In geography , a confluence (also: conflux ) occurs where two or more watercourses join to form a single channel . A confluence can occur in several configurations: at the point where a tributary joins a larger river ( main stem ); or where two streams meet to become the source of a river of a new name (such as the confluence of the Monongahela and Allegheny rivers, forming the Ohio River ); or where two separated channels of a river (forming a river island ) rejoin at the downstream end. The point of confluence where the channel flows into a larger body of water may be called the river mouth .
32-843: The Calvert Prong is one of the two prongs whose confluence creates the Little Warrior River in Alabama , United States. The other prong is the Blackburn Fork . This article related to a river in Alabama is a stub . You can help Misplaced Pages by expanding it . Confluence Confluences are studied in a variety of sciences. Hydrology studies the characteristic flow patterns of confluences and how they give rise to patterns of erosion, bars, and scour pools. The water flows and their consequences are often studied with mathematical models . Confluences are relevant to
64-630: A confluence is an industrial site, as in Philadelphia or Mannheim . Often a confluence lies in the shared floodplain of the two rivers and nothing is built on it, for example at Manaus , described below. One other way that confluences may be exploited by humans is as sacred places in religions . Rogers suggests that for the ancient peoples of the Iron Age in northwest Europe, watery locations were often sacred, especially sources and confluences. Pre-Christian Slavic peoples chose confluences as
96-433: A gradients, cascades and an adequate junction angle which is sympathetic to the direction of the watercourse’s flow to minimise turbulent flow, maximise evacuation velocity and to ultimately maximise hydraulic efficiency. Since rivers often serve as political boundaries, confluences sometimes demarcate three abutting political entities, such as nations, states, or provinces, forming a tripoint . Various examples are found in
128-606: A reformation taking place under the auspices of the Government." It was five years before the ten-hour day was extended to all government employees engaged in manual labor; this was accomplished via an executive order by President Martin Van Buren on 31 March 1840. The Naval Aircraft Factory was established at the League Island site in 1917. Just after of the end World War I , a 350-ton capacity hammerhead crane
160-441: A stream contaminated with acid mine drainage combines with a stream with near-neutral pH water; these reactions happen very rapidly and influence the subsequent transport of metals downstream of the mixing zone." A natural phenomenon at confluences that is obvious even to casual observers is a difference in color between the two streams; see images in this article for several examples. According to Lynch, "the color of each river
192-401: A vast assortment of subjects which concern confluences. In hydraulic civil engineering , where two or more underground culverted / artificially buried watercourses intersect, great attention should be paid to the hydrodynamic aspects of the system to ensure the longevity and efficiency of the structure. Engineers have to design these systems whilst considering a list of factors that ensure
224-453: Is a large mixed-use campus where nearly 15,000 people are employed by more than 120 companies representing a mix of industries, including cell therapy production facilities, global fashion companies, and a commercial shipyard. The U.S. Navy still operates a Naval Inactive Ship Maintenance Facility and a few engineering activities at the site. The yard has its origins in a commercial shipyard founded in 1776 on Philadelphia 's Front Street on
256-494: Is determined by many things: type and amount of vegetation in the watershed, geological properties, dissolved chemicals, sediments and biologic content – usually algae ." Lynch also notes that color differences can persist for miles downstream before they finally blend completely. Hydrodynamic behaviour of flow in a confluence can be divided into six distinct features which are commonly called confluence flow zones (CFZ). These include The broader field of engineering encompasses
288-678: Is now the site of 120 companies with 10,000 employees. New businesses continue to be attracted to the campus, and existing ones expand. Clothing retailer and manufacturer Urban Outfitters consolidated its Philadelphia headquarters on the site. Tasty Baking Company , makers of Tastykakes , has moved their bakery to the 26th Street side of The Yard. Other occupants include Rittenhouse Ventures, Aker Philadelphia Shipyard, Rhoads Industries Inc. in Navy Building 57, Energy Efficient Buildings Hub (EEB Hub), RevZilla.com , and Mark Group, Inc. In January 2013, PIDC announced its intention to increase
320-774: Is used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals or a canal and a lake. A one-mile (1.6 km) portion of the Industrial Canal in New Orleans accommodates the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal ; therefore those three waterways are confluent there. The term confluence can also apply to the process of merging or flowing together of other substance. For example, it may refer to
352-530: The Delaware River ; it was designated an official United States Navy site in 1801. From 1812 until 1865, it was a large ship production center. The first ship launched to the water was the USS Franklin . This event was watched by more than 50,000 spectators. The rapid development of other shipbuilding companies pledged Philadelphia to improve production processes. This was the first shipyard in
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#1732797869899384-829: The United States Navy reserve fleets , the fleet "mothballed" ships and submarines. Many of the ships in the fleet were reactivated for the Korean War and some for the Vietnam War . The control of the reserve fleet was later transferred to the Naval Inactive Ship Maintenance Facility (NISMF). The USS Chandeleur (AV-10) was used as a barracks ship for the crew at the Atlantic Reserve Fleet, Philadelphia. The City of Philadelphia became
416-637: The City of Philadelphia; its offices are now located at The Navy Yard. A comprehensive master plan was completed in 2004 to redeveloped the former industrial yard to a mixed-use campus. It proposed adaptive reuse of some Navy buildings as office space; maintenance of buildings and campus elements with strong historic interest, such as the Navy Yard Marine Parade Grounds; and construction of new buildings for offices and other purposes as needed for new tenants. This construction has been in
448-545: The change was applicable only to the Philadelphia Navy Yard. On 29 August 1836, a committee of Philadelphia Navy Yard mechanics appealed to President Andrew Jackson to extend the law, "The Committee are sure that if the example is set in Philadelphia it will be [illegible] required in other places and they will not attempt to disguise the pleasure it would give them as Citizens and as Workingmen to see
480-440: The discharge point is structurally stable as the entrance of the lateral culvert into the main structure may compromise the stability of the structure due to the lack of support at the discharge, this often constitutes additional supports in the form of structural bracing. The velocities and hydraulic efficiencies should be meticulously calculated and can be altered by integrating different combinations of geometries, components such
512-499: The distribution of living organisms (i.e., ecology ) as well; "the general pattern [downstream of confluences] of increasing stream flow and decreasing slopes drives a corresponding shift in habitat characteristics." Another science relevant to the study of confluences is chemistry , because sometimes the mixing of the waters of two streams triggers a chemical reaction, particularly in a polluted stream. The United States Geological Survey gives an example: "chemical changes occur when
544-580: The facility operational, and the planned closing was unsuccessfully litigated to the US Supreme Court in Dalton v. Specter . When the yard finally closed in 1995, it cost the region 7,000 jobs. This followed years in which the region had lost industrial jobs to restructuring and movement of manufacturing overseas. US Senator Arlen Specter charged that the Department of Defense did not disclose
576-575: The following acknowledgment "I would respectfully observe – Seems to be inevitable, sooner or later, for as the working man are seconded by all the Master workmen, city councils etc. there is no probability they will secede from their demands." Their petition was granted and on 31 August 1835 the president ordered the Secretary of the Navy to grant the ten-hour work day, effective 3 September 1835. However,
608-544: The landlord and owner of the League Island site in March 2000, when the Philadelphia Authority for Industrial Development (PAID) took title to roughly 1,000 acres from the Navy. Today, the site is operated as a mixed-use industrial park under the name "The Navy Yard". The Philadelphia Industrial Development Corporation (PIDC) manages the planning, operation, and development of The Navy Yard on behalf of PAID and
640-558: The list below. A number of major cities, such as Chongqing , St. Louis , and Khartoum , arose at confluences; further examples appear in the list. Within a city, a confluence often forms a visually prominent point, so that confluences are sometimes chosen as the site of prominent public buildings or monuments, as in Koblenz , Lyon , and Winnipeg . Cities also often build parks at confluences, sometimes as projects of municipal improvement, as at Portland and Pittsburgh . In other cases,
672-553: The merger of the flow of two glaciers . Philadelphia Naval Shipyard The Philadelphia Naval Shipyard was the first United States Navy shipyard and was historically important for nearly two centuries. Construction of the original Philadelphia Naval Shipyard began during the American Revolution in 1776 at Front and Federal Streets in what is now the Pennsport section of Philadelphia. In 1871, it
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#1732797869899704-527: The number of apartments on site for employees (near 1,000) and additional infrastructure development. This is made possible by the public financing of shipyards and investments of private companies. According to the plan for 2013, the number of employees at the shipyard amount to around 30,000 people. In March 2013, the Canadian Pacific – Bulkmatic Transport transload site on Langley Ave was closed. The Athletic Base Ball Club of Philadelphia hosts
736-527: The official report on the closing. This resulted in a controversy that led to further legal disputes, but no actions. Since its transfer from the government to the City of Philadelphia, the west end of property has been leased to Aker Kværner , a tanker and commercial shipbuilding firm. Atlantic Reserve Fleet, Philadelphia opened at the Philadelphia Naval Shipyard in 1946 to store the many surplus ships after World War II. As part of
768-656: The section called the Corporate Center. As of 2010, US Navy activities include Naval Support Activity Philadelphia , the Naval Surface Warfare Center Ship Systems Engineering Station, Naval Facilities Engineering Command Mid-Atlantic Public Works Department Pennsylvania (NAVFAC MIDLANT PWD PA), and the Naval Inactive Ship Maintenance Facility (NISMF). This last stores decommissioned and mothballed warships and auxiliary naval vessels. The Navy Yard
800-453: The sites for fortified triangular temples, where they practiced human sacrifice and other sacred rites. In Hinduism , the confluence of two sacred rivers often is a pilgrimage site for ritual bathing. In Pittsburgh, a number of adherents to Mayanism consider their city's confluence to be sacred. Mississippi basin Atlantic watersheds Pacific watersheds Occasionally, "confluence"
832-560: The workday in the Philadelphia Navy Yard was sunrise to sunset, with time off for breakfast. In the summer of 1835 Philadelphia Navy Yard shipwrights, joiners and other workers led the effort to reduce the workday by combining the direct action of a strike, with political pressure to the executive branch. After first seeking workday reduction by a request to the Secretary of the Navy via shipyard Commandant Commodore James Barron, on 29 August 1835 they appealed directly to President Andrew Jackson . Commodore Barron endorsed his workers' request with
864-503: The workforce dropped to 12,000, as the Navy stabilized its fleet. In the 1960s, the Navy began to contract with private companies to construct new ships. The yard built its last new ship, the command ship Blue Ridge , in 1970. Because of foreign competition and reduced needs due to the end of the Cold War , the defense Base Realignment and Closure Commission recommended closure of the yard in 1991. The city and state struggled to keep
896-479: The world to use floating dry docks in the building process to improve an operating time of the ships. After the advent of ironclad warships made the site obsolete, new facilities were built in 1871 on League Island at the confluence of the Delaware and Schuylkill rivers. Beginning in the early 19th century, many Philadelphia workers agitated for a reduction in the arduous twelve-hour workday. Prior to 1835,
928-629: The yard employed 40,000 people who built 53 ships and repaired 574. During this period, the yard built the famed battleship New Jersey and its 45,000-ton sister ship, Wisconsin . In the Naval Laboratory, Philip Abelson developed the liquid thermal diffusion technique for separating uranium-235 for the Manhattan Project . The memorial chapel to the Four Chaplains is located on the grounds. After World War II,
960-602: The yard for the war effort. The U.S. Navy ended most of its activities at the shipyard in the 1990s, closing the base after recommendations by the Base Realignment and Closure commission. In 2000, the Philadelphia Industrial Development Corporation, on behalf of the City of Philadelphia, acquired it and began to redevelop the land. First called Philadelphia Naval Business Center , it is now known as The Navy Yard . It
992-894: Was ordered for the yard. Manufactured in 1919 by the McMyler-Interstate Company in Bedford, Ohio , the crane was called the League Island Crane by its builder. Weighing 3,500 tons, the crane was shipped to the yard in sections. At the time, it was the world's largest crane. For many years, the "League Island Crane" was the Navy's largest crane. Mustin Field opened at the Naval Aircraft Factory in 1926 and operated until 1963. The shipyard's greatest period came in World War II , when
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1024-476: Was replaced by a new, much larger yard developed around facilities on League Island , at the confluence of the Delaware and Schuylkill rivers. The Navy Yard expansion stimulated the development over time of residences and businesses in South Philadelphia , where many shipyard workers lived. During World War II , some 40,000 workers operated on shifts around the clock to produce and repair ships at
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