Which is the Widest River in India?

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Widest River of India – Brahmaputra

Brahmaputra is the widest river of India as well as in the Asian sub continent. The river has many major rivers as its tributaries like- Manas, Dihang and Lohit etc; contributing enormously into the flow of Brahmaputra. Manas River is ranked 9^th in the world in terms of discharge which is 7641 cubic meters/second and contributes to nearly 5.5% in Brahmaputra’s flow. The bank to bank width of Brahmaputra reaches to around 26 km in Dibrugarh, Assam; which may reach up to 36 km during the monsoon.

The Brahmaputra is Trans Boundary River; that is, it flows through China, India and Bangladesh and is also the few rivers in India having a masculine name (‘Brahma-putra’meaning ‘the son of Brahma’). The Brahmaputra flows for 3848 km (2391 miles) with its depth ranging from 38 mtrs to 120 mtrs at different locations. The third highest mountain peak in the world- ‘Kanchenjunga’ (3586 mtrs) is the highest mountain in Brahmaputra Basin.

Brahmaputra is also the longest river flowing in India, in terms of water discharge. The average water discharge of Brahmaputra is 19,800 cubic meter/second, which may reach up to 100000 cubic meter/second during floods.

The upper reaches of Brahmaputra were unexplored till 1984-86; when its origin from a glacier in the ‘Mansarovar Lake’ region was established.

The Mythology of Origin

Both India and Tibet have their own mythological beliefs related to the river. Tibetans believe that there was a great lake; south east of Mt. Kailash and Lake Mansarovar in Western Tibet. A noble being decided on making a way for the water to flow; with the noble thought that the water should be used by the people of the region. So, the noble man cut a way through the Himalayas, for the river to flow.

In Tibet, Brahmaputra is called as ‘Yarlung Tsangpo’ and is considered very auspicious by the locals. The mountains through which the river flows are believed to have miraculous abilities and are considered holy.

The Indian belief of the origin of Brahmaputra is based on a mythological story. Hindus believe that Brahmaputra is the son of Amogha and Brahma; Amogha was the wife of sage Santanu. The child so born had features resembling Brahma and he also had a watery form. He was thus named ‘Brahmakunda’ and was place by Santanu, in the middle of four mountains- Gandhamadana, Sambwartakka, Jarudhi and Kailash.

Another sage named Parashurama (incarnation of Lord Vishnu) had committed a great sin by murdering his mother with an axe; on behest of his father. As a punishment for the great sin committed the axe got stuck permanently in his hand. Saddened by his sin and its repercussion; Parashurama started visiting holy places to seek forgiveness.

During his journey he came across Brahmakunda which had grown to a huge lake and decided to make a way for it to flow through mountains; possibly to help people residing in the region. When his noble deed was completed, the river thus formed was named ‘Brahmaputra’ and the axe miraculously came out; relieving him of the misery.

Origin and Course

In Tibet the Brahmaputra is known as ‘Yarlung Tsangpo’; probably due to its origin in the ‘Tsang’ province of Tibet. The river originates from Angsi glacier in the Burang County in western part of Tibet Autonomous Region in China. Burang County is an administrative head quarter and shares border with Indian state of Uttrakhand and the country of Nepal.

From its origin the river flows for nearly 1100 km (800 miles) to the East, between the Himalayas in the south and the Kailash Mountain range in North. It passes through ‘Yarlung Tsangpo Great Canyon’ which is the deepest canyon in the world and a little longer than the Grand Canyon USA. Some major tributaries of the Tsangpo in Tibet are – Raka Zangbo, Lhasa, Nyang Qu and Nyang Chu.

After flowing to East the river changes the direction to North East, entering the Tsangpo gorge; among the mountains of Gyala Peri and Namcha Barwa. Thereon it turns south and flows south west passing through the ‘Tsangpo Canyon’ which is very deep with the height of walls reaching up to 5 km.

The river enters into India at the North Eastern state of Arunachal Pradesh; turning southwards thereafter. The river is called Dihang or Siang in Arunachal Pradesh and flows for nearly 35 km before being joined by the Dibang and Lohit Rivers; after which, it enters in to the Assam valley.

Brahmaputra debouches out of mountains entering the plains of northeastern Assam; obtaining a width of 20 to 26 km in some parts of the Assam. During its flow in Assam the river is met by many Himalayan streams- Subhansiri, Bhareli, Manas and Sankosh etc. The normal bank to bank width of the Brahmaputra in Assam during the dry season is approx 8 km.

The river also forms the largest River Island in the world while flowing through Assam; which is called ‘Majuli Island’ (The first Island in India which was made a district in 2016). The Island is formed as the Brahmaputra divides in to two channels between Dibrugarh and Lakhimpur districts before meeting again at 100 km downstream. The southern and northern channels are called the Brahmaputra and Kherkutia Channels respectively.

Traversing through the capital of Assam- Guwahati, the river passes through the Shillong Plateau obtaining at places a width as narrow as 1 km. It was among these narrow passages that the Battle of Saraighat was fought between Mughal Empire and Ahom Kingdom in March 1671.

Saraighat also has the distinction of having the first Rail/Road Bridge across Brahmaputra; which was opened for public in 1962.

The Brahmaputra enters Bangladesh after turning southwards from Dhubri in India. Further the river is joined by Teesta River on its right bank, after passing through Chilmari in Bangladesh. Thereon it traverse for 240 km south and is called the Jamuna River.

Another river known as the Dhaleshwari River separates from the Jamuna near Chak Gopal, Bangladesh and continues to flow in south east direction. Further the Brahmaputra meets Padma (a distributary of Ganga) near Goalanda in Bangladesh.

Thereon the river flows in southeast for 120 km as Padma River. Padma is confluence with Maghna River at Chandpur from where it enters Bay of Bengal.

The Brahmaputra River Basin

The basin of Brahmaputra River is enormous around 6,51,334 square km. It is also a classic example of ‘braiding’- forming temporary islands along its flow, due to separated channels. The river is also at the risk of River Channel Migration and Avulsions.

The river has shifted its course for about 90 km westwards in the previous two and a half centuries leaving behind the old Brahmaputra.

River Channel Migration occurs as a result of sedimentation and bank erosion; while, avulsions is a process where a river abandons its channel and forms a new one. It occurs due to the difference in slopes of channels i.e. the river mostly flows through the channel with more slope or gradient.

The Ganga-Brahmaputra Delta is the largest delta in the world with an area of 59,750 square kilometers. The Brahmaputra Delta alone is home to 130 million people and around 6 lakh reside on the islands formed by the river.

The Floods of Brahmaputra

The river being the Asia’s largest in terms of water discharge is flooded each year during the monsoon from July to September. Though, devastating and destructive when massive; the occasional floods are also useful for the wildlife and the ecology of the land as they deposit alluvium increasing the fertility of the soil.

The floods of 1998 and 2004 had displaced millions and destroyed nearly the same number of houses apart from damaging 10000 km of roads and not to mention the loss of life due to the flood and it’s after effects.

Major Bridges on Brahmaputra

1) Bogibeel Bridge

Being 4.94 km long it is the largest rail and road bridge across a river in India. The bridge connects the districts Dhemaji and Dibrugarh in Assam.

2) Dhola Sadia Bridge

The bridge is build across the Lohit River and connects the states of Assam and Arunachal Pradesh. It is 9.1 km long and is also called the ‘Bhupen Hazarika Setu’.

3) Kolia Bhomora Setu

It is the 3 km long concrete bridge across Brahmaputra connecting Sonitpur and Nagaon districts of Assam.