• Covers approximately 40,000 acres.
  • Spans seven townships in CT and NY.
  • Length 20 miles, elevation drop 962 ft.
  • Watershed population: 65,587 people (1990 census).
  • Major tributaries: Silvermine River, Comstock Brook.
  • Public reservoirs on upper Silvermine & Comstock.
  • Good recreational fishing at many sites.
  • Major oyster beds at mouth, in Long Island Sound.
  • Important transportation corridor (US Rte. 7).  

Monitoring Water Quality in the Norwalk River
The Norwalk River Watershed Association provides funding to the Harbor Watch/River Watch Program for the on-going monitoring of water quality throughout the Norwalk River. Harbor Watch/River Watch is based out of Earthplace in Westport, CT and provides NRWA with periodic water quality reports (available for download below), as well as presents a summary of the year's findings at our annual meeting each Spring.

Download Water Quality Reports

The Norwalk River watershed lies in an area that's bounded by the Housatonic River watershed on the north and east, the Hudson River watershed on the west, and Long Island Sound on the south.  Within this area (shown in here in yellow), the Norwalk is one of several rivers that flow SSE into the Sound.

Its neighbor to the east is the Saugatuck River, which arrives at the Sound in Westport.  On the southwest its neighbor is the small Fivemile River (not shown on this map) and the Rippowam, which drains the area above the source of the Fivemile and brings its water down to Stamford.  Above the Rippowam, the land west of the Norwalk River drains into the Hudson via the Titicus River (in the greyed-in part of the map).

The Norwalk River enters Long Island Sound at Veteran's Park in South Norwalk, 40 miles northeast of Manhattan.  At the river's mouth is a tidal estuary and harbor used by hundreds of pleasure and fishing boats.  Marine life is abundant, and oyster fishing has been an important activity going back to pre-colonial times.

Educational tours of the harbor are offered by the Maritime Aquarium, and an annual Oyster Festival is sponsored by the Norwalk Seaport Association.   One mile offshore is a chain of islands which serve as a wildlife refuge and, in specific areas, as a popular destination for boaters.  One particular attraction is the historic Sheffield lighthouse.

Upriver from Norwalk, one first reaches the town of Wilton and then the town of Ridgefield.  These two towns, combined with the city of Norwalk, contain more than 78 percent of the watershed.  Their western neighbors, New Canaan and Lewisboro (NY), contain nearly 16 percent, entirely within the sub-watershed of the Norwalk River's largest tributary, the Silvermine River.  The towns to the east, Weston and Redding, contain just 6 percent of the watershed.  This is shown in more detail here.  A wealth of online information is available concerning the upriver communities of Wilton, Ridgefield, Lewisboro, and Redding. For the entire county of Fairfield CT, an excellent online resource is the blue pages.  
Two-thirds of the households in the watershed -- mostly within the urban and village districts -- obtain their water from public water supply systems. Most of the rest get their water from private drilled wells, and a small number use private dug wells.  Sewage disposal is predominantly by public sewage systems in the urban areas and by private septic systems in the more rural and suburban areas. The ratio for the entire watershed is 56 percent of all households using public sewage disposal systems.  This is shown graphically here.

Many pollutants reach the Norwalk River through stormwater runoff from urban zones, roads, and other impervious areas.  Some common misconceptions about water runoff are discussed by the Natural Resources Defence Council, and runoff from roads is described by the Environmental Protection Agency.  Another EPA document describes the economic benefits of controlling stormwater runoff.  Technical details on this subject are available from the North Carolina State University concerning runoff from:  urban areas,  roads,  construction projects,  and industrial sites.
The Norwalk River's banks have undergone human modification in many places, often to the detriment of the river's water quality and posing threats to the plant and animal life that lives along the river.  The importance of these streamside "riparian" areas is discussed here.  In June 1998, several local groups joined forces to restore a section of the Norwalk River's riverbank in Wilton to a more natural condition.  (See article here.)  Similar projects are being planned for other points in the watershed. "Toolbox" of riparian buffer management developed by the Long Island Sound NEP. Check our events calendar to see what has been scheduled.
The most serious problem in the recent water-quality tests on the Norwalk River is the presence of bacteria, part of which may come from unmaintained or malfunctioning septic systems.  Background information about septic-system maintenance can be found here. Questions about local regulations and practices should be directed to local health departments. For an in-depth explanation of the subject, various books can be consulted.  Some technical details are available online about septic systems, and on the related, important subject of underground storage tanks. Alternate Sewage Treatment Systems- White Paper (PDF)

Throughout the Norwalk River watershed, a new lending arrangement termed a watershed improvement loan is available to provide local property owners with another method for handling certain types of critical improvements, such as repairs to malfunctioning septic systems or removal or replacement of in-ground fuel tanks.
Discharges from "point sources" such as wastewater treatment plants and industrial discharge pipes are not nearly as severe a problem as they were ten or twenty years ago.  But despite the many improvements, some serious areas of concern remain. 
One of the most dramatic changes that's currently taking place within the Norwalk River watershed (and throughout much of North America) is the displacement of the native plant life by aggressive invasive species. Read more about specific Invasive threats in our Invasive Species Section. Also available: A list of Invasive Species in the Norwalk River Watershed are listed here. Multiple links to Invasive Species Information is listed on our links page

Flooding is a natural process for rivers, and it produces many beneficial side effects such as the distribution of fresh water over a wide area to replenish groundwater supplies that are critical for the private wells that many households depend upon. But in a congested region like Fairfield County, floods can also pose a great threat to life and property.

The Norwalk River has not had a significant flood since 1955.  A modern repeat of the 1955 flood would do over $21 million in damage along the river, according to a Connecticut study, and the State has identified the region as a "high risk basin in immediate need of better flood control management and hazard mitigation."  The immediate danger can be reduced by adopting a flood warning system (see article), by increasing building setbacks from the river, and by setting aside as open space property adjacent to or upland of the river system in order to reduce impervious surfaces and increase absorption.

Do your part...Excess leaves can clog culverts, fill ponds or the backside of a dam, and make the river shallower and more prone to flooding or the need for expensive dredging. Property owners should let anyone who works with them or for them know that this material should not be blown or dumped into any river, pond, or wetland. No matter which waterway or wetland is a dumping target, dumping in those sensitive areas can have serious consequences (see article).





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Norwalk River Watershed Association, a 501(c)(3) nonprofit membership organization