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Indian Physical Geography
1 . Physiographic Divisions of India
A. The Himalayas
● Age & Origin: Youngest fold mountains (Tertiary period, ~50 million yrs ago).
● Formed due to collision of Indo-Australian Plate with Eurasian Plate. Still rising –
seismically active.
● Dimensions: 2,400 km long, 250–350 km wide, average height 6,000 m.
● Division (longitudinal):
○ Trans-Himalaya–Karakoram(K2/GodwinAusten8,611m),Ladakh,Zanskarranges.
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Cold deserts of Ladakh.
○ Greater Himalaya (Himadri) – Highest peaks(Everest,Kanchenjunga,NandaDevi).
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Glaciers (Siachen, Gangotri, Yamunotri).
○ Lesser Himalaya (Himachal) – Pir Panjal, Dhauladhar, Mahabharat range. Valleys
(Kangra, Kashmir, Kathmandu). Hill stations (Shimla, Mussoorie).
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○ Shiwaliks – Outer Himalayas; unconsolidated sediments. Duns (Dehradun, Kotli
Dun).
● Division (regional):
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○ Punjab Himalaya (Indus–Satluj).
○ Kumaon Himalaya (Satluj–Kali).
○ Nepal Himalaya (Kali–Tista).
○ Assam Himalaya (Tista–Dihang).
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○ Purvanchal: Naga, Patkai, Mizo hills (dissected by rivers).
● Significance:
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○ Climatic barrier (stops monsoon winds).
○ Perennial rivers.
○ Rich forests, biodiversity hotspots.
○ Strategic military frontier.
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B. Indo-Gangetic-Brahmaputra Plain
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● Formation: Foreland basin filled by alluvium from Himalayas & Peninsular rivers.
● Extent: Punjab to Assam (~3,200 km; area 7 lakh sq. km).
● Subdivisions:
○ Bhabar: Pebble zone, porous, no streams.
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○ Tarai: Marshy, springs, dense forests (Jim Corbett region).
○ Bangar: Old alluvium, less fertile, kankar.
○ Khadar: New alluvium, floodplains, highly fertile.
● Regional Units:
○ Punjab–Haryana Plain: Doabs (Bari, Bist).
○ Ganga Plain: Upper (western UP), Middle (Bihar), Lower (West Bengal).
○ Brahmaputra Valley: Alluvial, flood-prone.
● Importance:
○ India’s breadbasket (rice, wheat, sugarcane).
○ Densely populated – Delhi, Lucknow, Kolkata.
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○ Aquifers – irrigation source.
C. Peninsular Plateau
● Age: Archean (>2.5 bn yrs), stable block of Indian Shield.
● Boundaries: Aravallis (NW), Rajmahal hills (NE), Western & Eastern Ghats.
● Divisions:
○ Central Highlands – Aravallis, Malwa, Bundelkhand, Chotanagpur plateau (rich in
coal, iron, mica).
○ Deccan Plateau– Lava origin (Deccan Traps), black cotton soil. Triangular in shape.
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● Hill Ranges:
○ Western Ghats: Sahyadri, Nilgiris, Anaimalai, Cardamom hills. High rainfall zone.
○ Eastern Ghats: Dissected, lower height, interrupted by rivers (Godavari, Krishna).
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● Mineral Richness: 97% of India’s coal reserves, 80% iron ore, bauxite, manganese.
● Economic Value: Hydroelectric potential, cotton & sugarcane cultivation.
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D. Coastal Plains
● West Coast (narrow, ~50 km): Konkan (Mumbai–Goa), Kanara (Karnataka),Malabar(Kerala
backwaters, lagoons).
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● EastCoast(broad,80–120km):NorthernCircars(Andhra),Coromandel(TamilNadu).Fertile
deltas.
● Ports: Kandla, Mumbai, Kochi (west); Chennai, Vishakhapatnam, Paradip (east).
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E. Islands
● Andaman & Nicobar: 572 islands, volcanic + coral origin. Barren Island (active volcano),
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Narcondam. Strategic naval base (Malacca Strait).
● Lakshadweep: 36 islands (coral atolls, reefs). HQ – Kavaratti. Rich fisheries, coconut.
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2. Drainage Systems of India
● Definition: Drainage = flow of water through well-defined channels.
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● Drainagepatterns:dendritic(Ganga),trellis(Chotanagpur),radial(Amarkantak),rectangular
(Bundelkhand).
A. Himalayan Rivers
● Nature: Perennial (glacier + rainfall).
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● Major Systems:
○ IndusSystem–Indus(Jammu–Kashmir,Pakistan),tributaries:Jhelum,Chenab,Ravi,
Beas, Satluj.
○ Ganga System – Bhagirathi + Alaknanda (Devprayag confluence). Tributaries:
Yamuna, Ghaghara, Gandak, Kosi, Son.
○ Brahmaputra System – Tsangpo in Tibet, enters Arunachal as Dihang.Tributaries:
Subansiri, Manas, Dibang. Known for floods, braided channels.
● Features:
○ Deep valleys, gorges (Indus at Gilgit).
○ Enormous silt load → fertile plains.
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Large deltas (Sundarbans).
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○ Ox-bow lakes, floodplains.
B. Peninsular Rivers
● Nature: Seasonal, dependent on monsoon.
● Two categories:
○ East-flowing: Mahanadi, Godavari, Krishna, Kaveri – form deltas.
○ West-flowing: Narmada, Tapti, Mandovi, Zuari, Periyar – form estuaries.
● Important Rivers:
○ Godavari: Dakshin Ganga, longest in peninsular India.
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○ Krishna: Water disputes (Karnataka–Andhra–Maharashtra).
○ Kaveri: Dispute between Tamil Nadu & Karnataka.
○ Narmada & Tapti: Flow through rift valleys (faulting).
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● Features:
○ Shorter, shallower valleys.
○ Numerous waterfalls (Jog on Sharavathi, Hogenakkal on Kaveri).
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○ Limited alluvial deposits.
C. Comparative Table – Himalayan vs Peninsular Rivers
Feature
Origin
Himalayan Rivers
Glaciers + rainfall
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Monsoon rains, springs
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Nature Perennial Seasonal (except few)
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Course Long, meandering Short, swift
Valleys V-shaped, deep gorges Shallow, weathered
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Deposition Alluvial plains, fertile deltas stuaries (west), smaller deltas
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(east)
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Drainage Patterns Dendritic, antecedent, braided Radial, trellis, rectangular
Utility I rrigation, navigation, fertile Hydropower, irrigation in deltas
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floodplains
Examples Ganga, Indus, Brahmaputra Godavari, Krishna, Narmada, Kaveri
Dr. Gaurav J. Sontake | Contact- 7827779142 | SUPERSIMPLIFIED, Sadashiv Peth, Pune -30
Svādhyāya: Free UPSC Self-Study Program
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Dr. Gaurav J. Sontake | Contact- 7827779142 | SUPERSIMPLIFIED, Sadashiv Peth, Pune -30
