927 -73.46164 Whipstick Road East Comstock Brook East Comstock 1 41.23247 -73.46502 Millstone Road East Comstock Brook Comstock 3 41.21262 -73.45841 Nod Hill Road Comstock Brook Comstock 2 41.20518 -73.44822 Middlebrook Farm Road Comstock Brook Wilton SD1 41.20519 -73.44824 Middlebrook Farm Road; Stormwater outfall Comstock Brook Comstock 1 41.19597 -73.43747 Lovers Lane Comstock Brook

Table A4.2. Comstock Brook E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020). Note: Due to East Comstock 2 drying up, the geometric mean was calculated using fewer than the requisite 8 values % exceeding 5/12/20 5/28/20 6/10/20 6/23/20 7/7/20 7/29/2020 8/12/2020 8/17/2020 9/1/2020 9/22/2020 Geomean SSM East Comstock 2 50 59 91 199 127 521 Dry Dry 1553 Dry 178 14% East Comstock 1 35 44 866 40 66 210 866 201 152 114 137 20% Comstock 3 44 53 35 35 214 89 1159 160 65 43 88 10% Comstock 2 387 >2420 144 435 105 770 >2420 436 197 91 393 30% Comstock 1 261 46 579 133 403 326 365 649 76 55 203 20% Weather Dry Dry Dry Dry Dry Dry Dry Wet Dry Dry

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Table A4.3. Comstock Brook mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) East Comstock 2 17.9 5.69 199 East Comstock 1 19.3 7.27 196 Comstock 3 17.3 8.77 235 Comstock 2 16.7 5.33 238 Comstock 1 17.5 6.74 290

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Appendix 5: Deadman’s Brook

Table A5.1. GPS coordinates and site locations for Deadman’s Brook. Site Name Latitude Longitude Site location notes River Name Deadman 9 41.17826 -73.33006 Tupelo Road Deadman's Brook Deadman 8 41.17267 -73.33152 Highland Road Deadman's Brook Deadman 7 41.16502 -73.33419 Silent Grove North Deadman's Brook Deadman 5 41.15869 -73.33498 North Avenue Deadman's Brook Deadman 4 41.15487 -73.34130 Leslie Lane Deadman's Brook Deadman 3.5 41.15141 -73.34782 Deerwood Lane Deadman's Brook Deadman 3 41.14682 -73.35434 Evergreen Ave Deadman's Brook Deadman 2 41.14199 -73.35834 Myrtle Ave Deadman's Brook Deadman 1 41.13975 -73.35843 Jesup Road Deadman's Brook

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Table A5.2. Deadman’s Brook E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020). Note: Deadman 2 geometric mean calculated using fewer than the requisite 8 values because the site dried up at the end of the monitoring season. Indicator % exceeding bacteria 5/6/2020 5/21/2020 6/2/2020 6/25/2020 7/9/2020 7/23/2020 8/12/2020 8/24/2020 9/2/2020 9/24/2020 Geomean SSM Deadman 9 E. coli 67 66 11 3 62 23 27 5 1300 16 30 10% Deadman 8 E. coli 93 40 114 72 365 770 37 387 >2420 Dry 189 22% Deadman 7 E. coli 126 2420 1986 690 1733 68 187 91 1961 49 390 50% Deadman 5 E. coli 68 96 238 488 922 775 49 78 1733 328 255 30% Deadman 4 E. coli 101 50 50 63 435 206 258 1961 977 16 161 20% Deadman 3.5 E. coli 52 50 96 308 2599 1633 870 731 3973 128 400 50% Deadman 3 E. coli 46 91 921 409 977 >4839 192 234 >4839 Dry 490 44% Deadman 2 E. coli 111 148 921 1159 1454 731 Dry Dry Dry Dry 515 67% Deadman 1 Enterococci <10 96 683 292 1376 1576 145 373 12033 160 366 40% Weather Dry Dry Dry Dry Wet Wet Dry Dry Wet Dry

Table A5.3. Deadman’s Brook mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Deadman 9 19.3 3.59 238 Deadman 8 18.9 3.90 217 Deadman 7 16.7 6.15 368 Deadman 5 18.4 7.69 327 Deadman 4 18.0 8.17 309 Deadman 3.5 18.2 7.54 297 Deadman 3 17.1 8.85 277 Deadman 2 17.1 9.18 308 Deadman 1 19.8 6.69 13981

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Appendix 6: Little River

Table A6.1. GPS coordinates and site locations for the Little River Site Name Latitude Longitude Site location notes River Name Little 4 41.33821 -73.37624 Pocahontas Road Little River Little 2A 41.32423 -73.36592 Black Rock Turnpike Unnamed Tributary Little 2 41.30905 -73.36563 Cross Highway Little River Little 1 41.29182 -73.36918 Greenbush Road Little River

Table A6.2. Little River E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: Weather Underground – Danbury Muni Station, October 16, 2020). Little 2A dried up at the end of the monitoring season and the geometric mean is calculated with fewer than the requisite 8 values % exceeding 5/13/2020 5/26/2020 6/9/2020 6/24/2020 7/16/2020 7/28/2020 8/13/2020 8/19/2020 9/10/2020 9/16/2020 Geomean SSM Little 4 5 17 9 70 45 46 49 199 488 Dry 43 0% Little 2A 54 19 22 Dry 30 32 Dry Dry Dry Dry 29 0% Little 2 N/A 19 43 579 247 172 160 156 111 N/A 124 13% Little 1 31 10 37 123 291 579 18 74 171 32 67 10% Weather Dry N/A Dry N/A Dry Dry Dry Wet Dry Dry

Table A6.3. Little River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Little 4 22.2 5.97 141 Little 2A 15.4 6.84 204 Little 2 19.2 8.12 166 Little 1 17.5 9.30 172

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Appendix 7: Noroton River

Table A7.1. GPS coordinates and site locations for Noroton River Site Name Latitude Longitude Site location notes River Name Noroton 8 41.15925 -73.51421 West Road and Greenley Road intersection Noroton River Noroton 7 41.14108 -73.51167 209 Frogtown Road Noroton River Noroton 5 41.11868 -73.50130 47 Jelliff Mill Road Noroton River Noroton 4 41.10290 -73.50982 137 Woodway Road Noroton River Noroton 3 41.09540 -73.51430 Camp Avenue Noroton River Noroton 2 41.07530 -73.51550 668 Connecticut 106 Noroton River Noroton 1.5 41.06186 -73.50814 1308 E Main Street Noroton River

Table A7.2. Noroton River E. coli and Enterococci concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: M. Long, personal communication, October 15, 2020). Note: Geometric mean for Noroton 1.5 was calculated with fewer than the requisite 8 values. Indicator % exceeding bacteria 5/14/2020 5/27/2020 6/2/2020 6/18/2020 7/9/2020 7/30/2020 8/25/2020 8/31/2020 9/17/2020 9/28/2020 Geomean SSM Noroton 8 E. coli 24 548 179 248 461 260 51 70 108 187 148 0% Noroton 7 E. coli 126 161 115 22 687 131 38 70 32 93 90 10% Noroton 5 E. coli 31 31 6 70 23 124 12 2 6 5 16 0% Noroton 4 E. coli 73 133 89 109 461 219 153 185 66 143 138 0% Noroton 3 E. coli 55 187 517 2420 1373 308 1733 1034 921 1300 641 60% Noroton 2 E. coli 155 196 179 130 731 151 1159 37 21 219 165 20% Noroton 1.5 Enterococci N/A N/A N/A 504 2723 776 435 404 368 1187 699 57% Weather Dry Dry Dry Dry Wet Dry Dry Dry Dry Dry

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Table A7.3. Noroton River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Noroton 8 20.6 5.76 312 Noroton 7 19.4 8.01 249 Noroton 5 22.2 8.24 301 Noroton 4 21.0 9.77 293 Noroton 3 19.4 8.82 302 Noroton 2 20.6 7.60 448 Noroton 1.5 20.8 7.85 10984

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Appendix 8: Norwalk River

Table A8.1. GPS coordinates and site locations for Norwalk River Site Name Latitude Longitude Site location notes River Name Norwalk 23 41.29005 -73.49349 22 South Street Unnamed Ridgefield SD1 41.29077 -73.49155 Ligi’s Way Unnamed Norwalk 21 41.29444 -73.48843 68 Farmingville Road Ridgefield Brook Norwalk 19 41.31672 -73.49001 Limestone Road Ridgefield Brook Norwalk 15 41.30870 -73.46884 Stonehenge Road Norwalk River Norwalk 13 41.26550 -73.44079 787 Branchville Road Norwalk River Norwalk 9.5 41.24590 -73.43409 Old Mill Road Norwalk River Norwalk 9 41.20354 -73.43094 School Road Norwalk River Norwalk 6 41.18341 -73.42276 187 Danbury Road Norwalk River Norwalk 4 41.14349 -73.42669 10 Glover Avenue Norwalk River Norwalk 1 41.11947 -73.41701 40 Cross Street Norwalk River

Table A8.2. Norwalk River E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020)

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% exceeding 5/4/2020 5/21/2020 6/1/2020 6/16/2020 7/14/2020 7/28/2020 8/12/2020 8/27/2020 9/8/2020 9/24/2020 Geomean SSM Norwalk 23 23 76 166 124 166 113 137 816 1414 30 141 20% Norwalk 21 16 105 435 291 206 1046 770 1300 167 152 255 30% Norwalk 19 12 22 3 29 49 14 10 4 5 2 10 0% Norwalk 15 30 42 153 272 130 26 15 43 18 36 49 0% Norwalk 13 47 69 161 173 172 178 75 106 132 120 113 0% Norwalk 9.5 32 22 579 53 80 65 114 172 93 63 82 10% Norwalk 9 37 83 99 291 196 192 816 488 105 488 192 10% Norwalk 6 23 131 236 488 162 238 548 N/A 86 81 155 0% Norwalk 4 47 73 240 185 238 411 238 N/A 81 57 136 0% Norwalk 1 101 68 155 155 96 93 137 N/A 179 85 113 0% Weather Wet Dry Dry Dry Dry Dry Dry Wet Dry Dry

Table A8.3. Norwalk River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Norwalk 23 18.5 9.62 1199 Norwalk 21 18.6 6.36 871 Norwalk 19 21.0 7.44 659 Norwalk 15 19.5 9.04 636 Norwalk 13 20.8 9.23 501 Norwalk 9.5 20.4 8.78 458 Norwalk 9 18.6 9.21 418 Norwalk 6 19.0 9.19 429 Norwalk 4 20.2 10.21 449 Norwalk 1 21.2 10.03 420

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Appendix 9: Rippowam River

Table A9.1. GPS coordinates and site locations for Rippowam River Site Name Latitude Longitude Site location notes River Name Rippowam 12 41.18524 -73.52999 Oenoke Ridge Rippowam River Rippowam 11.5 41.17561 -73.52919 West Road Rippowam River Rippowam 11 41.17234 -73.53126 Dans Highway Rippowam River Rippowam 10 41.16153 -73.53843 Ponus Ridge Road Rippowam River Rippowam 9 41.15023 -73.53412 Cascade Road Rippowam River Rippowam 8 41.11302 -73.54619 High Ridge Road Rippowam River Rippowam 7 41.10559 -73.5586 Cedar Heights Road Rippowam River Rippowam 5 41.08559 -73.55664 Long Ridge Road Rippowam River Rippowam 4 41.06617 -73.55763 Cold Spring Road Rippowam River Rippowam 3 41.06593 -73.54912 Bridge Street Rippowam River Rippowam 2 41.05904 -73.54664 W North Street Rippowam River Rippowam 0.5 41.04813 -73.54542 Richmond Hill Avenue Rippowam River

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Table A9.2. Rippowam River E. coli and Enterococci concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: M. Long, personal communication, October 15, 2020) Indicator % exceeding Bacteria 5/11/2020 5/26/2020 6/11/2020 6/17/2020 7/18/2020 7/23/2020 8/17/2020 9/1/2020 9/14/2020 9/29/2020 Geomean SSM Rippowam 12 E. coli 28 140 613 172 185 1120 144 219 291 111 197 20% Rippowam 11.5 E. coli 20 61 131 31 91 252 93 29 11 23 49 0% Rippowam 11 E. coli 23 16 30 16 59 201 68 22 488 365 59 0% Rippowam 10 E. coli 46 114 84 135 68 921 73 435 152 345 151 10% Rippowam 9 E. coli 105 345 99 42 115 378 152 31 129 58 108 0% Rippowam 7 E. coli 219 114 249 166 345 2420 727 1842 365 276 404 30% Rippowam 4 E. coli 140 210 214 411 186 182 141 499 411 75 213 0% Rippowam 2 E. coli 148 291 291 649 293 521 187 118 651 153 278 20% Rippowam 0.5 Enterococci 41 161 N/A 393 450 723 504 364 546 565 331 44% Weather Wet Dry Dry Dry Wet Wet Wet Dry Dry Dry

Table A9.3. Rippowam River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Rippowam 12 18.7 7.46 203 Rippowam 11.5 19.5 8.33 203 Rippowam 11 21.8 6.58 195 Rippowam 10 21.5 6.49 208 Rippowam 9 19.1 7.14 263 Rippowam 7 19.2 8.68 341 Rippowam 4 19.2 8.55 445 Rippowam 2 19.6 8.61 472 Rippowam 0.5 20.9 7.82 18388

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Appendix 10: Saugatuck River

Table A10.1. GPS coordinates and site locations for Saugatuck River Site Name Latitude Longitude Site location notes River Name West Saug 6 41.2573 -73.41533 86 Old Farm Road West Branch Saugatuck River West Saug 5 41.24954 -73.41377 20 Indian Valley Road West Branch Saugatuck River West Saug 4 41.22465 -73.38366 3 Michaels Way West Branch Saugatuck River West Saug 3 41.21162 -73.388 Intersection of Georgetown Road and Old Mill Road West Branch Saugatuck River West Saug 2 41.1948 -73.38763 23 Stonebridge Road West Branch Saugatuck River West Saug 1 41.17809 -73.37404 21 Cavalry Road West Branch Saugatuck River Saugatuck 7 41.29439 -73.3948 Route 53 and 107 intersection Saugatuck River Saugatuck 6 41.24343 -73.34785 153 Valley Forge Road Saugatuck River Saugatuck 5 41.22469 -73.3467 18 Davis Hill Road Saugatuck River Saugatuck 4 41.20722 -73.35043 1 Cartbridge Road Saugatuck River Saugatuck 3 41.1883 -73.36441 27 River Road Saugatuck River Saugatuck 2 41.17553 -73.36193 Weston Road Saugatuck River Saugatuck 1 41.16748 -73.36647 Pulloff by Michele Ln on Clinton Avenue Saugatuck River Saugatuck 0.75 41.14719 -73.36469 Kings Highway North Saugatuck River Saugatuck 0.5 41.14098 -73.36312 State Street East Saugatuck River Saugatuck 0.25 41.12274 -73.36912 Bridge Street Saugatuck River

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Table A10.2. Saugatuck River E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020) Indicator % exceeding Bacteria 5/7/2020 5/20/2020 6/3/2020 6/24/2020 7/6/2020 7/20/2020 8/13/2020 8/27/2020 9/3/2020 9/15/2020 Geomean SSM West Saug 6 E. coli 31 12 23 Dry 228 Dry Dry Dry 461 Dry 62 0% West Saug 5 E. coli 17 59 40 18 46 27 13 1046 156 Dry 50 11% West Saug 4 E. coli 126 58 150 59 96 33 41 49 111 69 71 0% West Saug 2 E. coli 17 31 96 83 108 162 50 96 2092 167 102 10% West Saug 1 E. coli 71 291 110 435 228 225 133 130 172 25 144 0% Saugatuck 7 E. coli 68 24 82 28 41 149 99 49 77 102 62 0% Saugatuck 5 E. coli 16 17 24 55 81 66 78 57 140 68 49 0% Saugatuck 4 E. coli 15 17 50 140 172 114 76 90 193 58 69 0% Saugatuck 3 E. coli 31 15 47 96 82 62 45 33 96 38 47 0% Saugatuck 2 E. coli 23 28 74 99 135 102 46 50 88 41 59 0% Saugatuck 1 E. coli 19 72 120 126 435 117 206 104 181 86 113 0% Saugatuck 0.75 Enterococci 10 31 75 75 63 75 108 121 158 41 61 0% Saugatuck 0.5 Enterococci <10 109 63 247 75 85 187 41 216 20 72 0% Saugatuck 0.25 Enterococci 10 120 31 496 171 10 10 52 171 <10 44 0% Weather Dry Dry Dry Dry Dry Dry Dry Wet Wet Dry

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Table A10.3. Saugatuck River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) West Saug 6 15.6 9.90 286 West Saug 5 17.6 7.24 209 West Saug 4 20.1 7.93 189 West Saug 2 19.2 7.67 231 West Saug 1 19.0 8.88 232 Saugatuck 7 19.6 8.85 279 Saugatuck 5 14.7 10.12 185 Saugatuck 4 16.2 9.70 190 Saugatuck 3 17.7 9.78 190 Saugatuck 2 18.7 9.00 174 Saugatuck 1 19.2 8.37 212 Saugatuck 0.75 21.9 8.15 15148 Saugatuck 0.5 22.3 7.63 27572 Saugatuck 0.25 21.6 7.89 33312

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Appendix 11: Silvermine River

Table A11.1. GPS coordinates and site locations for Silvermine River Site Name Latitude Longitude Site location notes River Name Silvermine 10 41.19871 -73.49241 North Wilton Road Silvermine River Silvermine 9 41.18679 -73.48749 Valley Road Silvermine River Silvermine 8 41.17791 -73.48174 Hickok Road Silvermine River Silvermine 7 41.17371 -73.47799 Mariomi Road Silvermine River Silvermine 6 41.17121 -73.47128 Huckleberry Hill Road Silvermine River Silvermine 5 41.16107 -73.46265 New Canaan Road Silvermine River Silvermine 4 41.15971 -73.45277 Borglum Road Silvermine River Silvermine 3 41.15126 -73.44539 Perry Avenue Silvermine River Silvermine 2 41.14726 -73.44293 Walking path from Silvermine Avenue to Silvermine Elementary Silvermine River Silvermine 1.5 41.13685 -73.43902 Bonnie Doone Lane Silvermine River

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Table A11.2. Silvermine River E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020). Note: Geometric mean for Silvermine 2 was calculated with fewer than the requisite 8 values % exceeding 5/12/2020 5/27/2020 6/10/2020 6/22/2020 7/14/2020 7/21/2020 8/13/2020 8/25/2020 9/8/2020 9/16/2020 Geomean SSM Silvermine 10 2 31 156 28 35 125 47 34 18 16 30 0% Silvermine 9 3 <1 26 178 166 39 19 153 50 22 28 0% Silvermine 8 34 276 79 102 96 53 68 42 78 124 80 0% Silvermine 7 35 88 193 172 308 201 97 79 28 42 94 0% Silvermine 6 26 54 39 28 68 48 27 43 62 44 42 0% Silvermine 5 33 105 120 161 116 144 53 64 68 137 90 0% Silvermine 4 74 47 88 N/A 332 770 131 206 172 81 146 11% Silvermine 2 N/A N/A N/A 378 345 345 N/A N/A N/A N/A 356 0% Silvermine 1.5 34 133 816 1120 291 517 219 179 214 365 268 20% Weather Dry Dry Dry Dry Dry Dry Dry Dry Dry Dry Table A11.3. Silvermine River mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Silvermine 10 18.4 6.99 241 Silvermine 9 20.6 7.05 222 Silvermine 8 19.1 7.46 214 Silvermine 7 19.4 8.11 215 Silvermine 6 19.9 8.42 217 Silvermine 5 20.7 8.01 242 Silvermine 4 20.1 7.16 225 Silvermine 2 23.0 8.01 266 Silvermine 1.5 19.6 7.80 260

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Appendix 12: Stony Brook

Table A12.1. GPS coordinates and site locations for Stony Brook Site Name Latitude Longitude Site location notes River Name Stony 6 41.15178 -73.39100 Newtown Avenue Stony Brook Stony 5 41.15033 -73.38739 Partrick Road Stony Brook Stony 4 41.14883 -73.38424 Earthplace sanctuary Stony Brook Stony 3 41.14322 -73.38062 Stony Brook Road Stony Brook Stony 2 41.13653 -73.36993 Post Road Stony Brook Stony 1 41.13223 -73.36838 Sylvan Lane Stony Brook

Table A12.2. Stony Brook E. coli concentrations, geometric means, and % of samples exceeding the CT DEEP single sample maximum (Rainfall data: P. DiPietro, Personal communication, October 16, 2020) Indicator % exceeding Bacteria 5/13/2020 5/28/2020 6/11/2020 6/23/2020 7/13/2020 7/21/2020 8/12/2020 8/19/2020 9/2/2020 9/22/2020 Geomean SSM Stony 6 E. coli 219 1046 548 >2420 821 1298 236 523 290 613 609 50% Stony 5 E. coli 186 548 214 290 42 82 43 311 168 88 146 0% Stony 4 E. coli 206 411 1300 488 387 651 333 >4839 3106 56 572 40% Stony 3 E. coli 225 260 816 119 237 93 234 >4839 582 141 321 30% Stony 2 E. coli 27 71 78 133 40 >2420 2092 77 615 77 165 30% Stony 1 Enterococci 85 120 4106 1935 906 85 52 426 1160 388 380 40% Weather Dry Dry Dry Dry Dry Dry Dry Wet Wet Dry

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Table A12.3. Stony Brook mean water temperature, dissolved oxygen, and conductivity for each site Mean water Mean dissolved Mean temperature (°C) oxygen (mg/L) conductivity (µS) Stony 6 19.3 7.35 323 Stony 5 20.7 7.21 269 Stony 4 20.1 7.72 266 Stony 3 19.9 8.73 228 Stony 2 21.7 7.29 315 Stony 1 22.5 7.89 20974

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Citations

“Danbury Muni Station.” Weather Underground. The Weather Company, LLC. Web. Accessed: 16 October 2020. State of Connecticut Department of Energy and Environmental Protection. “Comprehensive Characterization Report Rippowam/Mill River Watershed Management and Infrastructure Program.” (2011). www.ct.gov/deep/lib/deep/water/watershed_management/wm_plans/rippowam_mill_20 10.pdf State of Connecticut Department of Energy and Environmental Protection. "Connecticut Water Quality Standards." (2013): 22-90. Eregulations.ct.gov. Web. Accessed: 28 Nov. 2016. The Norwalk River Watershed Initiative Committee. The Norwalk River Watershed Action Plan. 1998. 38 pp. “Tweed New Haven Regional Airport.” Weather Underground. The Weather Company, LLC. Web. Accessed: 16 October 2020.

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