The major Himalayan rivers are the Indus, the Ganga, and the Brahmaputra. These rivers are long and are joined by many large and important tributaries. A river along with its tributaries may be called a river system.

The Indus River System

The river Indus rises in Tibet, near Lake Mansarovar. It enters India in the Ladakh district of Jammu and Kashmir. One of the Himalayan rivers, Indus forms a picturesque gorge in this part. The Zaskar, the Nubra, the Shyok, and the Hunza, join it in the Kashmir region. The Indus flows through Baltistan and Gilgit and emerges from the mountains at Attock.

The Satluj, the Beas, the Ravi, the Chenab, and the Jhelum join together to enter the Indus near Mithankot in Pakistan. The Indus flows southwards eventually reaching the Arabian Sea, east of Karachi.

The Indus Plain has a very gentle slope. With a total length of 2900 km, the Indus is one of the longest rivers in the world. A little over a third of the Indus basin is located in India in the states of Jammu and Kashmir, Himachal Pradesh, and Punjab, and the rest are in Pakistan.

The Ganga River System

The headwaters of the Ganga called the "Bhagirathi' is fed by the Gangotri Glacier and joined by the Alaknanda at Devprayag in Uttaranchal. At Haridwar, the Ganga emerges from the mountains onto the plains. The Himalayan River, Ganga is joined by many tributaries from the Himalayas, a few of them being major rivers such as the Yamuna, the Ghaghara, the Gandak, and the Kosi.

The river Yamuna rises from the Yamunotri Glacier in the Himalayas. It flows parallel to the Ganga and as a right bank tributary meets the Ganga at Allahabad. The Ghaghara, the Gandak and the Kosi rise in the Nepal Himalaya.

They are the rivers, which flood parts of the northern plains every year, causing widespread damage to life and property but enriching the soil for the extensive agricultural lands. The main tributaries, which come from the peninsular uplands are the Chambal, the Betwa, and the Son.

These rise from semi-arid areas, have shorter courses and do not carry much water in them. Enlarged with the waters from its right and left bank tributaries, the Ganga flows eastwards till Farakka in West Bengal. This is the northernmost point of the Ganga delta.

The river bifurcates here; the Bhagirathi-Hooghly (a distributary) flows southwards through the deltaic plains to the Bay of Bengal. The mainstream flows southwards into Bangladesh and is joined by the Brahmaputra. Further downstream, it is known as the Meghna.

This mighty river, with waters from the Ganga, and the Brahmaputra, flows into the Bay of Bengal. The delta formed by these rivers is known as the Sunderban delta. The length of the Ganga is over 2500 km. Look at Figure 3.4; can you identify the type of drainage pattern formed by the Ganga river system?

Ambala is located on the water divide between the Indus and the Ganga river systems. The plains from Ambala to the Sunderban stretch over nearly 1800 km, but the fall in its slope is hardly 300 meters. In other words, there is a fall of just one meter for every 6 km. Therefore, the river develops large meanders.

The Brahmaputra River System

The Brahmaputra rises in Tibet east of Mansarovar lake is very close to the sources of the Indus and the Satluj. It is slightly longer than the Indus, and most of its course lies outside India. It flows eastwards parallel to the Himalayas.

On reaching the Namcha Barwa (7757 m), it takes a U-turn and enters. India in Arunachal Pradesh through a gorge. Here, it is called the Dihang and it is joined by the Dibang, the Lohit, and many other tributaries to form the Brahmaputra in Assam. In Tibet, the river carries a smaller volume of water and less silt as it is a cold and dry area.

In India, it passes through a region of high rainfall. Here the river carries a large volume of water and a considerable amount of silt. One of the Mighty Himalayan Rivers, Brahmaputra has a braided channel in its entire length in Assam and forms many riverine islands. Do you remember the name of the world's largest riverine island formed by the Brahmaputra?

Yes, it is Majuli Island and has a total area of 1,250 square kilometers. Every year during the rainy season, the river overflows its banks, causing widespread devastation due to floods in Assam and Bangladesh.

Unlike other north Indian rivers, the Brahmaputra is marked by huge deposits of silt on its bed causing the river bed to rise. The river also shifts its channel frequently.

Read More: Peninsular Rivers: Narmada, Godavari, Mahanadi, Krishna and Kaveri Basin