Ganges-Brahmaputra delta
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The Ganges Delta (also known as the Sundarbans Delta or the Bengal Delta) is a
river delta A river delta is a landform A landform is a natural or artificial feature of the solid surface of the Earth or other planetary body A planet is an astronomical body Astronomy (from el, ἀστρονομία, literally meaning the ...

river delta
in the
Bengal Bengal (; Bengali language, Bengali: ', ) is a geopolitical, cultural and historical region in South Asia, specifically in the eastern part of the Indian subcontinent at the apex of the Bay of Bengal, predominantly covering present-day Bang ...

Bengal
region of
South Asia South Asia is the southern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere, Eastern and Northern Hemisphere, Northern Hemisphere of the Earth, Hemispheres. It shares the ...

South Asia
, consisting of
Bangladesh Bangladesh (, bn, , ), officially the People's Republic of Bangladesh, is a country in . It is the in the world, with a population exceeding 163 million people, in an area of , making it one of the in the world. Bangladesh shares land bor ...

Bangladesh
and the Indian state of
West Bengal West Bengal (, Bengali Bengali or Bengalee, or Bengalese may refer to: *something of, from, or related to Bengal, a large region in South Asia * Bengalis, an ethnic and linguistic group of the region * Bengali language, the language they spe ...

West Bengal
. It is the world's largest river delta and it empties into the
Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or 19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to th ...

Bay of Bengal
with the combined waters of several
river system In geomorphology, drainage systems, also known as river systems, are the patterns formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by the topography of land, whether a particular region is dominated by hard ...
s, mainly those of the
Brahmaputra river The Brahmaputra (), called Yarlung Tsangpo The Yarlung Tsangpo, also called Yarlung Zangbo () or Yalu Zangbu () is the upper stream of the Brahmaputra River The Brahmaputra (), called Yarlung Tsangpo in Tibet, Siang/Dihang River in Aruna ...

Brahmaputra river
and the
Ganges river The Ganges ( ) or Ganga ( , ) is a trans-boundary river of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere, Eastern and Northern Hemisphere, Northern Hemisphere of the Earth, He ...

Ganges river
. It is also one of the most fertile regions in the world, thus earning the nickname the ''Green Delta''. The delta stretches from the
Hooghly River The Hooghly River (''Hugli''; Anglicized alternatively spelled ''Hoogli'' or ''Hugli'') or the Bhāgirathi-Hooghly, called the 'Ganga' or the 'Kati-Ganga' in mythological texts, is the eastern distributary of the Ganges River in West Bengal, In ...

Hooghly River
east as far as the
Meghna River The Meghna River ( bn, মেঘনা নদী) is one of the major rivers in Bangladesh, one of the three that form the Ganges Delta, the largest delta on earth, which fans out to the Bay of Bengal. A part of the Surma-Meghna River System, Me ...

Meghna River
.


Geography

The Ganges Delta has the shape of a triangle and is considered to be an "arcuate" (arc-shaped) delta. It covers more than and, although the delta lies mostly in Bangladesh and India, rivers from
Bhutan Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul, ), officially known as the Kingdom of Bhutan ( dz, འབྲུག་རྒྱལ་ཁབ་, Druk Gyal Khap), is a landlocked country in the Eastern Himalayas. It is bordered by Ch ...

Bhutan
, Tibet, India, and
Nepal Nepal (; ne, :ne:नेपाल, नेपाल ), officially the Federal Democratic Republic of Nepal ( ne, सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in S ...

Nepal
drain into it from the north. Approximately 60% of the delta is in
Bangladesh Bangladesh (, bn, , ), officially the People's Republic of Bangladesh, is a country in . It is the in the world, with a population exceeding 163 million people, in an area of , making it one of the in the world. Bangladesh shares land bor ...

Bangladesh
and 40% in
West Bengal West Bengal (, Bengali Bengali or Bengalee, or Bengalese may refer to: *something of, from, or related to Bengal, a large region in South Asia * Bengalis, an ethnic and linguistic group of the region * Bengali language, the language they spe ...

West Bengal
,
India India, officially the Republic of India (: ), is a country in . It is the by area, the country, and the most populous in the world. Bounded by the on the south, the on the southwest, and the on the southeast, it shares land borders wit ...

India
. Most of the delta is composed of
alluvial Alluvium (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of t ...
soils made up by small sediment particles that finally settle down as river currents slow down in the estuary. Rivers carry these fine particles with them, even from their sources at glaciers as
fluvio-glacialFluvio refers to things related to rivers and glacial refers to something that is of ice. Fluvio-glacial refers to the meltwater Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves ...
. Red and red-yellow
laterite Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by int ...
soils are found as one heads farther east. The soil has large amounts of minerals and nutrients, which is good for agriculture. It is composed of a labyrinth of
channels Channel, channels, channeling, etc., may refer to: Geography * Channel (geography), in physical geography, a landform consisting of the outline (banks) of the path of a narrow body of water. Australia * Channel Country, region of outback Austr ...
,
swamp A swamp is a forested wetland A wetland is a distinct ecosystem that is flooded by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (Anoxic waters, anoxic) processes preva ...

swamp
s, lakes, and flood plain sediments (chars). The
Gorai-Madhumati River The Gorai-Madhumati River ( bn, গড়াই-মধুমতি ''Gôŗai-Modhumoti'') is one of the longest rivers in Bangladesh and a distributary of the Ganges. In the upper reaches it is called the Gorai, and the name changes to Madhumati ...
, one of the distributaries of the Ganges, divides the Ganges Delta into two parts: the geologically young, active, eastern delta, and the older, less active, western delta.


Population

Between 125 and 143 million people live on the delta, despite risks from floods caused by
monsoons A monsoon () is traditionally a seasonal reversing wind Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. Winds are commonly classified by their scale (spatial), spatial scal ...
, heavy run-off from the melting snows of the
Himalayas The Himalayas, or Himalaya (; Sanskrit Sanskrit (, attributively , ''saṃskṛta-'', nominalization, nominally , ''saṃskṛtam'') is a classical language of South Asia belonging to the Indo-Aryan languages, Indo-Aryan branch of the Ind ...

Himalayas
, and
North Indian Ocean tropical cyclone In the Indian Ocean The Indian Ocean is the third-largest of the world's oceanic divisions, covering or 19.8% of the water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, ...
s. A large part of the nation of
Bangladesh Bangladesh (, bn, , ), officially the People's Republic of Bangladesh, is a country in . It is the in the world, with a population exceeding 163 million people, in an area of , making it one of the in the world. Bangladesh shares land bor ...

Bangladesh
lies in the Ganges Delta; many of the country's people depend on the delta for survival. It is believed that upwards of 300 million people are supported by the Ganges Delta; approximately 400 million people live in the
Ganges River The Ganges ( ) or Ganga ( , ) is a trans-boundary river of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere, Eastern and Northern Hemisphere, Northern Hemisphere of the Earth, He ...

Ganges River
Basin, making it the most populous river basin in the world. Most of the Ganges Delta has a population density greater than 200/km2 (520 people per square mile), making it one of the most densely populated regions in the world.


Wildlife

Three
terrestrial ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion A bioregion is an ecology, ecologically and geographically defined area that is smaller than a b ...
s cover the delta. The Lower Gangetic plains moist deciduous forests ecoregion covers most of the delta region, although the forests have mostly been cleared for agriculture and only small enclaves remain. Thick stands of tall grass, known as canebrakes, grow in wetter areas. The
Sundarbans freshwater swamp forests The Sundarbans is a mangrove area in Ganges Delta, the delta formed by the confluence of the Ganges, Brahmaputra River, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans from the Hooghly River in India's state of West Bengal to the Bal ...
ecoregion lies closer to the Bay of Bengal; this ecoregion is flooded with slightly brackish water during the dry season, and fresh water during the monsoon season. These forests, too, have been almost completely converted to intensive agriculture, with only of the protected. Where the delta meets the Bay of Bengal, Sundarbans mangroves form the world's largest mangrove ecoregion, covering an area of in a chain of 54 islands. They derive their name from the predominant mangrove species, ''Heritiera fomes'', which are known locally as ''sundri'' or ''sundari''. Animals in the delta include the Indian python (''Python molurus''), clouded leopard (''Neofelis nebulosa''), Indian elephant (''Elephas maximus indicus'') and crocodiles, which live in the Sundarbans. Approximately 1,020 endangered Bengal tigers (''Panthera tigris tigris'') are believed to inhabit the Sundarbans. The Ganges–Brahmaputra basin has tropical deciduous forests that yield valuable timber: Shorea robusta, sal, teak, and peepal trees are found in these areas. It is estimated that 30,000 chital (''Axis axis'') are in the Sundarbans part of the delta. Birds found in the delta include kingfishers, eagles, woodpeckers, the shalik (''common myna, Acridotheres tristis''), the swamp francolin (''Francolinus gularis''), and the doel (''Oriental magpie robin, Copsychus saularis''). Two species of dolphin can be found in the delta: the Irrawaddy dolphin (''Orcaella brevirostris'') and the Ganges and Indus river dolphin, Ganges river dolphin (''Platanista gangetica gangetica''). The Irrawaddy dolphin is an oceanic dolphin which enters the delta from the Bay of Bengal. The Ganges river dolphin is a true river dolphin, but is extremely rare and considered endangered. Trees found in the delta include Heritiera littoralis, sundari, garjan (''Rhizophora'' spp.), bamboo, mangrove palm (''Nypa fruticans''), and mangrove date palm (''Phoenix paludosa'').


Geology

The Ganges Delta lies at the junction of three tectonic plates: the Indian Plate, the Eurasian Plate, and the Burma Plate. The edge of the Eocene paleoshelf runs approximately from Kolkata to the edge of the Shillong Plateau. The edge of the paleoshelf marks the transition from the thick continental crust in the northwest to the thin continental or oceanic crust in the southeast. The enormous sediment supply from the Himalayan collision has extended the delta about seaward since the Eocene. The sediment thickness southeast of the edge of the paleoshelf beneath the Ganges Delta can exceed 16 km (10 miles).


Economy

Approximately two-thirds of the Bangladesh people work in agriculture and grow crops on the fertile floodplains of the delta. The major crops that are grown in the Ganges Delta are jute, tea, and rice. Fishing is also an important activity in the delta region, with fish being a major source of food for many of the people in the area. In the last decades of the 20th century, scientists helped the poor people of the delta to improve fish farming methods. By turning unused ponds into viable fish farms and improving methods of raising fish in existing ponds, many people can now earn a living raising and selling fish. Using new systems, fish production in existing ponds has increased 800%. Shrimp are farmed in containers or cages that are submerged in open water. Most are exported. As there is a maze of many river branches, the area is difficult to pass. Most islands are only connected with the mainland by simple wooden ferryboats. Bridges are rare. Some islands are not yet connected to the electric grid, so island residents tend to use solar cells for a bit of electric supply.


Arsenic pollution

Arsenic is a naturally occurring substance in the Ganga Delta that has detrimental effects on health and may enter the food chain, especially in key crops such as rice.


Climate

The Ganges Delta lies mostly in the tropical wet climate zone, and receives between of rainfall each year in the western part, and in the eastern part.. Hot, dry summers and cool, dry winters make the climate suitable for agriculture.


Cyclones and flooding

In November 1970, the deadliest tropical cyclone of the twentieth century hit the Ganges Delta region. The 1970 Bhola cyclone killed 500,000 people (official death toll), with another 100,000 missing. The Guinness Book of World Records estimated the total loss of human life from the Bhola cyclone at 1,000,000. 1991 Bangladesh Cyclone, Another cyclone hit the delta in 1991, killing about 139,000 people. It also left many people homeless. People have to be careful on the river delta as severe flooding also occurs. In 1998, the Ganges flooded the delta, killing about 1,000 people and leaving more than 30 million people homeless. The Bangladesh government asked for $900 million to help feed the people of the region, as the entire rice crop was lost.


History of the Bengal Delta

The history of the Bengal delta has been a concern of emerging scholarship by environmental historians. Indian historian Vinita Damodaran has extensively profiled famine management practices by the East India Company, and related these practices to major ecological changes wrought about by forest and land management practices. Debjani Bhattacharyya has shown how Calcutta was constructed as an urban centre through tracing ecological changes wrought upon by colonial powers involving land, water and humans throughout the mid-18th to the early 20th centuries. In terms of recent scholarship that focuses more on the eastern part of the Bengal/Ganges Delta, Iftekhar Iqbal argues for the inclusion of the Bengal Delta as an ecological framework within which to study the dynamics of agrarian prosperity or decline, communal conflicts, poverty and famine, especially throughout the colonial period. Iqbal has tried to show how resistance movements such as the Faraizi movement can be studied in relation to colonial ecological management practices. A strong criticism of environmental history scholarship with regards to the Bengal/Ganges delta is that most of the scholarship is limited to the 18th to the 21st centuries, with a general dearth of ecological history of the region prior to the 18th century.


Future of the delta

One of the greatest challenges people living on the Ganges Delta may face in coming years is the threat of current sea level rise, rising sea levels caused by climate change. An increase in sea level of could result in six million people losing their homes in Bangladesh. Important gas reserves have been discovered in the delta, such as in the Titas and Bakhrabad gas fields. Several major oil companies have invested in exploration of the Ganges Delta region.


Tidal river management

To offset land loss, Sedimentation enhancing strategies, tidal river management has been implemented in the delta. This method has been implemented in 5 beels and resulted in benefits including decreased Waterlogging (agriculture), waterlogging, creation of Agricultural land, agricultural areas, improved navigation and land creation.


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See also

*Doab *Gangotri *Gangetic Plain *Indian Subcontinent *
Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or 19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to th ...

Bay of Bengal
*Bengal Tiger


Notes


References

* * * *


External links

* The Golden Fibre Trade Centre
Ganges Delta: Most Fertile Land for Growing Raw Jute
* {{Authority control Ganges, . Ganges basin River deltas of Asia Bay of Bengal Landforms of Bangladesh Landforms of India Landforms of West Bengal Environment of Bangladesh Environment of West Bengal Sundarbans Regions of West Bengal Regions of India