Describe the drainage patterns in India.

Introduction: A Drainage Pattern (अपवाह प्रतिरूप) refers to the spatial geometrical arrangement and design formed by a master river and its tributaries in a river basin, determined by regional geological structure, lithology, slope gradients, and climatic history.

1. Major Drainage Patterns Found in India:

• 1. Dendritic Drainage Pattern (वृक्षाकार प्रतिरूप):
  • Characteristics: Resembles the branches of a tree; develops in regions of uniform rock lithology and gentle regional slope.
  • Indian Examples: Indo-Gangetic Plain (Ganga, Yamuna and tributaries), Mahanadi, Godavari, Krishna.
• 2. Radial Drainage Pattern (अरीय / चक्राकार प्रतिरूप):
  • Characteristics: Rivers originate from a central elevated dome/plateau summit and radiate outward in all directions.
  • Indian Examples: Amarkantak Plateau (MP)—Narmada flows west, Son flows north-east, and Johilla flows north; Parasnath Hills (Jharkhand); Girnar Hills (Gujarat).
• 3. Trellis Drainage Pattern (जालीनुमा प्रतिरूप):
  • Characteristics: Master streams flow parallel along synclinal strikes while secondary tributaries join them at right angles ($90^circ$) cutting through alternating bands of hard and soft rocks.
  • Indian Examples: Folded mountains of the Himalayas, Singhbhum (Chotanagpur), and Satpura strike valleys.
• 4. Rectangular Drainage Pattern (आयताकार प्रतिरूप):
  • Characteristics: Controlled by strongly jointed and faulted bedrock where rivers follow rectangular joint fractures.
  • Indian Examples: Faulted regions of the Vindhyan Range (MP) and Colorado-type joint blocks.
• 5. Centripetal Drainage Pattern (अभिकेंद्री प्रतिरूप):
  • Characteristics: Streams from all surrounding highlands converge into a central low depression or inland lake basin.
  • Indian Examples: Loktak Lake (Manipur), Sambhar Salt Lake (Rajasthan).
• 6. Parallel Drainage Pattern (समानांतर प्रतिरूप):
  • Characteristics: Swift streams flowing parallel to each other down steep, uniform topographic slopes.
  • Indian Examples: Short, swift west-flowing rivers descending the steep scarp of the Western Ghats (Konkan/Malabar) into the Arabian Sea.

Conclusion: Drainage patterns provide critical geomorphological insights into tectonic evolution, lithological variations, and watershed engineering in India.