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95-629: The Griffith Wetlands Important Bird Area is a group of wetlands lying close to the Riverina town of Griffith in southern New South Wales , Australia . It lies within the Murrumbidgee Irrigation Area . North and South Lake Wyangan are used for water storage; they contain an area of cumbungi . Nericon Swamp is a shallow swamp usually dry enough to be grazed by cattle, though it sometimes fills from local rains when it supports large numbers of waders . Barren Box Swamp

190-711: A sink or a source of carbon, depending on the specific wetland. If they function as a carbon sink, they can help with climate change mitigation . However, wetlands can also be a significant source of methane emissions due to anaerobic decomposition of soaked detritus , and some are also emitters of nitrous oxide . Humans are disturbing and damaging wetlands in many ways, including oil and gas extraction , building infrastructure, overgrazing of livestock , overfishing , alteration of wetlands including dredging and draining, nutrient pollution , and water pollution . Wetlands are more threatened by environmental degradation than any other ecosystem on Earth, according to

285-581: A deep gorge (the " Yarlung Tsangpo Grand Canyon ") across the eastern extremity of the Himalayas with canyon walls that extend upward for 5,000 m (16,000 ft) and more on each side. During that stretch, the river crosses the China-India line of actual control to enter northern Arunachal Pradesh, where it is known as the Dihang (or Siang) River, and turns more southerly. The Yarlung Tsangpo leaves

380-407: A diversion of the channel into the existing floodplain channel. The Brahmaputra channel is governed by the peak and low flow periods during which its bed undergoes tremendous modification. The Brahmaputra's bank line migration is inconsistent with time. The Brahmaputra river bed has widened significantly since 1916 and appears to be shifting more towards the south than towards the north. Together with

475-402: A frequency and duration to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally included swamps, marshes, bogs, and similar areas.' For each of these definitions and others, regardless of the purpose, hydrology is emphasized (shallow waters, water-logged soils). The soil characteristics and

570-1259: A polar climate, wetland temperatures can be as low as −50 °C (−58 °F). Peatlands in arctic and subarctic regions insulate the permafrost , thus delaying or preventing its thawing during summer, as well as inducing its formation. The amount of precipitation a wetland receives varies widely according to its area. Wetlands in Wales , Scotland , and western Ireland typically receive about 1,500 mm (59 in) per year. In some places in Southeast Asia , where heavy rains occur, they can receive up to 10,000 mm (390 in). In some drier regions, wetlands exist where as little as 180 mm (7.1 in) precipitation occurs each year. Temporal variation: Surface flow may occur in some segments, with subsurface flow in other segments. Wetlands vary widely due to local and regional differences in topography , hydrology , vegetation , and other factors, including human involvement. Other important factors include fertility, natural disturbance, competition, herbivory , burial and salinity. When peat accumulates, bogs and fens arise. The most important factor producing wetlands

665-540: A portion of the overall water cycle, which also includes atmospheric water (precipitation) and groundwater . Many wetlands are directly linked to groundwater and they can be a crucial regulator of both the quantity and quality of water found below the ground. Wetlands that have permeable substrates like limestone or occur in areas with highly variable and fluctuating water tables have especially important roles in groundwater replenishment or water recharge. Substrates that are porous allow water to filter down through

760-496: A protective barrier to coastal shoreline. Mangroves stabilize the coastal zone from the interior and will migrate with the shoreline to remain adjacent to the boundary of the water. The main conservation benefit these systems have against storms and storm surges is the ability to reduce the speed and height of waves and floodwaters. Brahmaputra The Brahmaputra is a trans-boundary river which flows through Southwestern China , Northeastern India , and Bangladesh . It

855-422: A strong influence on wetland water chemistry, particularly in coastal wetlands and in arid and semiarid regions with large precipitation deficits. Natural salinity is regulated by interactions between ground and surface water, which may be influenced by human activity. Carbon is the major nutrient cycled within wetlands. Most nutrients, such as sulfur , phosphorus , carbon , and nitrogen are found within

950-410: A unique kind of wetland where lush plant growth and slow decay of dead plants (under anoxic conditions) results in organic peat accumulating; bogs, fens, and mires are different names for peatlands. Variations of names for wetland systems: Some wetlands have localized names unique to a region such as the prairie potholes of North America's northern plain, pocosins , Carolina bays and baygalls of

1045-515: A wetland is "an ecosystem that arises when inundation by water produces soils dominated by anaerobic and aerobic processes, which, in turn, forces the biota, particularly rooted plants, to adapt to flooding". Sometimes a precise legal definition of a wetland is required. The definition used for regulation by the United States government is: 'The term "wetlands" means those areas that are inundated or saturated by surface or ground water at

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1140-422: A wetland system includes its plants ( flora ) and animals ( fauna ) and microbes (bacteria, fungi). The most important factor is the wetland's duration of flooding. Other important factors include fertility and salinity of the water or soils. The chemistry of water flowing into wetlands depends on the source of water, the geological material that it flows through and the nutrients discharged from organic matter in

1235-403: A wetland) affects hydro-periods (temporal fluctuations in water levels) by controlling the water balance and water storage within a wetland. Landscape characteristics control wetland hydrology and water chemistry. The O 2 and CO 2 concentrations of water depend upon temperature , atmospheric pressure and mixing with the air (from winds or water flows). Water chemistry within wetlands

1330-558: A whole. To replace these wetland ecosystem services , enormous amounts of money would need to be spent on water purification plants, dams, levees, and other hard infrastructure, and many of the services are impossible to replace. Floodplains and closed-depression wetlands can provide the functions of storage reservoirs and flood protection. The wetland system of floodplains is formed from major rivers downstream from their headwaters . "The floodplains of major rivers act as natural storage reservoirs, enabling excess water to spread out over

1425-594: A wide area, which reduces its depth and speed. Wetlands close to the headwaters of streams and rivers can slow down rainwater runoff and spring snowmelt so that it does not run straight off the land into water courses. This can help prevent sudden, damaging floods downstream." Notable river systems that produce wide floodplains include the Nile River , the Niger river inland delta, the Zambezi River flood plain,

1520-536: Is 135 m (440 ft) (at Sadiya ). The river is prone to catastrophic flooding in the spring when the Himalayan snow melts. The average discharge of the Brahmaputra is about ~22,000 m /s (780,000 cu ft/s), and floods reach about 103,000 m /s (3,600,000 cu ft/s). It is a classic example of a braided river and is highly susceptible to channel migration and avulsion . It

1615-788: Is a stub . You can help Misplaced Pages by expanding it . Wetland Wetlands exist on every continent , except Antarctica . The water in wetlands is either freshwater , brackish or saltwater . The main types of wetland are defined based on the dominant plants and the source of the water. For example, marshes are wetlands dominated by emergent herbaceous vegetation such as reeds , cattails and sedges . Swamps are dominated by woody vegetation such as trees and shrubs (although reed swamps in Europe are dominated by reeds, not trees). Mangrove forest are wetlands with mangroves , halophytic woody plants that have evolved to tolerate salty water . Examples of wetlands classified by

1710-621: Is a natural phenomenon which is ecologically important because it helps maintain the lowland grasslands and associated wildlife. Periodic floods also deposit fresh alluvium, replenishing the fertile soil of the Brahmaputra River Valley. Thus flooding, agriculture, and agricultural practices are closely connected. The effects of flooding can be devastating and cause significant damage to crops and houses, serious bank erosive with consequent loss of homesteads, school and land, and loss of many lives, livestock, and fisheries. During

1805-726: Is also called Tsangpo-Brahmaputra and red river of India (when referring to the whole river including the stretch within the Tibet Autonomous Region ). In its Tibetan and Indian names, the river is unusually masculine in gender. The upper reaches of the Brahmaputra River, known as the Yarlung Tsangpo from the Tibetan language, originates on the Angsi Glacier , near Mount Kailash, located on

1900-699: Is also one of the few rivers in the world that exhibits a tidal bore . It is navigable for most of its length. The Brahmaputra drains the Himalayas east of the Indo-Nepal border, south-central portion of the Tibetan plateau above the Ganga basin, south-eastern portion of Tibet, the Patkai hills, the northern slopes of the Meghalaya hills, the Assam plains, and northern Bangladesh. The basin, especially south of Tibet,

1995-442: Is called Brahmaputra and Doima (mother of water) and Burlung-Buthur by native Bodo tribals, it then enters the state of Assam , and becomes very wide—as wide as 20 km (12 mi) in parts of Assam. The reason for such an unusual course and drastic change is that the river is antecedent to the Himalayas, meaning that it had existed before them and has entrenched itself since they started rising. The Dihang, winding out of

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2090-562: Is characterized by high levels of rainfall. Kangchenjunga (8,586 m) is the only peak above 8,000 m and hence is the highest point within the Brahmaputra basin. The Brahmaputra's upper course was long unknown, and its identity with the Yarlung Tsangpo was only established by exploration in 1884–86. The river is often called the Tsangpo-Brahmaputra river. The lower reaches are sacred to Hindus . While most rivers on

2185-535: Is crucial in planning upstream engineering to prevent flooding on the bridge. China had built the Zangmu Dam in the upper course of the Brahmaputra River in the Tibet region and it was operationalised on 13 October 2015. The main tributaries from the mouth: tributary tributary (km) (km ) (m /s) ( Sunkosh ) ( Bhareli ) ( Siyom ) (Matsang Tsangpo) Period: 1971–2000 The Kachari group called

2280-440: Is determined by the pH , salinity , nutrients, conductivity , soil composition, hardness , and the sources of water. Water chemistry varies across landscapes and climatic regions. Wetlands are generally minerotrophic (waters contain dissolved materials from soils) with the exception of ombrotrophic bogs that are fed only by water from precipitation. Because bogs receive most of their water from precipitation and humidity from

2375-412: Is hydrology, or flooding . The duration of flooding or prolonged soil saturation by groundwater determines whether the resulting wetland has aquatic, marsh or swamp vegetation . Other important factors include soil fertility, natural disturbance, competition, herbivory , burial, and salinity. When peat from dead plants accumulates, bogs and fens develop. Wetland hydrology is associated with

2470-880: Is known as Brahmaputra or Luit in Assamese , Yarlung Tsangpo in Tibetan , the Siang/Dihang River in Arunachali , and Jamuna River in Bengali . By itself, it is the 9th largest river in the world by discharge, and the 15th longest . It originates in the Manasarovar Lake region, near Mount Kailash , on the northern side of the Himalayas in Burang County of Tibet where it is known as

2565-520: Is significantly influenced by the melting of snow in the upper part of its catchment area. This increase in river flow, caused by the substantial retreat of snow, leads to a higher downstream discharge. Such a rise in discharge often results in severe catastrophic issues, including flooding and erosion. The Brahmaputra River is characterized by its significant rates of sediment discharge, the large and variable flows, along with its rapid channel aggradations and accelerated rates of basin denudation. Over time,

2660-451: Is the only place in the world where both crocodiles and alligators coexist. The saltwater crocodile inhabits estuaries and mangroves. Snapping turtles also inhabit wetlands. Birds , particularly waterfowl and waders use wetlands extensively. Mammals of wetlands include numerous small and medium-sized species such as voles , bats , muskrats and platypus in addition to large herbivorous and apex predator species such as

2755-545: Is usually saturated with water". More precisely, wetlands are areas where "water covers the soil , or is present either at or near the surface of the soil all year or for varying periods of time during the year, including during the growing season". A patch of land that develops pools of water after a rain storm would not necessarily be considered a "wetland", even though the land is wet. Wetlands have unique characteristics: they are generally distinguished from other water bodies or landforms based on their water level and on

2850-671: The Holocene . One idea about the most recent avulsion is that the change in the course of the main waters of the Brahmaputra took place suddenly in 1787, the year of the heavy flooding of the river Tista. In the middle of the 18th century, at least three fair-sized streams flowed between the Rajshahi and Dhaka Divisions, viz., the Daokoba, a branch of the Tista, the Monash or Konai, and

2945-519: The Jamalpur and Mymensingh districts. In an 8.8 magnitude earthquake on 2 April 1762 , however, the main channel of the Brahmaputra at Bhahadurabad point was switched southwards and opened as Jamuna due to the result of tectonic uplift of the Madhupur tract . Rising temperatures significantly contribute to snow melting in the upper Brahmaputra catchment. The discharge of the Brahmaputra River

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3040-505: The Millennium Ecosystem Assessment from 2005. Methods exist for assessing wetland ecological health . These methods have contributed to wetland conservation by raising public awareness of the functions that wetlands can provide. Since 1971, work under an international treaty seeks to identify and protect " wetlands of international importance ." A simplified definition of wetland is "an area of land that

3135-688: The Pantanal in South America, and the Sundarbans in the Ganges - Brahmaputra delta. Wetlands contribute many ecosystem services that benefit people. These include for example water purification , stabilization of shorelines, storm protection and flood control . In addition, wetlands also process and condense carbon (in processes called carbon fixation and sequestration ), and other nutrients and water pollutants . Wetlands can act as

3230-676: The Yamuna of India). In the vast Ganges Delta , it merges with the Ganges , popularly known as the Padma in Bangladesh, and becomes the Meghna and ultimately empties into the Bay of Bengal . At 3,000 km (1,900 mi) long, the Brahmaputra is an important river for irrigation and transportation in the region. The average depth of the river is 30 m (100 ft) and its maximum depth

3325-735: The Yarlung Tsangpo River . The Brahmaputra flows along southern Tibet to break through the Himalayas in great gorges (including the Yarlung Tsangpo Grand Canyon ) and into Arunachal Pradesh. It enters India near the village of Gelling in Arunachal Pradesh and flows southwest through the Assam Valley as the Brahmaputra and south through Bangladesh as the Jamuna (not to be confused with

3420-444: The atmosphere , their water usually has low mineral ionic composition. In contrast, wetlands fed by groundwater or tides have a higher concentration of dissolved nutrients and minerals. Fen peatlands receive water both from precipitation and ground water in varying amounts so their water chemistry ranges from acidic with low levels of dissolved minerals to alkaline with high accumulation of calcium and magnesium . Salinity has

3515-576: The beavers , coypu , swamp rabbit , Florida panther , jaguar , and moose . Wetlands attract many mammals due to abundant seeds, berries, and other vegetation as food for herbivores, as well as abundant populations of invertebrates, small reptiles and amphibians as prey for predators. Invertebrates of wetlands include aquatic insects such as dragonflies , aquatic bugs and beetles , midges, mosquitos , crustaceans such as crabs, crayfish, shrimps, microcrustaceans, mollusks like clams, mussels, snails and worms. Invertebrates comprise more than half of

3610-445: The 1998 flood, over 70% of the land area of Bangladesh was inundated, affecting 31 million people and 1 million homesteads. In the 1998 flood which had an unusually long duration from July to September, claimed 918 human lives and was responsible for damaging 1,600 km (990 mi) of roads and 6,000 km (3,700 mi) embankments, and affecting 6,000 km (2,300 sq mi) of standing crops. The 2004 floods, over 25% of

3705-639: The Bay of Bengal through the Meghna estuary and lesser channels flowing through the delta. The growth of the Ganga-Brahmaputra Delta is dominated by tidal processes. The Ganga Delta , fed by the waters of numerous rivers, including the Ganga and Brahmaputra, is 105,000 km (41,000 sq mi), one of the largest river deltas in the world. The Ganges – Brahmaputra – Meghna system has

3800-646: The Bay of Bengal. This final part of the river is called Meghna. The Brahmaputra enters the plains of Bangladesh after turning south around the Garo Hills below Dhuburi, India. After flowing past Chilmari, Bangladesh, it is joined on its right bank by the Tista River and then follows a 240 km (150 mi) course due south as the Jamuna River. (South of Gaibanda, the Old Brahmaputra leaves

3895-460: The Brahmaputra at Pandu was 72,726 m /s (2,568,300 cu ft/s) August 1962 while the lowest was 1,757 m /s (62,000 cu ft/s) in February 1968. The increased rates of snow and glacial melt are likely to increase summer flows in some river systems for a few decades, followed by a reduction in flow as the glaciers disappear and snowfall diminishes. This is particularly true for

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3990-656: The Himalayas to the south and the Kailas Range to the north. In Tibet, the Tsangpo receives a number of tributaries. The most important left-bank tributaries are the Raka Zangbo (Raka Tsangpo), which joins the river west of Xigazê (Shigatse), and the Lhasa (Kyi), which flows past the Tibetan capital of Lhasa and joins the Tsangpo at Qüxü . The Nyang River joins the Tsangpo from the north at Zela (Tsela Dzong). On

4085-526: The Indian subcontinent have female names, this river has a rare male name. Brahmaputra means "son of Brahma " in Sanskrit . It is known by various names in different regional languages: Brôhmôputrô in Assamese ; Tibetan : ཡར་ཀླུངས་གཙང་པོ་ , Wylie : yar klung gtsang po Yarlung Tsangpo ; simplified Chinese : 布拉马普特拉河 ; traditional Chinese : 布拉馬普特拉河 ; pinyin : Bùlāmǎpǔtèlā Hé . It

4180-639: The Okavango River inland delta, the Kafue River flood plain, the Lake Bangweulu flood plain (Africa), Mississippi River (US), Amazon River (South America), Yangtze River (China), Danube River (Central Europe) and Murray-Darling River (Australia). Groundwater replenishment can be achieved for example by marsh , swamp , and subterranean karst and cave hydrological systems. The surface water visibly seen in wetlands only represents

4275-687: The Salangi. The Lahajang and the Elengjany were also important rivers. In Renault's time, the Brahmaputra as a first step towards securing a more direct course to the sea by leaving the Mahdupur Jungle to the east began to send a considerable volume of water down the Jinai or Jabuna from Jamalpur into the Monash and Salangi. These rivers gradually coalesced and kept shifting to the west till they met

4370-522: The Southeastern US, mallines of Argentina, Mediterranean seasonal ponds of Europe and California, turloughs of Ireland, billabongs of Australia, among many others. Wetlands are found throughout the world in different climates. Temperatures vary greatly depending on the location of the wetland. Many of the world's wetlands are in the temperate zones , midway between the North or South Poles and

4465-502: The US, the best known classifications are the Cowardin classification system and the hydrogeomorphic (HGM) classification system. The Cowardin system includes five main types of wetlands: marine (ocean-associated), estuarine (mixed ocean- and river-associated), riverine (within river channels), lacustrine (lake-associated) and palustrine (inland nontidal habitats). Peatlands are

4560-610: The United States' commercial fish and shellfish stocks depend solely on estuaries to survive. Amphibians such as frogs and salamanders need both terrestrial and aquatic habitats in which to reproduce and feed. Because amphibians often inhabit depressional wetlands like prairie potholes and Carolina bays, the connectivity among these isolated wetlands is an important control of regional populations. While tadpoles feed on algae, adult frogs forage on insects. Frogs are sometimes used as an indicator of ecosystem health because their thin skin permits absorption of nutrients and toxins from

4655-560: The adjacent floodplain. Lastly, flood basins are often formed between the levees of adjacent rivers. During the monsoon season (June–October), floods are a very common occurrence. Deforestation in the Brahmaputra watershed has resulted in increased siltation levels, flash floods, and soil erosion in critical downstream habitat, such as the Kaziranga National Park in middle Assam. Occasionally, massive flooding causes huge losses to crops, life, and property. Periodic flooding

4750-705: The ancient pilgrimage centre of Hajo , the Brahmaputra cuts through the rocks of the Shillong Plateau , and is at its narrowest at 1 km (1,100 yd) bank-to-bank. The terrain of this area made it logistically ideal for the Battle of Saraighat , the military confrontation between the Mughal Empire and the Ahom Kingdom in March 1671. The first combined railroad/roadway bridge across the Brahmaputra

4845-626: The capital of Bangladesh, and joins the Meghna River above Munshiganj. The Jamuna joins with the Ganga north of Goalundo Ghat, below which, as the Padma, their combined waters flow to the southeast for a distance of about 120 km (75 mi). After several smaller channels branch off to feed the Ganga-Brahmaputra delta to the south, the main body of the Padma reaches its confluence with the Meghna River near Chandpur and then enters

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4940-650: The construction of Brahmaputra Express Highways. The course of the Brahmaputra River has changed dramatically over the past 250 years, with evidence of large-scale avulsion, in the period 1776–1850, of 80 km (50 mi) from east of the Madhupur tract to the west of it. Prior to 1843, the Brahmaputra flowed within the channel now termed the "Old Brahmaputra" . The banks of the river are mostly weakly cohesive sand and silts, which usually erodes through large scale slab failure, where previously deposited materials undergo scour and bank erosion during flood periods. Presently,

5035-444: The contemporary slow migration of the river, the left bank is being eroded away faster than the right bank. The Brahmaputra River experiences high levels of bank erosion (usually via slab failure) and channel migration caused by its strong current, lack of riverbank vegetation, and loose sand and silt which compose its banks. It is thus difficult to build permanent structures on the river, and protective structures designed to limit

5130-588: The deepening of the Bengal Basin caused by erosion will result in the increase in hydraulic radius, and hence allowing for the huge accumulation of sediments fed from the Himalayan erosion by efficient sediment transportation. The thickness of the sediment accumulated above the Precambrian basement has increased over the years from a few hundred meters to over 18 km (11 mi) in the Bengal fore-deep to

5225-471: The dry season when water availability is crucial for the irrigation systems. The course of the Brahmaputra River has changed drastically in the past two and a half centuries, moving its river course westwards for a distance of about 80 km (50 mi), leaving its old river course, appropriately named the old Brahmaputra river, behind. In the past, the floodplain of the old river course had soils which were more properly formed compared to graded sediments on

5320-634: The equator. In these zones, summers are warm and winters are cold, but temperatures are not extreme. In subtropical zone wetlands, such as along the Gulf of Mexico , average temperatures might be 11 °C (52 °F). Wetlands in the tropics are subjected to much higher temperatures for a large portion of the year. Temperatures for wetlands on the Arabian Peninsula can exceed 50 °C (122 °F) and these habitats would therefore be subject to rapid evaporation. In northeastern Siberia , which has

5415-403: The flood problem remains unsolved. At least a third of the land of Majuli Island has been eroded by the river. Recently, it is suggested that a highway protected by concrete mat along the river bank and excavation of the river bed can curb this menace. This project, named the Brahmaputra River Restoration Project, is yet to be implemented by the government. Recently the Central Government approved

5510-429: The following areas: According to the Ramsar Convention: The economic worth of the ecosystem services provided to society by intact, naturally functioning wetlands is frequently much greater than the perceived benefits of converting them to 'more valuable' intensive land use – particularly as the profits from unsustainable use often go to relatively few individuals or corporations, rather than being shared by society as

5605-416: The interface between truly terrestrial ecosystems and aquatic systems, making them inherently different from each other, yet highly dependent on both." In environmental decision-making, there are subsets of definitions that are agreed upon to make regulatory and policy decisions. Under the Ramsar international wetland conservation treaty , wetlands are defined as follows: An ecological definition of

5700-563: The irrigation system. Together, the wetlands have been identified by BirdLife International as a fragmented 38 km (15 sq mi) Important Bird Area (IBA) because they regularly support small numbers of the endangered Australasian bittern as well as occasionally supporting over 1% of the world populations of sharp-tailed sandpipers , red-necked avocets and chestnut teals . 34°09′42″S 145°51′21″E  /  34.16167°S 145.85583°E  / -34.16167; 145.85583 This Riverina geography article

5795-462: The known animal species in wetlands, and are considered the primary food web link between plants and higher animals (such as fish and birds). Depending on a wetland's geographic and topographic location, the functions it performs can support multiple ecosystem services , values, or benefits. United Nations Millennium Ecosystem Assessment and Ramsar Convention described wetlands as a whole to be of biosphere significance and societal importance in

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5890-421: The left bank of the mainstream and flows past Jamalpur and Mymensingh to join the Meghna River at Bhairab Bazar.) Before its confluence with the Ganga, the Jamuna receives the combined waters of the Baral , Atrai , and Hurasagar Rivers on its right bank and becomes the point of departure of the large Dhaleswari River on its left bank. A tributary of the Dhaleswari, the Buriganga ("Old Ganga"), flows past Dhaka,

5985-399: The levee top and the surrounding floodplains is typically 1 m (3 ft) along small channels and 2–3 m (7–10 ft) along major channels. Crevasse splay, a sedimentary fluvial deposit which forms when a stream breaks its natural or artificial levees and deposits sediment on a floodplain, are often formed due to a breach in the levee, forming a lobe of sediments which progrades onto

6080-400: The majority of the river's flow, continues due south as the Jamuna ( Jomuna ) to merge with the lower Ganga, called the Padma River ( Pôdma ). The eastern branch, formerly the larger, but now much smaller, is called the lower or Old Brahmaputra ( Brommoputro ). It curves southeast to join the Meghna River near Dhaka . The Padma and Meghna converge near Chandpur and flow out into

6175-510: The mountains, and one in late summer caused by runoff from monsoon rains. The river flow is strongly influenced by snow and ice melting of the glaciers, which are located mainly on the eastern Himalaya regions in the upstream parts of the basin. The snow and glacier melt contribution to the total annual runoff is about 27%, while the annual rainfall contributes to about 1.9 m (6 ft 3 in) and 22,000 m /s (780,000 cu ft/s) of discharge. The highest recorded daily discharge in

6270-423: The mountains, turns towards the southeast and descends into a low-lying basin as it enters northeastern Assam state. Just west of the town of Sadiya, the river again turns to the southwest and is joined by two mountain streams, the Lohit, and the Dibang. Below that confluence, about 1,450 km (900 mi) from the Bay of Bengal, the river becomes known conventionally as the Brahmaputra ("Son of Brahma"). In Assam,

6365-406: The northern side of the Himalayas in Burang County of Tibet . The source of the river was earlier thought to be on the Chemayungdung glacier, which covers the slopes of the Himalayas about 60 mi (97 km) southeast of Lake Manasarovar in southwestern Tibet. From its source, the river runs for nearly 1,100 km (680 mi) in a generally easterly direction between the main range of

6460-409: The only bridge to span the river's major distributary, the Jamuna , was thus opened in June 1998. Constructed at a narrow braid belt of the river, it is 4.8 km (3.0 mi) long with a platform 18.5 m (61 ft) wide, and it is used to carry railroad traffic as well as gas, power and telecommunication lines. Due to the variable nature of the river, the prediction of the river's future course

6555-534: The operating Jamuna river. This change of river course resulted in modifications to the soil-forming process, which include acidification, the breakdown of clays and buildup of organic matter, with the soils showing an increasing amount of biotic homogenization, mottling, the coating around Peds and maturing soil arrangement, shape and pattern. In the future, the consequences of local ground subsidence coupled with flood prevention propositions, for instance, localised breakwaters, that increase flood-plain water depths outside

6650-405: The part of Tibet to enter Indian state of Arunachal Pradesh , where the river is called Siang. It makes a very rapid descent from its original height in Tibet and finally appears in the plains, where it is called Dihang. It flows for about 35 km (22 mi) southward after which, it is joined by the Dibang River and the Lohit River at the head of the Assam Valley. Below the Lohit, the river

6745-781: The plants and animals controlled by the wetland hydrology are often additional components of the definitions. Wetlands can be tidal (inundated by tides) or non-tidal. The water in wetlands is either freshwater , brackish , saline , or alkaline . There are four main kinds of wetlands – marsh , swamp , bog , and fen (bogs and fens being types of peatlands or mires ). Some experts also recognize wet meadows and aquatic ecosystems as additional wetland types. Sub-types include mangrove forests , carrs , pocosins , floodplains , peatlands, vernal pools , sinks , and many others. The following three groups are used within Australia to classify wetland by type: Marine and coastal zone wetlands, inland wetlands and human-made wetlands. In

6840-679: The plateau to the south are the Burhi Dihing, the Disang, the Dikhu, and the Kopili. Between Dibrugarh and Lakhimpur Districts , the river divides into two channels—the northern Kherkutia channel and the southern Brahmaputra channel. The two channels join again about 100 km (62 mi) downstream, forming the Majuli island, which is the largest river island in the world. At Guwahati , near

6935-511: The population of Bangladesh or 36 million people, were affected by the floods; 800 people died; 952 000 houses were destroyed and 1.4 million were badly damaged; 24 000 educational institutions were affected including the destruction of 1200 primary schools, 2 million governments and private tube wells were affected, over 3 million latrines were damaged or washed away, this increases the risks of waterborne diseases including diarrhea and cholera. Also, 1.1 million ha (2.7 million acres) of

7030-498: The rice crop was submerged and lost before it could be harvested, with 7% of the yearly aus (early season) rice crop lost; 270,000 ha (670,000 acres) of grazing land was affected, 5600 livestock perished together with 254 00 poultry and 63 million tonnes (69 million short tons) of lost fish production. Flood-control measures are taken by the water resource department and the Brahmaputra Board, but until now

7125-464: The right bank, a second river called the Nyang Qu (Nyang Chu) meets the Tsangpo at Xigazê. After passing Pi (Pe) in Tibet, the river turns suddenly to the north and northeast and cuts a course through a succession of great narrow gorges between the mountainous massifs of Gyala Peri and Namcha Barwa in a series of rapids and cascades. Thereafter, the river turns south and southwest and flows through

7220-399: The river "Dilao", "Tilao". Early Greek accounts of Curtius and Strabo give its name as Dyardanes ( Ancient greek Δυαρδάνης) and Oidanes. In the past, the course of the lower Brahmaputra was different and passed through the Jamalpur and Mymensingh districts. Some water still flows through that course, now called the Old Brahmaputra, as a distributary of the main channel. A question about

7315-468: The river is mighty, even in the dry season, and during the rains, its banks are more than 8 km (5.0 mi) apart. As the river follows its braided 700 km (430 mi) course through the valley, it receives several rapidly flowing Himalayan streams, including the Subansiri, Kameng, Bhareli, Dhansiri, Manas, Champamati, Saralbhanga, and Sankosh Rivers. The main tributaries from the hills and from

7410-540: The river system in Bangladesh is when and why the Brahmaputra changed its main course, at the site of the Jamuna and the "Old Brahmaputra" fork that can be seen by comparing modern maps to historic maps before the 1800s. The Brahmaputra likely flowed directly south along its present main channel for much of the time since the last glacial maximum , switching back and forth between the two courses several times throughout

7505-449: The river's erosion rate has decreased to 30 m (98 ft) per year as compared to 150 m (490 ft) per year from 1973 to 1992. This erosion has, however, destroyed so much land that it has caused 0.7 million people to become homeless due to loss of land. Several studies have discussed the reasons for the avulsion of the river into its present course, and have suggested a number of reasons including tectonic activity, switches in

7600-491: The river's erosional effects often face numerous issues during and after construction. In fact, a 2004 report by the Bangladesh Disaster and Emergency Sub-Group (BDER) has stated that several of such protective systems have 'just failed'. However, some progress has been made in the form of construction works which stabilize sections of the river, albeit with the need for heavy maintenance. The Bangabandhu Bridge ,

7695-406: The second-greatest average discharge of the world's rivers—roughly ~44,000 m /s (1,600,000 cu ft/s), and the river Brahmaputra alone supplies about 50% of the total discharge. The rivers' combined suspended sediment load of about 1.87 billion tonnes (1.84 billion tons) per year is the world's highest. In the past, the lower course of the Brahmaputra was different and passed through

7790-429: The soil and underlying rock into aquifers which are the source of much of the world's drinking water . Wetlands can also act as recharge areas when the surrounding water table is low and as a discharge zone when it is high. Mangroves , coral reefs , salt marsh can help with shoreline stabilization and storm protection. Tidal and inter-tidal wetland systems protect and stabilize coastal zones. Coral reefs provide

7885-537: The soil of wetlands. Anaerobic and aerobic respiration in the soil influences the nutrient cycling of carbon, hydrogen, oxygen, and nitrogen, and the solubility of phosphorus thus contributing to the chemical variations in its water. Wetlands with low pH and saline conductivity may reflect the presence of acid sulfates and wetlands with average salinity levels can be heavily influenced by calcium or magnesium. Biogeochemical processes in wetlands are determined by soils with low redox potential. The life forms of

7980-412: The soils and plants at higher elevations. Plants and animals may vary within a wetland seasonally or in response to flood regimes. There are four main groups of hydrophytes that are found in wetland systems throughout the world. Submerged wetland vegetation can grow in saline and fresh-water conditions. Some species have underwater flowers, while others have long stems to allow the flowers to reach

8075-530: The sources of water include tidal wetlands , where the water source is ocean tides ); estuaries , water source is mixed tidal and river waters; floodplains , water source is excess water from overflowed rivers or lakes; and bogs and vernal ponds , water source is rainfall or meltwater . The world's largest wetlands include the Amazon River basin , the West Siberian Plain ,

8170-504: The south. The ongoing subsidence of the Bengal Basin and the high rate of Himalayan uplift continues to contribute to the large water and sediment discharges of fine sand and silt, with 1% clay, in the Brahmaputra River. Climatic change plays a crucial role in affecting the basin hydrology. Throughout the year, there is a significant rise in hydrograph, with a broad peak between July and September. The Brahmaputra River experiences two high-water seasons, one in early summer caused by snowmelt in

8265-406: The spatial and temporal dispersion, flow, and physio-chemical attributes of surface and ground waters. Sources of hydrological flows into wetlands are predominantly precipitation , surface water (saltwater or freshwater), and groundwater. Water flows out of wetlands by evapotranspiration , surface flows and tides , and subsurface water outflow. Hydrodynamics (the movement of water through and from

8360-719: The surface of the water. When trees and shrubs comprise much of the plant cover in saturated soils, those areas in most cases are called swamps . The upland boundary of swamps is determined partly by water levels. This can be affected by dams Some swamps can be dominated by a single species, such as silver maple swamps around the Great Lakes . Others, like those of the Amazon basin , have large numbers of different tree species. Other examples include cypress ( Taxodium ) and mangrove swamps. Many species of fish are highly dependent on wetland ecosystems. Seventy-five percent of

8455-496: The surface. Submerged species provide a food source for native fauna, habitat for invertebrates, and also possess filtration capabilities. Examples include seagrasses and eelgrass . Floating water plants or floating vegetation are usually small, like those in the Lemnoideae subfamily (duckweeds). Emergent vegetation like the cattails ( Typha spp.), sedges ( Carex spp.) and arrow arum ( Peltandra virginica ) rise above

8550-464: The surrounding environment resulting in increased extinction rates in unfavorable and polluted environmental conditions. Reptiles such as snakes , lizards , turtles , alligators and crocodiles are common in wetlands of some regions. In freshwater wetlands of the Southeastern US, alligators are common and a freshwater species of crocodile occurs in South Florida. The Florida Everglades

8645-440: The types of plants that live within them. Specifically, wetlands are characterized as having a water table that stands at or near the land surface for a long enough period each year to support aquatic plants . A more concise definition is a community composed of hydric soil and hydrophytes . Wetlands have also been described as ecotones , providing a transition between dry land and water bodies. Wetlands exist "...at

8740-463: The upstream course of the Teesta River, the influence of increased discharge, catastrophic floods and river capture into an old river course. From an analysis of maps of the river between 1776 and 1843, it was concluded in a study that the river avulsion was more likely gradual than catastrophic and sudden, and may have been generated by bank erosion, perhaps around a large mid-channel bar, causing

8835-441: The water breakers, may alter the water levels of the floodplains. Throughout the years, bars, scroll bars, and sand dunes are formed at the edge of the flood plain by deposition. The height difference of the channel topography is often not more than 1–2 m (3–7 ft). Furthermore, flooding over the history of the river has caused the formation of river levees due to deposition from the overbank flow. The height difference between

8930-613: Was constructed at Saraighat . It was opened to traffic in April 1962. The environment of the Brahmaputra floodplains in Assam have been described as the Brahmaputra Valley semi-evergreen forests ecoregion . In Bangladesh, the Brahmaputra is joined by the Teesta River (or Tista), one of its largest tributaries. Below the Tista, the Brahmaputra splits into two distributary branches. The western branch, which contains

9025-442: Was originally an ephemeral swamp; it has been divided into three parts, with 60% of it remaining a natural wetland which holds water only in wet years; the other 40% is used for water storage and recycling, with reed beds and grazed margins. Campbell's Swamp is a black box - lignum swamp containing extensive open areas punctuated by stands of reeds and cumbungi; it fills occasionally from local rainfall or with water released from

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