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Arun River (Nepal)
Encyclopedia
The Arun River is a trans-boundary river
and is part of the Kosi
or Sapt Koshi
river system in Nepal
. It originates in Tibet Autonomous Region
of People's Republic of China
where it is called Bum-chu.
the river's name changes to Arun.
of Tibet. Around 17 kilometres (10.6 mi) downstream the Men-chu joins it. The Dingri county
occupies the upper reaches of the Bum-chu and the lateral valleys formed by its tributaries, the foremost of which are Lolo-chu, Shel-chu, Rongpu-chu, Trakar-chu, Kharda-chu, Ra-chu Tsangpo, and Langkor Gya-chu. The Yeru Tsanpo confluences with Bum-chu in Tingkye County
, which accommodates the lower Bum-chu valley. Another river that meets Bum-chu is Trakar-chu. The river flows past the town of Kharda, gateway to the Khangzhung east face of Everest. With the force of its accumulated waters carves its way, South of Drengtrang, through the main chain of the Himalayas
directly between the mountain massifs of Everest
and Kangchenjunga
into Nepal.
or Sapta Koshi drains eastern Nepal. It is known as Sapt Koshi
because of the seven rivers which join together in east-central Nepal to form this river. The main rivers forming the Koshi system are – the Sun Kosi
, the Indravati River
, the Bhoté Koshi, the Dudh Kosi
, the Arun River, Barun River
, and Tamur River
. The combined river flows through the Chatra gorge in a southerly direction to emerge from the hills.
The Sun Kosi contributes 44 per cent of the total water in the Sapta Koshi , the Arun 37 per cent and the Tamur 19 per cent.
The river leaves the Tibet region at a height of about 3500 metres (11,482.9 ft).
South of the Himalayas, the flow of the Arun increases substantially in the seasonally-humid environment of east Nepal. The landscape south of the border tends to be steep with less than 15 percent of the area having a sustained slope of less than 15° and is strongly dissected by stream channels. Many of the hill slopes are structurally unstable, and the region is seismically active. An earthquake in August 1988, with an epicentre more than 50 km south of the Arun basin, had a magnitude of 6.7 on the Richter scale and resulted in more than 100 deaths in the Arun basin alone The northern third of the Nepalese portion of the Arun basin supports a rich, though human-modified, forest of mixed hardwoods, Chir pine, fir, and rhododendron at elevations of over 1000 metres (3,280.8 ft). The vegetation in the southern two-thirds of the area has been extensively modified for subsistence agriculture. Most of the half-million people in the Arun basin live in this southern area between 300 metres (984.3 ft) and 1000 metres (3,280.8 ft) in widely scattered villages near the slopes they farm.
Trans-boundary river
A trans-boundary river is a river that crosses at least one political border, either a border within a nation or an international boundary. The country of Bangladesh has the greatest number of these rivers, almost all of which cross national boundaries....
and is part of the Kosi
Koshi River
The Kosi River or Koshi —also Saptakoshi for its seven Himalayan tributaries—is a trans-boundary river flowing through Nepal and India. Some of the rivers of the Koshi system, such as the Arun, the Sun Kosi and the Bhote Koshi, originate in the Tibet Autonomous Region of China...
or Sapt Koshi
Sapt Koshi
Sapt Koshi is a large river in eastern Nepal. It flows into India to join the Ganges. The river name "Sapta" means "seven" in area languages, as seven rivers flow together out of the eastern himalaya to create the Sapta Koshi river. The seven rivers are the Indrawati, Bhote Koshi, Tama Koshi,...
river system in Nepal
Nepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
. It originates in Tibet Autonomous Region
Tibet Autonomous Region
The Tibet Autonomous Region , Tibet or Xizang for short, also called the Xizang Autonomous Region is a province-level autonomous region of the People's Republic of China , created in 1965....
of People's Republic of China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
where it is called Bum-chu.
Name
In Tibet, the river is called Bum-chu., also transliterated Phung-Chu or from Chinese as Peng Qu or Pumqu. Men Qu or Moinqu is an upper tributary draining glaciers from Xixabangma (Shishapangma). In NepalNepal
Nepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
the river's name changes to Arun.
Tibet
The Tibetan name Bum-chu may refer to a religious ceremony attempting to divine prospects for the coming year from the level of water in a pot or well., Chu is the Tibetan word for water. The river originates near Zurtso in Nyalam CountyNyalam County
Nyalam County is a county in Tibet's Xigazê Prefecture. It borders on Nepal.The land area of the county is 7,903 square km. The population as of 2003 was 10,000. The postal code for the county is 858300.The county seat is in Nyalam Town....
of Tibet. Around 17 kilometres (10.6 mi) downstream the Men-chu joins it. The Dingri county
Tingri County
Tingri County or Dhringgri County , is a county of the Xigazê Prefecture in the Tibet Autonomous Region.The county comprises the upper valley of the Bum-chu or Arun River, with the valleys of its tributaries plus the valleys of the Rongshar Tsangpo and the Lapchi Gang Tsanpo which flow south into...
occupies the upper reaches of the Bum-chu and the lateral valleys formed by its tributaries, the foremost of which are Lolo-chu, Shel-chu, Rongpu-chu, Trakar-chu, Kharda-chu, Ra-chu Tsangpo, and Langkor Gya-chu. The Yeru Tsanpo confluences with Bum-chu in Tingkye County
Dinggyê County
Dinggyê County or Tingche County is a county of the Xigazê Prefecture in the Tibet Autonomous Region. Jin Co and Duolo Co are located in this county.-See also:*Dinggyê...
, which accommodates the lower Bum-chu valley. Another river that meets Bum-chu is Trakar-chu. The river flows past the town of Kharda, gateway to the Khangzhung east face of Everest. With the force of its accumulated waters carves its way, South of Drengtrang, through the main chain of the Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
directly between the mountain massifs of Everest
Mount Everest
Mount Everest is the world's highest mountain, with a peak at above sea level. It is located in the Mahalangur section of the Himalayas. The international boundary runs across the precise summit point...
and Kangchenjunga
Kangchenjunga
Kangchenjunga is the third highest mountain of the world with an elevation of and located along the India-Nepal border in the Himalayas.Kangchenjunga is also the name of the section of the Himalayas and means "The Five Treasures of Snows", as it contains five peaks, four of them over...
into Nepal.
Kosi River System
The KosiKoshi River
The Kosi River or Koshi —also Saptakoshi for its seven Himalayan tributaries—is a trans-boundary river flowing through Nepal and India. Some of the rivers of the Koshi system, such as the Arun, the Sun Kosi and the Bhote Koshi, originate in the Tibet Autonomous Region of China...
or Sapta Koshi drains eastern Nepal. It is known as Sapt Koshi
Sapt Koshi
Sapt Koshi is a large river in eastern Nepal. It flows into India to join the Ganges. The river name "Sapta" means "seven" in area languages, as seven rivers flow together out of the eastern himalaya to create the Sapta Koshi river. The seven rivers are the Indrawati, Bhote Koshi, Tama Koshi,...
because of the seven rivers which join together in east-central Nepal to form this river. The main rivers forming the Koshi system are – the Sun Kosi
Sun Kosi
The Sun Kosi or Matsang Tsangpo is a trans-boundary river and is part of the Kosi or Sapta Kosi river system in Nepal. It originates in Tibet Autonomous Region of China.-Etymology:...
, the Indravati River
Indravati River, Nepal
-Kosi river system:The Kosi or Sapt Kosi drains eastern Nepal. It is known as Sapt Koshi because of the seven rivers which join together in east-central Nepal to form this river. The main rivers forming the Kosi system are – the Sun Kosi River, the Indravati River, the Bhola Koshi, the Dudh Kosi,...
, the Bhoté Koshi, the Dudh Kosi
Dudh Kosi
-Kosi river system:The Kosi or Sapt Kosi drains eastern Nepal. It is known as Sapt Koshi because of the seven rivers which join together in east-central Nepal to form this river. The main rivers forming the Kosi system are – the Sun Kosi, the Indravati River, the Bhola Kosi, the Dudh Kosi, the Arun...
, the Arun River, Barun River
Barun River
The Barun River is a tributary of the Arun River and is part of the Kosi river system in Nepal.-Kosi river system:The Kosi or Sapt Kosi drains eastern Nepal. It is known as Sapt Koshi because of the seven rivers which join together in east-central Nepal to form this river...
, and Tamur River
Tamur River
The Tamur River is a major river in eastern Nepal, which begins around Kanchenjunga. The Tamur and the Arun join the Sun Kosi at Tribenighat to form the giant Saptakoshi which flows through Mahabharat Range on to the Gangetic plain-Kosi river system:...
. The combined river flows through the Chatra gorge in a southerly direction to emerge from the hills.
The Sun Kosi contributes 44 per cent of the total water in the Sapta Koshi , the Arun 37 per cent and the Tamur 19 per cent.
Nepal
The Arun is the largest trans-Himalayan river passing through Nepal and also has the greatest snow and ice covered area of any Nepalese river basin. The Arun drains more than half of the area contributing to the Sapta Kosi river system but provides only about a quarter of the total discharge. This apparent contradiction is caused by the location of more than 80 percent of the Arun's drainage area in the rain shadow of the Himalayas. Average annual rainfall in Tibet is about 300 millimetres (11.8 in).The river leaves the Tibet region at a height of about 3500 metres (11,482.9 ft).
South of the Himalayas, the flow of the Arun increases substantially in the seasonally-humid environment of east Nepal. The landscape south of the border tends to be steep with less than 15 percent of the area having a sustained slope of less than 15° and is strongly dissected by stream channels. Many of the hill slopes are structurally unstable, and the region is seismically active. An earthquake in August 1988, with an epicentre more than 50 km south of the Arun basin, had a magnitude of 6.7 on the Richter scale and resulted in more than 100 deaths in the Arun basin alone The northern third of the Nepalese portion of the Arun basin supports a rich, though human-modified, forest of mixed hardwoods, Chir pine, fir, and rhododendron at elevations of over 1000 metres (3,280.8 ft). The vegetation in the southern two-thirds of the area has been extensively modified for subsistence agriculture. Most of the half-million people in the Arun basin live in this southern area between 300 metres (984.3 ft) and 1000 metres (3,280.8 ft) in widely scattered villages near the slopes they farm.