Brahmaputra
The Brahmaputra ( Sanskrit for "son of Brahma") is the main strand of the most water-rich river in Asia, which flows into the Indian Ocean as Meghna .
As one of the longest rivers on earth, it flows with a length of around 3,100 kilometers to the confluence with the Ganges through the area of the states China , India and Bangladesh . Its course is partly changeable, partly difficult to access and crosses several cultural areas, which has led to many different names of individual sections.
Names of the river sections
The east-facing upper reaches of the Brahmaputra in Tibet is called Matsang or Tachog Tsangpo ( རྟ་ མཆོག་ གཙང་ པོ rta mchog gtsang po ) in Tibetan , Mǎquán Hé 馬 泉河 / 马 泉河 in Chinese ; after that it is called in Tibetan Yarlung Tsangpo ཡར་ ཀླུང་ གཙང་ པོ yar klung gtsang po , "the purifying one", according to another source "water coming down from the highest peak", and in Chinese Yǎlǔ Zàngbù Jiāng 雅魯藏布江 / 雅鲁藏布江 .
In the Indian state of Arunachal Pradesh , the river that bends sharply to the south is called Dihang or Siang . After changing direction to the west at the confluence of the largest tributary, the Lohit , now flowing through the state of Assam , it is called Brahmaputra ( ब्रह्मपुत्र ), which means "son of Brahma" in Sanskrit . An older name of this section of the river was (in Sanskrit scriptures and in parts of Assam) Luit or Lohitya , as the Lohit used to be the upper reaches instead of the larger Dihang. Today the name is spoken in Hindi ब्रह्मपुत्र , Brahmaputra , in Assamese ব্ৰহ্মপুত্ৰ and in Bengali ব্রহ্মপুত্র Brohmoputro .
When turning south, the river enters the national territory of Bangladesh and leads partly from there, partly from the junction of the Old Brahmaputra (formerly the main stream) the name Jamuna . From the meeting with the significantly less voluminous Ganges , the current swings in its southeastern direction and is now called Padma , until it takes its name Meghna from the confluence of the last major tributary to the confluence with the Bay of Bengal .
River course
Tsangpo high valley
The Brahmaputra (Tsangpo) rises on the north side of the Central Himalayas 130 km east of the Gang Rinpoche ( Kailash ). After the union of three source streams, the middle and most water-rich of which flows from the Jema Yangdzom glacier (Tib .: rje ma g.yang 'dzoms ), the river is called Matsang for the next 268 kilometers . The river runs for a total of 2057 kilometers within Tibet , mostly about 160 kilometers north parallel to the main line of the Himalayas to the east. Its often straight valley there, accompanied by significant fault lines , separates the Himalayas in the south from the Transhimalaya in the north. The high valley, characterized by dry grassland, is wide and populated for long stretches, interrupted by narrow passages. The ramified Tsangpo is over 650 kilometers of river and at an altitude of more than 3,650 meters it is the highest shipping route on earth. Its mean water flow is between a good 900 m³ / s at Yangcun (near Lhasa ) and almost 2000 m³ / s at the beginning of the large gorges.
Gorges in the Pemako
In the Dihang gorges , called Yarlung Tsangpo Canyon in the upper part , the river cuts through the mountains in a north-easterly and then south-westerly direction. This 250 kilometer long, up to 3000 meter deep gorge is overlooked by around 5000 meters on both sides by individual peaks ( Namjagbarwa , 7782 m , Gyala Peri , 7294 m ) and is often referred to as the deepest gorge on earth. In 1913, FM Bailey succeeded in proving that the Tsangpo forms the upper reaches of the Brahmaputra, and it was not until 1998 that the most impassable section of the Tsangpo, with several waterfalls of up to 35 meters high , could be reached by one of the international expeditions there. This sacred area, called Pemako , was long kept secret by the Tibetans .
From the confluence of the Parlung Zangbo , the river is called Dihang . The narrow valley below the gorges in the state of Arunachal Pradesh, only a few hundred meters high, receives high monsoonal rainfall, but without a pronounced dry season, which is why the river rapidly increases its water flow and dense rainforest covers the slopes. From this breakthrough valley , the Siang (Dihang) suddenly enters the extensive Bengal lowlands. Its water flow here is almost 6000 m³ / s.
Brahmaputra (Jamuna) in the lowlands of Bengal
The suddenly reduced gradient causes the heavily sediment-laden river to form a large, flat alluvial cone at the foot of the mountain , over which it reaches the deepest area of the plain of Assam in a strongly intertwined course and there on the western flow direction of its largest tributary, the equally widely ramified Lohit, swings in. Together with the Dibang, which opened shortly before, of almost the same size, the Lohit carries about 4000 m³ / s and thus increases the current called Brahmaputra by around 65%. In the further course the river bed reaches a width of almost 15 kilometers several times, which is however only completely filled in 3 months of the monsoon season. Then the river at Pandu in Assam can carry up to 55,500 m³ / s of water, whereas the minimum discharge is only a good 1000 m³ / s (mean discharge of the Rhine : 2300 m³ / s).
In the further course, the Brahmaputra flow in close succession to water-rich tributaries, with the southern edge of the Himalayas being exceeded in rainfall by the hill country in the south (Shillong Plateau). The city of Cherrapunji located there became famous for its record rainfall. It partially borders directly on the river, first at the Kaziranga National Park , then at the largest city on its banks, Guwahati , where the one kilometer wide narrowest part of the Brahmaputra is, and finally at the westernmost foothills of the plateau, where the river flows down Turns south and reaches Bangladesh.
Delta area and old Brahmaputra
Where the Tista joins the stream now called Jamuna from the west , the Old Brahmaputra branches off to the east as a small arm of the river . The main stream retains its intertwined character and has an average flow rate of 21,200 m³ / s. The catchment area of the Brahmaputra covers 651,335 km² so far.
After the confluence with the main branch of the Ganges, also called Padma (11,400 m³ / s), the mighty river flows under this name to the southwest.
The lowest section of the river reaches the Bay of Bengal as the Lower Meghna , divided into several estuary arms. With an average water flow of 36,500 m³ / s, the current is only exceeded by the Amazon and the Congo . The total length of the river system is around 3350 km
Together with numerous smaller estuaries branching off from Brahmaputra, Ganges and Upper Meghna, the Lower Meghna forms the largest estuary delta on earth, known as the Ganges delta .
The old Brahmaputra follows its former streams across the Dhaka division , flowing through the city of Mymensingh and flowing , divided into two arms, on the one hand into the Upper Meghna, on the other hand into another branch of the Jamuna, the Dhaleshwari, which with one of its branches , which touches Buriganga , also the capital of Bangladesh, Dhaka .
Features and evolution of the river system
The course of the Brahmaputra is essentially mapped out by tectonic processes and structures that the ongoing collision process between the Indian plate and the Eurasian plate has so far produced.
The west-east running Tsangpo traces over long stretches of the earth's seam that separates the two plates. There is evidence that the eastern Tsangpo to the Miocene of the upper reaches of the by Myanmar flowing Irrawaddy was. The diversion to the south to what is now the lowlands of Assam took place before the Himalayas rose sharply; the breakthrough valley of the Dihang across the line of the highest peak in the Himalayas is therefore antecedent .
In the western valley of the Tsangpo, many tributaries flow in the opposite direction, so that it is assumed that this section of the valley originally drained to the west. The river would then have followed today's Kali Gandaki over a pass that is only 75 meters higher today and might even have created its gigantic valley gorge.
The rugged gorge of the Yarlung Tsangpo has been shaped on the one hand by flowing glaciers , mainly from the Ice Age , and on the other by repeated eruptions of ice reservoirs up to 680 meters deep that formed in front of them and reached around 300 kilometers into the Tibetan highlands. In addition to the loess drifts , the sediments of these ice reservoirs produced the fertile soil for today's “bread basket of Tibet”.
Tectonic uplifts also have a significant effect on the structure of the river system in the estuary area . The lower course of the Brahmaputra, which is united with the Ganges and represents the largest river in Asia, has only existed since the end of the 18th century. Before that, both rivers flowed separately into the Bay of Bengal, with the Brahmaputra running further east, along today's Old Brahmaputra and creating the broad channels of today's Upper Meghna. The westward shift to the current Jamuna-Lauf has taken place above all since an earthquake in 1782. At the same time, the western part of the Ganges delta rises, making the Padma arm of the Ganges its dominant main stream.
Depending on the course of the estuary, the Brahmaputra is either the main strand of the largest river system in Asia, as it is today, or, separated from the Ganges (but with the Upper Meghna still flowing into it), after the Yangtze River (with 31,900 m³ / s) the second largest river with approximately 25,000 m³ / s.
use
The river gradient of the Dihang gorges begins at around 3000 meters and ends a short distance away at only 300 meters. It thus represents one of the largest hydroelectric potentials on earth. In China there are therefore efforts to establish one in Mêdog (Metog) at the northeasternmost point of the river bend around the Namjagbarwa / Namcha Barwa, in which the Yarlung Tsangpo changes its direction from northeast to southwest To build a 160 meter high dam for a hydroelectric power plant, which would be the largest on earth with 26 turbines and a planned output of 40,000 MW. In China, feasibility studies are also being carried out on the discharge of water in the semi - arid northeast of the country.
There are even greater ambitions on the Indian side. Seven large power plants were completed on the Brahmaputra tributaries in India by 2016, more are under construction, and above all: over 140 are in the planning stage. There are also concrete plans in India to divert water from the north to the south. The ambitious project envisages the connection of 14 rivers from the Himalayas with 16 rivers on the Indian peninsula in order to shift water from surplus areas to scarce areas. In addition to controlling floods, 35 million additional hectares of land are to be irrigated and over 34,000 megawatts of electricity generated.
For a long time, attempts have been made to regulate the lowland sections of the river through technical measures and to make them more usable for commercial river navigation. Due to the great technical effort involved, this has only been successful to a very limited extent. Often times, the river creates new river beds when it floods, causing great economic damage. In addition, there is a tendency for the Jamuna bed to widen; from an average of 6.2 kilometers in width in 1830 to 10.6 kilometers in 1992, which may be due to an increase in sediment transport.
Web links
- The Yarlong Zangbo Canyon
- Brahmaputra at Banglapedia
- on the course of the Brahmaputra in Bangladesh
- Brahmaputra Jamuna river system
Individual evidence
- ↑ a b c Xiang Huang, Mika Sillanpää, Egil T. Gjessing, Rolf D. Vogt: Water quality in the Tibetan Plateau: Major ions and trace elements in the headwaters of four major Asian rivers . In: Science of the Total Environment . tape 407 , 2009, p. 6242–6254 , doi : 10.1016 / j.scitotenv.2009.09.001 ( PDF ( Memento from June 21, 2012 in the Internet Archive ); 827 kB [accessed on January 19, 2016] Table 1. The values there (length to mouth 3350 km) correspond most closely to image measurements (material on google earth). The length from the mouth of the Ganges to the sea (240 km) was subtracted. Water quality in the Tibetan Plateau: Major ions and trace elements in the headwaters of four major Asian rivers ( Memento of the original from June 21, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ a b World Resources Institute wri.org ( Memento of the original from March 3, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ GRDC: Ganges Basin. Bahadurabad Station . Retrieved July 8, 2015
- ↑ Tibet Travel Guide ( Memento from February 2, 2011 in the Internet Archive )
- ↑ discharge data from Yangcun and Tsela D'Zang
- ↑ Note: This superlative is more likely to apply to the Kali Gandaki gorge .
- ↑ a b Mean outflows from Dihang (Siang), Lohit and Dibang
- ↑ Mean discharge: 18,100 m³ / s ( discharge data from Brahmaputra at Pandu )
- ↑ Note: The next smaller river is the Orinoco with 35,000 m³ / s .
- ↑ L. Rüber, R. Britz, SO Kullander, R. Zardoya: Evolutionary and biogeographic patterns of the Badidae (Teleostei: Perciformes) inferred from mitochondrial and nuclear DNA sequence data. In: Molecular phylogenetics and evolution. Volume 32, Number 3, September 2004, pp. 1010-1022, PMID 15354300 .
- Jump up ↑ Vijay P. Singh, Nayan Sharma, C. Shekhar P. Ojha: The Brahmaputra basin water resources . Dordrecht 2004 - 610 pp. ISBN 1-4020-1737-5
- ^ David R. Montgomery, Bernard Hallet, Liu Yuping, Noah Finnegan, Alison Anders, Alan Gillespie, Harvey M. Greenberg: Evidence for Holocene megafloods down the Tsangpo River gorge, southeastern Tibet . (PDF; 803 kB) In: Quaternary Research , 62, 2004, pp. 201-207
- ↑ Karl Grobe: Giant dam on Yarlung Tsangpo. In: Berliner Zeitung . June 3, 2010, accessed July 10, 2015 .
- ↑ Water fight at Yarlung Tsangpo
- ↑ SAO / NASA ADS Physics Abstract Service, bibcode : 2007AGUFM.H11C0644Z
- ↑ Chinese engineers propose world's biggest hydro-electric project in Tibet
- ^ Hydropower Development in Arunachal Pradesh; Hydro Power Projects ; India Ministry of Power, April 2, 2012 , accessed February 16, 2018
- ↑ Modi's Grand Plan to Divert Himalayan Rivers Faces Obstacles; Environmental Change and Security Program, December 22, 2015 , accessed February 16, 2018
- ↑ India and China arm on the water ; Der Standard, April 21, 2016 , accessed February 16, 2018
- ↑ Nasreen Islam Khan, Aminul Islam: Quantification of erosion patterns in the Brahmaputra-Jamuna River using geographical information system and remote sensing techniques . Hydrological Processes, 17, pp. 959-966, 2003. doi: 10.1002 / hyp.1173
