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Encyclopedia > River delta
Nile River delta, as seen from Earth orbit. Photo courtesy of NASA.
Nile River delta, as seen from Earth orbit. Photo courtesy of NASA.

A delta is a landform where the mouth of a river flows into an ocean, sea, desert, estuary, lake or another river. It builds up sediment outwards into the flat area which the river's flow encounters (as a deltaic deposit) transported by the water and set down as the currents slow. Deltaic deposits of larger, heavily-laden rivers are characterized by the main channel dividing amongst often substantial land masses into multiple streams known as distributaries. These divide and come together again to form a maze of active and inactive channels. This hydrogeologic formation is known as an alluvial fan. This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... A landform comprises a geomorphological unit, and is largely defined by its surface form and location in the landscape, as part of the terrain, and as such, is typically an element of topography. ... For other uses, see River (disambiguation). ... Animated map exhibiting the worlds oceanic waters. ... This article is about the body of water. ... This article is about arid terrain. ... For other meanings, see Estuary (disambiguation) Río de la Plata estuary An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ... For other uses, see Lake (disambiguation). ... This article or section cites very few or no references or sources. ... distributary in Else and Hase at Melle A seasonal Distributary of the Kaveri river on the Kaveri delta, near Nannilam, India. ... A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China’s XinJiang Province. ...

Contents

Delta formation

This arcuate delta has formed on the south-west coastline of Greenland, near Narsarsuaq.
This arcuate delta has formed on the south-west coastline of Greenland, near Narsarsuaq.

The deposit at the mouth of a river is usually roughly triangular in shape. The triangular shape and the increased width at the base are due to blocking of the river mouth, with resulting continual formation of distributaries at angles to the original course. These distributaries start out flowing fairly fast, but slow as more sediment is deposited and ultimately, the water flows elsewhere. This change in flow affects the particle size in the suspended and bed loads, the size of the particles decrease as the flow slows and the larger particles are deposited. This deposition goes on continually in a cyclic fashion, creating alternating sediment beds of coarse and fine grain deposits. Herodotus the great historian used this term for the Nile river delta because the sediment deposit at its mouth had the shape of upper-case Greek letter Delta: Δ. Image File history File links Codrington, Stephen. ... Image File history File links Codrington, Stephen. ... Map of Greenland Narsarsuaq (variously spelled, the name is Greenlandic for Great Plain) was the principal city of Greenland in the times of Erik the Red whose farm Brattahlíð was nearby. ... This article or section does not adequately cite its references or sources. ... Particle size, also called grain size, refers to the diameter of individual grains of sediment, or the lithified particles in clastic rocks. ... Suspended Load is the term for the fine particles that are light enough to be carried in a stream without touching the stream bed. ... Bed load is a term to describe the larger particles (relative to the suspended load) that are carried along the bottom of a stream. ... In geology a bed is the smallest division of a geologic formation or stratigraphic rock series marked by well-defined divisional planes (bedding planes) separating it from layers above and below. ... Herodotus of Halicarnassus (Greek: HÄ“ródotos Halikarnāsseús) was a Greek historian who lived in the 5th century BC (ca. ... NASA satellite photograph of the Nile Delta (shown in false colour) The Nile Delta (Arabic:دلتا النيل) is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. ... Majuscules or capital letters (in the Roman alphabet: A, B, C, ...) are one type of case in a writing system. ... Technical note: Due to technical limitations, some web browsers may not display some special characters in this article. ... Look up Δ, δ in Wiktionary, the free dictionary. ...


Where delta formation is often river-dominated and less subject to tidal or wave action, a delta may take on a multi-lobed shape which resembles a bird's foot.The formation consists of three main forms, the topset, foreset, and bottomset beds.The bottomset beds are created from the suspended sediment that settles out of the water as the river flows into the body of water and loses energy. These are laid down in horizontal layers and consist of smaller sediment. The foreset beds in turn build over the bottomset beds as the main delta form advances. The foreset beds consist of the bed load that the river is moving along which consists of larger sediments that roll along the main channel. When it reaches the edge of the form, the bed load rolls over the edge, and builds up in steeply angled layers over the top of the bottomset beds. The topset beds in turn overlay the foresets, and are horizontal layers of smaller sediment size that form as the main channel of the river shifts elsewhere and the larger particles of the bed load no longer are deposited.As the channels move across the top of the delta, the suspended load settles out in horizontal beds over the top. The Mississippi Delta is an example of this type. This article is about tides in the Earths oceans. ... For the TV movie also known as The Ocean Waves, see I Can Hear the Sea. ... For other uses, see Bird (disambiguation). ... False-color image of the larger Mississippi Delta Closeup of the currently active delta front Mississippi Delta Lobes The Mississippi River Delta is the modern area of land (the river delta) built up by alluvium deposited by the Mississippi River as it slows down and enters the Gulf of Mexico. ...


The most famous delta is that of the Nile River, and it is this delta from which the term is derived, because the Nile delta has a very characteristic triangular shape, like the (upper-case) Greek letter delta (Δ). Ganges/Brahmaputra combination (this delta spans most of Bangladesh and West Bengal) is the world's largest delta, and empties into the Bay of Bengal. Other rivers with notable deltas include the Sacramento-San Joaquin, the Rhine, the Rhône, the Danube, the Ebro, the Volga, the Lena, the Tigris-Euphrates, the Indus, the Krishna-Godavari, the Truckee, the Carson River, the Kaveri, the Ayeyarwady, and the Mekong. For other uses, see Nile (disambiguation). ... For alternate meanings, such as the musical instrument, see triangle (disambiguation). ... The Greek alphabet (Greek: ) is an alphabet consisting of 24 letters that has been used to write the Greek language since the late 8th or early 8th century BC. It was the first alphabet in the narrow sense, that is, a writing system using a separate symbol for each vowel... Look up Δ, δ in Wiktionary, the free dictionary. ... This article is about the river. ... The Brahmaputra is one of the major rivers of Asia. ... , West Bengal (Bengali: পশ্চিমবঙ্গ Poshchimbôŋgo) is a state in eastern India. ... The Sacramento River is the longest river in the U.S. state of California. ... The San Joaquin River, 330 miles (530 km) long, is the second-longest river in California, United States. ... For other uses, see Rhine (disambiguation). ... Length 800 km Elevation of the source 1753 m Average discharge 1800 m³/ s Area watershed 100,200 km² Origin Rhône glacier Mouth Mediterranean Sea Basin countries Switzerland, France The River Rhône ( Latin Rhodanus, French Rhône, Occitan Rose, German Rotten) is one of the major rivers (ca. ... Danube Delta - Landsat satellite photo (2000) The Danube Delta (Delta Dunării in Romanian), split between Tulcea County of Romania and Odessa Oblast of Ukraine, is the largest and best preserved of European deltas, with an area of 3446 km², after the Volga Delta. ... For the Spanish truck maker of the same name, see Ebro trucks. ... “Volga” redirects here. ... The Lena (Russian: Ле́на) in Siberia is the 10th longest river in the world and has the 9th largest watershed. ... ecoregion : Tigris-Euphrates alluvial salt marsh (Ref PA0906). ... The Indus River {Urdu: Sindh; Sindhi: Sindhu; Punjabi (Shahmukhi: سندھ, Gurmukhi: ਸਿੰਧੂ) ; Hindi and Sanskrit: सिन्धु ; Persian: حندو ; Pashto: ّآباسنFather of Rivers; Tibetan: Lion River; Chinese: Yìndù; Greek: Ινδός Indos} is the longest and most important river in Pakistan. ... Krishna in Vijayawada in 2007 The River Krishna (meaning dark (feminine) in Sanskrit, also called the Krishnaveni, is one of the longest rivers of India (about 1300 km in length). ... Godavari river map The Godavari River, adjacent to the town of Kovvur This article is about Godavari River in India. ... Truckee is a town located in Nevada County, California. ... The Carson River is a river in northern California and northwestern Nevada in the United States, approximately 150 mi (241 km) long. ... This article is about a river. ... The Ayeyarwady River or Irrawaddy River (Burmese: ; MLCTS: ) is a river that flows through Burma (Myanmar). ... The Mekong is one of the world’s major rivers. ...


Other rivers, particularly those located on coasts with significant tidal range, do not form a delta but enter into the sea in the form of an estuary. Notable examples include the Saint Lawrence River and the Tagus estuary. The tidal range is the vertical difference between the highest high tide and the lowest low tide. ... For other meanings, see Estuary (disambiguation) Río de la Plata estuary An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ... a broat veiew of the St LAwrence River, with a Quebec City on a background The Saint Lawrence River (In French: fleuve Saint-Laurent) is a large south west-to-north east flowing river in the middle latitudes of North America, connecting the Great Lakes with the Atlantic Ocean. ... The Tagus (Latin Tagus, Spanish Tajo, Portuguese Tejo, pron. ...


In rare cases the river delta is located inside a large valley and is called an inverted river delta. Sometimes a river will divide into multiple branches in an inland area, only to rejoin and continue to the sea; such an area is known as an inland delta, and often occur on former lake beds. The Niger Inland Delta is the most notable example. The Amazon has also an inland delta before the island of Marajo. An inverted river delta is special category of river delta in which the narrow end of the delta is located at the point of outflow of the delta, rather than the point of inflow. ... Inland can mean: Inland Fräkne Hundred - a hundred of Bahusia in Sweden Inland Northern Hundred - a hundred of Bahusia in Sweden Inland Southern Hundred - a hundred of Bahusia in Sweden Inland Torpe Hundred - a hundred of Bahusia in Sweden This is a disambiguation page — a navigational aid which lists other... The Niger Inland Delta is a large area of lakes and swamps in Mali, around the bifurcated River Niger and its tributary, the River Bani. ... This article is about the river. ... Marajo is an inhabited island, located at the mouth of the Amazon River in Brazil. ...


List of deltas

The Ganges river delta in India and Bangladesh is one of the most fertile regions in the world.
The Ganges river delta in India and Bangladesh is one of the most fertile regions in the world.

ImageMetadata File history File links Download high resolution version (1400x1370, 804 KB) GANGES RIVER DELTA, BANGLADESH, INDIA (STS066-92-013). ... ImageMetadata File history File links Download high resolution version (1400x1370, 804 KB) GANGES RIVER DELTA, BANGLADESH, INDIA (STS066-92-013). ... Ganga redirects here. ... Shoreline of the Étang de Vaccarès For other uses, see Camargue (disambiguation). ... The Rhône River, or the Rhône (French Rhône, Arpitan Rôno, Occitan Ròse, standard German Rhone, Valais German Rotten), is one of the major rivers of Europe, running through Switzerland and France. ... Colorado River Delta as seen from space (2004) The Colorado River Delta is the region of land where the Colorado River historically flowed into the Gulf of California, (the Sea of Cortez). ... Danube Delta - Landsat satellite photo (2000) The Danube Delta (Delta Dunării in Romanian), split between Tulcea County of Romania and Odessa Oblast of Ukraine, is the largest and best preserved of European deltas, with an area of 3446 km², after the Volga Delta. ... Eberswalde crater, formerly known as Holden NE crater, is a partially buried impact crater in Margaritifer Terra, Mars. ... This article is about the Spanish river. ... For other uses of this name see Fraser River (disambiguation). ... Ganges River Delta, Bangladesh and India The Ganges Delta (or the Bengal Delta) is a river delta in the South Asia region of Bengal, consisting of Bangladesh and the state of West Bengal, India. ... Indus River Delta The Indus River Delta occurs where the Indus River flows into the Arabian Sea in Pakistan. ... Origin of the Chao Phraya River in Nakhon Sawan A view of the Chao Phraya River in Bangkok The Chao Phraya (Thai: ) is a major river in Thailand, with its low alluvial river plain marking the mainland of the country. ... Lena Delta Wildlife Reserve is located in the delta of Lena River in the far north of eastern Siberia. ... For other uses, see Mackenzie River (disambiguation). ... Mekong River Delta from space, February 1996 Mekong Delta, February 2005. ... False-color image of the larger Mississippi Delta Closeup of the currently active delta front Mississippi Delta Lobes The Mississippi River Delta is the modern area of land (the river delta) built up by alluvium deposited by the Mississippi River as it slows down and enters the Gulf of Mexico. ... The Niger Inland Delta is a large area of lakes and swamps in Mali, around the bifurcated River Niger and its tributary, the River Bani. ... The Niger Delta, the delta of the Niger River in Nigeria, is a densely populated region sometimes called the Oil Rivers because it was once a major producer of palm oil. ... NASA satellite photograph of the Nile Delta (shown in false colour) The Nile Delta (Arabic:دلتا النيل) is the delta formed in Northern Egypt where the Nile River spreads out and drains into the Mediterranean Sea. ... The Ogooué (or Ogowe) is the principal river of Gabon in west central Africa. ... Elephants in the Okavango Delta seen from the dubious safety of a makoro (small boat). ... The Orinoco Delta, also known as the Deltaic System (Sistema Deltáico), is a vast river delta of the Orinoco River, located in eastern Venezuela. ... View of the delta from space (ISS, 2003) The Paraná Delta is the delta of the Paraná River in Argentina. ... The Peace-Athabasca Delta is a large freshwater, inland delta in northeastern Alberta located where the Peace and Athabasca Rivers join the Slave River. ... Map of Pearl River Delta (details) The Pearl River Delta Region (PRD) in China occupies the low-lying areas alongside the Pearl River estuary where the Pearl river flows into the South China Sea. ... The Rio Grande Valley is an area located in the southernmost tip of Texas. ... For other uses, see Rhine (disambiguation). ... The Meuse (Maas) at Maastricht Meuse near Grave The Meuse (Dutch & German Maas) is a major European river, rising in France and flowing through Belgium and the Netherlands before draining into the North Sea. ... The Scheldt (Dutch: Schelde, French Escaut) is a 350 km[1] long river in northern France, western Belgium and the southwestern part of the Netherlands. ... The San Joaquin-Sacramento Delta. ... Volga Delta and northwestern Caspian Sea Lotus plant—The Volga Delta is the only place in Russia where pelicans, flamingoes, and lotuses may be found. ... Yangtze River Delta The Yangtze River Delta (Chinese 长江三角洲/長江三角洲 chángjiāng sānjiÇŽozhōu) or Yangtze Delta, generally comprises the triangular-shaped territory of Shanghai, southern Jiangsu province and northern Zhejiang province. ... The Yukon Delta is one of the biggest deltas in the world. ...

See also

Wikimedia Commons has media related to:
River deltas

Image File history File links Commons-logo. ... Delta switching, also known as avulsion, is the process by which some rivers--such as the Mississippi River--change their course near their deltas. ... For other meanings, see Estuary (disambiguation) Río de la Plata estuary An estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. ... Mega Delta is a generic term given to the very large Asian river deltas, viz. ... A vast alluvial fan blossoms across the desolate landscape between the Kunlun and Altun mountain ranges that form the southern border of the Taklimakan Desert in China’s XinJiang Province. ...

External links

  • Louisiana State University Geology - World Deltas


  Results from FactBites:
 
River delta - Wikipedia, the free encyclopedia (436 words)
A delta is a triangular shaped landform where the mouth of a river flows into an ocean, sea, desert or lake, building outwards (as a deltaic deposit) from sediment carried by the river and deposited as the water current is dissipated.
Deltaic deposits of larger, heavily-laden rivers are characterised by the river channel dividing into multiple streams (distributaries), these divide and come together again to form a maze of active and inactive channels.
Other rivers with notable deltas include the Ganges/Brahmaputra combination (this delta spans most of Bangladesh and West Bengal), the Niger, the Amazon, the Mississippi, the Sacramento-San Joaquin, the Rhine, the Rhône, the Danube, the Ebro, the Volga, the Lena, the Tigris-Euphrates, the Indus, the Krishna-Godavari, the Kaveri, the Ayeyarwady, and the Mekong.
Encyclopedia4U - River delta - Encyclopedia Article (211 words)
A delta is the mouth of a river where it flows into an ocean, sea, or lake, building outwards (as a deltaic deposit) from sediment carried by the river and deposited as the water current is dissipated.
Deltaic deposits of larger, heavily-ladden rivers are characterised by the river channel dividing into multiple streams (distributaries), these anastomizing (dividing and coming together again) to form a maze of active and inactive channels.
The most famous delta is that of the Nile River, and it is this delta from which the term is derived, because the Nile delta has a very characteristic triangular shape, like the (upper-case) letter delta (Δ).
  More results at FactBites »

 
 

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