📌 Chapter 02 · Drainage Systems · Complete Notes
Himalayan & Peninsular Drainage — Complete Notes
Indus, Ganga, Brahmaputra, Godavari, Krishna, Cauvery — complete notes for UPSC & PSC exams.
📊 Himalayan vs Peninsular Drainage — Key Differences
| Feature | Himalayan Rivers | Peninsular Rivers |
|---|---|---|
| Nature | Perennial (flow throughout year) | Seasonal (depend on rainfall) |
| Origin | Glaciers and snowfields | Rainfall and springs |
| Type | Antecedent (older than mountains) | Consequent (follow slope) |
| Course | Long; meanders in plains | Short; straight; steep gradient |
| Erosion | Heavy erosion; carry large sediment | Less erosion; hard rock |
| Delta/Estuary | Form large deltas (Ganga-Brahmaputra) | Some form deltas; some estuaries (Narmada, Tapi) |
| Direction | Flow south/southeast | Flow east (most); some west (Narmada, Tapi) |
🌊 Indus River System
- Origin: Mansarovar Lake (Tibet); enters India through Ladakh
- Length: 2,900 km (709 km in India)
- Tributaries (left bank): Zaskar, Shyok, Nubra, Hunza
- Tributaries (right bank): Suru, Zanskar, Dras
- Five rivers of Punjab: Jhelum, Chenab, Ravi, Beas, Sutlej (all tributaries of Indus)
- Indus Waters Treaty (1960): India gets Ravi, Beas, Sutlej; Pakistan gets Indus, Jhelum, Chenab
⭐ Indus Waters Treaty (1960): Signed between India and Pakistan with World Bank mediation. India gets the three eastern rivers (Ravi, Beas, Sutlej). Pakistan gets the three western rivers (Indus, Jhelum, Chenab). This treaty has survived three wars between India and Pakistan.
🌊 Ganga River System
- Origin: Gangotri glacier (Uttarakhand); called Bhagirathi at source
- Length: 2,525 km; longest river in India
- Joins Yamuna at: Prayagraj (Allahabad) — Triveni Sangam
- Left bank tributaries: Ramganga, Gomti, Ghaghra, Gandak, Kosi, Mahananda
- Right bank tributaries: Yamuna, Son, Damodar
- Kosi: Called “Sorrow of Bihar” — changes course frequently; causes floods
- Delta: Sundarbans — world’s largest delta; shared with Bangladesh
- Ganga Action Plan (1985): To clean the Ganga; Namami Gange (2014)
🌊 Brahmaputra River System
- Origin: Chemayungdung glacier (Tibet); called Tsangpo in Tibet
- Enters India as: Dihang (Arunachal Pradesh)
- Length in India: ~916 km
- Gorge: Dihang gorge — deepest gorge in the world (~5,500m deep)
- Tributaries: Dibang, Lohit, Subansiri, Manas, Teesta
- Majuli Island: World’s largest river island; Assam; Brahmaputra river
- Floods: Annual floods in Assam; carries enormous sediment
🌊 Peninsular Rivers
| River | Origin | Length | Drains into | Key Facts |
|---|---|---|---|---|
| Godavari | Trimbakeshwar, Maharashtra | 1,465 km | Bay of Bengal | Longest peninsular river; “Dakshin Ganga”; Nagarjuna Sagar dam |
| Krishna | Mahabaleshwar, Maharashtra | 1,400 km | Bay of Bengal | 2nd longest peninsular river; Nagarjuna Sagar, Srisailam dams |
| Cauvery | Talakaveri, Karnataka | 800 km | Bay of Bengal | “Dakshin Ganga” of South; Mettur dam; Cauvery water dispute (Karnataka-Tamil Nadu) |
| Mahanadi | Raipur, Chhattisgarh | 858 km | Bay of Bengal | Hirakud dam (longest dam in India); Odisha |
| Narmada | Amarkantak, MP | 1,312 km | Arabian Sea | Flows west; forms estuary; Sardar Sarovar dam; Marble Rocks (Bhedaghat) |
| Tapi (Tapti) | Betul, MP | 724 km | Arabian Sea | Flows west; parallel to Narmada; Ukai dam |
📝 Exam Tip — Key River Facts:
• Longest river in India = Ganga (2,525 km)
• Longest peninsular river = Godavari (1,465 km) = “Dakshin Ganga”
• Largest river basin = Ganga basin
• Majuli Island = world’s largest river island = Brahmaputra = Assam
• Narmada and Tapi = flow west = form estuaries (not deltas)
• Kosi = “Sorrow of Bihar” = changes course = floods
• Hirakud dam = longest dam in India = Mahanadi = Odisha
• Longest river in India = Ganga (2,525 km)
• Longest peninsular river = Godavari (1,465 km) = “Dakshin Ganga”
• Largest river basin = Ganga basin
• Majuli Island = world’s largest river island = Brahmaputra = Assam
• Narmada and Tapi = flow west = form estuaries (not deltas)
• Kosi = “Sorrow of Bihar” = changes course = floods
• Hirakud dam = longest dam in India = Mahanadi = Odisha
✅ Chapter 02 Revision Checklist
✅ Himalayan rivers = perennial = antecedent; Peninsular rivers = seasonal = consequent
✅ Indus origin: Mansarovar Lake (Tibet); enters India through Ladakh
✅ Indus Waters Treaty (1960): India = Ravi, Beas, Sutlej; Pakistan = Indus, Jhelum, Chenab
✅ Ganga origin: Gangotri glacier; Bhagirathi at source; 2,525 km = longest river in India
✅ Triveni Sangam: Ganga + Yamuna + Saraswati (mythical) = Prayagraj
✅ Kosi = “Sorrow of Bihar” = changes course = floods
✅ Sundarbans = world’s largest delta = Ganga-Brahmaputra = India + Bangladesh
✅ Brahmaputra = Tsangpo (Tibet) = Dihang (Arunachal) = Brahmaputra (Assam)
✅ Dihang gorge = deepest gorge in world = ~5,500m deep
✅ Majuli Island = world’s largest river island = Brahmaputra = Assam
✅ Godavari = longest peninsular river (1,465 km) = “Dakshin Ganga”
✅ Narmada and Tapi = flow west = form estuaries (not deltas)
✅ Hirakud dam = longest dam in India = Mahanadi = Odisha
✅ Cauvery water dispute = Karnataka vs Tamil Nadu
✅ Sardar Sarovar dam = Narmada = Gujarat
✅ Indus origin: Mansarovar Lake (Tibet); enters India through Ladakh
✅ Indus Waters Treaty (1960): India = Ravi, Beas, Sutlej; Pakistan = Indus, Jhelum, Chenab
✅ Ganga origin: Gangotri glacier; Bhagirathi at source; 2,525 km = longest river in India
✅ Triveni Sangam: Ganga + Yamuna + Saraswati (mythical) = Prayagraj
✅ Kosi = “Sorrow of Bihar” = changes course = floods
✅ Sundarbans = world’s largest delta = Ganga-Brahmaputra = India + Bangladesh
✅ Brahmaputra = Tsangpo (Tibet) = Dihang (Arunachal) = Brahmaputra (Assam)
✅ Dihang gorge = deepest gorge in world = ~5,500m deep
✅ Majuli Island = world’s largest river island = Brahmaputra = Assam
✅ Godavari = longest peninsular river (1,465 km) = “Dakshin Ganga”
✅ Narmada and Tapi = flow west = form estuaries (not deltas)
✅ Hirakud dam = longest dam in India = Mahanadi = Odisha
✅ Cauvery water dispute = Karnataka vs Tamil Nadu
✅ Sardar Sarovar dam = Narmada = Gujarat