Distributary
Encyclopedia
A distributary, or a distributary channel, is a stream
that branches off and flows away from a main stream channel. They are a common feature of river delta
s. The phenomenon is known as river bifurcation
. The opposite of a distributary is a tributary
. Distributaries usually occur as a stream nears a lake
or the ocean
, but they can occur inland as well, such as in an endorheic
basin, or when a tributary stream bifurcates as it nears its confluence with a larger stream. In some cases, a minor distributary can "steal" so much water from the main channel that it can become the main route.
, or the West Channel of the Mackenzie River
), or one that will (e.g. Annacis Channel and Annieville Channel of the Fraser River
, separated by Annacis Island
).
In Australia, the term anabranch
is used to refer to a distributary that diverts from the main course of the river and rejoins it later. In North America
an anabranch is called a braided stream.
, the Atchafalaya River
is an important distributary of the Mississippi River
. Because the Atchafalaya takes a steeper route to the Gulf of Mexico
than the main channel, it has captured more and more of the Mississippi's flow over several decades, including capturing the Red River
, which was formerly a tributary of the Mississippi. The Old River Control Structure
, a dam
which regulates the outflow from the Mississippi into the Atchafalaya, was completed in 1963 to prevent the Atchafalaya from capturing the main flow of the Mississippi and stranding the ports of Baton Rouge and New Orleans.
An example of inland distributaries is the Teton River
, a tributary of Henrys Fork in Idaho
, which splits into two distributary channels, the North Fork and South Fork, which join Henrys Fork miles apart.
Another example occurs on the Continental Divide
at Parting of the Waters
National Landmark within Wyoming's Teton Wilderness
, where North Two Ocean Creek splits into two distributaries, Pacific Creek and Atlantic Creek, which ultimately flow into their respective oceans.
, which flows southward into the Rio Negro and forms a unique natural canal
between the Orinoco and Amazon
river systems. It is the largest river on the planet that links two major river systems.
, a distributary of the Kaveri River
, and the Hoogli River, a distributary of the Ganges River
, both in India
. Also, the Munneru is the distributary of the Krishna River
.
form distributaries, most of which flow only intermittently during times of high river levels and end in shallow lakes or simply peter out in the deserts.
Yarriambiack Creek
, which flows from the Wimmera River
into Lake Coorong, and Tyrrell Creek, which flows from the Avoca River
into Lake Tyrrell
, are two distributaries in Victoria
.
The Narran River
flows from the Balonne River
in Queensland
into Narran Lake in New South Wales
.
Stream
A stream is a body of water with a current, confined within a bed and stream banks. Depending on its locale or certain characteristics, a stream may be referred to as a branch, brook, beck, burn, creek, "crick", gill , kill, lick, rill, river, syke, bayou, rivulet, streamage, wash, run or...
that branches off and flows away from a main stream channel. They are a common feature of river delta
River delta
A delta is a landform that is formed at the mouth of a river where that river flows into an ocean, sea, estuary, lake, reservoir, flat arid area, or another river. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river...
s. The phenomenon is known as river bifurcation
River bifurcation
River bifurcation occurs when a river flowing in a single stream separates into two or more separate streams which continue downstream. Some rivers form complex networks of distributaries, especially in their deltas...
. The opposite of a distributary is a tributary
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...
. Distributaries usually occur as a stream nears a lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
or the ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
, but they can occur inland as well, such as in an endorheic
Endorheic
An endorheic basin is a closed drainage basin that retains water and allows no outflow to other bodies of water such as rivers or oceans...
basin, or when a tributary stream bifurcates as it nears its confluence with a larger stream. In some cases, a minor distributary can "steal" so much water from the main channel that it can become the main route.
Related terms
Common terms to name individual river distributaries in English-speaking countries are arm and channel. They may refer to a distributary that won't rejoin the channel it has branched off (e.g., the North, Middle, and South Arms of the Fraser RiverFraser River
The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Mount Robson in the Rocky Mountains and flowing for , into the Strait of Georgia at the city of Vancouver. It is the tenth longest river in Canada...
, or the West Channel of the Mackenzie River
Mackenzie River
The Mackenzie River is the largest river system in Canada. It flows through a vast, isolated region of forest and tundra entirely within the country's Northwest Territories, although its many tributaries reach into four other Canadian provinces and territories...
), or one that will (e.g. Annacis Channel and Annieville Channel of the Fraser River
Fraser River
The Fraser River is the longest river within British Columbia, Canada, rising at Fraser Pass near Mount Robson in the Rocky Mountains and flowing for , into the Strait of Georgia at the city of Vancouver. It is the tenth longest river in Canada...
, separated by Annacis Island
Annacis Island
Annacis Island is an island located in the South Arm of the Fraser River in Delta, British Columbia, Canada. The island is now mostly industrial, and it contains one of the Metro Vancouver's secondary wastewater treatment plants...
).
In Australia, the term anabranch
Anabranch
An anabranch is a section of a river or stream that diverts from the main channel or stem of the watercourse and rejoins the main stem downstream. Local anabranches can be the result of small islands in the watercourse...
is used to refer to a distributary that diverts from the main course of the river and rejoins it later. In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
an anabranch is called a braided stream.
North America
In LouisianaLouisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
, the Atchafalaya River
Atchafalaya River
The Atchafalaya River is a distributary of the Mississippi River and Red River in south central Louisiana in the United States. It flows south, just west of the Mississippi River....
is an important distributary of the Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...
. Because the Atchafalaya takes a steeper route to the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
than the main channel, it has captured more and more of the Mississippi's flow over several decades, including capturing the Red River
Red River (Mississippi watershed)
The Red River, or sometimes the Red River of the South, is a major tributary of the Mississippi and Atchafalaya Rivers in the southern United States of America. The river gains its name from the red-bed country of its watershed. It is one of several rivers with that name...
, which was formerly a tributary of the Mississippi. The Old River Control Structure
Old River Control Structure
The Old River Control Structure is a floodgate system located in a branch of the Mississippi River in central Louisiana. It regulates the flow of water leaving the Mississippi into the Atchafalaya River, thereby preventing the Mississippi river from changing course. Completed in 1963, the...
, a dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
which regulates the outflow from the Mississippi into the Atchafalaya, was completed in 1963 to prevent the Atchafalaya from capturing the main flow of the Mississippi and stranding the ports of Baton Rouge and New Orleans.
An example of inland distributaries is the Teton River
Teton River (Idaho)
The Teton River is an tributary of the Henrys Fork of the Snake River in southeastern Idaho in the United States. It drains through the Teton Valley along the west side of the Teton Range along the Idaho-Wyoming border at the eastern end of the Snake River Plain...
, a tributary of Henrys Fork in Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
, which splits into two distributary channels, the North Fork and South Fork, which join Henrys Fork miles apart.
Another example occurs on the Continental Divide
Continental Divide
The Continental Divide of the Americas, or merely the Continental Gulf of Division or Great Divide, is the name given to the principal, and largely mountainous, hydrological divide of the Americas that separates the watersheds that drain into the Pacific Ocean from those river systems that drain...
at Parting of the Waters
Parting of the Waters
Parting of the Waters is an unusual hydrologic site at Two Ocean Pass on the Continental Divide, within the Teton Wilderness Area of Wyoming's Bridger-Teton National Forest. Two Ocean Pass separates the headwaters of Pacific Creek, which flows Westerly to the Pacific Ocean, and Atlantic Creek,...
National Landmark within Wyoming's Teton Wilderness
Teton Wilderness
Teton Wilderness is located in Wyoming, United States. Created in 1964, the Teton Wilderness is located within Bridger-Teton National Forest and consists of 585,238 acres . The wilderness is bordered on the north by Yellowstone National Park and to the west by Grand Teton National Park and the John...
, where North Two Ocean Creek splits into two distributaries, Pacific Creek and Atlantic Creek, which ultimately flow into their respective oceans.
South America
The Casiquiare is an inland distributary of the upper OrinocoOrinoco
The Orinoco is one of the longest rivers in South America at . Its drainage basin, sometimes called the Orinoquia, covers , with 76.3% of it in Venezuela and the remainder in Colombia...
, which flows southward into the Rio Negro and forms a unique natural canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...
between the Orinoco and Amazon
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
river systems. It is the largest river on the planet that links two major river systems.
Europe
- The IJsselIJsselRiver IJssel , sometimes called Gelderse IJssel to avoid confusion with its Hollandse IJssel namesake in the west of the Netherlands, is a branch of the Rhine in the Dutch provinces of Gelderland and Overijssel...
, the Waal and the NederrijnNederrijnthumb|left|300px|Course of the NederrijnNederrijn is the name of the Dutch part of the River Rhine from the confluence at the town of Angeren of the cut-off Rhine bend of Oude Rijn and the Pannerdens Kanaal...
(Lower Rhine) are the three principal distributaries of the Rhine. - The Akhtuba RiverAkhtuba RiverThe Akhtuba River ; also transliterated Achtuba on some maps)is a left distributary of the Volga River.The Akhtuba splits off the Volga above the city Volgograd , and flows towardthe Volga Delta and Caspian Sea....
is a major distributary of the Volga. - The Tärendö RiverTärendö RiverThe Tärendö River , is a small tributary river to the Kalix River in Norrbotten, Sweden.It is the second largest bifurcation in the world ....
in northern SwedenSwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
is an inland distributary, far from the mouth of the river. It begins at the Torne RiverTorne RiverThe Torne River , is a river in northern Sweden and Finland. Approximately half of the river's length is a part of the border between these two countries. It rises at Lake Torne near the border with Norway and flows generally southeast for a distance of into the Gulf of Bothnia...
and ends at the Kalix RiverKalix RiverThe Kalix River is one of the four major rivers of Norrland, northern Sweden, that are untouched by water power...
.
Asia
Notable distributaries are the Kollidam RiverKollidam River
The Kollidam is a river in southeastern India. The Kollidam is the northern distributary of the Kaveri River as it flows through the delta of Thanjavur. It splits from the main branch of the Kaveri River at the island of Srirangam and flows eastward into the Bay of Bengal. The distribution...
, a distributary of the Kaveri River
Kaveri River
The Kaveri , also spelled Cauvery in English, is a large Indian river. The origin of the river is traditionally placed at Talakaveri, Kodagu in the Western Ghats in Karnataka, flows generally south and east through Karnataka and Tamil Nadu and across the southern Deccan plateau through the...
, and the Hoogli River, a distributary of the Ganges River
Ganges River
The Ganges or Ganga, , is a trans-boundary river of India and Bangladesh. The river rises in the western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of North India into Bangladesh, where it empties into the Bay of Bengal. By discharge it...
, both in India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
. Also, the Munneru is the distributary of the Krishna River
Krishna River
The Krishna River , is one of the longest rivers in central-southern India, about . It is also referred to as Krishnaveni in its original nomenclature...
.
Africa
- The Nile River has two distributaries, the RosettaRosettaRosetta is a port city on the Mediterranean coast of Egypt. It is located east of Alexandria, in Beheira governorate. It was founded around AD 800....
and the DamiettaDamiettaDamietta , also known as Damiata, or Domyat, is a port and the capital of the Damietta Governorate in Egypt. It is located at the intersection between the Mediterranean Sea and the Nile, about north of Cairo.-History:...
branches. According to Pliny the ElderPliny the ElderGaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...
it had in ancient times seven distributaries (east to west):- The Pelusiac
- The Tanitic
- The Mendesian
- The Phatnitic
- The Sebennytic
- The Bolbitine
- The Canopic
- See History of the Nile Delta.
- The Okavango RiverOkavango RiverThe Okavango River is a river in southwest Africa. It is the fourth-longest river system in southern Africa, running southeastward for . It begins in Angola, where it is known as the Cubango River...
ends in many distributaries in a large inland delta called the Okavango DeltaOkavango DeltaThe Okavango Delta , in Botswana, is the world's largest inland delta. It is formed where the Okavango River empties onto a swamp in an endorheic basin in the Kalahari Desert, where most of the water is lost to evaporation and transpiration instead of draining into the sea...
. It is an example of distributaries that do not flow into any other body of water.
- The Okavango River
Australia
A number of the rivers that flow inland from the Great Dividing RangeGreat Dividing Range
The Great Dividing Range, or the Eastern Highlands, is Australia's most substantial mountain range and the third longest in the world. The range stretches more than 3,500 km from Dauan Island off the northeastern tip of Queensland, running the entire length of the eastern coastline through...
form distributaries, most of which flow only intermittently during times of high river levels and end in shallow lakes or simply peter out in the deserts.
Yarriambiack Creek
Yarriambiack Creek
Yarriambiack Creek, a distributary of the Wimmera River, leaves the river near Drung Drung, about 20 kilometres east of Horsham, and flows northwards about 140 kilometres through Warracknabeal, ending in Lake Coorong just east of Hopetoun. Its flow is intermittent and depends almost entirely on the...
, which flows from the Wimmera River
Wimmera River
The Wimmera River is a river in Western Victoria, Australia. It begins in the Pyrenees, and flows into Lake Hindmarsh and Lake Albacutya, although in many years flows do not reach these terminal lakes and the river contracts to a series of pools of varying sizes...
into Lake Coorong, and Tyrrell Creek, which flows from the Avoca River
Avoca River
The Avoca River drains a substantial part of Victoria, the southernmost state of mainland Australia. The river rises at the foot of Mount Lonarch in the Central Highlands near the small town of Amphitheatre, and flows north for 270 km through Avoca, Charlton and Quambatook...
into Lake Tyrrell
Lake Tyrrell
Lake Tyrrell is a shallow, salt-crusted depression located in the Mallee district of north-west Victoria. It covers approximately 180 square kilometres is 314 kilometres northwest of Melbourne. While much of the time it is dry, the lake is occasionally fed by Tyrrell Creek, a distributary of the...
, are two distributaries in Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
.
The Narran River
Narran River
The Narran River is a river which spans the Queensland-New South Wales border in Australia. It flows into Narran Lake, near Brewarrina. It is the easterly-most of the branches of the Balonne River that flows to the Barwon River...
flows from the Balonne River
Balonne River
The Balonne River, part of the Murray-Darling Basin system, is a short but important part of the inland river group of south-eastern Queensland. This river is a continuation of the Condamine River. After flowing through Surat the river flows south south-westerly down through the E.J...
in Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
into Narran Lake in New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
.