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Woonasquatucket River Watershed



While the river itself is only 19 miles long the Woonasquatucket watershed covers 50 square miles and encompasses all the land where precipitation and groundwater eventually drain to the river.

The Woonasquatucket River's headwaters are 300 feet above sea level in the town of North Smithfield. From there the river flows 19 miles south and east to downtown Providence, where it joins the Moshassuck River to form the Providence River, which in turn flows into Narragansett Bay. The headwaters, around Primrose Pond and some other nearby ponds, are approximately 300 feet higher than the mouth of the river in Providence, which is at sea level. The lower reaches of the river, up to the Rising Sun Dam near Donigian Park in Olneyville, rise and fall with the tide in Narragansett Bay.

Natural History

The bedrock under the hills of the Woonasquatucket watershed formed more than 600 million years ago when the African continent pushed volcanic islands of the old Atlantic up against the North American continent.   Lower in the watershed, in the Johnston-Providence area, the bedrock, only 300 million years old, formed during the “coal age” when giant ferns and cycads covered all of Narragansett Bay.

Fast forward to the last ice age, 10 to 40 thousand years ago, when the tilt of the earth and the earth’s path around the sun produced year-round low temperatures that did not melt snow in the northern regions.   As this continental glacier melted back across Rhode Island, first sand and gravel were deposited in the ancient river valley, and then the meltwater from the glacier cut a channel that still flows today as the Woonasquatucket River.  

Over the last 10 to 12 thousand years, lichens, wildflowers and shrubs have grown and contributed to the development of topsoil.   This, in turn, supported the growth of cone-bearing trees and hardwoods. Native Americans migrated here to forage for the abundant berries, shellfish, and small game.   Europeans arrived on Rhode Island shores in 1636, and the land between the Moshassuck and the Woonasquatucket was given to Roger Williams in a treaty.

Although European mill industries developed along the river, dammed its free flow and dumped wastes into the water, even the urban part of the river still displays amazing wildlife.   No longer do salmon or herring swim against the current from the ocean to spawn in the Woonasquatucket or its tributaries, but elver, young eels, manage to migrate from the Atlantic’s Sargasso Sea, up Narragansett Bay, and up the impoundments as far as the river and its tributaries in Johnston and North Providence.

Other fish – trout, bluegills, pumpkinseeds, catfish and suckers — live in the lower river where painted turtles sun on its banks.   Mute swans, mallards, and hooded mergansers cruise the waters looking for food.   Gulls poke along bars in the lower river at ebb tide, and raccoons forage the embankments.

Red maples predominate the riverbank into downtown Providence, and orchid-like arrow arum and violet vervain stake a claim between the factories of Olneyville.   The remains of the floodplain at Donigian Park grow box elder trees.

Birds that winter in Latin America nest along the Woonasquatucket in warmer months. Yellow-throated warblers, kingbirds, orioles and flycatchers have found suitable habitat to raise offspring in Providence and further upstream pockets of forested swampland offer abundant nesting areas.   Great Blue Heron forage the Dyerville area. Just along the Providence-Johnston border red-tailed hawks nest and hunt the river margin. Further out in the watershed red-shouldered and broad-winged hawks have nested. Great horned, barred, and screech owls find homes among the hardwoods covering the hills.

Fox, coyote, rabbits, otters, shrews, and gray, red, and flying squirrels claim the name mammal along with the human residents of the watershed.   Even bear and moose have ventured here, and white-tailed deer proliferate.

Modern History

The name of the river derives from this because to the Native Americans who lived here "Woonasquatucket" (woon-AHS-kwa-tuk-it) meant "the place where the salt water ends" or the meeting of the river and the sea.

Ever since Roger Williams arrived in 1636 and joined the Native Americans who lived in the region, the Woonasquatucket River valley has been settled by a wide variety of people from around the world. From the early settlers who farmed the land, to the immigrants of the 19th Century who built and worked in the mills, to the new wave of residents in the 20th century-each group of people has left their mark on the watershed. They farmed, fished and built industries, leaving us with a legacy of farmhouses, mills, churches and homes that contribute to the fabric of our communities. At the mouth of the river the City of Providence grew to become the capitol of Rhode Island as well as a center for art, industry and culture.

Recent history has painted the picture of a river on the rebound.   In 1998 President Clinton designated the Woonasquatucket River an American Heritage River one of only fourteen in the nation.   The Rhode Island Watershed Partnership selected the Woonasquatucket River as one of its two pilot watersheds.   In June of 2001, the Rhode Island Rivers Council designated the Woonasquatucket River Watershed Council (WRWC) as the official watershed organization.   On the ground several key efforts are underway to improve the health of watershed.   Many of the activities now underway are the direct result of the efforts of the Woonasquatucket Watershed Team (WWT) or its members.   The Woonasquatucket Watershed Team consists of members of the WRWC, as well as representatives of state agencies (RIDEM, RIDOA, RIDOH, RIDOT and NBC (quasi-governmental agency)), federal agencies (EPA, NRCS, USGS and USDA- Forest Service), non-governmental organizations and concerned citizens.  

Water Quality

The Woonasquatucket is one of the more diverse of Rhode Island's watersheds in terms of its land use. Highly urbanized in the southern portions and rural in the more northern reaches, the watershed is home to a wide array of both assets and problem areas.   Environmental challenges on the river include water pollution from stormwater and combined-sewer overflows; sediment contamination from former industrial uses (a Superfund project is underway to clean up dioxin along the river in North Providence and Johnston, R.I.) and illegal dumping.


Fecal coliform concentrations frequently exceed the water quality standard along the entire length of the river between Georgiaville Pond and the mouth of the river. The concentrations are highest during wet weather conditions, particularly in the lowermost section of the river that is influenced by combined sewer overflows (CSOs).

Combined Sewer Overflow (CSO)

Flow from a combined sewer that is discharged into a receiving water without going to a treatment works. A CSO is distinguished from bypasses which are diversions of waste streams from any portion of a treatment works.


The nutrient levels within the river are relatively low above the Smithfield wastewater treatment facility (WWTF) discharge, but are consistently 2-3 fold higher throughout the river below the WWTF. The increase in the nutrient concentrations downstream of the WWTF has resulted in the excess growth of aquatic vegetation and low dissolved oxygen levels in impoundments particularly in summer.


Dissolved metals concentrations have been measured below Stillwater Pond. Heavy metals that exceed Rhode Island water quality standards throughout the reach consist of cadmium, copper, and lead. Dissolved mercury data are not available for the river, although mercury has been detected in fish tissues.


Woonasquatucket Reservoirs

Volunteers of Watershed Watch, a program organized by the University of Rhode Island, collected the available water quality data for the major reservoirs in the Woonasquatucket River watershed.   These reservoirs consist of Upper Sprague Reservoir, Lower Sprague Reservoir, Waterman Reservoir, Slack Reservoir, Stillwater Reservoir South-end, Stillwater Reservoir, Stillwater Pond and Georgiaville Pond. The available data consist primarily of nutrients, chlorophyll, dissolved oxygen, pH and bacteriological data (fecal coliform and E. coli).   Neither metals nor organic compounds were monitored in the reservoirs.   In general, water quality in the reservoirs meets regulatory standards for primary and secondary recreation (swimming and boating).   However, Slack Reservoir is threatened by elevated fecal coliform concentrations which exceeded the Rhode Island water quality standard at times.


The Rhode Island Department of Environmental Management (RIDEM) staff has continued efforts to locate and eliminate dry weather pollution discharges to the Woonasquatucket River. During the 2000 sampling season, RIDEM and USEPA personnel completed the investigation of previously identified dry weather discharges to the river. Identified discharges were traced and several significant sources have been targeted or eliminated.   In addition to identifying and eliminating dry weather sources, RIDEM will continue to obtain the necessary information for Woonasquatucket River TMDL development. The most substantial data deficiency to be noted by Louis Berger was the lack of adequate wet weather monitoring data. RIDEM will work in cooperation with Louis Berger and the Narragansett Bay Commission (NBC) to perform the necessary wet weather monitoring during the 2001 summer season. In-stream stations and major storm water discharges will be sampled during at least three storm events. This monitoring should provide the necessary information to estimate storm water pollutant loadings to the river and to evaluate storm water effects on Woonasquatucket River water quality

As part of the URI Watershed Watch Program, the Watershed Council has been monitoring water quality at Donigian Park in Providence since 2003 and at Cricket Park (Greystone) in Johnston/North Providence since 2005.   Every week or every other week from May to October we monitor the dissolved oxygen content and temperature of the river water at both sites. In addition, on a monthly basis we monitor for pH, alkalinity, nutrients, and bacteria at both sites.   Many of the lakes and ponds in the watershed are also being monitored.


The Rhode Island Department of Environmental Management (DEM) ordered a complete characterization of stretches along the river as well as pond and reservoir sampling and this task was completed by the Louis Berger consulting group.   More than 350 stormwater outfalls have been identified thus far and efforts continue to track down illicit discharges in dry weather.   The next step is to complete wet weather monitoring this summer and identify sources of metals, bacteria, and other pollutants.   DEM, with cooperation from EPA and the Urban Rivers Team undertook to map stormwater outfalls and identify dry weather discharges. The results of that study are still pending.   Development of a TMDL for the Woonasquatucket is not just a requirement of the Clean Water Act, but will help to regulate and monitor the health of the river and to identify problem areas.  


All the communities in the Woonasquatucket River watershed are either required or eligible for Phase II regulation.   Required communities include Providence, North Providence, Johnston, Smithfield.   Eligible communities include Glocester and North Smithfield.

Fish Restoration

The Rising Sun Mill Fish Passage project, which will restore fish passage for the lower Woonasquatucket River with the construction of a denil fish ladder and plunge pool to allow upstream and downstream fish access to the reservoir, received $37,500 from the Habitat Restoration Trust Fund.

The CRMC also awarded $32,000 to the Woonasquatucket River Watershed Council for the Dyerville Dam project on and along the Woonasquatucket River, which includes the restoration of anadromous fish passage and habitat restoration.   The project aims to increase the functional wildlife and buffer value of the area, promote stream-bank stabilization and link to downstream efforts to promote fish restoration in the Woonasquatucket River system.

Organizations & Links

Woonasquatucket River Watershed Council

The WRWC was organized in 1999, and was recognized by the Rivers Council as the Watershed Council for the Woonasquatucket watershed in 2001.   WRWC has a full time executive director and program director with board members representing all the towns in the watershed.   They work with community volunteers, and residents actively support their activities but the WRWC does not currently have a membership program or charge membership dues.   The WRWC mailing list includes over 2.000 names.   The WRWC is supported by grants, individual donations and local fundraisers.   The Woonasquatucket River Watershed Council is undertaking a systematic restoration of river habitats, targeting 75 wetlands and 235 upland and riparian sites, and is working to restore passage for migratory herring and shad in the lower reaches of the river.

Alicia Lehrer, Executive Director
27 Sims Avenue
Providence, RI 02909
(401) 861-9046

Informational Links