Rivers of India: Notes for UPSC & SSC

Two families of rivers

Indian rivers fall into two groups: Himalayan rivers (Indus, Ganga and Brahmaputra systems) and Peninsular rivers (Godavari, Krishna, Kaveri, Mahanadi, Narmada, Tapi and others). The Western Ghats are the main water divide of the peninsula, so most peninsular rivers flow east into the Bay of Bengal.

The Indus system

• Indus rises in Tibet near Lake Mansarovar, flows through Ladakh and then Pakistan into the Arabian Sea.
• Five Punjab tributaries: Jhelum, Chenab, Ravi, Beas and Sutlej. The Jhelum rises at Verinag; the Chenab forms from the Chandra and Bhaga; the Beas joins the Sutlej at Harike; the Sutlej rises near Rakas Tal and enters India at Shipki La.
• Under the Indus Waters Treaty of 1960, the eastern rivers (Ravi, Beas, Sutlej) were allocated to India and the western rivers (Indus, Jhelum, Chenab) to Pakistan.

The Ganga system

The Bhagirathi rises from the Gangotri glacier at Gaumukh; the Alaknanda rises near the Satopanth glacier above Badrinath. They meet at Devprayag in Uttarakhand, and only below this point is the river called the Ganga. It enters the plains at Haridwar. The Ganga is about 2,525 km long, the longest river in India.

• Right-bank tributaries: Yamuna and Son. The Yamuna rises at the Yamunotri glacier and joins the Ganga at Prayagraj (Triveni Sangam). The Chambal, Sind, Betwa and Ken are tributaries of the Yamuna.
• Left-bank tributaries: Ramganga, Gomti, Ghaghara, Gandak, Kosi and Mahananda.
• The Kosi floods frequently and keeps shifting its course — the 'Sorrow of Bihar'. The Damodar, flowing through a rift valley in the Chota Nagpur plateau, was the 'Sorrow of Bengal' and is now managed by the Damodar Valley Corporation.
• In Bangladesh the Ganga is called the Padma; it joins the Jamuna (Brahmaputra) and then the Meghna before reaching the Bay of Bengal.

The Brahmaputra system

The Brahmaputra rises from the Chemayungdung glacier in the Kailash range near Lake Mansarovar. It changes name across three countries, which is a favourite exam question.

In Assam the river is braided and forms Majuli, among the largest river islands in the world. Together, the Ganga and Brahmaputra (with the Meghna) build the world's largest delta, whose mangrove forest is the Sundarbans, shared by India and Bangladesh.

Peninsular rivers — origins and facts

East-flowing vs west-flowing

• East-flowing (Mahanadi, Godavari, Krishna, Kaveri) cross gentle slopes and slow down near the coast, dropping sediment — they build deltas on the Bay of Bengal.
• West-flowing (Narmada, Tapi, Sabarmati, Mahi, Periyar) are short and swift or run through hard-rock rift valleys, so they carry little silt to the coast and form estuaries on the Arabian Sea.
• The Narmada and Tapi are the only large peninsular rivers that flow west, and both do so through rift valleys created by faulting, not river erosion.

Major dams and projects