Drainage Systems in India

Drainage

• Drainage describes the river system of a geographic area.
• A drainage basin is the area drained by a single river system.
• An elevated area separating two drainage basins is called a water divide.
• The Amazon River has the largest drainage basin in the world.

Drainage systems in India

• India's drainage systems are shaped by its diverse relief features, with major groups being the Himalayan rivers and the Peninsular rivers.
• Himalayan rivers are perennial, meaning they have water throughout the year.
• These rivers receive water from rain and melted snow from the Himalayas.
• The Indus and Brahmaputra rivers originate in the north of the Himalayas.
• Himalayan rivers have long courses, forming gorges in the upper reaches and displaying significant erosional activity.
• Himalayan rivers form meanders, oxbow lakes, and floodplains in the middle and lower courses.
• They also have well-developed deltas.
• Peninsular rivers are generally shallower than their Himalayan counterparts.
• Some Peninsular rivers originate in the central highlands and flow westward.
• Many Peninsular rivers originate in the Western Ghats and flow eastward towards the Bay of Bengal.

Major Himalayan rivers

• The major Himalayan rivers are the Indus, the Ganga, and the Brahmaputra.

Drainage Patterns

• Drainage patterns within a basin are influenced by land slope, underlying rock structure, and climate.
• Dendritic pattern resembles a tree's branches and develops in areas with uniform rock and slope.
• Trellis pattern develops where hard and soft rocks exist parallel to each other, with tributaries joining the main river at right angles.
• Rectangular pattern develops in strongly jointed rocky terrains.
• Radial pattern occurs when streams flow out from a central peak or dome.
• Combinations of several drainage patterns may be present in a single basin.

Figure 3.2: A Gorge

• A gorge is a narrow, steep-sided valley formed by the erosive power of a river cutting through a mountain range.

Figure 3.3: A Delta

• A delta is a landform created at the mouth of a river where it meets a larger body of water.
• It is formed by the deposition of sediment carried downstream by the river.