The Sunkoshi, also spelt Sunkosi, is a river of Nepal that is part of the
Koshi Koshi or Kōshi may refer to:
Places
*Koshi River, a river in Nepal
*Koshi District, Niigata, a former district in Niigata Prefecture, Japan
* Koshi Province, a historic province of Japan
*Kōshi, Kumamoto, a city in Kumamoto Prefecture, Japan
*Ko ...
or Saptkoshi River system in
Nepal
Nepal (; ne, :ne:नेपाल, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in S ...
. Sunkoshi has two
source streams, one that arises within Nepal in
Choukati
Chaukati is a village in Sindhupalchok District in the Bagmati Zone of central Nepal. At the time of the 1991 Nepal census
The 1991 Nepal census was a widespread national census conducted by the Nepal Central Bureau of Statistics.
Working with ...
, and the other more significant stream that flows in from
Nyalam County
Nyalam County (; Tibetan: gnya' lam rdzong) is a county in Tibet's Shigatse Prefecture. It borders on Nepal.
The land area of the county is . The population as of 2003 was 10,000. The postal code for the county is 858300.
The county seat is in ...
in the
Tibet
Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa, Taman ...
region of China.
[ (See especially Figure 1).] The latter is called
Bhote Koshi
Bhote Koshi in Nepal and Poiqu in Tibet, both names roughly mean "Tibetan river," is the name given to the upper course (main tributary) of the Sun Kosi river. It is part of the Koshi River system in Nepal.Shrestha, A. B., Eriksson, M., Mool, ...
in Nepal and Matsang Tsangpo in Tibet. Due to the significant flows from Bhote Koshi, the Sun Koshi river basin is often regarded as a trans-border river basin.
River course
The Sunkoshi's headwaters are located in the Zhangzangbo Glacier
A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
in Tibet.[Mool, P. K.; Joshi, S. P.; Bajracharya, S. R. (2001). Glacial Lake Outburst Floods and Damage in the Country. Pages 121–136 in: Inventory of Glaciers, Glacial Lakes and Glacial Lake Outburst Floods: Monitoring and Early Warning Systems in the Hindu Kush-Himalayan Region, Nepal. International Centre for Integrated Mountain Development, Kathmandu.] Both Sunkoshi and Bhotekoshi river courses together form one basin that covers an area of about .[
The ]Indravati
Indravati River is a tributary of the Godavari River, in central India.
The Indravati River
is a stream of the river Godavari. Its starting point, found to be the Ghats of Dandakaranya, range from a hilltop village Mardiguda of Thuamula Ra ...
meets the Sunkoshi at Dolaghat
Dolalghat is a village development committee in Kabhrepalanchok District in Bagmati Province of central Nepal.
Demographics
At the time of the 1991 Nepal census it had a population of 1,714 and had 323 houses in it.
Transport
It is linked by Ar ...
, up to where it is followed by the Arniko Rajmarg
The Araniko Highway () connects Kathmandu with Kodari, northeast of the Kathmandu Valley, on the Nepal-China border. It is among the most dangerous of highways in Nepal due to extremely steep slopes on each side of the road from Barabise onwa ...
. From there, the Sunkoshi flows eastwards through the valley formed between the Mahabharat Range
The Lower Himalayan Range ( ne, पर्वत शृङ्खला parbat shrinkhalā) – also called the Middle Himalayas or Lesser Himalayas or Himachal – is a major east–west mountain range with elevations 3,700 to 4,500 m (12,000 to ...
and the Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over 10 ...
.[ Tamakosi, Likhu, Dudhkosi, Arun and Tamor are its left tributaries and Indravati is the right tributary.
The average annual flow is 2.2 x 1010 m3. The average ]sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sa ...
load is 5.4 x 107 m3.
The Tamur and the Arun rivers join the Sunkoshi at Tribenighat to form the Saptkoshi, which flows through the Chatra Gorge
The Chatra Gorge is a canyon cut by the Kosi River across the Mahabharat Range 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 Nep ...
across the Mahabharat Range
The Lower Himalayan Range ( ne, पर्वत शृङ्खला parbat shrinkhalā) – also called the Middle Himalayas or Lesser Himalayas or Himachal – is a major east–west mountain range with elevations 3,700 to 4,500 m (12,000 to ...
on to the Gangetic plain
The Indo-Gangetic Plain, also known as the North Indian River Plain, is a fertile plain encompassing northern regions of the Indian subcontinent, including most of northern and eastern India, around half of Pakistan, virtually all of Bangla ...
.[Sharma, U. P. (1996). Ecology of the Koshi river in Nepal-India (north Bihar): a typical river ecosystem. In: Jha, P. K., Ghimire, G. P. S., Karmacharya, S. B., Baral, S. R., Lacoul, P. (eds.) Environment and biodiversity in the context of South Asia. Proceedings of the Regional Conference on Environment and Biodiversity, 7–9 March 1994, Kathmandu. Ecological Society, Kathmandu. Pp 92–99.]
There are few more smaller tributaries of the Sunkoshi such as Rosi Khola, Junga Khola, and Sapsu Khola.
Names and etymology
ne, सुनकोशी
In Nepali language
Nepali (; , ) is an Indo-Aryan language native to the Himalayas region of South Asia. It is the official, and most widely spoken, language of Nepal, where it also serves as a '' lingua franca''. Nepali has official status in the Indian st ...
, the word "sun" means gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...
and golden; and the word "kosi" means river.
Koshi River system
The Koshi River drains eastern Nepal. It is also known as Saptkoshi River because of the seven rivers joining in east-central Nepal to form this river. The main rivers forming the Koshi River system are Sunkoshi, Indravati
Indravati River is a tributary of the Godavari River, in central India.
The Indravati River
is a stream of the river Godavari. Its starting point, found to be the Ghats of Dandakaranya, range from a hilltop village Mardiguda of Thuamula Ra ...
, Tamba Koshi, Bhote Koshi
Bhote Koshi in Nepal and Poiqu in Tibet, both names roughly mean "Tibetan river," is the name given to the upper course (main tributary) of the Sun Kosi river. It is part of the Koshi River system in Nepal.Shrestha, A. B., Eriksson, M., Mool, ...
, Dudh Kosi
Dudh Koshi (दुधकोशी नदी, ''Milk-Koshi River'') is a river in eastern Nepal. It is the highest river in terms of elevation.
Koshi river system
The Kosi River, or Sapt Koshi, drains eastern up. It is known as Sapta Koshi because ...
, Arun and Tamur River
The Tamor River is a major river in eastern Nepal, which begins around Kanchenjunga. The Tamor and the Arun join the Sun Koshi at Tribenighat to form the giant Saptakoshi which flows through Mahabharat Range on to the Gangetic plain
Koshi rive ...
s. The Saptkoshi River flows through the Chatra Gorge
The Chatra Gorge is a canyon cut by the Kosi River across the Mahabharat Range 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 Nep ...
in a southerly direction into northern Bihar
Bihar (; ) is a state in eastern India. It is the 2nd largest state by population in 2019, 12th largest by area of , and 14th largest by GDP in 2021. Bihar borders Uttar Pradesh to its west, Nepal to the north, the northern part of West ...
and joins the Ganges
The Ganges ( ) (in India: Ganga ( ); in Bangladesh: Padma ( )). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international river to which India, Bangladesh, Nepal and China are the riparian states." is ...
.
The Sunkoshi contributes about 44% of the total water of the Saptakoshi, the Arun 37% and the Tamur 19%.
Infrastructures
*Sunkosi–Kamala multipurpose project: The Sunkoshi has a 90% reliable flow of . It was proposed to divert the water from a small weir
A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of l ...
across the river near Kurule through a tunnel and a 61.4 MW associated power house to the Kamala River, flowing through central Nepal. Some of water would be transferred to the Kamala River for the purposes of irrigation and further generation of power.
Hazards
In July 1981, a sudden ice avalanche
An avalanche is a rapid flow of snow down a slope, such as a hill or mountain.
Avalanches can be set off spontaneously, by such factors as increased precipitation or snowpack weakening, or by external means such as humans, animals, and eart ...
caused a Glacial Lake Outburst Flood
A glacial lake outburst flood (GLOF) is a type of outburst flood caused by the failure of a dam containing a glacial lake. An event similar to a GLOF, where a body of water contained by a glacier melts or overflows the glacier, is called a j ...
in the moraine-dammed Zhangzangbu-Cho Lake in the headwaters of the Poiqu in Tibet. The ensuing debris
Debris (, ) is rubble, wreckage, ruins, litter and discarded garbage/refuse/trash, scattered remains of something destroyed, or, as in geology, large rock fragments left by a melting glacier, etc. Depending on context, ''debris'' can refer to ...
flow destroyed bridges, and sections of both the Arniko and the Nepal–China highways.[
On 2 August 2014, a landslide at Jure blocked the river downstream from Barabise and created a large lake that submerged a ]hydropower
Hydropower (from el, ὕδωρ, "water"), also known as water power, is the use of falling or fast-running water to produce electricity or to power machines. This is achieved by converting the gravitational potential or kinetic energy of a w ...
station. This huge rockslide of approximately blocked the Sunkoshi River upstream of Jure village. This landslide killed approximately 155 people, destroyed approximately 120 houses completely and 37 partially. The area has been declared a flood
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...
crisis zone, and local communities are evacuated. Power supply was interrupted, and the Arniko Highway blocked.
Water sports
The Sunkoshi is used for both rafting
Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a ...
and intermediate kayaking. It has grade III-IV rapids. The most common put in point of a Sunkoshi river trip is Dolaghat, at an elevation of and it ends at the Chatra Gorge at , a distance of around .
The first successful descent of the Sunkoshi was made in late September 1970 by Daniel C. Taylor, Terry Bech, Cheri Bremer-Kamp, and Carl Schiffler. They entered the river at Dolaghat and exited at the Nepal-India border. Their expedition took four days. Prior to this successful trip, there are four known unsuccessful attempts to descend the river, and one unsuccessful attempt to ascend the river in a jet boat under the leadership of Edmund Hillary.[Taylor, D. C. "Yeti: An Ecology of a Mystery." New Delhi: Oxford University Press, pp. 119-130.]
Notes
References
External links
Sun Kosi River
OpenStreetMap, retrieved 19 December 2021.
Bhote Kosi River
(Upper Sun Kosi), OpenStreetMap, retrieved 19 December 2021.
Arun River
OpenStreetMap, retrieved 19 December 2021.
Sapta Kosi River
OpenStreetMap, retrieved 19 December 2021.
{{Kosi basin
Rivers of the Province No. 1
Rivers of Tibet
International rivers of Asia