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A () is a
wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
ecosystem An ecosystem (or ecological system) is a system formed by Organism, organisms in interaction with their Biophysical environment, environment. The Biotic material, biotic and abiotic components are linked together through nutrient cycles and en ...
in the north eastern part of
Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...
which physically is a bowl or saucer shaped shallow depression, also known as a backswamp.MK Alam; ''Wave attack in Haor areas of Bangladesh and cement concrete blocks as structural revetment material''; ''Progress in Structural Engineering, Mechanics and Computation: Proceedings'' (ed. Alphose Zingoni); page 325; Taylor & Francis; 2004; ''Bio-ecological Zones of Bangladesh'';
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
and Natural Resources, Bangladesh Country Office; page 31; The World Conservation Union (IUCN); 2002;
Bangladesh & Desertification
, Sustainable Development Networking Programme (SDNP), Bangladesh; ''Retrieved: 2007-12-04''
During
monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...
s receive
surface runoff Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other ...
water from rivers and canals to become vast stretches of turbulent water.


In Bangladesh and in the deltaic part of the Indian state of West Bengal, which lie in the floodplain of three great rivers, the Bengali language has several terms to differentiate between lakes, including , , and ., Official website of

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
in Bangladesh; ''Retrieved: 2007-12-03'' All four are similar types of freshwater wetlands. The distinctions among a , or are usually small. A is usually a depression or topographic low generally produced by erosion or other geographical process. These are marshy in character. Sometimes are remains of a river that has changed its course. Many of the dry up in the winter but during the rains expand into broad and shallow sheets of water, which may be described as fresh water lagoons. are generally smaller than , but there also are large like Chalan Beel in
Rajshahi Division Rajshahi Division () is one of the eight first-level administrative divisions of Bangladesh. It has an area of and a population at the 2022 Census of 20,353,119. Rajshahi Division consists of 8 districts, 70 upazilas (the next lower administrat ...
, through which the Atrai River passes. It has shrunk over the years but still occupies an area of 26 km2 in the dry season. Sometimes small permanent water bodies within the remain after the dry up. These are also called , which occupy the lowest part of the depressions. A or is an
oxbow lake An oxbow lake is a U-shaped lake or stream pool, pool that forms when a wide meander of a river is meander cutoff, cut off, creating a free-standing body of water. The word "oxbow" can also refer to a U-shaped bend in a river or stream, whether ...
, namely moribund beds of the Bhairab, Kaliganga, Gorai and Kumar rivers. A simple definition was provided by hydrologist Saila Parveen, " – seasonal wetland, – oxbow lake, and – perennial water body." or are found mostly in the moribund delta as in greater Comilla, Faridpur,
Dhaka Dhaka ( or ; , ), List of renamed places in Bangladesh, formerly known as Dacca, is the capital city, capital and list of cities and towns in Bangladesh, largest city of Bangladesh. It is one of the list of largest cities, largest and list o ...
and
Pabna Pabna () is a city of Pabna District, Bangladesh and the administrative capital of the eponymous Pabna District. It is on the north bank of the Padma River and has a population of about . Etymology * According to the historian Radharaman Saha ...
districts. The is predominantly a feature of north-eastern Bangladesh. are seen all over Bangladesh and the neighboring districts of West Bengal.


Geography and geology

In a country where one third of all area can be termed as wetlands, the basin is an internationally important wetland ecosystem, spread over Sunamganj, Habiganj, Moulvibazar districts and Sylhet Sadar Upazila, as well as Kishoreganj and Netrokona districts outside the core area. It is a mosaic of wetland habitats, including rivers, streams and irrigation canals, large areas of seasonally flooded cultivated plains, and hundreds of and . This zone contains about 400 and , varying in size from a few hectares to several thousand hectares.Khokon, Leaquat Hossain, ''64 Jela Bhraman'', 2007, p. 79, Anindya Prokash, Dhaka, . The core area, alternatively referred to as the Haor basin or the Sylhet basin, is estimated to spread over an area between 4,450 km2 and 25,000 square kilometres''Communities and forest management in South Asia''; page 32; The World Conservation Union (IUCN); by experts. The total area of -type wetland ecosystem in Bangladesh is 80,000 square kilometres. The basin is bounded by the hill ranges of India –
Meghalaya Meghalaya (; "the abode of clouds") is a states and union territories of India, state in northeast India. Its capital is Shillong. Meghalaya was formed on 21 January 1972 by carving out two districts from the Assam: the United Khasi Hills an ...
on the north,
Tripura Tripura () is a States and union territories of India, state in northeastern India. The List of states and union territories of India by area, third-smallest state in the country, it covers ; and the seventh-least populous state with a populat ...
and
Mizoram Mizoram is a states and union territories of India, state in northeastern India, with Aizawl as its Capital city, capital and largest city. It shares 722-kilometres (449 miles) of international borders with Bangladesh to the west, and Myanmar t ...
on the south, and
Assam Assam (, , ) is a state in Northeast India, northeastern India, south of the eastern Himalayas along the Brahmaputra Valley, Brahmaputra and Barak River valleys. Assam covers an area of . It is the second largest state in Northeast India, nor ...
and
Manipur Manipur () is a state in northeastern India with Imphal as its capital. It borders the Indian states of Assam to the west, Mizoram to the south, and Nagaland to the north and shares the international border with Myanmar, specifically t ...
on the east. The basin extends north to the foot of the Garo and Khasia Hills, and east along the upper Surma Valley to the Indian border. The Tippera surface lies directly to the south of the Haor Basin, and is partly low and deltaic and partly higher ground with a piedmont fringe to the east. It includes about 47 major and some 6,300 of varying size, of which about 3,500 are permanent and 2,800 are seasonal. These area is low because of
subsidence Subsidence is a general term for downward vertical movement of the Earth's surface, which can be caused by both natural processes and human activities. Subsidence involves little or no horizontal movement, which distinguishes it from slope mov ...
of tectonic Dauki fault. In the geological depression of the basin, subsidence is continuing at an estimated rate of 20 mm per year. In some places it has sunk by around 10 m in the last few hundred years. The area, by some experts, is further divided into three zones by standards of morphology and
hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydro ...
:


Climate and floods

The basin is a remote and difficult area that is flooded every year during
monsoon A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in Atmosphere of Earth, atmospheric circulation and precipitation associated with annu ...
. Some of the most extensive seasonally flooded areas in South Asia are situated in bowl-shaped depressions known as located between the natural levees of rivers subject to overflow during the monsoon. The major rivers in the area are Surma and Kushiyara. Some of the tributaries are: Manu, Khowai, Jadukhata, Piyain, Mogra, Mahadao and Kangsha. The hilly rivers coming down from the Khasi and Jaintia hills in Meghalaya carry particularly high volumes of water as they come from some of the rainiest places in the world. During July to November due to flood these areas go under deep water and look like seas with erosive water surface. During wind storm these waves reach up to 1.5 m in height. It remains under water for seven months of the year, turning settlements mostly built on earthen mounds into islands. The fight against natural calamity of the locals people, mostly day laborers, relies on traditional and indigenous methods which with limited effect. Many villages have already been washed away, and many more are on the verge of extinction, forcing people to migrate to urban centers.


Flora

The Haor Basin is the only region in Bangladesh where remnant patches of freshwater
swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s and reed lands still exists. Once extensive forests of Hijal in the area used to provide an important source of firewood, but these forests are now almost completely destroyed. In recent times, various herbs and aquatic plants are being collected for use as fuel. On top of that, aquatic plants are also being collected for use as fertilizers. Only a few patches remain of the swamp forests that once dominated the area, featuring flood tolerant trees like Hijal ('' Barringtonia acutangula'') and Koroch ('' Pongamia pinnata'').
Joseph Dalton Hooker Sir Joseph Dalton Hooker (30 June 1817 – 10 December 1911) was a British botanist and explorer in the 19th century. He was a founder of geographical botany and Charles Darwin's closest friend. For 20 years he served as director of the Ro ...
(1817–1911) did the original survey of local flora sometime in 1850, recorded in his ''Himalayan Journals'' (published by the
Calcutta Kolkata, also known as Calcutta (List of renamed places in India#West Bengal, its official name until 2001), is the capital and largest city of the Indian States and union territories of India, state of West Bengal. It lies on the eastern ba ...
Trigonometrical Survey Office and The Minerva Library of Famous Books; Ward, Lock, Bowden & Co., 1891). The findings of his travels along the Surma and visiting the wetlands of Sylhet are reflected in his ''Flora of British India''. Three habitat types in the Sylhet region were identified on the basis of botanical records of Kanjilal (U.N. Kanjilal, P.C. Kanjilal & A. Das; ''Flora of Assam''; 1934): Upland vegetation, Emergent vegetation, and Aquatic vegetation. The hijal or hual, korij or koroch, bhui dumur (''
Ficus heterophylla ''Ficus heterophylla'' is a fig plant species, in the family Moraceae, which can be found in India, southern China, Indo-China and western Malesia Malesia is a biogeographical region straddling the Equator and the boundaries of the Indomal ...
''), nol ('' Arundo donax''), khagra ('' Pharagmites karka''), ban golap ('' Rosa involucratia'') and barun ('' Crataeva nurvala'') are the main plant species found in the swamp forests. All of them are flood-tolerant species and can survive in the submerged condition for extended periods of time. However, among these, hijal, tamal and koroj trees are of the greatest value to the people and the environment. Other plant species available in the wetlands include madar ('' Erythrina variegata''), gab ('' Diospyros peregrina''), makna (''
Euryale ferox ''Euryale ferox'', commonly known as prickly waterlily, makhana, or Gorgon plant, is a species of water lily found in southern and eastern Asia, and the only extant member of the genus ''Euryale''. The edible seeds, called fox nuts or ''makhana' ...
''), singara ('' Trapa bispinosa''), jaldumur (a kind of ''
Ficus ''Ficus'' ( or ) is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphytes in the family (biology), family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few spe ...
''), chitki ('' Phyllanthus reticulatus''), thankuni ('' Centella asiatica''), kalmi (''
Ipomoea aquatica ''Ipomoea aquatica'', commonly known as water spinach or kangkung, is a semi- aquatic, tropical plant grown as a vegetable for its tender shoots. ''I. aquatica'' is generally believed to have been first domesticated in Southeast Asia. It is wi ...
''), helencha ('' Enhydra flactuans''), hogla ('' Typha elephantina''), duckweed,
water hyacinth ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth, is an aquatic plant native to South America, naturalized throughout the world, and often invasive species, invasive outside its native rang ...
, lotus and water lily.


Conservation

Three zones of international importance for conservation and sustainable utilization - the Meghna estuary, and Hail- - have been declared as Ramsar sites under the
Ramsar Convention The Ramsar Convention on Wetlands of International Importance Especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of Ramsar site, Ramsar sites (wetlands). It is also known as the Convention on We ...
for protection of wetlands, of which Bangladesh is a signatory. The Bangladesh government has also declared the Tanguar an Ecologically Critical Area. The Haor basin has a number of government bodies working to preserve the environment, including the Forest Resources Management Project, Management of Aquatic Ecosystem through Community Husbandry, Haor and Floodplain Resource, Conservation and Management of Medicinal Plants and Coastal and Wetland Biodiversity Management at Cox's Bazar and Hakaluki Haor.


Human habitation

Prior to the 12th century there is almost no information available on the human habitation here. The information up to the 17th century is sketchy. During the British period, this area was not stringently surveyed, and not a lot of information is available. It is believed that the early settlers of the area were Hindus and other ethnic groups including Garo, Hajong, Khasi and Koch people coming down from the hills to the north. They were drawn to the area because of its productivity and favorable tenurial terms. With the expansion of Muslim power in the south and the west further Hindu migration continued in the 13th and 14th century. Following an Afghan defeat in Orissa in 1592, a large number of Afghans moved into the area. Expansion of Muslim population continued after the Muslim conquest of Sylhet in 1612, accelerating after the British conquest of Sylhet in 1765. By the 1770s all the cultivable land was brought under plough cultivation. From the 1780s, population and area under cultivation declined till early 20th century, mostly due to successive natural calamities including floods and earthquakes. The basin became an important fishing zone during this time. Population growth picked up again in the 20th century, again due to the opportunity to cultivate land for a nominal rent. In the region, villages are tightly nucleated and built on the natural
levee A levee ( or ), dike (American English), dyke (British English; see American and British English spelling differences#Miscellaneous spelling differences, spelling differences), embankment, floodbank, or stop bank is an elevated ridge, natural ...
s (locally known as ''kanda''s). The villages are very large in size because no settlement can take place beyond the levees. During the dry cropping season, the satellite villages are established deep inside beds, far from parent villages. After harvesting and before inundation, the village structures are dismantled and transported back to parent villages along with harvests.


Economy

These and support major subsistence and commercial fisheries, while the seasonally flooded lake margins support major rice-growing activities. The main crop grown in the basin is boro rice or dry season rice. Early monsoon flash floods often cause extensive damage to the boro crop. Protection in the form of full flood dykes or submersible dykes is being provided in some of the developed areas. Among the varieties of rice cultivated in winter, the Boro season, in the knee-deep water of marshlands, the Hashi (BR-17), the Shahjalal (BR-18) and the Mongol (BR-19) varieties are best suited for the areas. and , along with the rivers, canals and the floodplain, are a major source of fish production. But, due to silting, and excessive harvesting of fish to meet the demand of growing populations production of fish from this source is gradually dwindling. In recent years, the wetlands have also been used for rearing domestic ducks. Due to scarcity of cultivable land, government lands ( land) including the wetlands are increasing getting transferred to private ownership in Bangladesh. Thus most of the and have now been sold or leased to private individuals for cultivation during the dry season. This transfer is governed by the Haor Development Board Ordinance (Ordinance No. IX of 1977) are under the direct control of the Revenue Department in the Ministry of Land Administration and Land Reforms.


Tourism

are unique wetlands and have started attracting tourists. The best time to visit the haors is at the end of the monsoons, say around August–September, when they are full with water. Thereafter, the water in the haors starts receding but still provides an awe-inspiring sight. In winter, the and receive thousands of migratory birds. It is the ideal season for bird-watchers, but then the are reduced in size and lose much of their watery grandeur. As summer sets in the are no more there, but one can still see numerous . ''
Lonely Planet Lonely Planet is a travel guide book publisher. Founded in Australia in 1973, the company has printed over 150 million books. History 20th century Lonely Planet was founded by married couple Maureen Wheeler, Maureen and Tony Wheeler. In 19 ...
'' describes these areas as "some of the most fascinating rural areas of Bangladesh." According to the Ministry of Water Resources of Bangladesh, there were 144 of tourist spots in the Haor area in 2012, of which 37 were natural and 107 were manmade. The Ministry declared its aims to increase the current GDP rate of the tourism sector from 0.70 in 2012 to 2% by 2015 and then to 5% by 2021. 13 tourism development projects were declared including 2 eco-parks, 6 tourist spots, 3 nos of bird watching tower, a fish park, a wildlife sanctuary, and a tourist center near Hammam Waterfall including hotels, restaurants, and parking areas.
International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
(IUCN) considers the increase in tourist traffic as "a potential opportunity for the dwellers for improving their livelihoods." IUCN Bangladesh initiated a ''community-based tourism'' project in the Tanguar Haor wetland area (a Ramsar site) as one of the ways for sustainable management of wetland resources.Promoting responsible tourism to develop climate resilient tourism industry
International Union for Conservation of Nature (IUCN)


See also

* Geography of Bangladesh * Beel * Rivers in Bangladesh


Notes


References


Further reading

*


External links

* {{Rivers in and around Bengal, collapsible=yes Depressions (geology) *