Physiography and Drainage Systems of India
~12 min read
- Six divisions: Himalayas, Northern Plains, Peninsular Plateau, Indian Desert, Coastal Plains, Islands.
- Rivers: Himalayan (Indus, Ganga, Brahmaputra — perennial, snow-fed) and Peninsular (Godavari, Krishna, Kaveri, Narmada, Tapi — rainfed).
- Largest: River basin: Ganga. Longest in India: Ganga (~2,525 km in India). Brahmaputra is mighty but most of length is in Tibet/Bangladesh.
India's physiography divides cleanly into six regions, with three river systems (Himalayan north-flowing, peninsular east-flowing, peninsular west-flowing) draining them. NDA tests the regions, the rivers, and their tributaries.
Six Physiographic Divisions
| Division | Features |
|---|---|
| 1. The Himalayas | Three parallel ranges — Greater Himalayas (Himadri, highest), Lesser (Himachal, hill stations), Outer (Shiwaliks, foothills). Three regional segments: Western, Central, Eastern. |
| 2. Northern Plains | Indus-Ganga-Brahmaputra alluvial plain. Punjab, Ganga, Brahmaputra plains. Bhabar (boulder zone) → Tarai (marshy) → Bhangar (old alluvium) → Khadar (new alluvium). |
| 3. Peninsular Plateau | Oldest landmass. Central Highlands (Aravalli, Vindhyas, Satpura) + Deccan Plateau (south of Narmada). Western and Eastern Ghats border it. |
| 4. Indian Desert (Thar) | Rajasthan; sand dunes (barchan), low rainfall (< 150 mm), summer heat. |
| 5. Coastal Plains | Eastern (broader, deltas of Godavari, Krishna, Kaveri, Mahanadi) and Western (narrow, Konkan-Malabar). |
| 6. Islands | Andaman & Nicobar (Bay of Bengal, volcanic), Lakshadweep (Arabian Sea, coral). |
The Himalayas
- Himadri (Greater Himalayas): Highest range. Mt Everest (Nepal, 8,848 m), K2 (Karakoram, 8,611 m), Kanchenjunga (India, 8,586 m).
- Himachal (Lesser Himalayas): Hill stations — Shimla, Mussoorie, Darjeeling, Dalhousie. Pir Panjal, Mahabharat ranges.
- Shiwaliks (Outer): Foothills. Duns (valleys) between Shiwaliks and Himachal — Dehradun, Kotli Dun.
Major passes: Khyber, Bolan (Pakistan/Afghanistan border), Karakoram, Nathula (Sikkim), Bom Di La (Arunachal).
River Systems
Himalayan rivers (perennial, snow + monsoon fed):
- Indus system: Indus, Jhelum, Chenab, Ravi, Beas, Sutlej. Indus Treaty (1960) divides waters with Pakistan.
- Ganga system: Ganga + Yamuna + Ramganga + Ghaghara + Gandak + Kosi + Son. Largest basin in India.
- Brahmaputra: Originates Tibet (as Tsangpo) → Arunachal (as Siang/Dihang) → Assam (Brahmaputra) → Bangladesh (Jamuna). Joins Ganga in Bangladesh delta.
Peninsular rivers (mostly rainfed, seasonal):
| River | Direction | Note |
|---|---|---|
| Godavari | East to Bay of Bengal | Largest peninsular river ("Dakshin Ganga"); origin Trimbakeshwar, Maharashtra |
| Krishna | East | Origin Mahabaleshwar; tributaries Bhima, Tungabhadra |
| Kaveri | East | Origin Talakaveri (Karnataka); flows through TN |
| Mahanadi | East | Odisha; Hirakud Dam (longest in India) |
| Narmada | West (rift valley) | Origin Amarkantak; flows in rift valley between Vindhyas and Satpuras |
| Tapi (Tapti) | West (rift valley) | Origin Multai (MP); flows parallel south of Narmada |
Drainage Patterns
India's rivers form three principal drainage patterns:
- Dendritic (tree-like) — most Indian rivers including Ganga.
- Trellis — rectangular branching, where tributaries join at right angles (parts of Himalayan foothills).
- Radial — from a central high (Amarkantak gives rise to Narmada west, Son north, Mahanadi east).
NDA PYQ Examples
Q: Which is the largest peninsular river in India?
(a) Krishna (b) Godavari (c) Kaveri (d) Narmada
Answer: (b) Godavari — also called 'Dakshin Ganga'.
Q: Narmada and Tapi flow in:
(a) Estuaries (b) Deltas (c) Rift valleys (d) Indo-Gangetic plains
Answer: (c) Rift valleys — between Vindhyas and Satpuras.
Q: Which is the longest river in India by length within Indian territory?
(a) Brahmaputra (b) Indus (c) Ganga (d) Godavari
Answer: (c) Ganga — ~2,525 km within India.
Drill Physiography and Drainage Systems of India for NDA
NDA-pattern items on Physiography and Drainage Systems of India with answer keys and explanations.
Start Free Mock TestFrequently Asked Questions
Why do Narmada and Tapi not form deltas?
They flow through rift valleys (faulted depressions) and meet the Arabian Sea in narrow estuaries rather than spreading into low-gradient deltaic plains.
What is the difference between Bhabar and Tarai?
Both are in the northern plains foot of the Himalayas. Bhabar = narrow belt of coarse pebbles and gravel where streams emerge from hills; rivers go underground here. Tarai = south of Bhabar, marshy zone where rivers reappear; once dense forest, now largely cleared for agriculture.
Which Indian state has the most rivers?
Madhya Pradesh — gives rise to Narmada, Son, Chambal, Mahanadi, Tapi (partly). It's a high plateau, so rivers radiate outward.
What is the source of the Ganga?
Bhagirathi from Gangotri glacier + Alaknanda from Satopanth glacier. They meet at Devprayag (Uttarakhand) and below it the river is called Ganga.
Why is the Brahmaputra called Tsangpo in Tibet?
Same river, different names by region. Tsangpo (Tibet) → Siang or Dihang (Arunachal Pradesh) → Brahmaputra (Assam) → Jamuna (Bangladesh).