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 .
26-686: Râul Doamnei is a left tributary of the river Argeș in Romania . Its source is on the eastern slope of Moldoveanu Peak ( Făgăraș Mountains ), the highest mountain peak in Romania. It discharges into the Argeș just north of Pitești . Its upper course, upstream from the confluence with the Zârna , is also called Valea Rea . Its length is 107 km (66 mi) and its basin size is 1,836 km (709 sq mi). It frequently dries up in summer, owing to
52-440: A cataract into another becomes the upper fork, and the one it descends into, the lower ; or by relative volume: the smaller stream designated the little fork, the larger either retaining its name unmodified, or receives the designation big . Tributaries are sometimes listed starting with those nearest to the source of the river and ending with those nearest to the mouth of the river . The Strahler stream order examines
78-467: A lake . A tributary does not flow directly into a sea or ocean . Tributaries, and the main stem river into which they flow, drain the surrounding drainage basin of its surface water and groundwater , leading the water out into an ocean. The Irtysh is a chief tributary of the Ob river and is also the longest tributary river in the world with a length of 4,248 km (2,640 mi). The Madeira River
104-520: A tree data structure . 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 the distribution of living organisms (i.e., ecology ) as well; "the general pattern [downstream of confluences] of increasing stream flow and decreasing slopes drives
130-602: 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,
156-406: A West Fork as well (now filled in). Forks are sometimes designated as right or left. Here, the handedness is from the point of view of an observer facing upstream. For instance, Steer Creek has a left tributary which is called Right Fork Steer Creek. These naming conventions are reflective of the circumstances of a particular river's identification and charting: people living along the banks of
182-414: 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
208-630: 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
234-482: 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
260-414: A forking of the stream to the right and to the left, which then appear on their charts as such; or the streams are seen to diverge by the cardinal direction (north, south, east, or west) in which they proceed upstream, sometimes a third stream entering between two others is designated the middle fork; or the streams are distinguished by the relative height of one to the other, as one stream descending over
286-439: A river, with a name known to them, may then float down the river in exploration, and each tributary joining it as they pass by appears as a new river, to be given its own name, perhaps one already known to the people who live upon its banks. Conversely, explorers approaching a new land from the sea encounter its rivers at their mouths, where they name them on their charts, then, following a river upstream, encounter each tributary as
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#1732790200518312-586: Is Romanian for "The river". As such, it may form part of the Romanian names given in full for virtually all rivers. However, since Doamnei is the genitive of Doamnă ("a lady"), Râul is part of the name itself in this case. The following rivers are tributaries to the Râul Doamnei (from source to mouth): According to legend, the first wife of Wallachian Prince Vlad III the Impaler died during
338-533: Is the largest tributary river by volume in the world with an average discharge of 31,200 m /s (1.1 million cu ft/s). A confluence , where two or more bodies of water meet, usually refers to the joining of tributaries. The opposite to a tributary is a distributary , a river or stream that branches off from and flows away from the main stream. Distributaries are most often found in river deltas . Right tributary , or right-bank tributary , and left tributary , or left-bank tributary , describe
364-774: 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
390-571: The 1462 siege of Poenari Castle by an Ottoman army led by Vlad's half-brother Radu cel Frumos . A former servant of Vlad, held as a prisoner and servant to the Ottomans but still loyal to the Prince, having seen the shadow of Vlad's wife behind a window and shot an arrow in that direction, with a message informing that the Ottoman army was going to attack the castle the next morning. Upon reading
416-407: The arrangement of tributaries in a hierarchy of first, second, third and higher orders, with the first-order tributary being typically the least in size. For example, a second-order tributary would be the result of two or more first-order tributaries combining to form the second-order tributary. Another method is to list tributaries from mouth to source, in the form of a tree structure , stored as
442-587: 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
468-405: The message, Vlad's wife flung herself off the castle's tower and into the stream below the castle, preferring death to Ottoman captivity. The stream was then named in recollection of the event. A fictionalized version of these events is depicted in the 1992 film Bram Stoker's Dracula , although in the film, the river the princess throws herself into is the Argeș itself. The ecosystem of the river
494-723: The midpoint. In the United States, where tributaries sometimes have the same name as the river into which they feed, they are called forks . These are typically designated by compass direction. For example, the American River in California receives flow from its North, Middle, and South forks. The Chicago River 's North Branch has the East, West, and Middle Fork; the South Branch has its South Fork, and used to have
520-428: The orientation of the tributary relative to the flow of the main stem river. These terms are defined from the perspective of looking downstream, that is, facing the direction the water current of the main stem is going. In a navigational context, if one were floating on a raft or other vessel in the main stream, this would be the side the tributary enters from as one floats past; alternately, if one were floating down
546-453: 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"
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#1732790200518572-613: 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
598-401: 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
624-472: The tributary, the main stream meets it on the opposite bank of the tributary. This information may be used to avoid turbulent water by moving towards the opposite bank before approaching the confluence. An early tributary is a tributary that joins the main stem river closer to its source than its mouth, that is, before the river's midpoint ; a late tributary joins the main stem further downstream, closer to its mouth than to its source, that is, after
650-554: The works upstream that have redirected part of its water supply toward a reservoir serving the hydroelectric plant on the Argeș. Râul Doamnei flows through a hilly region, forming narrow strips of fertile plain on both of its banks. The following towns and villages are situated along the river Râul Doamnei, from source to mouth: Slatina , Sboghițești , Corbi , Domnești , Pietroșani , Coșești , Dârmănești , Purcăreni , Colibași and Ștefănești . The stream's name literally means "the lady's river", or "the princess's river". Râul
676-432: Was affected by the building of the reservoir. Before its building, Romanichthys valsanicola , an endemic fish species, used to populate this river. Currently this species, listed as critically endangered , is only found along a 1 km stretch of the river Vâlsan . Tributary A tributary , or an affluent , is a stream or river that flows into a larger stream ( main stem or "parent" ), river, or
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