Brahmaputra River -- Britannica Online Encyclopedia

10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia

Brahmaputra River

Brahmaputra River, Bengali Jamuna, Tibetan Tsangpo, Chinese (Pinyin) Yarlung Zangbo Jiang or (Wade-Giles TABLE OF CONTENTS romanization) Ya-lu-tsang-pu Chiang, major river of Central Introduction and South Asia. It �ows some 1,800 miles (2,900 Physical features km) from its source in the People Himalayas to its Economy con�uence with the Study and exploration Ganges (Ganga) River, after which the mingled Brahmaputra River. waters of the two rivers empty into the Bay of Bengal.

Encyclopædia Britannica, Inc. Along its course the Brahmaputra passes through the Tibet Autonomous Region of China, the Indian states of Arunachal Pradesh and Assam, and Bangladesh. For most of its length, the river serves as an important inland waterway. It is not, however, navigable between the mountains of Tibet and the plains of India. In its lower course the river is both a creator and a destroyer— depositing huge quantities of fertile alluvial soil but also

Tsangpo (Brahmaputra) River flowing causing disastrous and frequent �oods. through the Himalayas in the Tibet Autonomous Region of China. PHYSICAL FEATURES

The Brahmaputra’s source is the Chemayungdung Glacier, which covers the slopes of the Himalayas about 60 miles (100 km) southeast of Lake Mapam in southwestern Tibet. The three headstreams that arise there are the Kubi, the Angsi, and the Chemayungdung. From its source the river runs for nearly 700 miles (1,100 km) in a generally easterly direction between the Great Himalayas range to the south and the Kailas Range to the north. Throughout its upper course the river is generally known as the Tsangpo (“Puri�er”); it is also known by its Chinese name (Yarlung Zangbo) and by other local Tibetan names.

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 �ows past the Tibetan capital of Lhasa and joins the Tsangpo at Qüxü. The Nyang Qu (Gyamda) River joins the river from the north at Zela (Tsela Dzong). On the right bank a second river called the Nyang Qu (Nyang Chu) meets the Tsangpo at Xigazê. https://www.britannica.com/print/article/77154 1/8 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia 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 Namjagbarwa (Namcha Barwa) in a series of rapids and cascades. Thereafter, the river turns south and southwest and �ows through a deep gorge (the “Grand Canyon” of the Shoals in the Tsangpo (Brahmaputra) River, Tsangpo) across the eastern extremity of the Himalayas Tibet Autonomous Region, China. with canyon walls that extend upward for 16,500 feet © Lukas Hlavac/Shutterstock.com (5,000 metres) and more on each side. During that stretch the river enters northern Arunachal Pradesh state in northeastern India, where it is known as the Dihang (or Siang) River, and turns more southerly.

The Dihang, winding out of the mountains, turns toward 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 con�uence, about 900 miles (1,450 km) from the Bay of Bengal, the river becomes known conventionally as the Brahmaputra (“Son of Brahma”). In Assam the river is mighty, even in the dry season, and

Shaiva temple at Sibsagar near the during the rains its banks are more than 5 miles (8 km) Brahmaputra River, Assam, India. apart. As the river follows its braided 450-mile (700-km)

Foto Features course through the valley, it receives several rapidly rushing Himalayan streams, including the Subansiri, Kameng, Bhareli, Dhansiri, Manas, Champamati, Saralbhanga, and Sankosh rivers. The main tributaries from the hills and from the plateau to the south are the Burhi Dihing, the Disang, the Dikhu, and the Kopili.

The Brahmaputra enters the plains of Bangladesh after turning south around the Garo Hills below Dhuburi, India. After �owing past Chilmari, Bangladesh, it is joined on its right bank by the Tista River and then follows a 150-mile (240-km) course due south as the Jamuna River. (South of Gaibanda, the Old Brahmaputra leaves the left bank of the main stream and �ows past Jamalpur and Mymensingh to join the Meghna River at Bhairab Bazar.) Tista River, a major tributary of the Before its con�uence with the Ganges, the Jamuna Brahmaputra River, flowing through the https://www.britannica.com/print/article/77154 2/8 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia After passing Pi (Pe) in Tibet, the river turns suddenly to Siwalik Hills, … receives the combined waters of the Baral, Atrai, and the north and northeast and cuts a course through a Anupam Manur Hurasagar rivers on its right bank and becomes the point succession of great narrow gorges between the of departure of the large Dhaleswari River on its left bank. mountainous massifs of Gyala Peri and Namjagbarwa A tributary of the Dhaleswari, the Buriganga (“Old Ganges”), �ows past Dhaka, the capital of (Namcha Barwa) in a series of rapids and cascades. Bangladesh, and joins the Meghna River above Munshiganj. Thereafter, the river turns south and southwest and �ows The Jamuna joins with the Ganges north of Goalundo Ghat, below which, as the Padma, their through a deep gorge (the “Grand Canyon” of the combined waters �ow to the southeast for a distance of about 75 miles (120 km). After several Shoals in the Tsangpo (Brahmaputra) River, Tsangpo) across the eastern extremity of the Himalayas smaller channels branch off to feed the Ganges-Brahmaputra delta to the south, the main Tibet Autonomous Region, China. with canyon walls that extend upward for 16,500 feet body of the Padma reaches its con�uence with the Meghna River near Chandpur and then © Lukas Hlavac/Shutterstock.com (5,000 metres) and more on each side. During that enters the Bay of Bengal through the Meghna estuary and lesser channels �owing through the stretch the river enters northern Arunachal Pradesh state delta. The Meghna forms the eastern limit of the Sundarbans, a vast tract of forest and in northeastern India, where it is known as the Dihang (or Siang) River, and turns more saltwater swamp that constitutes much of the Ganges-Brahmaputra delta. The growth of the southerly. delta is dominated by tidal processes. The Dihang, winding out of the mountains, turns toward The Ganges-Brahmaputra system has the third greatest average discharge of the world’s rivers the southeast and descends into a low-lying basin as it —roughly 1,086,500 cubic feet (30,770 cubic metres) per second; approximately 700,000 cubic enters northeastern Assam state. Just west of the town of feet (19,800 cubic metres) per second of the total is supplied by the Brahmaputra alone. The Sadiya, the river again turns to the southwest and is joined rivers’ combined suspended sediment load of about 1.84 billion tons per year is the world’s by two mountain streams, the Lohit and the Dibang. highest. Below that con�uence, about 900 miles (1,450 km) from the Bay of Bengal, the river becomes known CLIMATE conventionally as the Brahmaputra (“Son of Brahma”). In The climate of the Brahmaputra valley varies from the harsh, cold, and dry conditions found in Assam the river is mighty, even in the dry season, and Tibet to the generally hot and humid conditions prevailing in Assam state and in Bangladesh. Shaiva temple at Sibsagar near the during the rains its banks are more than 5 miles (8 km) Tibetan winters are severely cold, with average temperatures below 32 °F (0 °C), while summers Brahmaputra River, Assam, India. apart. As the river follows its braided 450-mile (700-km) are mild and sunny. The upper river valley lies in the rain shadow of the Himalayas, and Foto Features course through the valley, it receives several rapidly precipitation there is relatively light: Lhasa receives about 16 inches (400 mm) annually. rushing Himalayan streams, including the Subansiri, Kameng, Bhareli, Dhansiri, Manas, Champamati, Saralbhanga, and Sankosh rivers. The main The Indian and Bangladeshi parts of the valley are governed by the monsoon (wet, dry) climate, tributaries from the hills and from the plateau to the south are the Burhi Dihing, the Disang, though it is somewhat modi�ed there compared with other parts of the subcontinent; the hot the Dikhu, and the Kopili. season is shorter than usual, and the average annual temperature ranges from 79 °F (26 °C) in Dhuburi, Assam, to 85 °F (29 °C) in Dhaka. Precipitation is relatively heavy, and humidity is high The Brahmaputra enters the plains of Bangladesh after throughout the year. The annual rainfall—between 70 and 150 inches (1,780 and 3,810 mm)— turning south around the Garo Hills below Dhuburi, India. falls mostly between June and early October; however, light rains also fall from March to May. After �owing past Chilmari, Bangladesh, it is joined on its right bank by the Tista River and then follows a 150-mile HYDROLOGY (240-km) course due south as the Jamuna River. (South of Gaibanda, the Old Brahmaputra leaves the left bank of The course of the Brahmaputra has changed continually over time. The most spectacular of the main stream and �ows past Jamalpur and these changes was the eastward diversion of the Tista River and the ensuing development of Mymensingh to join the Meghna River at Bhairab Bazar.) the new channel of the Jamuna, which occurred in 1787 with an exceptionally high �ood in the Tista River, a major tributary of the Before its con�uence with the Ganges, the Jamuna Tista. The waters of the Tista suddenly were diverted eastward into an old abandoned course, Brahmaputra River, flowing through the https://www.britannica.com/print/article/77154 2/8 https://www.britannica.com/print/article/77154 3/8 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia causing the river to join the Brahmaputra opposite Bahadurabad Ghat in Mymensingh district. Until the late 18th century the Brahmaputra �owed past the town of Mymensingh and joined the Meghna River near Bhairab Bazar (the path of the present-day Old Brahmaputra channel). At that time a minor stream called the Konai- Jenai—probably a spill channel of the Old Brahmaputra— followed the course of today’s Jamuna River (now the main Brahmaputra channel). After the Tista �ood of 1787 Satellite image of the Ganges-Brahmaputra reinforced it, the Brahmaputra began to cut a new delta cyclone, November 12, 1970. channel along the Konai-Jenai and gradually converted it NOAA after 1810 into the main stream, now known as the Jamuna.

Along the lower courses of the Ganges and Brahmaputra and along the Meghna, the land undergoes constant erosion and deposition of silt because of the shifts and changes in these active rivers. Vast areas are subject to inundation during the wet monsoon months. The shifts in the course of the Jamuna since 1787 have been considerable, and the river is never in exactly the same place for two successive years. Islands and sizable newly deposited lands (chars) in the river appear and disappear seasonally. The chars are valuable to the economy of Bangladesh as additional cultivable areas.

In Tibet the waters of the Brahmaputra are clear because little silt is carried downstream. As soon as the river enters Assam, however, the silt load becomes heavy. Because of the speed and volume of water in the northern tributaries that �ow down from the rain-soaked Himalayan slopes, their silt load is much heavier than that carried by the tributaries crossing the hard rocks of the old plateau to the south. In Assam the deep channel of the Brahmaputra follows the southern bank closer than the northern. This tendency is reinforced by the silt- laden northern tributaries pushing the channel south.

Another important feature of the river is its tendency to �ood. The quantity of water carried by the Brahmaputra in India and Bangladesh is enormous. The river valley in Assam is enclosed by hill ranges on the north, east, and south and receives more than 100 inches (2,540 mm) of rainfall annually, while in the Bengal Plain heavy rainfall—averaging 70 to 100 inches—is reinforced by the huge discharge of the Tista, Torsa, and Jaldhaka rivers. Extensive �ooding is virtually an annual occurrence in the Brahmaputra valley during the summer monsoon. In addition, tidal surges accompanying tropical cyclones sweeping inland from the Bay of Bengal periodically bring great destruction to the delta region. One such storm—the Ganges- Brahmaputra delta cyclone (also called the Bhola cyclone) of November 1970—caused an estimated 300,000 to 500,000 deaths and inundated a vast area. In the 21st century the delta has also been affected by rising sea levels as a result of global warming. https://www.britannica.com/print/article/77154 4/8 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia causing the river to join the Brahmaputra opposite PLANT AND ANIMAL LIFE Bahadurabad Ghat in Mymensingh district. Until the late Along the upper reaches of the Brahmaputra (Tsangpo) 18th century the Brahmaputra �owed past the town of on the high Plateau of Tibet, the vegetation is mainly Mymensingh and joined the Meghna River near Bhairab xerophytic (drought-resistant) shrubs and grasses. As the Bazar (the path of the present-day Old Brahmaputra river descends from Tibet, increased precipitation channel). At that time a minor stream called the Konai- supports the growth of forests. Forests of sal (genus Jenai—probably a spill channel of the Old Brahmaputra— Shorea)—a valuable timber tree that is also utilized to followed the course of today’s Jamuna River (now the cultivate the lac insect, which produces the resin used to main Brahmaputra channel). After the Tista �ood of 1787 Indian rhinoceros (Rhinoceros unicornis) in make shellac—are found in Assam. At even lower Satellite image of the Ganges-Brahmaputra reinforced it, the Brahmaputra began to cut a new Kaziranga National Park, Assam, India. delta cyclone, November 12, 1970. elevations, tall reed jungles grow in the swamps and channel along the Konai-Jenai and gradually converted it © Jeremy Richards/Shutterstock.com depressed water-�lled areas (jheels) of the immense NOAA after 1810 into the main stream, now known as the �oodplains. Around towns and villages in the Assam Jamuna. Valley, the many fruit trees yield plantains, papayas, mangoes, and jackfruit. Bamboo thickets Along the lower courses of the Ganges and Brahmaputra and along the Meghna, the land abound throughout Assam and Bangladesh. Nipa palms (Nypa fruticans) and other halophytic undergoes constant erosion and deposition of silt because of the shifts and changes in these (salt-tolerant) �ora predominate in the delta region’s mangrove swamps. active rivers. Vast areas are subject to inundation during the wet monsoon months. The shifts The most-notable animal of the swamps in Assam is the one-horned rhinoceros, which has in the course of the Jamuna since 1787 have been considerable, and the river is never in exactly become extinct in other parts of the world; Kaziranga National Park (designated a UNESCO the same place for two successive years. Islands and sizable newly deposited lands (chars) in World Heritage site in 1985) provides a refuge for the rhinoceros and for other wildlife in the the river appear and disappear seasonally. The chars are valuable to the economy of valley, including elephants, Bengal tigers, leopards, wild buffalo, and deer. Numerous varieties Bangladesh as additional cultivable areas. of �sh include the pabda (Omdok pabda), chital (Notopterus chitala), and mrigal (Cirrhinus In Tibet the waters of the Brahmaputra are clear because little silt is carried downstream. As cirrhosus). soon as the river enters Assam, however, the silt load becomes heavy. Because of the speed and volume of water in the northern tributaries that �ow down from the rain-soaked PEOPLE Himalayan slopes, their silt load is much heavier than that carried by the tributaries crossing The people living in the different sections of the the hard rocks of the old plateau to the south. In Assam the deep channel of the Brahmaputra Brahmaputra valley are of diverse origin and culture. follows the southern bank closer than the northern. This tendency is reinforced by the silt- North of the Great Himalayas, the Tibetans practice laden northern tributaries pushing the channel south. Buddhism and speak the Tibetan language. They engage Another important feature of the river is its tendency to �ood. The quantity of water carried by in animal husbandry and cultivate the valley with the Brahmaputra in India and Bangladesh is enormous. The river valley in Assam is enclosed by irrigation water taken from the river. hill ranges on the north, east, and south and receives more than 100 inches (2,540 mm) of The ancestry of the Assamese includes peoples speaking rainfall annually, while in the Bengal Plain heavy rainfall—averaging 70 to 100 inches—is Stupa on the bank of the Tsangpo (Brahmaputra) River, Tibet Autonomous Tibeto-Burman languages from the surrounding reinforced by the huge discharge of the Tista, Torsa, and Jaldhaka rivers. Extensive �ooding is Region, China. highlands and peoples from the lowlands of India to the virtually an annual occurrence in the Brahmaputra valley during the summer monsoon. In © Naomi Duguid/Asia Access south and west. The Assamese language is akin to Bengali, addition, tidal surges accompanying tropical cyclones sweeping inland from the Bay of Bengal which is spoken in West Bengal state in India and in periodically bring great destruction to the delta region. One such storm—the Ganges- Bangladesh. Since the late 19th century a vast number of immigrants from the Bengal Plain of Brahmaputra delta cyclone (also called the Bhola cyclone) of November 1970—caused an Bangladesh have entered Assam, where they have settled to cultivate vacant lands, particularly estimated 300,000 to 500,000 deaths and inundated a vast area. In the 21st century the delta the low �oodplains. In the Bengal Plain itself the river �ows through an area that is densely has also been affected by rising sea levels as a result of global warming. https://www.britannica.com/print/article/77154 4/8 https://www.britannica.com/print/article/77154 5/8 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia populated by the Bengali people, who cultivate the fertile valley. The hilly margins of the plain are inhabited by the tribal Garo, Khasi, and Hajong of Meghalaya state in India.

ECONOMY

IRRIGATION AND FLOOD CONTROL

Flood-control schemes and the building of embankments were initiated after 1954. In Bangladesh the Brahmaputra embankment running west of the Jamuna River from north to south helps to control �oods. The Tista Barrage Project is both an irrigation and a �ood-protection scheme.

Until the 21st century, little power had been harnessed Boat traffic on the Buriganga (“Old Ganges”) along the Brahmaputra, although the estimated potential River, Dhaka, Bangladesh. was great—some 12,000 megawatts in India alone. An © Dmitry Chulov/Dreamstime.com increasing number of hydroelectric stations have been completed in Assam, most notably the Kopili Hydel Project in the south of the state. Another major project, the Ranganadi plant, has been built in Arunachal Pradesh, which has considerably more generating capacity than the Kopili station. In addition, a giant hydropower installation in Tibet on the Tsangpo River became fully operational in late 2015.

NAVIGATION AND TRANSPORT

Near Lhazê (Lhatse Dzong) in Tibet, the river becomes navigable for about 400 miles (640 km). Coracles (boats made of hides and bamboo) and large ferries ply its waters at 13,000 feet (4,000 metres) above sea level. The Tsangpo is spanned in several places by suspension bridges.

Because it �ows through a region of heavy rainfall in Assam and Bangladesh, the Brahmaputra is more important for inland navigation than for irrigation. The river has long formed a waterway between the Indian states of West Bengal and Assam, although, on occasion, political con�icts have disrupted the movement of traf�c through Bangladesh. The Brahmaputra is navigable throughout the Bengal Plain and Assam upstream to Dibrugarh, 700 miles (1,100 km) from the sea. In addition to all types of local craft, powered launches and steamers easily travel up and down the river, carrying bulky raw materials, timber, and crude oil.

The Brahmaputra remained unbridged throughout its course in the plains until the Saraighat Bridge—carrying both road and rail traf�c—was opened in 1962 near Guwahati, Assam. A second crossing in Assam, the Kalia Bhomora road bridge near Tezpur, was opened in 1987. https://www.britannica.com/print/article/77154 6/8 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia 10/12/2017 Brahmaputra River -- Britannica Online Encyclopedia populated by the Bengali people, who cultivate the fertile valley. The hilly margins of the plain Ferries, however, have continued as the most important—and in Bangladesh the only—means are inhabited by the tribal Garo, Khasi, and Hajong of Meghalaya state in India. of crossing the Brahmaputra. Sadiya, Dibrugarh, Jorhat, Tezpur, Guwahati, Goalpara, and Dhuburi are important towns and crossing points in Assam, while Kurigram, Rahumari, ECONOMY Chilmari, Bahadurabad Ghat, Phulchari, Sarishabari, Jagannathganj Ghat, Nagarbari, Sirajganj, IRRIGATION AND FLOOD CONTROL and Goalundo Ghat are major crossing points in Bangladesh. The railheads are located at Bahadurabad Ghat, Phulchari, Jagannathganj Ghat, Sirajganj, and Goalundo Ghat. Flood-control schemes and the building of embankments were initiated after 1954. In Bangladesh the Brahmaputra STUDY AND EXPLORATION embankment running west of the Jamuna River from The upper course of the Brahmaputra was explored as early as the 18th century, although it north to south helps to control �oods. The Tista Barrage remained virtually unknown until the 19th century. The explorations of the Indian surveyor Project is both an irrigation and a �ood-protection Kinthup (reported in 1884) and of J.F. Needham in Assam in 1886 established the Tsangpo scheme. River as the upper course of the Brahmaputra. Various British expeditions in the �rst quarter of Until the 21st century, little power had been harnessed the 20th century explored the Tsangpo upstream in Tibet to Xigazê, as well as the river’s Boat traffic on the Buriganga (“Old Ganges”) along the Brahmaputra, although the estimated potential mountain gorges. More-recent scienti�c work has concentrated on understanding the River, Dhaka, Bangladesh. was great—some 12,000 megawatts in India alone. An hydrology of the Brahmaputra for watershed management and �ood-hazard mitigation. © Dmitry Chulov/Dreamstime.com increasing number of hydroelectric stations have been Na�s Ahmad completed in Assam, most notably the Kopili Hydel Project in the south of the state. Another major project, the Ranganadi plant, has been built in Deryck O. Lodrick Arunachal Pradesh, which has considerably more generating capacity than the Kopili station. The Editors of Encyclopædia Britannica In addition, a giant hydropower installation in Tibet on the Tsangpo River became fully operational in late 2015. Source: NAVIGATION AND TRANSPORT "Brahmaputra River". Encyclopædia Britannica. Encyclopædia Britannica Online. Encyclopædia Britannica Inc., 2017. Web. 11 Oct. 2017 Near Lhazê (Lhatse Dzong) in Tibet, the river becomes navigable for about 400 miles (640 km). . Coracles (boats made of hides and bamboo) and large ferries ply its waters at 13,000 feet (4,000 metres) above sea level. The Tsangpo is spanned in several places by suspension bridges.

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