Southwest Conservation District

Hamden office:
Northern Research Station
51 Millpond Rd
Hamden, CT 06514

Phone: 203-287-8179

Fax: 203-288-5077

Norwalk River Watershed InitiativeByram Watershed CoalitionPequonnock River Initiative

"We envision a restored Norwalk River Watershed system: one that is healthy, dynamic and will remain so for generations to come; one that offers clean water and functioning wetlands; one in which a diversity of freshwater and anadromous fish as well as other wildlife and plants are once again sustained; one in which the river system is an attractive community resource that enhances quality of life, education, tourism and recreation; and above all, one in which growth respects this vision and all people participate in the stewardship of the watershed."  

Norwalk River Watershed Initiative Committee
The Norwalk River Watershed Action Plan (October 1998)


                   The Watershed /About Us/Our Plan /Water Quality Concerns /What We Do/Projects & Events /Watershed Town Links/Downloads /Water Quality Reports/Contact Us

Please See Our Recently Launched, ​Dedicated Website
 for Up-To-Date News and Water Quality Data at 


The Watershed

The Norwalk River Watershed is a regional basin of approximately 64 square miles that extends into six Connecticut municipalities - New Canaan, Norwalk, Redding, Ridgefield, Weston, and Wilton and one in New York - Lewisboro. There are two major tributaries, Comstock Brook and the Silvermine River, that form sub-basins within the Norwalk River Watershed. While upper reaches of the watershed exhibit more forested and suburban landscapes, the lower reaches and near the outlet into Norwalk Harbor are heavily urbanized.

About Us

The Norwalk River Watershed Initiative (NRWI), established in 1996, is a partnership among the seven watershed municipalities; federal and state governments; conservation and environmental groups; businesses and the public to address local water quality and resource protection issues within the Norwalk River Watershed. Unlike other organizations, the NRWI maintains an active membership among representatives from the watershed municipalities and local water companies recognizing the importance of collaboration and local leadership to effective watershed management.

Our Plan

The Norwalk River Watershed has a rich history of watershed planning and represents one of the earliest community-driven, locally-led initiatives in the U.S. to restore and protect watershed resources. The Initiative’s activities are guided by the Norwalk River Watershed Action Plan which was first adopted and published in 1998 followed by a supplement in 2004. Most recently, an extensive update was completed in 2011 with the development of a watershed based plan using guidelines outlined by the Connecticut Department of Energy and Environmental Protection (CTDEEP). This new plan outlines major goals and objectives as in previous versions plus includes a pollutant load assessment, specific recommendations with estimated load reductions, and an emphasis on Non-Point Source Runoff Management. The overall goal of the 2011 Norwalk River Watershed Action Plan is to identify and implement recommendations in the Plan which will improve water quality in the Norwalk River and its tributaries, which will ultimately lead to segments being removed from the state impaired waters list (See below for links to this document).

Water Quality Concerns

In 2005, the CTDEEP developed a Total Maximum Daily Load (TMDL) for indicator bacteria for the Norwalk River and various tributaries. Despite significant accomplishments from watershed stakeholders, sections of the mainstem and its tributaries do not meet the State’s Water Quality Standards for their designated uses due to elevated levels of indicator bacteria and are categorized as impaired. To meet these total daily maximum loads the bacteria levels in the impaired waters must be reduce by as much as 76% in some segments. Indicator bacteria loads can be attributed to a variety of sources, including failed or improperly maintained septic systems, urban stormwater, illicit discharges to storm sewers, hobby farms, wildlife and pet waste. Indicator bacteria levels are the primary pollutant of concern for recreational uses in the river and shellfishing in the Norwalk Harbor. Some segments of the river have also been identified as impaired for fish and other aquatic life support. Other major concerns in the watershed include flooding, streambank and channel erosion, and excessive nutrient loads to impoundments (lakes, ponds, reservoirs). High levels of nutrients, both phosphorous and nitrogen, have caused water quality concerns in the tributaries and mainstem, as well as Long Island Sound. Localized nutrient inputs such as lawn fertilizers, failing septic systems and illicit discharges contribute to these high levels causing eutrophication in impoundments and variations in dissolved oxygen levels that can impact aquatic life. Extreme bank erosion from flooding and loss of riparian buffer exacerbates the impact of bacteria and nutrient loads, as well as silt and other pollutants, through stormwater runoff.

What We Do

The Norwalk River mainstem, the Silvermine River and Comstock Brook have long term water quality data collected by various agencies. Harbor Watch, a local CT state certified water quality testing and monitoring service, has been monitoring 12 sites throughout the watershed for over 10 years. Continual monitoring is important to understand the relative contributions of various pollution sources, guide environmental decision-making, and to measure the progress toward watershed management goals. Over the past 10 years, planning efforts supported by a successful water quality monitoring program by Harbor Watch, have identified and led to the detection and correction of a number of point source “hot spots”, including illicit discharge to stormwater sewers and failing septic systems. The Harbor Watch program has also been instrumental in guiding the Initiative’s focus in addressing pollution from non-point sources as well.

Although progress has been made to address point sources of pollution from wastewater treatment, non-point sources of pollution from stormwater runoff continue to degrade our rivers and streams and are major contributors to water quality impairment. We have all witnessed these diffuse sources as runoff from roads, parking lots, and lawns carrying with it leachate from septic systems; fertilizers and pesticides; animal waste from wildlife, pets and hobby farms; oils, salts, silt and other toxins. Discharge from non-point sources are most effectively controlled through volunteer programs administered at the state and local level. This aspect of watershed management requires broad collaboration and local leadership among communities.

Current Projects & Events

Residential Rain Garden Workshop

Our sponsored Rain Garden Workshop at the Wilton Playshop was a great success.  The weather was cooperative and the participants enthusiastic. Click on the link below to view the photos of the installation of this 100 square foot garden.  Notice a drain pipe was installed from a downspout under a stone walkway to the garden where it opened to a stone inlet.   The plantings for this wet and relatively shaded site include Boneset, Joe Pye Weed, Button Bush and Blue Lobelia. The new perennial plantings were installed in their "early season" state in April but ore recent photos will be coming. For  additional information on rain gardens visit or click the link below to download the Rain Garden Design Guide for Homeowners in Connecticut.

LINK to Rain Garden Workshop Photos:             LINK to Rain Garden Design Guide:



NEW!  The CT NEMO program has developed a FREE mobile app for designing, installing and maintaining a rain garden.  For more information and download:

About CT NEMO:

"The NEMO (Nonpoint Education for Municipal Officials) Program was created in 1991 at the University of Connecticut, as a collaboration of the Cooperative Extension System, the Connecticut Sea Grant College Program and the Natural Resources Management and Engineering Department. NEMO was created in recognition of the relative lack of education and assistance available for community land use decision makers. Local land use decisions are a key determinant of the social, economic and environmental health of our communities, yet our local decision makers are volunteers with little or no training in land planning or natural resource protection.

The original NEMO pilot project was an outgrowth of the Long Island Sound Study National Estuary Program. With a grant from USDA, UConn staff developed a presentation that used remote sensing and geographic information system (GIS) technologies to inform local land use decision makers about the links between land use and water quality. The original project focused on three pilot communities along Connecticut’s coast, but within a few years, NEMO had evolved into a program responding to requests from communities across the state."


Ridgefield Storm Drain Project - Identification and Management of Indicator Bacteria Pollution Source

Steep Brook in Ridgefield is the home of the headwaters for the Norwalk River. The brook runs through the center of town and captures storm water run-off from Prospect Ridge on the east and Main Street on the west. It's beginnings are noted in the vicinity of Rowland Ln. and it can be followed crossing Market, Governor and Prospect Streets as it heads north. Over the years, this section of Steep Brook has been identified as having concentrations of E. coli bacteria from an unknown source in excess of State water Quality Standards.  It is listed as an impaired water segment in the "State of Connecticut Integrated Water Quality Report" and contributes to the elevated bacteria level in the Norwalk River. A systematic study of the storm drain network and watercourses has recently been completed to isolate the source of the bacteria.  The study was performed by Harbor Watch at Earthplace which entailed field sampling, lab analysis and data assessment of storm drains discharging into Steep Brook.  A final report will be issued soon.


Comstock Brook Outflow - Identification and Management of Indicator Bacteria Pollution Source 

 Comstock Brook is a tributary of the Norwalk River which runs through Wilton and joins the river just south of Merwin Meadows.  Based on historical test data, Comstock Brook has had a history of elevated E. coli levels from a pipe discharging storm water from Middlebrook Farm Road.  Elevated bacteria counts at each catch basin along the road were observed on days that had experienced heavy rainfall days prior to sampling.  A septic system along the network has been replaced which appears to have reduced the bacteria counts.  Further testing will be needed to confirm.

Residential Rain Garden Installation Project in Silvermine


Rain gardens are a proven, environmentally friendly technique for receiving and filtering storm water runoff. They are a beautiful solution to reduce the impact of storm water pollution in our rivers and streams and the Long Island Sound. To this end, the NRWI is continuing its educational and outreach efforts with a CT DEEP grant funded Residential Rain Garden Installation Project in the Silvermine sub-watershed community. This project will provide for the design, excavation, and plantings for nine residential rain gardens within a selected Silvermine neighborhood. The project is scheduled to begin this fall/winter with an informational mailing and presentation to the Silvermine residents of the Rae Lane neighborhood.  STAY TUNED! 





How to Contact Us

For more information or questions on the Watershed, the Initiative, or our projects, please contact our Watershed Coordinator, Cindy Ingersoll, at cindyingersoll5@gmail.comIf you would like to know more about what you could do as residents of our watershed community to help protect and restore our rivers and streams, we would be happy to provide you with helpful information and resources.

 Links to Watershed Towns

City of Norwalk Town of Wilton Town of Ridgefield
Town of New Canaan Town of Redding Town of Weston
Town of Lewisboro    




 Maps &  Downloads                                        Water Quality Reports                                 

2011 Norwalk River Watershed Based Plan   2009 Summer Harbor Watch Report - Norwalk River
NRW Wetland Soils + Dams   2009 Summer Harbor Watch Report - Silvermine River
NRW Impaired Waters Listing   2010 Summer Harbor Watch Report - Norwalk River
NRW Sub-basin Areas   2011 Summer Harbor Watch Report - Norwalk River
Historical Trends in Water Quality   2012 Summer Harbor Watch Report - Silvermine River
Rain Garden Workshop Demo Site    2012 Summer Harbor Watch Report - Norwalk River



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