Kosi River Map

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Kosi River Map
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The Kosi or Koshi River is an intermittent river running both in Nepal and India. This famous river is also known in other names such as Saptakoshi or Sapt Koshi. The Kosi River has seven tributaries in the Himalayan mountain ranges.

Kosi River: An Overview

The Kosi River is a trans-boundary river, running across important cities in Bihar and Nepal such as Biratnagar, Purnia, and Katihar. The Koshi River System includes some rivers that have their sources in the self-governing territory of Tibet in China. These rivers include the Sun Kosi, the Arun, and the Bhote Kosi.

The Kosi River is famous for being one of the biggest tributaries of the Ganga (or the Ganges).

The Kosi river valley is bounded by steep margins that disconnect it from the Yarlung Zangbo River to the north, the Mahananda River to the east, the Gandaki to the west and the Ganga to the south. The Kosi River meets important tributaries in the Mahabharat Range around 30 miles or 48 km to the north of the boundary of India and Nepal.

Beneath the furthest bases of the Shivalik Mountain Range, the Kosi River has formed a megafan. The megafan is 15,000 km2 in area, forcing an entry to over 12 separate canals with changing itineraries because of inundation. The main tributaries of the Koshi River are the Kamlā, Budhi Gandak, and Bāghmati (also known as Kareh). In addition, the river also has some small tributaries such as Bhutahi Balān. Throughout an extensive period spanning 250 years, the river has changed its itinerary on 120 km (75 miles) from the east to the west. The unsteady characteristics of the river has been ascribed to the high level of siltation transported by the river during the monsoon periods. Deluging in the Indian subcontinent has severe outcomes and the nation ranks second all over the world next to Bangladesh in terms of casualties because of inundation, representing 20% of casualties from deluge in the world. The Kosi River has another name, the Sorrow of Bihar. It drains the terrains of northern Bihar with one of its main tributaries like the Gandak River. North Bihar is marked as the most inundation-prone region in India.

The Kosi is a perennial river similar to the Ramganga and the drainage basin is situated in part in Corbett National Park. From Mohan across Dhikuli upto Ramnagar, the Kosi creates the eastern frontier of Jim Corbett National Park.

Geography of the Kosi Basin

The catchment area of the Koshi in Nepal is surrounded to the west by the catchment areas of the Bagmati (supplying waters to Kathmandu Plateau) and the Gandaki. The Kanchenjunga in the Himalayas is its catchment basin on the east. The seven important tributaries of the Koshi River are as follows:

  • Tamakoshi or Tamba Koshi
  • Sun Kosi
  • Indravati
  • Dudh Kosi
  • Arun
  • Likhu
  • Tamur
The Sun Kosi meets the Dudh Kosi near Harkapur, a village in Nepal. The Arun, flowing from the north, meets the Sunkoshi, which is flowing from the west, at Triveni. The Arun and Dudhkoshi surround Mount Everest. Subsequently, the Tamar River joins it from the east. The merged stream then becomes the Saptakoshi, signifying “Seven Koshis”. The Saptakoshi goes past the Mahabharat or Lesser Himalayan Range in a deep canyon, the length of which is around 10 km (6.2 mi). The Saptakoshi river rises from the hills at Barāhkṣetra in Nepal and is known as the Koshi. After running a further distance of 58 km (36 miles), it penetrates Bihar in India in the vicinity of Bhimnagar. After an additional distance of 260 km (160 miles), the Koshi meets the Ganges close to Kursela. The overall length of the river is 729 km (453 miles).

The alluvial cone of the Kosi is one of the biggest in the world, and stretches from Barāhkṣetra through Nepal and subsequently eastern Mithila and northeast Bihar to the Ganges. The cone has a length of 180 km (110 miles) and width of 150 km (93 miles). The fan demonstrates proof of sidewise watercourse changing for more than 120 km (75 mi) for the last 250 years, through 12 important water canals as a minimum. The Kosi River, which ran close to Purnea in the 18th century, currently runs to the west of Saharsa. Pictures taken from satellite demonstrate old canals with a meeting point prior to 1731 when the Mahananda River was flowing to the north of Lava. The alluvial fan and its bordering territories have been analyzed through remote sensing methods. These information have been merged with geophysical and environmental data to deduce reasons accountable for the sidewise switches.

National parks on the riverbanks of the Kosi River

The following national parks and wildlife reserves are situated on the riverbanks of the Kosi River:

  • The Koshi Tappu Wildlife Reserve
  • The Sagarmatha National Park
Koshi Tappu Wildlife Reserve

This wildlife reserve is essentially a marshland located on the plains drained by the Sapta Koshi River in the eastern Terai in Nepal. It was listed in the Gazette of India as a wildlife reserve in 1976. This wildlife reserve encompasses an expanse of 68 sq mile or 175 km2. It is also one of the most popular bird watching spots in the Indo-Gangetic plain. This famous wildlife reserve is home to huge numbers of propagating Bristled Grassbird, Swamp Francolin, Finn’s Weaver, and Hodgson's Bushchat.

The Koshi River creates the important watershed of the wildlife reserve and houses about 441 categories of birds, 80 types of fishes, 114 water birds, 30 coastal birds, 2 ibises, and 20 ducks.

You will also see the imperiled Bengal Florican in this area. The migrant birds find the Koshi Barrage as a quite peaceful place and make it their natural habitat. In the winter, more than 87 types of migrant birds come here. Taking into consideration its wide variety of plants and animals, the site has received the recognition of a Ramsar site in 1987, which is a quite important status all over the world. The imperiled Gangetic dolphin (colloquially named as the sons in Bihar), Gharial crocodile, and freshwater dolphins have been found in the Kosi River.

You will find the last living population of arna or Nepalese wild buffalo in this reserve (the estimated population is around 150). The area is also home to a number of other types of wildlife like rock python, spotted deer, hog deer, blue bull, and wild boar. The foliage comprises diverse broad-leafed forests that are usually seen on the riverbanks. Patches of grasslands are also seen.

During monsoon, the area is inundated with intensities varying from 10 to 300 cm (3.9 to 120 inches). Bird watching is a popular activity beside the eastern escarpment at twilight and sunrise. It draws significant numbers of tourists to the area. Gangetic River Dolphin, also named as sons in Bihar, is an imperiled variety of freshwater dolphin.

Sagarmatha National Park

This national park is situated in the eastern part of Nepal, comprising the southern half of Mt. Everest and portions of the Himalayas. The national park has been recognized as a World Heritage Site by the UNESCO and was opened to the common public on July 19, 1976. In Sanskrit language, Sagarmatha stands for “Forehead of Universe” (Matha: Forehead and Sagar: Heavens or Sky). It is also the contemporary name for Mount Everest in Nepali dialect. The park encompasses an expanse of 1,148 km2 (443 sq mi) and varies in terms of height from its lowest tip of 2,845 meters (9,334 feet) at Jorsalle to 8,848 meters (29,029 feet) at the pinnacle of Mt. Everest, which is the tallest peak in the world. Other peaks are Cho-Oyu, Lhotse, Nuptse, Thamserku, Pumori, and Amadablam and all of their elevations are more than 6,000 meters (20,000 feet).

The higher catchment basin of the Dudh Kosi River is situated in the park. The different varieties of flora and fauna seen in the park are dependent on the elevation.

The jungles in Sagarmatha National Park are home to 118 different varieties of birds, which include Blood Pheasant, Himalayan Monal, Alpine and Red-billed Chough. The park also houses a range of endangered species, which include the following:

  • Wild yak
  • Musk deer
  • Asian Black Bear
  • Snow leopard
  • Red panda
  • Deer
  • Himalayan thars
  • Hares
  • Langur monkeys
  • Martens
  • Mountain foxes
  • Himalayan wolves
You will see the following varieties of plants in the national park:

  • Juniper
  • Birch
  • Blue Pines
  • Firs
  • Rhododendron
  • Bamboo
As the height augments, flora is limited to mosses and lichens. The visitor center of the park is situated atop a hill in Namche Bazaar. In this area, a troupe of the Nepal Royal Army is posted to look after the park. The access of the park to the south is one or two hundred meters at an elevation of 2,835 m (9,300 ft) to the north of Mondzo, a one-day trip from Lukla.

The existence of the Sherpas with their distinctive traditions adds additional importance to this park. The park received the recognition of a World Heritage Site from UNESCO in 1979 for its unusual natural, traditional, and geographical features.

Last Updated on September 15, 2020