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The Ganges Delta (also known as the Sundarbans Delta or the Bengal Delta) is a river delta in the Bengal region of the Indian subcontinent, consisting of Bangladesh and the Indian state of West Bengal. It is the world's largest river delta and it empties into the Bay of Bengal with the combined waters of several river systems, mainly those of the Brahmaputra river and the Ganges river. It is also one of the most fertile regions in the world, thus earning the nickname the Green Delta (Otherwise known as the blue lake). The delta stretches from the Hooghly River east as far as the Meghna River.
The Ganges Delta has the shape of a triangle and is considered to be an "arcuate" (arc-shaped) delta. It covers more than 105,000 km2 (41,000 sq mi), and although the delta lies mostly in Bangladesh and India, rivers from Bhutan, Tibet, India, and Nepal drain into it from the north. Approximately 60% of the delta is in Bangladesh and, 40% in West Bengal, India. Most of the delta is composed of alluvial 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-glacial. Red and red-yellow laterite 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, swamps, lakes, and flood plain sediments (chars). The Gorai-Madhumati River, 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.
Between 125 and 143 million people live on the delta,[ citation needed ] despite risks from floods caused by monsoons, heavy runoff from the melting snows of the Himalayas, and North Indian Ocean tropical cyclones. A large part of the nation of Bangladesh lies in the Ganges Delta, and 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, and approximately 400 million people live in the Ganges River Basin, making it the most populous river basin in the world. Most of the Ganges Delta has a population density of more than 200 people per km2 (520 people per square mile)[ citation needed ], making it one of the most densely populated regions in the world.
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Three terrestrial ecoregions 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 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 130 square kilometres (50 sq mi) of the ecoregion's 14,600 square kilometres (5,600 sq mi) protected. Where the delta meets the Bay of Bengal, Sundarbans mangroves form the world's largest mangrove ecoregion, covering an area of 20,400 square kilometres (7,900 sq mi) 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: sal, teak, and peepal trees are found in these areas. The delta region has mangrove trees.
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 ( Acridotheres tristis ), the swamp francolin (Francolinus gularis), and the doel ( Copsychus saularis ). Two species of dolphin can be found in the delta: the Irrawaddy dolphin (Orcaella brevirostris) and the 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 sundari, garjan ( Rhizophora spp.), bamboo, mangrove palm ( Nypa fruticans ), and mangrove date palm ( Phoenix paludosa ). Many endangered species live here.
The Ganges Delta lies at the junction of three tectonic plates: the Indian Plate, the Eurasian Plate, and the Burma Plate. 400 kilometres (250 mi) seaward since the Eocene. The sediment thickness southeast of the edge of the paleoshelf beneath the Ganges Delta can exceed 16 km (10 miles).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
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 recent years,[ when? ] scientists have been helping 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 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.
The Ganges Delta lies mostly in the tropical wet climate zone, and receives between 1,500 to 2,000 mm (59 to 79 in) of rainfall each year in the western part, and 2,000 to 3,000 mm (79 to 118 in) in the eastern part.[ citation needed ]. Hot, dry summers and cool, dry winters make the climate suitable for agriculture.
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.
Another cyclone hit the delta in 1991, killing about 139,000 people.
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.
The history of the Bengal delta has been a concern of emerging scholarship by environmental historians.
Vinita Damodaran has extensively profiled famine management practices by the British colonial administration, 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 century.
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 century, and there is a general dearth of ecological history of the region prior to the 18th century.
One of the greatest challenges people living on the Ganges Delta may face in coming years is the threat of rising sea levels caused by climate change. An increase in sea level of 0.5 metres (1 ft 8 in) 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.
The Ganges Brahmaputra Delta lies at the junction of three plates: the Indian Plate, the Eurasian Plate and the Burma Platelet.
The edge of the pre-delta Eocene paleoshelf is marked by the shallow-water Sylhet Limestone, which runs NNE from near Calcutta to the edge of the Shillong Plateau ... The Sylhet Limestone drops ... indicating the presence of thick continental crust. East of the hinge zone the great thickness of sediments indicates that the crust is greatly thinned or oceanic ... The enormous supply of sediments provided by the Himalayan collision fed the [Ganges-Brahmaputra Delta (GBD)] and has produced ~400 km of progradation of the shelf edge since the Eocene ... Total sediment thickness beneath the GBD southeast of the hinge zone exceeds 16 km.
In Bangladesh, scientists are turning unused ponds into viable fish farms and improving fish raising in the existing ones. The project has led to a new way for the rural poor to earn an income ... Using new systems developed through research, fish production in existing ponds has increased eightfold.
The Ganges, or Ganga, is a trans-boundary river of Asia which flows through India and Bangladesh. The 2,601 km (1,616 mi) river originates from the Gangotri Glacier of western Himalayas in the Indian state of Uttarakhand, and flows south and east through the Gangetic Plain of India and Bangladesh, eventually emptying into the Bay of Bengal.
India lies on the Indian Plate, the northern part of the Indo-Australian Plate, whose continental crust forms the Indian subcontinent. The country is situated north of the equator between 8°4' north to 37°6' north latitude and 68°7' to 97°25' east longitude. It is the seventh-largest country in the world, with a total area of 3,287,263 square kilometres (1,269,219 sq mi). India measures 3,214 km (1,997 mi) from north to south and 2,933 km (1,822 mi) from east to west. It has a land frontier of 15,200 km (9,445 mi) and a coastline of 7,516.6 km (4,671 mi).
The Bay of Bengal is the northeastern part of the Indian Ocean, bounded on the west and northwest by India, on the north by Bangladesh, and on the east by Myanmar and the Andaman Islands of India and Myanmar and the Nicobar Islands of India. Its southern limit is a line between Sangaman Kanda, Sri Lanka and the north westernmost point of Sumatra (Indonesia). It is the largest water region called a bay in the world. There are countries dependent on the Bay of Bengal in South Asia and Southeast Asia.
Bangladesh is a densely-populated, low-lying, mainly riverine country located in South Asia with a coastline of 580 km (360 mi) on the northern littoral of the Bay of Bengal. The delta plain of the Ganges (Padma), Brahmaputra (Jamuna), and Meghna Rivers and their tributaries occupy 79 percent of the country. Four uplifted blocks occupy 9 percent, and steep hill ranges up to approximately 1,000 metres (3,300 ft) high occupy 12 percent in the southeast and in the northeast. Straddling the Tropic of Cancer, Bangladesh has a tropical monsoon climate characterised by heavy seasonal rainfall, high temperatures, and high humidity. Natural disasters such as floods and cyclones accompanied by storm surges periodically affect the country. Most of the country is intensively farmed, with rice the main crop, grown in three seasons. Rapid urbanisation is taking place with associated industrial and commercial development. Exports of garments and shrimp plus remittances from Bangladeshis working abroad provide the country's three main sources of foreign exchange income.
The Brahmaputra, called Yarlung Tsangpo in Tibet, Siang/Dihang River in Arunachal Pradesh and Luit or Dilao in Assam, is a trans-boundary river which flows through China, India and Bangladesh. It is the ninth largest river in the world by discharge, and the 15th longest.
The Indo-Gangetic Plain, also known as the Indus-Ganga Plain and the North Indian River Plain, is a 630-million-acre (2.5-million km2) fertile plain encompassing northern regions of the Indian subcontinent, including most of northern and eastern India, the eastern parts of Pakistan, virtually all of Bangladesh and southern plains of Nepal. The region is named after the Indus and the Ganges rivers and encompasses a number of large urban areas. The plain is bound on the north by the Himalayas, which feed its numerous rivers and are the source of the fertile alluvium deposited across the region by the two river systems. The southern edge of the plain is marked by the Chota Nagpur Plateau. On the west rises the Iranian Plateau.
Khulna Division is one of the eight divisions of Bangladesh. It has an area of 22,285 km2 (8,604 sq mi) and a population of 15,563,000 at the 2011 Census. Its headquarters & Largest city is Khulna city in Khulna District.
The Sundarbans National Park is a national park, tiger reserve, and biosphere reserve in West Bengal, India. It is part of the Sundarbans on the Ganges Delta, and adjacent to the Sundarban Reserve Forest in Bangladesh. The delta is densely covered by mangrove forests, and is one of the largest reserves for the Bengal tiger. It is also home to a variety of bird, reptile and invertebrate species, including the salt-water crocodile. The present Sundarban National Park was declared as the core area of Sundarban Tiger Reserve in 1973 and a wildlife sanctuary in 1977. On 4 May 1984 it was declared a national park. It is a UNESCO World Heritage Site inscribed in 1987, and it has been designated as a Ramsar site since 2019. It is considered as a World Network of Biosphere Reserve from 1989.
The Sundarbans is a mangrove area in the delta formed by the confluence of the Ganges, Brahmaputra and Meghna Rivers in the Bay of Bengal. It spans from the Hooghly River in India's state of West Bengal to the Baleswar River in Bangladesh. It comprises closed and open mangrove forests, agriculturally used land, mudflats and barren land, and is intersected by multiple tidal streams and channels. Four protected areas in the Sundarbans are enlisted as UNESCO World Heritage Sites namely Sundarbans National Park, Sundarbans West, Sundarbans South and Sundarbans East Wildlife Sanctuaries. The Sundarbans mangrove forest covers an area of about 10,000 km2 (3,900 sq mi), of which forests in Bangladesh's Khulna Division extend over 6,017 km2 (2,323 sq mi) and in West Bengal, they extend over 4,260 km2 (1,640 sq mi) across the South 24 Parganas and North 24 Parganas districts. The most abundant tree species are sundri and gewa. The forests provide habitat to 453 faunal wildlife, including 290 bird, 120 fish, 42 mammal, 35 reptile and eight amphibian species.
The Bengal Fan, also known as the Ganges Fan, is the largest submarine fan on Earth. The fan is about 3,000 km (1,900 mi) long, 1,430 km (890 mi) wide with a maximum thickness of 16.5 km (10.3 mi). The fan resulted from the uplift and erosion of the Himalayas and the Tibetan Plateau produced by the collision between the Indian Plate and the Eurasian Plate. Most of the sediment is supplied by the Ganges and Brahmaputra rivers which supply the Lower Meghna delta in Bangladesh and the Hoogly delta in West Bengal (India). Several other large rivers in Bangladesh and India provide smaller contributions. Turbidity currents have transported the sediment through a series of submarine canyons, some of which are more than 1,500 miles (2,414 km) in length, to be deposited in the Bay of Bengal up to 30 degrees latitude from where it began. To date, the oldest sediments recovered from the Bengal fan are from Early Miocene age. Their mineralogical and geochemical characteristics allow to identify their Himalayan origin and demonstrate that the Himalaya was already a major mountain range 20 million years ago.
The Baleshwari River is located in Bangladesh, forming part of the eastern border of Bagerhat District and the western border of Barguna District. It borders on the east the largest mangrove forest in the world, in the Ganges-Brahmaputra delta, the Bangladesh part of which is set aside as the Sundarbans Reserve Forest. The Baleshwar River flows south into the Haringhata River, which flows into the Bay of Bengal.
The Lower Gangetic plains moist deciduous forests, or ecoregion IM0120, is a tropical moist deciduous forest ecoregion of Bangladesh and India. The ecoregion covers an area of 254,100 square kilometres (98,100 sq mi), comprising most of Bangladesh and the Indian states of West Bengal, Bihar and Tripura, and extending into adjacent states of Orissa, Uttar Pradesh and a tiny part of Assam.
Geography of West Bengal, a state in eastern India, is diverse, of high peaks of Himalaya in the northern extremes to where Himalayas are in the north and sea is at the south, with both plains and plateaus covering the remaining region.
Lohachara Island was an islet which was permanently flooded in the 1980s. It was located in the Hooghly River as part of the Sundarban delta in the Sundarban National Park, located near the Indian state of West Bengal. The definite disappearance of the island was reported by Indian researchers in December 2006, which led to international press coverage. No specific study was ever done to prove that the island was permanently inundated because of sea level rise.
Sundarbans usually refers to the Sundarbans freshwater swamp forests, the term applying generally to a tropical moist broadleaf forest ecoregion of India and Bangladesh. It may specifically refer to:
Sundarbans East Wildlife Sanctuary, a protected forest in Bangladesh, extends over an area of 31,227 ha. of mangrove forest. It was established in 1977 under the Bangladesh Wildlife (Preservation) (Amendment) Act, 1974, having previously been a forest reserve. It is the most fertile of the three, non-adjoining wildlife sanctuaries established in the Sundarbans at that time, the others being the Sundarbans West Wildlife Sanctuary and the Sundarbans South Wildlife Sanctuary. The dominant mangrove species is "sundri" from which the Sundarbans region gets its name.
Sundarbans West Wildlife Sanctuary is a UNESCO World Heritage Site and animal sanctuary in Bangladesh. The area of the reserve covers 715 km2. It is part of the larger Sundarbans region, one of the largest mangroveforests in the world. It is formed at the unified delta of the Ganges, Brahmaputra and Meghna rivers on the Bay of Bengal. The total area of the entire Sundarbans is about one million ha, 60% of which is found in Bangladesh, with the remainder in India. The region is divided by the Raimangal River. Within the Bangladeshi area of Sundarbans, there are three wildlife sanctuaries: Sundarbans East, Sundarbans South, and Sundarbans West.
The 2014 Sundarbans oil spill was an oil spill that occurred on 9 December 2014 at the Shela River in Sundarbans, Bangladesh, a UNESCO World Heritage site. The spill occurred when an oil-tanker named Southern Star VII, carrying 350,000 litres of furnace oil, was in collision with a cargo vessel and sank in the river. By December 17, the oil had spread over a 350 km2 (140 sq mi) area. The oil spread to a second river and a network of canals in Sundarbans, which blackened the shoreline. The spill threatened trees, plankton, and vast populations of small fish and dolphins. The spill occurred at a protected mangrove area, home to rare Irrawaddy and Ganges dolphins. By 12 January 2015, 70,000 litres of oil had been cleaned up by local residents, the Bangladesh Navy, and the government of Bangladesh.
Top dying disease is a disease that affects Heritiera fomes, a species of mangrove tree known as "sundri", a characteristic tree of the estuarine complex of the Ganges–Brahmaputra Delta in Bangladesh and West Bengal. Although an increase in certain trace elements in the sediment deposited where these trees grow may be a factor in the incidence of the disease, its cause has not been fully established.
Environmental impact of development in the Sundarbans, is the study of environmental impact on Sundarban, the largest single tract mangrove forest. It consist of a geographical area of 9,629 square kilometres (3,718 sq mi), including 4,185 square kilometres (1,616 sq mi) of reserve forest land, and is a natural region located partly in southern Bangladesh and partly in the Indian state of West Bengal. It is ecologically a southern part of the Gangetic delta between the Hooghly river in India on the west and the Meghna river in Bangladesh on the east and is bounded by the Ganga-Padma, the Padma-Meghna on the north and by the Bay of Bengal on the south. The area that is not reserve forest land is inhabited by human settlements with a total population around 4 million (2003).
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