Indian Drainage System Features & Patterns

Himalayan Drainage

Antecedent drainage i.e. Himalayan rivers are older than lesser Himalayas and Shiwaliks
Himalayan rivers are older than the structures they cut across
Perennial flowing River → fed by rain and melting glaciers
Geologically young with long course of flow
Flow through lose alluvial soils of northern plains
Form deep valley and gorges due to intensive erosion
Generate large quantities of sediment & cause annual flooding & form Deltas
Nature of river course is quiet changing, meandering , forming ox-bow lakes & high waterfalls
Have deeper basins and large catchment areas

Peninsular Drainage

Super-imposed drainage i.e. regional structures are older than the river valleys that cut through them.
Nature of flow is seasonal i.e. majorly during south west monsoon
Geologically older with shorter course of flow
Flow through hard granitic soils of peninsular India
Shallow graded valleys with little erosion.
Forms shallow valleys, small waterfalls, deltas and estuaries

West Flowing Rivers vs East Flowing Rivers of Peninsular India

West Flowing Rivers	Flow into Arabian sea Flow through rift valley in straight linear course Do not have extensive network of tributaries Geologically young Generally form estuaries and not deltas Their valley floors are much above the sea level Flow swiftly into the sea
East Flowing Rivers	Flow into bay of Bengal Have extensive network of tributaries Geologically old Have large catchment areas and form deltas Their valley floors are at sea level Flow sluggishly into the sea

Geographic area through which water flows across the land and drains into a common body of water, whether a stream, river, lake, or ocean
Watershed boundary will more or less follow the highest ridgeline around the stream channels and meet at the bottom or lowest point of the land where water flows out of the watershed, the mouth of the waterway

Also known as catchment basin
An area of land where surface water from rain, melting snow, or ice converges to a single point at a lower elevation.
Usually converses at the exit of the basin, where the waters join another water body viz. river, lake, reservoir, estuary, wetland, or sea
Hence it is an area drained by tributary streams that coalesce into a main channel

The line, which divides the surface runoff between two adjacent river basins, is called the topographic water divide, or the watershed divide.
It marks the highest points between the basins, but isolated peaks within a basin may reach higher elevations than any point on the divide.

The combined effects of climate and geology on the catchment topography yield an erosion pattern, which is characterized by a network of streams.
Some of the frequently observed stream patterns are as follows –

Dendritic River Pattern

River channel follows the slope of the terrain
Homogeneous beds of uniform resistance to erosion
Streams run in all directions without definite preference to any one particular region
Example → Indo – Gangetic Plains

Rectangular River Pattern

Trellis River Pattern

River joined by tributaries at approx. right angle
Develops in folded topography; alternate layers of hard & soft rocks
Longer streams have preference to one direction
Tributaries have preference to right angle to the main stream
Example → Appalachian Mountains of North America & Singhbhum (Chotanagpur Plateau)

Radial River Pattern

Streams flow in different directions from central peak
Outflowing rivers, away from a central point, analogous with the spokes of a wheel
Generally referred to rivers flowing through dome Mountains and volcanoes
Example → Rivers Narmada, Son and Mahanadi originating from Amarkantak Hills; Girnar Hills (Kathiwar, Gujarat), and Mikir Hills of Assam