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20-699: It is formed by the confluence of the rivers Bolshoy Abakan and Maly Abakan . It rises in the western Sayan Mountains and flows northeast through the Minusinsk Depression to the Yenisey . It is about 514 kilometres (319 mi) long from the Bolshoy Abakan's source , and 327 kilometres (203 mi) for the Abakan proper. Its drainage basin covers 32,000 square kilometres (12,000 sq mi). This Khakassia location article

40-602: A tripoint . Various examples are found in 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,

60-414: 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 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

80-630: 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

100-482: 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 a stream contaminated with acid mine drainage combines with a stream with near-neutral pH water; these reactions happen very rapidly and influence

120-557: 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 . Confluences are studied in

140-443: 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 the distribution of living organisms (i.e., ecology ) as well; "the general pattern [downstream of confluences] of increasing stream flow and decreasing slopes drives

160-460: Is a stub . You can help Misplaced Pages by expanding it . This article related to a river in Siberia is a stub . You can help Misplaced Pages by expanding it . Confluence (geography) 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

180-774: 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

200-468: The South Pole in a point of elevenfold complexity, though this is an example of points subject to dispute . International tripoints include: Some historic tripoints: While the exact line of an international border is normally fixed by a bilateral treaty, the position of the tripoints may need to be settled by a trilateral agreement. For example, China, Russia, and Mongolia have set the position of

220-508: The territorial waters ), and the same goes for countries with their only neighbour country, such as Portugal or Lesotho . Landlocked countries also have international tripoints. Likewise, the United States with two neighbouring countries has no international tripoints; however, it has a number of state tripoints as well as one point where four states meet . Indonesia has no international tripoints, just like Australia, Japan and

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240-517: The United States. Canada , as well, which has a maritime border with two other countries, has no international tripoints; however, it has five tripoints on land where the boundaries of provinces and territories meet, and one quadripoint where four provinces and territories meet . Japan has multiple prefectural tripoints; it also has prefectural quadripoints. In addition to the United States, Canada and Indonesia, Australia also has tripoints where

260-424: The boundaries of states meet. Border junctions (or "multiple points" or "multipoints" as they are also sometimes called) are most commonly threefold. There are also a number of quadripoints , and a handful of fivefold points, as well as unique examples of sixfold, sevenfold, and eightfold points (see quadripoint § Multipoints of greater numerical complexity ). The territorial claims of six countries converge at

280-587: 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 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

300-475: The merger of the flow of two glaciers . Tripoint A triple border , tripoint , trijunction , triple point , or tri-border area is a geographical point at which the boundaries of three countries or subnational entities meet. There are 175 international tripoints as of 2020. Nearly half are situated in rivers, lakes or seas. On dry land, the exact tripoints may be indicated by markers or pillars, and occasionally by larger monuments. Usually,

320-783: The more neighbours a country has, the more international tripoints that country has. China with 16 international tripoints and Russia with 11 to 14 lead the list of states by number of international tripoints. Other countries, like Brazil , India , and Algeria , have several international tripoints. Argentina has four international tripoints. South Africa , Pakistan and Nigeria have three international tripoints while Bangladesh and Mexico have only one. Within Europe, landlocked Austria has nine tripoints, among them two with Switzerland and Liechtenstein . Island countries , such as Japan and Australia , have no international tripoints (some, like Bahrain and Singapore , have tripoints in

340-453: 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"

360-613: 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 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

380-401: 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 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

400-628: The two relevant tripoints (the junction points of the China–Russia border , the Mongolia–Russia border , and the China–Mongolia border ) by the trilateral agreement signed in Ulaanbaatar on January 27, 1994. The agreement specified that a marker was to be erected at the eastern tripoint, called Tarvagan Dakh (Tarbagan Dakha), but that no marker would be erected at the western tripoint (which

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