The Info List - Confluence

In geography, a confluence (also: conflux) occurs where two or more flowing bodies of water join together to form a single channel.[1] 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 at Pittsburgh, forming the Ohio); or where two separated channels of a river (forming a river island) rejoin at the downstream end.


1 Scientific study of confluences

1.1 Confluence
Flow Zones (River)

2 Confluences and humankind 3 Notable confluences

3.1 Africa 3.2 Asia 3.3 Australia 3.4 Europe 3.5 North America 3.6 South America

4 Confluences not of two rivers 5 Gallery 6 See also 7 Notes 8 References 9 External links

Scientific study of confluences[edit] 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.[2] The water flows and their consequences are often studied with mathematical models.[3] 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 a corresponding shift in habitat characteristics."[4] 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 the subsequent transport of metals downstream of the mixing zone."[5] 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.[6] Confluence
Flow Zones (River)[edit] Hydrodynamic behaviour of flow in a confluence can be divided into six distinct features[7] which are commonly called confluence flow zones (CFZ). These include

Hydrodynamic features of a river/flume confluence can be separated into six identifiable distinct zones, also called confluence flow zones.

Stagnation Zone Flow Deflection Zone Flow Separation Zone / Recirculation Zone Maximum Velocity Zone Flow Recovery Zone Shear Layers

Confluences and humankind[edit]

The fountain at Point State Park
Point State Park
in Pittsburgh, at the apex of the confluence of the Allegheny (top) and the Monongahela

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 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, 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 employed by humans is as a sacred place in a religion. Rogers suggests that for the ancient peoples of the Iron Age
Iron Age
in northwest Europe, watery locations were often sacred, especially sources and confluences.[8] Pre-Christian Slavic peoples chose confluences as the sites for fortified triangular temples, where they practiced human sacrifice and other sacred rites.[9] In Hinduism, the confluence of two sacred rivers often is a pilgrimage site for ritual bathing.[10] In Pittsburgh, a number of adherents to Mayanism consider their city's confluence to be sacred.[11] Notable confluences[edit]

The White Nile
White Nile
and Blue Nile
Blue Nile
merge at Khartoum; April 2013 satellite view


At Lokoja, Nigeria, the Benue River
flows into the Niger. At Kazungula
in Zambia, the Chobe River
flows into the Zambezi. The confluence defines the tripoint of Zambia
(north of the rivers), Botswana
(south of the rivers) and Namibia
(west of the rivers). The land border between Botswana
and Zimbabwe
to the east also reaches the Zambezi
at this confluence, so there is a second tripoint (Zambia-Botswana-Zimbabwe) only 150 meters downstream from the first. See Kazungula
and Quadripoint, and Gallery below for image. The Sudanese capital of Khartoum
is located at the confluence of the White Nile
White Nile
and the Blue Nile, the beginning of the Nile.


The Nam Khan
Nam Khan
flows into the Mekong
at Luang Prabang
Luang Prabang
in Laos

82 km north of Basra
in Iraq
at the town of Al-Qurnah
is the confluence of the rivers Tigris
and Euphrates, forming the Shatt al-Arab. At Devprayag
in India, the Ganges
originates at the confluence of the Bhagirathi
and the Alaknanda; see images above. Near Allahabad, India, the Yamuna
flows into the Ganges. In Hinduism, this is a pilgrimage site for ritual bathing;[12] during a Kumbh Mela event tens of millions of people visit the site. In Hindu belief the site is held to be a triple confluence (Triveni Sangam), the third river being the metaphysical (not physically present) Sarasvati.[13] Kuala Lumpur, the capital of Malaysia, is where the Gombak River (previously known as Sungai Lumpur, which means "muddy river") flows into the Klang River
at the site of the Jamek Mosque. Recently, the Kolam Biru (Blue Pool), a pool with elaborate fountains, has been installed at the apex of the confluence.[14] The Nam Khan
Nam Khan
flows into the Mekong
at Luang Prabang
Luang Prabang
in Laos.

The confluence of the Jialing and the Yangtze
in Chongqing. The Yangtze
flows left to right across the bottom of the image.

The Jialing flows into the Yangtze
at Chongqing
in China. The confluence forms a focal point in the city, marked by Chaotianmen Square, built 1998.[15] Visitors to the square behold a vast panorama of ships, bridges, skyscrapers, and people.[16] In the Far East, the Amur forms the international boundary between China
and Russia. The Ussuri, which also demarcates the border, flows into the Amur at a point midway between Fuyuan in China
and Khabarovsk in Russia. The apex of the confluence is located in a rural area, part of China, where a commemorative park, Dongji Square, has been built; it features an enormous sculpture representing the Chinese character for "East".[17] The Amur- Ussuri
border region was the location of the Sino-Soviet border conflict
Sino-Soviet border conflict
of 1969; the borderline near the confluence was settled peacefully by treaty in 2008.[18]


The two largest rivers in Australia, the Murray and its tributary the Darling, converge at Wentworth, New South Wales
Wentworth, New South Wales
(see Gallery below for image). The Franklin flows into the Gordon in south-western Tasmania.

The Seine
becomes a single channel at the west end of the Île de la Cité in Paris. The Pont Neuf
Pont Neuf
can be seen.

Europe[edit] Seine

The Seine
divides in the historical center of Paris, flowing around two river islands, the Île Saint-Louis
Île Saint-Louis
and the Île de la Cité. At the downstream confluence, where the river becomes a single channel again, the Île de la Cité
Île de la Cité
is crossed by the famous Pont Neuf, adjacent to an equestrian statue of King Henri IV
Henri IV
and the historically more recent Vert Galant park. The site has repeatedly been portrayed by artists including Monet,[19] Renoir,[20] and Pissarro.[21] Further upstream, the Marne empties into the Seine
at Charenton-le-Pont, just southeast of the Paris
city limits. The site is dominated by the Huatian Chinagora, a four-star hotel under Chinese management. See Gallery for image.

The Mosel flows into the Rhine
at Koblenz.


The Rhine
carries much river traffic, and major inland ports are found at its confluence with the Ruhr at Duisburg
(see Gallery below), and with the Neckar
at Mannheim; see Mannheim
Harbour. The Main flows into the Rhine
just south of Mainz
(see Gallery for image). The Mosel flows into the Rhine
further north at Koblenz. The name "Koblenz" itself has its origin in the Latin name "Confluentes". In German, this confluence is known as the "Deutsches Eck" ("German corner") and is the site of an imposing monument to German unification featuring an equestrian statue of Kaiser Wilhelm I. Upstream in Switzerland, a small town also named Koblenz
(for the same reason) is where the Aare joins the Rhine.


The triple confluence in Passau; from left to right, the Inn, the Danube, and the Ilz.

Passau, Germany, sometimes called the Dreiflüssestadt (City of Three Rivers), is the site of a triple confluence, described thus in a guidebook: "from the north the little Ilz
sluices brackish water down from the peat-rich Bavarian Forest, meeting the cloudy brown of the Danube
as it flows from the west and the pale snow-melt jade of the Inn from the south [i.e., the Alps] to create a murky tricolour."[22] The Thaya flows into the Morava in a rural location near Hohenau an der March in Austria, forming the tripoint of Austria, Czechia, and Slovakia. The Morava flows into the Danube
at Devín, on the border between Slovakia
and Austria
(see Gallery below for image). The Sava
flows into the Danube
at Belgrade, the capital of Serbia. In karst topography, which arises in soluble rock, rivers sometimes flow underground and form subterranean confluences, as at Planina Cave in Slovenia, where the Pivka and Rak merge to form the Unica.[23]


Lyon, France
lies where the Saône
flows into the Rhone. A major new museum of science and anthropology, the Musée des Confluences, opened on the site in 2014. The Lusatian Neisse
Lusatian Neisse
flows into the Oder
at a rural location in Poland opposite the German village of Ratzdorf. The two rivers form the Oder-Neisse line, the postwar boundary of Germany and Poland. The Triangle of Three Emperors, a former political tripoint, lies in present-day Poland. The empires that abutted (in the decades before World War I) were the Austrian, German, and Russian. Rovaniemi, the capital of Finnish Lapland and one of the largest towns above the Arctic Circle, is at the confluence of rivers Ounasjoki
and Kemijoki. Kryvyi Rih, Ukraine
is located (and named after) on the confluence of the Saksahan
and Inhulets River. The Oka flows into the Volga
at Nizhny Novgorod
Nizhny Novgorod
in Russia. The Alexander Nevsky Cathedral overlooks the site. See Gallery below for image.

North America[edit]

The confluence of the Allegheny and Monongahela at Pittsburgh, forming the Ohio

The Ohio flows into the Mississippi at Cairo.

The Rideau Falls
Rideau Falls
in Ottawa, where the Rideau River
tumbles into Ottawa River
at its mouth.

Mississippi basin

Vicksburg, Mississippi
Vicksburg, Mississippi
lies atop bluffs overlooking the confluence of the Mississippi River
with its tributary the Yazoo. Both rivers, as well as the bluffs, played an important role in the Vicksburg Campaign, a pivotal event of the American Civil War. The Missouri
flows into the Mississippi River
at Jones- Confluence
Point State Park, just north of St. Louis, Missouri. Slightly further upstream, the Illinois
flows into the Mississippi. The Madison, Jefferson and Gallatin Rivers in Three Forks, Montana form the confluence of the Missouri
River. At Keokuk, Iowa, the Des Moines River
flows into the Mississippi. This forms the political tripoint between the U.S. states of Iowa, Missouri, and Illinois. Just south of Cairo, Illinois, the Ohio River
flows into the Mississippi, forming the tripoint between the states of Illinois, Missouri, and Kentucky. The Ohio River
is formed by the confluence of the Monongahela and Allegheny rivers, located in Pittsburgh, Pennsylvania. The site is of great historical significance; in the 1970's it was upgraded by the creation of Point State Park, highlighted by a large fountain.

Atlantic watersheds

At Harpers Ferry, West Virginia, the Shenandoah River
flows into the Potomac River, at the tripoint of the U.S. states of Virginia, West Virginia, and Maryland. At Philadelphia, Pennsylvania, the Schuylkill River
flows into the Delaware River, next to the former Philadelphia
Naval Shipyard; the site remains industrial. At Cohoes, New York, a few miles north of Albany, the Mohawk River flows into the Hudson in three channels separated by islands. The confluence is historically important: upstream traffic on or along the Hudson often took a left turn at the Mohawk, which offers a uniquely level passageway through the Appalachian Mountains
Appalachian Mountains
that assisted commerce and the settlement of the West. At Ottawa, the capital of Canada, the Rideau River
flows -- unusually, as a waterfall -- into the Ottawa
River; see Rideau Falls. On the island separating the two portions of the falls is a park with military monuments, among them the Ottawa
Memorial. The Hochelaga Archipelago, including the island and city of Montreal, is located where the Ottawa
flows into the St. Lawrence River
in Quebec, Canada. Winnipeg, Canada, is at the confluence of the Red River, and the Assiniboine River. The area is referred to as The Forks by locals, and has been an important trade location for over 6000 years.

Pacific watersheds

The Green River
flows into the Colorado River
at the heart of Canyonlands National Park
Canyonlands National Park
in Utah's Canyon Country. See Gallery below for image. The Snake River
flows into the Columbia River
at the Tri-Cities of Washington. In Portland, Oregon, the Willamette River
flows into the Columbia at Kelley Point Park, built on land acquired from the Port of Portland in 1984. See Gallery below for image. Lytton, British Columbia, Canada, is located at the confluence of the muddy Fraser River
and the clearer Thompson River
(see Gallery below for image).

The confluence of the Rio Negro (black) and the Rio Solimões
Rio Solimões
(turbid) near Manaus, Brazil.

South America[edit]

Manaus, Brazil
Manaus, Brazil
is on the Rio Negro near its confluence with the Amazon (see Meeting of Waters). It is the chief port and a hub for the region's extensive river system. The Iguazú flows into the Paraná at the "Triple Frontier" (Spanish: La Triple Frontera, Portuguese: Tríplice Fronteira), the tripoint for Paraguay, Argentina, and Brazil.

Confluences not of two rivers[edit]

of canals This simplified diagram shows how a section of the Industrial Canal
Industrial Canal
in New Orleans
New Orleans
also serves as the channel for the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal. At the bottom, a portion of the Intracoastal is also shown to be "confluent" with the Mississippi River.

Occasionally "confluence" is used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals[24] or a canal and a lake.[25] A one-mile (1.6 km) portion of the Industrial Canal in New Orleans
New Orleans
accommodates the Gulf Intracoastal Waterway
Gulf Intracoastal Waterway
and the Mississippi River-Gulf Outlet Canal; therefore those three waterways are confluent there. The term confluence also applies to the merger of the flow of two glaciers.[26] For sample image, see Gallery below. Gallery[edit]

The Chobe (top of image, left side) flows into the Zambezi
at Kazungula
in Zambia.

The Ruak (left) flows into the Mekong, with Thailand
in the foreground, Laos
to the right, Myanmar
between the rivers.

The Darling flows into the Murray in Wentworth, Australia.

The Marne (left) flows into the Seine
near Paris.

The Yonne flows into the Seine
in Montereau. The site is marked by a statue of Napoleon, who won a victory there.

The flow of the Ruhr into the Rhine
at Duisburg, Germany is celebrated by the sculpture Rhine

The Main (brownish in color) flows into the Rhine
south of Mainz.

of the Danube
(light blue) and the Morava (dark blue) in Devín
on the border between Austria
and Slovakia.

In Yaroslavl
in Russia, the 1000th anniversary of the city (2010) was celebrated with a new park and monument at the confluence of the Kotorosl and the Volga.[27]

The Oka flows into the icy Volga
at Nizhny Novgorod, Russia, next to the Alexander Nevsky Cathedral.

This long row of old pilings marks the confluence of the Willamette (left) and the Columbia (right) at Portland, Oregon.

The confluence of the Fraser and Thompson rivers

of the Green River
(upper right) and the Colorado (lower right)

A glacial confluence in the Alps: Jungfraufirn and Grosser Aletschfirn merge to form the Aletsch Glacier
at Concordia Place.

See also[edit]

Wikimedia Commons has media related to Confluences.

mouth Aber and Inver as place-name elements


^ "Conflux – Definition of conflux by Merriam-Webster". merriam-webster.com.  ^ A widely cited work is James L. Best (1986) The morphology of river channel confluences. Progress in Physical Geography
10:157–174. For work citing Best, see [1]. ^ A recent contribution with review of earlier work is Laurent Schindfessel, Stéphan Creëlle and Tom De Mulder (2015) "Flow patterns in an open channel confluence with increasingly dominant tributary inflow," Water 7: 4724–4751; available on line. ^ Quoted from Beechie et al. (2012), who cite earlier work. Tim Beechie, John S. Richardson, Angela M. Gurnell, and Junjiro Negishi (2012) "Watershed processes, human impacts, and process-based restoration." In Philip Roni and Tim Beechie (eds.) (2012) Stream and Watershed Restoration: A Guide to Restoring Riverine Processes and Habitats, John Wiley & Sons. Excerpts available on line at Google Books. ^ U.S. Geological Survey, "How do contaminants mix at the confluence of two streams?", on line at [2]. ^ David Lynch (2014) "The Confluence
of Rivers"; Earth Science Picture of the Day, at [3]. ^ BEST, JAMES L. FLOW DYNAMICS AT RIVER CHANNEL CONFLUENCES: IMPLICATIONS FOR SEDIMENT TRANSPORT AND BED MORPHOLOGY. pp. 27–35. doi:10.2110/pec.87.39.0027.  ^ Rogers, Adam (2011) Late Roman Towns in Britain: Rethinking Change and Decline. Cambridge: Cambridge University Press, p. 42. Excerpts available on line at Google Books. ^ Gasparini, Evel (n.d.) "Slavic religion", in Encyclopedia Brittanica, on line edition: [4] ^ Source: Letizia (2017), who writes, "as rivers are considered holy entities, at the meeting of two streams the 'sacredness' of the first river add to that of the second one. The confluence seems to have a sort of 'additive fame' ... because it gives pilgrims the chance to bathe in two rivers at the same time." ^ Ann Rodgers, "So how did the Point get on a Mayan calendar?", Pittsburgh
Post-Gazette, June 22, 2008. On line at [5]. ^ See reporting in the New York Times ([6]) and The Atlantic ([7]). ^ The incorporation of invisible rivers into confluences elsewhere in the subcontinent is documented by Letizia (2017). ^ See New Straits Times, August 28, 2017, 'Najib launches River
of Life, Blue Pool projects", at [8]. ^ http://www.topchinatravel.com/china-attractions/chaotianmen-square.htm ^ See pictorial coverage at Google Maps: [9] ^ See Bruno Maçães, "Signs and Symbols on the Sino-Russian Border", published in The Diplomat. On line at [10]. ^ See [11]. ^ See [12] for image. ^ See [13]. ^ See [14]. ^ See Andrea Schulte-Peevers, Kerry Christiani, Marc Di Duca, Catherine Le Nevez, Tom Masters, Ryan Ver Berkmoes, and Benedict Walker (2016) Lonely Planet Germany, Lonely Planet Publishing. Excepts posted on line at Google Books: [15] ^ Kogovšek, Janja; Petrič, Metka; Zupan Hajna, Nadja; Pipan, Tanja. "Planinska jama" [Planina Cave]. In Šmid Hribar, Mateja; Golež, Gregor; Podjed, Dan; Kladnik, Drago; Erhartič, Bojan; Pavlin, Primož; Ines, Jerele. Enciklopedija naravne in kulturne dediščine na Slovenskem [Encyclopedia of Natural and Cultural Heritage in Slovenia] (in Slovenian). Retrieved 17 May 2012.  ^ The U.S. Army Corps of Engineers refers to the confluence of the Assawoman Canal with the Bethany Loop Canal in Delaware. See: "CENAP-OP-R-Quarterly Report, 2004-05-12". Philadelphia
Engineer District. Archived from the original on 2004-10-17. Retrieved 2006-03-11.  ^ Engineers in New Orleans
New Orleans
refer to the confluence of the 17th Street Canal and Lake Pontchartrain. See: "Interim Closure Structure at 17th St. Canal". Task Force Guardian. Archived from the original on 2006-06-25. Retrieved 2006-03-11.  ^ Vladimir Kotlyakov and Anna Komarova (2006) Elsevier's Dictionary of Geography: in English, Russian, French, Spanish and German. Elsevier. Passage cited may be accessed on Google Books. ^ See [16],


Letizia, Chiara (2017) "The Sacred Confluence, between Nature and Culture," in Marie Lecomte-Tilouine (ed.) Nature, Culture and Religion at the Crossroads of Asia. Routledge. Extracts available on line at Google Books.

External links[edit]

[17] A collection of full-size, vivid photographs of confluences, most of them mentioned in the