Narragansett Bay is a bay and estuary on the north side of Rhode Island Sound covering , of which is in

Rhode Island Rhode Island (, like ''road'') is a state in the New England region of the Northeastern United States. It is the smallest U.S. state by area and the seventh-least populous, with slightly fewer than 1.1 million residents as of 2020, but it ...

. The bay forms

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the Can ...

's largest estuary, which functions as an expansive natural harbor and includes a small archipelago. Small parts of the bay extend into

Massachusetts Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...

. There are more than 30 islands in the bay; the three largest ones are Aquidneck Island,

Conanicut Island Conanicut Island is the second-largest island in Narragansett Bay in the American state of Rhode Island. It is connected on the east to Newport on Aquidneck Island via the Claiborne Pell Bridge, commonly known as the Newport Bridge, and on t ...

, and

Prudence Island Prudence Island is the third-largest island in Narragansett Bay in the state of Rhode Island and part of the town of Portsmouth, Rhode Island, United States. It is located near the geographic center of the bay. It is defined by the United Sta ...

. Bodies of water that are part of Narragansett Bay include the Sakonnet River,

Mount Hope Bay Mount Hope Bay is a tidal estuary located at the mouth of the Taunton River on the Massachusetts and Rhode Island border. It is an arm of Narragansett Bay. The bay is named after Mount Hope, a small hill located on its western shore in what is ...

, and the southern, tidal part of the Taunton River. The bay opens on Rhode Island Sound and the Atlantic Ocean; Block Island lies less than southwest of its opening.

Etymology

"Narragansett" is derived from the southern New England Algonquian word meaning "(people) of the small point of land".

Geography

The watershed of Narragansett Bay has seven river sub-drainage basins, including the

Taunton Taunton () is the county town of Somerset, England, with a 2011 population of 69,570. Its thousand-year history includes a 10th-century monastic foundation, Taunton Castle, which later became a priory. The Normans built a castle owned by the ...

, Pawtuxet, and Blackstone Rivers, and they provide freshwater input at approximately per day. River water inflow has a seasonal variability, with the highest flow in the spring and the minimum flow in early fall. The bay is a ria estuary (a drowned river valley) which is composed of the Sakonnet River valley, the East Passage river valley, and the West Passage river valley. The

bathymetry Bathymetry (; ) is the study of underwater depth of ocean floors (''seabed topography''), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of water ...

varies greatly among the three passages, with the average depths of the East, West, and Sakonnet River passages being , , and respectively. Narragansett Bay is a

ria A ria (; gl, ría) is a coastal inlet formed by the partial submergence of an unglaciated river valley. It is a drowned river valley that remains open to the sea. Definitions Typically rias have a dendritic, treelike outline although they ca ...

that consists of a series of flooded river valleys formed of dropped crustal blocks in a horst and graben system that is slowly subsiding between a shifting fault system. Providence is

's capital and largest city and sits at the northernmost arm of the bay. Many of Providence's suburbs are also on the bay, including East Providence,

Warwick Warwick ( ) is a market town, civil parish and the county town of Warwickshire in the Warwick District in England, adjacent to the River Avon. It is south of Coventry, and south-east of Birmingham. It is adjoined with Leamington Spa and Whi ...

and Cranston. Newport is located at the south end of Aquidneck Island on the ocean, and is the home of the

United States Naval War College The Naval War College (NWC or NAVWARCOL) is the staff college and "Home of Thought" for the United States Navy at Naval Station Newport in Newport, Rhode Island. The NWC educates and develops leaders, supports defining the future Navy and associa ...

, the

Naval Undersea Warfare Center The Naval Undersea Warfare Center (NUWC) is the United States Navy's full-spectrum research, development, test and evaluation, engineering and fleet support center for submarines, autonomous underwater systems, and offensive and defensive weapons ...

, and a major

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

training center. The city of

Fall River, Massachusetts Fall River is a city in Bristol County, Massachusetts, United States. The City of Fall River's population was 94,000 at the 2020 United States Census, making it the tenth-largest city in the state. Located along the eastern shore of Mount H ...

is located at the confluence of the Taunton River and

, which form the northeasternmost part of Narragansett Bay. The southwest side of the bay includes the seaside tourist towns of Narragansett and

Wickford Wickford is a town and civil parish in the south of the English county of Essex, with a population of 33,486. Located approximately 30 miles (50 km) east of London, it is within the Borough of Basildon along with the original town of Basil ...

. Quonset Point, south of Warwick, gives its name to the

Quonset hut A Quonset hut is a lightweight prefabricated structure of corrugated galvanized steel having a semi cylindrical cross-section. The design was developed in the United States, based on the Nissen hut introduced by the British during World War ...

Oceanography

Tidal patterns

Tides in the watershed are measured at Providence, Fall River, Quonset Point, Conimicut Light, Prudence Island, and Newport. In shallow water, sound waves are used to measure water height by precisely measuring their travel time. In deeper water, tides are measured with pressure-sensing tide gauges that are placed on the ocean floor to measure water height. The bay's tides are semi-diurnal, meaning that the region experiences two high and low tides daily. The tides range in height from at the bay's mouth and at its head. Water depth varies about between high and low tide. The lunar, semi-diurnal M2 tide occurs at a period of 12.42 hours, with two tides occurring in the watershed every 24 hours and 50 minutes. The watershed's neap and spring tides occur every 14.8 days. In Narragansett bay, the tides show a distinct double-peak flood during high tide and single peak ebb during low tide.

Water circulation patterns

The movement of water within a system is its circulation. Estuaries are given a classification depending on the pattern of their circulations. The circulation classification can be well-mixed, partially mixed, salt wedge, or Fjord-type. For Narragansett, the circulation is mostly well-mixed; however, the Providence River does show some vertical stratification. Narragansett Bay circulation is made up of forces provided by the winds, tides, and changes in water

density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...

within the watershed. Its circulation is the result of the flow of fresh water at the head interacting with salt water at the point where the bay meets the open ocean. Residence time of water due to the circulation of Narragansett Bay is 10–40 days, with an average of 26 days. Tidal mixing is the dominant driver of circulation patterns in the bay, where currents can reach up to 2.5 feet per second. Non-tidal currents such as the flow of low salinity water at the surface out of the bay and high salinity deep water into the bay contribute to a current of about 0.33 feet per second. Winds also drive circulation patterns in the bay. In the winter, winds come from the northwest, helping move water towards the bay's mouth; in the summer, they are out of the southwest and move water towards the head of the bay. Wind-driven waves of over also help mix surface waters. Density-driven forces are the third factor affecting circulation. Fresh water inflow comes from natural sources such as atmospheric precipitation and inflow from the many rivers that feed into the watershed, and man-made sources such as water treatment plants. Fresh and saltwater mixing results in a salinity range in the bay of 24 parts per thousand (ppt) in the upper Providence River area to 32 ppt at the mouth of the bay. The bay's currents and circulation patterns greatly influence the sediment deposits within the region. The majority of the sediments within the bay are fine-grained material such as detritus, clay-silt, and sand-silt-clay. Scientists have been able to identify 11 types of sediment that range from coarse gravels to fine silts. the bay's currents deposit fine materials through the harbors of the lower and middle sections of the bay, and the coarse, heavy materials are deposited in the lower areas of the bay where the water velocities are higher.

Early history

The first visit by Europeans to the bay was probably in the early 16th century. At the time, the area surrounding the bay was inhabited by two different Indian tribes: the

Narragansetts The Narragansett people are an Algonquian American Indian tribe from Rhode Island. Today, Narragansett people are enrolled in the federally recognized Narragansett Indian Tribe. They gained federal recognition in 1983. The tribe was nearly lan ...

occupied the west side of the bay, and the

Wampanoags The Wampanoag , also rendered Wôpanâak, are an Indigenous people of the Northeastern Woodlands based in southeastern Massachusetts and historically parts of eastern Rhode Island,Salwen, "Indians of Southern New England and Long Island," p. ...

lived on the east side, occupying the land east to

Cape Cod Cape Cod is a peninsula extending into the Atlantic Ocean from the southeastern corner of mainland Massachusetts, in the northeastern United States. Its historic, maritime character and ample beaches attract heavy tourism during the summer mont ...

. It is accepted by most historians that first contact by Europeans was made by Giovanni da Verrazzano, an Italian explorer who entered the bay in his ship '' La Dauphine'' in 1524 after visiting New York Bay. Verrazzano called the bay ''Refugio'', the "Refuge". It has several entrances, however, and historians can only speculate as to the exact route of his voyage and the location where he laid anchor, along with a corresponding uncertainty over which tribe made contact with him. Verrazzano reported that he found clearings and open forests suitable for travel "even by a large army". Dutch navigator

Adriaen Block Adriaen (Arjan) Block (c. 1567 – buried April 27, 1627) was a Dutch private trader, privateer, and ship's captain who is best known for exploring the coastal and river valley areas between present-day New Jersey and Massachusetts during four v ...

explored and mapped the bay in 1614, and nearby Block Island is named in his honor. The first permanent Colonial settlement was established in 1636 by Roger Williams, a former member of the Massachusetts Bay Colony. He was friends with Narragansett ''

sachem Sachems and sagamores are paramount chiefs among the Algonquians or other Native American tribes of northeastern North America, including the Iroquois. The two words are anglicizations of cognate terms (c. 1622) from different Eastern Al ...

Canonicus Canonicus (c. 1565 – June 4, 1647) was a chief of the Narragansett Indigenous Peoples. He was wary of the colonial settlers, but he ultimately befriended Roger Williams and other settlers. Biography Canonicus was born around 1565,Benjami ...

, who provided him with land on which to build

Providence Plantations Providence Plantations was the first permanent European American settlement in the Colony of Rhode Island and Providence Plantations. It was established by a group of colonists led by Roger Williams and Dr. John Clarke who left Massachusetts Bay ...

. Around the same time, the

Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...

established a trading post approximately 12 miles (20 km) to the southwest which was under the authority of New Amsterdam in New York Bay. In 1643, Williams traveled to England and was granted a charter for the Colony of Rhode Island and Providence Plantations. The

Gaspee Affair The ''Gaspee'' Affair was a significant event in the lead-up to the American Revolution. HMS ''Gaspee'' was a British customs schooner that enforced the Navigation Acts in and around Newport, Rhode Island, in 1772. It ran aground in shallow ...

was an important naval event which moved the

thirteen colonies The Thirteen Colonies, also known as the Thirteen British Colonies, the Thirteen American Colonies, or later as the United Colonies, were a group of British colonies on the Atlantic coast of North America. Founded in the 17th and 18th cent ...

toward the

American Revolution The American Revolution was an ideological and political revolution that occurred in British America between 1765 and 1791. The Americans in the Thirteen Colonies formed independent states that defeated the British in the American Revoluti ...

. It occurred in Narragansett Bay in 1772 and involved the capture and burning of the British customs schooner ''Gaspee''. The American victory contributed to the eventual start of the war at the Battles of Lexington and Concord in Massachusetts three years later. The event is celebrated in

Pawtuxet Village Pawtuxet Village is a section of the New England cities of Warwick and Cranston, Rhode Island. It is located at the point where the Pawtuxet River flows into the Providence River and Narragansett Bay. History Pawtuxet means "Little Falls" in ...

as the Gaspee Days Celebration in June which includes burning the ship in effigy. Roger Williams and other early colonists named the islands Prudence,

Patience (or forbearance) is the ability to endure difficult circumstances. Patience may involve perseverance in the face of delay; tolerance of provocation without responding in disrespect/anger; or forbearance when under strain, especially when face ...

, Hope, Despair, and Hog. To remember the names, colonial school children often recited the poem: "Patience, Prudence, Hope, and Despair. And the little Hog over there."

Water properties and phytoplankton distribution

Narragansett Bay is divided by

into east and west passages. Its depth averages approximately 9.0 meters throughout the bay, but it is shallower in the west passage and deeper in the east.Narragansett Bay National Estuarine Research Reserve. 2009. An Ecological Profile of the Narragansett Bay National Estuarine Research Reserve.K.B. Raposa and M.L. Schwartz (eds.), Rhode Island Sea Grant, Narragansett, R.I. 176pp. Narragansett Bay receives freshwater input from several sources, including rivers (approximately 80%), direct precipitation (13%), wastewater treatment facilities (9%), and unknown amounts from ground-water and combined sewer overflows (CSOs). The freshwater input varies greatly from season to season as it is highest in winter and lowest in summer, while CSOs increase dramatically following heavy rain. Water from these freshwater inputs mixes with sea water to form a salinity gradient ranging from 24 ppt at the mouth of the

Providence River The Providence River is a tidal river in the U.S. state of Rhode Island. It flows approximately 8 miles (13 km). There are no dams along the river's length, although the Fox Point Hurricane Barrier is located south of downtown to protect t ...

to 32 ppt at the mouth of the bay. Water temperatures range between -0.5 °C and 24 °C over the year. Salinity and temperature patterns measured throughout the bay indicate a range of mixed to stratified conditions and the amount of time it takes for the total volume of fresh water in the bay to be equaled by the fresh water input (flushing time) varies from 40 days to 10 days, depending on freshwater input.

Dissolved oxygen Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen that is dissolved or carried in a given medium as a proportion of the maximal concentration that can be dissolved in that medium at the given temperature. It ca ...

levels in Narragansett Bay are seasonal with lower levels in the summer and higher levels in the winter. This is due to warmer temperatures and higher biological demand for oxygen in the summer and the opposite in the winter. Narragansett Bay is also subject to periodic summer hypoxic events in the Northern half of the bay, nearing anoxic conditions in some parts. Phytoplankton forms the base of the food chain for many of the bay's marine animals. General trends in phytoplankton biomass across the bay are characterized by highest levels in the Providence River and lowest levels in Rhode Island Sound, correlating with the North to South nutrient concentration gradient in the bay (24). Near the Providence River, biomass levels are highest in the summer and lowest in the winter. In the east and west passages there are peaks in the spring and fall. Annual blooms have shrunk over the last decade (2006 onward) as the amount of

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

(an important nutrient) supply to the bay has decreased by more than 50% due to wastewater treatment facilities switching to a new treatment that involves removal of nitrogen Narragansett Bay is the site of one of the world's longest-running plankton surveys, extending from 1957 through the present. Researchers at the

University of Rhode Island The University of Rhode Island (URI) is a public land-grant research university with its main campus in Kingston, Rhode Island, United States. It is the flagship public research as well as the land-grant university of the state of Rhode Isla ...

’s Graduate School of Oceanography collect samples weekly and the dataset contains 246 different species.The Narragansett Bay Long-Term Plankton Time Series, https://web.uri.edu/gso/research/plankton/.

Rivers

Providence_River_from_the_Crawford_Street_Bridge

* Blackstone River, Woonsocket, Cumberland, Lincoln, Central Falls, and Pawtucket, RI * Seekonk River, Pawtucket, East Providence, and Providence, RI * Ten Mile River, Pawtucket and East Providence, RI *

Moshassuck River The Moshassuck River is a river in the U.S. state of Rhode Island. It flows U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed April 1, 2011 from the town of Lincoln to the city of Provi ...

, Providence, RI * Woonasquatucket River, Providence, RI *

, Providence, Cranston, Warwick, East Providence, and Barrington, RI * Pawtuxet River, Cranston and Warwick, RI * Potowomut River, also called Greene River, Warwick, and North Kingstown, RI *

Quequechan River The Quequechan River is a river in Fall River, Massachusetts, that flows in a northwesterly direction from the northwest corner of the South Watuppa Pond through the heart of the city of Fall River and into the end of the Taunton River at Mou ...

, Fall River, MA * Barrington River, Barrington, RI * Palmer River, Barrington and Warren, RI *

Warren River The Warren River is a tidal extension of the Palmer River in the U.S. state of Rhode Island. It flows approximately 6.5 km (4 mi). There are no dams along the river's length. Course The river begins where the Palmer River widens just ...

, Warren and Barrington, RI * Taunton River, Fall River, MA * Sakonnet River, Tiverton, Little Compton, Portsmouth, and Middletown, RI * Kickamuit River, Warren and Bristol, RI

Notes

External links

Narragansett Bay Research Reserve on Prudence Island

Narragansett Bay Shipping

Narragansett Bay: A Friend's Perspective

Narragansett Bay.Org

Save the bay

Narragansett Bay Estuary Program

1777 Chart/Map of Narragansett Bay
by Charles Blaskowitz and William Faden at DavidRumsey.com
Guide to the Rhode Island Leased Oyster Bed Grounds Indenture records
from the Rhode Island State Archives
1983 Narragansett Bay Commission Annual Report
from the Rhode Island State Archives {{Authority control Bays of Rhode Island Bays of Massachusetts Estuaries of Rhode Island Bodies of water of Bristol County, Rhode Island Bodies of water of Kent County, Rhode Island Bodies of water of Newport County, Rhode Island Bodies of water of Providence County, Rhode Island Bodies of water of Washington County, Rhode Island