Drainage System of India

Introduction

• Drainage: Flow of water through well-defined channels.
• Drainage System: Network of such channels.
• Influenced by: Geological time, rock structures, slope, topography, water flow, periodicity.
• Drainage Basin: Area drained by a river and its tributaries.
• Water Divide: Elevated area separating two drainage basins.
• World’s largest basin: Amazon River.
• India’s largest basin: River Ganga.

Drainage Patterns

• Dendritic: Resembles tree branches (e.g., rivers of northern plains).
• Radial: Rivers originate from a hill, flow in all directions (e.g., Amarkantak range).
• Trellis: Tributaries flow parallel, join at right angles.
• Centripetal: Rivers discharge into a lake or depression.

Indian Drainage Systems

Based on Sea Orientation

• Arabian Sea Drainage
• Bay of Bengal Drainage
  • 77% towards Bay of Bengal, 23% to Arabian Sea.
  • Separated by Delhi ridge, Aravallis, Sahyadris.

Based on Origin

• Himalayan Drainage: Perennial rivers, water from rain and snow.
• Peninsular Drainage: Seasonal rivers, depend on rainfall.

Himalayan Rivers

• Perennial: Water year-round from rain and melted snow.
• Features: Deep gorges, V-shaped valleys, rapids, waterfalls.
• Middle and lower courses: Meanders, oxbow lakes.
• Notable rivers: Indus, Ganga, Brahmaputra.

Indus River System

• Total area: 11,65,000 sq.km; in India: 3,21,289 sq.km.
• Length: 2,880 km; in India: 1,114 km.
• Originates: Glacier near Bokhar Chu, Tibetan region.
• Tributaries: Shyok, Gilgit, Zaskar, Hunza, Nubra.

Main Tributaries

• Satluj: Origin - Rakas tal, Tibet.
• Beas: Origin - Beas Kund, Himachal Pradesh.
• Ravi: Origin - West of Rohtang Pass.
• Chenab: Origin - Baralacha Pass.
• Jhelum: Origin - Verinag, Kashmir.

Indus Water Treaty

• Signed: 19th September 1960 (India & Pakistan).
• Division: Eastern rivers (Satluj, Beas, Ravi) - India; Western rivers (Chenab, Jhelum, Indus) - Pakistan.

Ganga River System

• National river, largest in India.
• Length: 2525 km.
• Origin: Gangotri glacier, Uttarakhand.
• Main tributaries: Yamuna, Tamas, Son, Punpun (right bank); Ramganga, Gomati, Ghaghara, Gandak, Kosi, Mahanadi (left bank).

Brahmaputra River System

• Transboundary: China, India, Bangladesh.
• Origin: Chemayungdung glacier, Tibet.
• Features: Braided channel, riverine islands.
• Tributaries: Dibang, Lohit (left bank); Subansiri, Kameng (right bank).

Peninsular Rivers

• Characteristics: Fixed course, non-perennial.
• Notable rivers: Narmada, Tapi, Mahi, Sabarmati, Luni.

East Flowing Rivers

• Mahanadi: Origin - Sihawa, Raipur.
• Godavari: Origin - Western Ghats, Nashik.
• Krishna: Origin - Mahabaleshwar.
• Kaveri: Origin - Brahmagiri range.

Lakes in India

• Types of Lakes:
  • Tectonic, Crater, Glacial, Lagoons, Ox-bow
• Notable Lakes: Dal Lake, Wular Lake, Pangong Tso, Chilika Lake, Loktak Lake, Vembanad Lake.

Important Lakes by Region

• Jammu & Kashmir: Dal, Wular, Manasbal.
• Ladakh: Pangong Tso, Tso-moriri.
• Himachal Pradesh: Chandra Tal, Suraj Tal.
• Uttarakhand: Bhimtal, Roopkund.
• Kerala: Vembanad, Ashtamudi.
• Tamil Nadu: Kaliveli, Kolavai.
• Andhra Pradesh: Pulicat, Kolleru.

Conclusion

• Understanding the drainage system is crucial for geographical, ecological, and resource management perspectives.