Why this matters now
The Himalayan vs Peninsular contrast, drainage patterns and the concept of antecedent drainage are commonly tested — and tie together the rivers covered elsewhere on the site.
Key concepts
A drainage basin is the area drained by a river and its tributaries; a watershed/water divide separates two basins. Drainage is classified by source into Himalayan (Ganga, Indus, Brahmaputra) and Peninsular systems, and by orientation into Arabian Sea and Bay of Bengal drainage.
Himalayan vs Peninsular rivers
Himalayan rivers are perennial (fed by snowmelt + rain), long, with large basins, and are youthful — forming gorges, meanders and deltas, and are often antecedent (older than the mountains). Peninsular rivers are mostly seasonal (rain-fed), shorter, flow in shallow, mature valleys, and mostly drain east into the Bay of Bengal (except the west-flowing Narmada and Tapi).
Drainage patterns
Common drainage patterns include dendritic (tree-like, uniform rock), trellis (rectangular, folded/faulted terrain), radial (from a dome/volcano outward) and centripetal (toward a basin). Antecedent drainage (e.g. the Indus, Sutlej cutting across the Himalayas) predates the uplift; consequent rivers follow the slope.
UPSC angle
Know the Himalayan (perennial, youthful, antecedent) vs Peninsular (seasonal, mature, mostly east-flowing) contrast, drainage patterns (dendritic/trellis/radial/centripetal), and antecedent vs consequent drainage.
Frequently asked questions
What is a drainage basin?
The area drained by a river and its tributaries, separated from neighbouring basins by a watershed or water divide.
How do Himalayan and Peninsular rivers differ?
Himalayan rivers are perennial, long and youthful (often antecedent); Peninsular rivers are mostly seasonal, shorter and flow in mature valleys.
What is antecedent drainage?
A river older than the landform it crosses — it maintained its course by cutting down as the land rose (e.g. the Indus across the Himalayas).
What are common drainage patterns?
Dendritic, trellis, radial and centripetal patterns, determined by the underlying rock and slope.