Залив Наррагансетт: Описание и характеристики

Bay in the state of Rhode Island

Narragansett Bay is a bay and estuary on the north side of Rhode Island Sound covering , of which is in Rhode Island. The bay forms New England's largest estuary, which functions as an expansive natural harbor and includes a small archipelago. Small parts of the bay extend into Massachusetts. There are more than 30 islands in the bay; the three largest ones are Aquidneck Island, Conanicut Island, and Prudence Island. Bodies of water that are part of Narragansett Bay include the Sakonnet River, Mount Hope Bay, 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 20 mile (32 km) southwest of its opening.

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

The watershed of Narragansett Bay has seven river sub drainage basins, including the Taunton, 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 varies greatly among the three passages, with the average depths of the East, West, and Sakonnet River passages being 121 feet (37 m), 33 feet (10 m), and 25 feet (8 m) respectively. Narragansett Bay is a ria 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 Rhode Island'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 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 Undersea Warfare Center, and a major United States Navy training center. The city of Fall River, Massachusetts is located at the confluence of the Taunton River and Mount Hope Bay, which form the northeasternmost part of Narragansett Bay. The southwest side of the bay includes the seaside tourist towns of Narragansett and Wickford. Quonset Point, south of Warwick, gives its name to the Quonset hut.

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 3.6 feet (1 m) at the bay's mouth and 4.6 feet (1 m) at its head. Water depth varies about 4 feet (1 m) 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.

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 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. Verrazzano reported that he found clearings and open forests suitable for travel "even by a large army". Dutch navigator Adriaen Block 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 Canonicus, who provided him with land on which to build Providence Plantations. Around the same time, the Dutch 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 was an important naval event which moved the Thirteen Colonies toward the American Revolution. 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 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, 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."