In geography, a confluence (also: conflux) occurs where two or more
flowing bodies of water join together 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 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
Confluence Flow Zones (River)
2 Confluences and humankind
3 Notable confluences
3.5 North America
3.6 South America
4 Confluences not of two rivers
6 See also
9 External links
Scientific study of confluences
Confluences are studied in a variety of sciences.
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 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 the subsequent transport of metals downstream of the
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.
Confluence Flow Zones (River)
Hydrodynamic behaviour of flow in a confluence can be divided into six
distinct features 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
Flow Deflection Zone
Flow Separation Zone / Recirculation Zone
Maximum Velocity Zone
Flow Recovery Zone
Confluences and humankind
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 in northwest Europe, watery locations were
often sacred, especially sources and confluences. Pre-Christian
Slavic peoples chose confluences as 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
Mayanism consider their city's confluence to be
White Nile and
Blue Nile merge at Khartoum; April 2013 satellite
At Lokoja, Nigeria, the Benue
River flows into the Niger.
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
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.
Kazungula and Quadripoint, and Gallery below for image.
The Sudanese capital of
Khartoum is located at the confluence of the
White Nile and the Blue Nile, the beginning of the Nile.
Nam Khan flows into the
Luang Prabang in Laos
82 km north of
Iraq at the town of
Al-Qurnah is the
confluence of the rivers
Tigris and Euphrates, forming the Shatt
Devprayag in India, the
River originates at the confluence
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; 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.
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.
River flows into the
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
Chongqing in China. The
confluence forms a focal point in the city, marked by Chaotianmen
Square, built 1998. Visitors to the square behold a vast panorama
of ships, bridges, skyscrapers, and people.
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". 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.
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
The Franklin flows into the Gordon in south-western Tasmania.
Seine becomes a single channel at the west end of the Île de la
Cité in Paris. The
Pont Neuf can be seen.
Seine divides in the historical center of Paris, flowing around
two river islands, the
Île Saint-Louis and the Île de la Cité. At
the downstream confluence, where the river becomes a single channel
Île de la Cité
Île de la Cité is crossed by the famous Pont Neuf,
adjacent to an equestrian statue of King
Henri IV and the historically
more recent Vert Galant park. The site has repeatedly been portrayed
by artists including Monet, Renoir, and Pissarro.
Further upstream, the Marne empties into the
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.
Rhine carries much river traffic, and major inland ports are found
at its confluence with the Ruhr at
Duisburg (see Gallery below), and
Neckar at Mannheim; see
The Main flows into the
Rhine just south of
Mainz (see Gallery for
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."
The Thaya flows into the Morava in a rural location near Hohenau an
der March in Austria, forming the tripoint of Austria, Czechia, and
The Morava flows into the
Danube at Devín, on the border between
Austria (see Gallery below for image).
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.
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.
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
Ukraine is located (and named after) on the confluence of
Saksahan and Inhulets River.
The Oka flows into the
Nizhny Novgorod in Russia. The
Alexander Nevsky Cathedral overlooks the site. See Gallery below for
The confluence of the Allegheny and Monongahela at Pittsburgh, forming
The Ohio flows into the Mississippi at Cairo.
Rideau Falls in Ottawa, where the Rideau
River tumbles into Ottawa
River at its mouth.
Vicksburg, Mississippi lies atop bluffs overlooking the confluence of
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.
River flows into the Mississippi
Confluence Point State Park, just north of St. Louis, Missouri.
Slightly further upstream, the
River flows into the
The Madison, Jefferson and Gallatin Rivers in Three Forks, Montana
form the confluence of the
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.
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.
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 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
The Hochelaga Archipelago, including the island and city of Montreal,
is located where the
River flows into the St. Lawrence
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.
River flows into the Colorado
River at the heart of
Canyonlands National Park
Canyonlands National Park in Utah's Canyon Country. See Gallery below
River flows into the Columbia
River at the Tri-Cities of
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
River and the clearer Thompson
River (see Gallery below
The confluence of the Rio Negro (black) and the
Rio Solimões (turbid)
near 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
Confluence of canals
This simplified diagram shows how a section of the
Industrial Canal in
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
Occasionally "confluence" 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
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. For sample image, see Gallery below.
The Chobe (top of image, left side) flows into the
Kazungula in Zambia.
The Ruak (left) flows into the Mekong, with
Thailand in the
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
The Main (brownish in color) flows into the
Rhine south of Mainz.
Confluence of the
Danube (light blue) and the Morava (dark blue) in
Devín on the border between
Austria and Slovakia.
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.
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
Confluence of the Green
River (upper right) and the Colorado (lower
A glacial confluence in the Alps: Jungfraufirn and Grosser Aletschfirn
merge to form the Aletsch
Glacier at Concordia Place.
Wikimedia Commons has media related to Confluences.
Aber and Inver as place-name elements
^ "Conflux – Definition of conflux by Merriam-Webster".
^ 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 .
^ 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
^ U.S. Geological Survey, "How do contaminants mix at the confluence
of two streams?", on line at .
^ David Lynch (2014) "The
Confluence of Rivers"; Earth Science Picture
of the Day, at .
^ 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: 
^ 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 .
^ See reporting in the New York Times () and The Atlantic ().
^ 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
Life, Blue Pool projects", at .
^ See pictorial coverage at Google Maps: 
^ See Bruno Maçães, "Signs and Symbols on the Sino-Russian Border",
published in The Diplomat. On line at .
^ See .
^ See  for image.
^ See .
^ See .
^ 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: 
^ 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".
District. Archived from the original on 2004-10-17. Retrieved
^ Engineers in
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 ,
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
 A collection of full-size, vivid photographs of confluences, most
of them mentioned