The Himalayan River Systems

2.1 The Indus River System

Origin and Course

The Indus River is one of the world's longest rivers (3,180 km total). It originates from the Tibetan plateau near Mansarovar Lake (Sengge Khabab glacier, Tibet) at 5,165 m elevation. It flows northwest through Ladakh (India), cuts through the Karakoram and Hindu Kush ranges, enters Pakistan through Gilgit-Baltistan, and flows south to the Arabian Sea at Karachi.

Within India (Ladakh)

• The river cuts the spectacular Indus Gorge (depth ~5,200 m — deeper than Grand Canyon) near Gilgit
• Major Indian tributaries of the Indus: Zaskar, Nubra, Shyok, Hunza (Ladakh tributaries)
• Regulated by the Indus Waters Treaty (1960) between India and Pakistan — India gets exclusive use of eastern rivers (Ravi, Beas, Sutlej); Pakistan gets western rivers (Indus, Jhelum, Chenab)

Punjab Sub-System (Jhelum, Chenab, Ravi, Beas, Sutlej)

River	Length (km)	Origin	Special Feature
Jhelum	725	Verinag spring, Kashmir Valley	Wular Lake (India's largest freshwater lake); flows through Dal Lake area
Chenab	960	Bara Lacha La, Himachal Pradesh	Largest tributary of Indus; Baglihar Dam (Doda, J&K)
Ravi	725	Kullu Hills, Himachal Pradesh	Flows past Chamba; Thein (Ranjit Sagar) Dam
Beas	470	Beas Kund, Rohtang Pass, HP	Kullu-Manali valley; Beas-Sutlej Link tunnel
Sutlej	1,450	Rakas Lake (Tibet), near Mansarovar	Longest Punjab river; enters Gobind Sagar (Bhakra Dam reservoir)

Indus Waters Treaty (1960)

The 1960 World Bank-mediated treaty allotted the 3 eastern rivers (Ravi, Beas, Sutlej — annual flow ~41 BCM) to India and the 3 western rivers (Indus, Jhelum, Chenab — annual flow ~168 BCM) to Pakistan. India can use western rivers for non-consumptive purposes (run-of-river hydropower, irrigation below certain limits). The treaty has survived three India-Pakistan wars but faced strain after the 2019 Pulwama attack.

2.2 The Ganga River System

The Ganga is India's most sacred and most important river — India's national river (declared 2008).

Origin and Five Prayags

Origin: Rises from Gangotri Glacier (Gaumukh snout, 3,892 m) in Uttarkashi district, Uttarakhand. The Bhagirathi is the main headstream; the Alaknanda joins it at Devprayag to form the Ganga proper.

The five sacred confluences (prayags) in Uttarakhand:

• Vishnuprayag — Alaknanda + Dhauliganga
• Nandaprayag — Alaknanda + Nandakini
• Karnaprayag — Alaknanda + Pindar
• Rudraprayag — Alaknanda + Mandakini
• Devprayag — Alaknanda + Bhagirathi = Ganga

Key Facts

• Total length: 2,525 km (from Gaumukh to Ganga Sagar, Bay of Bengal)
• Basin area: 8.6 lakh sq km (26% of India's total area)
• Flows through: Uttarakhand → Uttar Pradesh → Bihar → Jharkhand (border) → West Bengal
• Right bank tributaries: Yamuna (1,376 km; joins at Allahabad/Prayagraj), Son (784 km)
• Left bank tributaries: Ramganga (596 km), Ghaghra/Karnali (1,080 km), Gandak (630 km), Kosi (720 km — "Sorrow of Bihar" due to frequent floods and course changes)
• Forms the Sundarbans delta (with Brahmaputra/Meghna) — world's largest mangrove forest (~10,200 sq km)
• Namami Gange Programme: Launched 2014; Rs 20,000 crore allocation for Ganga cleanup, sewage treatment, riverfront development

Yamuna River

• 2nd most important Ganga tributary; length 1,376 km
• Originates: Yamunotri glacier (3,293 m), Uttarkashi
• Passes: Delhi (750 km stretch is most polluted), Agra, Mathura, Allahabad
• Tributaries: Chambal, Betwa, Ken (right); Tons, Hindon (left)
• The Taj Mahal in Agra sits on Yamuna's bank

2.3 The Brahmaputra River System

The Brahmaputra is one of the world's largest rivers by discharge volume (annual discharge ~585 BCM — 3rd in Asia).

Names Across Countries

• Tibet: Tsangpo (meaning "purifier")
• Arunachal Pradesh (entry): Dihang
• Assam: Brahmaputra
• Bangladesh: Jamuna

Key Facts

• Total length: ~2,900 km (Tibet: ~1,625 km; India: 918 km; Bangladesh: 337 km)
• Originates: Chemayungdung glacier, Tibet, at 5,150 m; near Mansarovar Lake
• Enters India: through the Namcha Barwa gorge (7,782 m) in Arunachal — cuts through Himalayas via antecedent drainage
• World's deepest gorge: Yarlung Tsangpo Grand Canyon (5,382 m deep) — where it cuts around Namcha Barwa
• Majuli Island: World's largest river island (880 sq km); UNESCO Tentative List; Assam; Vaishnava satras (monasteries) — rapidly eroding due to floods
• Right bank tributaries: Lohit, Dibang, Subansiri, Kameng/Jia Bhoreli, Manas, Sankosh
• Left bank tributaries: Barak River (joins in Bangladesh as Surma)
• The Brahmaputra frequently causes devastating floods in Assam; carries 2.2 lakh kg/second suspended sediment

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