Drainage System of India

The Indian drainage system is broadly divided into two major groups based on their origin and characteristics: The Himalayan Rivers and The Peninsular Rivers.

1. The Himalayan River Systems

These rivers originate from the high altitude Himalayan glaciers. They are perennial in nature (have water throughout the year because they receive water from rain as well as melted snow). They have long courses, perform intensive erosional activity, form V-shaped valleys, and create large deltas. Major systems include:

A. The Indus River System

• Origin: Bokhar Chu glacier, near Lake Mansarovar in Tibet (China). Known as Singi Khamban (Lion's mouth) in Tibet.
• Course: Flows northwest entering India in Ladakh. Enters Pakistan through Gilgit-Baltistan and drains into the Arabian Sea near Karachi.
• Left-bank Tributaries (The Punjab rivers): Jhelum, Chenab, Ravi, Beas, and Sutlej. These five rivers meet at Panjnad before joining the Indus.
  • Jhelum: Originates at Verinag, flows through Wular Lake.
  • Chenab: Largest tributary, formed by Chandra and Bhaga rivers.
  • Sutlej: Originates from Rakas Lake (Tibet), enters India through Shipki La pass.
• Indus Water Treaty (1960): Mediated by the World Bank. India controls waters of eastern rivers (Ravi, Beas, Sutlej), Pakistan controls western rivers (Indus, Jhelum, Chenab).

B. The Ganga River System

• Origin: Gangotri glacier (Uttarakhand) where it is called the Bhagirathi. It becomes the Ganga after converging with the Alaknanda river at Devprayag.
• Course: Flows south and east through the northern plains. Splits into Hooghly (West Bengal) and Padma (Bangladesh). It joins the Brahmaputra (called Jamuna in Bangladesh) and forms the world's largest delta, the Sunderbans Delta, before flowing into the Bay of Bengal.
• Right-bank Tributaries: Yamuna (longest, originates from Yamunotri, joins Ganga at Prayagraj), Son.
• Left-bank Tributaries: Ramganga, Gomti, Ghaghara, Gandak, Kosi (known as the "Sorrow of Bihar" for frequent flooding), Mahananda.

C. The Brahmaputra River System

• Origin: Chemayungdung glacier of the Kailash range near Mansarovar lake.
• Course: Flows eastward parallel to the Himalayas in Tibet, where it is known as Tsangpo. Takes a U-turn at Namcha Barwa and enters Arunachal Pradesh as the Dihang. Flows through Assam as Brahmaputra, where it forms Majuli, the world's largest riverine island. Enters Bangladesh as Jamuna.
• Tributaries: Dibang, Lohit, Subansiri, Kameng, Manas, Teesta.

2. The Peninsular River System

These rivers are older than Himalayan rivers. They are generally seasonal (depend on monsoon rainfall), flow through broad, shallow valleys heavily graded, and are characterized by fixed courses and absence of meanders.

East-Flowing Rivers (Into Bay of Bengal)

These rivers form large deltas at their mouths.

• Mahanadi: Originates in Chhattisgarh, flows through Odisha.
• Godavari (Dakshin Ganga): The largest peninsular river system. Originates in Trimbakeshwar (Nasik, Maharashtra). Tributaries: Penganga, Indravati, Pranhita.
• Krishna: Originates near Mahabaleshwar (Maharashtra). Tributaries: Tungabhadra, Bhima, Musi.
• Cauvery (Kaveri): Originates in Brahmagiri hills (Karnataka), flows through Tamil Nadu. Often called the 'Ganga of the South'. Unlike other peninsular rivers, it receives rain in both summer (southwest monsoon) and winter (northeast monsoon).

West-Flowing Rivers (Into Arabian Sea)

These rivers do not form deltas; they form estuaries due to the steep slope of the Western Ghats and fast flow.

• Narmada: Largest west-flowing river. Originates at Amarkantak plateau (MP). Flows in a rift valley between Vindhya and Satpura ranges. Forms Dhuandhar falls near Jabalpur.
• Tapi (Tapti): Originates in Betul district (MP) in the Satpura range. Flows parallel to Narmada in a rift valley.
• Other small west-flowing rivers: Sabarmati, Mahi (crosses the Tropic of Cancer twice), Luni (flows into Rann of Kutch - an inland drainage), Periyar (Kerala).