Drainage System of India

Drainage System of India
Posted on 18-08-2023

Overview of Drainage Systems: Structure and Patterns

Introduction to Drainage Systems

The movement of water through distinct pathways constitutes the concept of 'drainage,' while the intricate network of these pathways is referred to as a 'drainage system.' Within this system, rivers play a pivotal role in channeling water collected from specific regions, termed 'catchment areas.' The collective region drained by a river and its tributaries is identified as a 'drainage basin,' with the boundary demarcation between two basins known as the 'watershed.' Distinctions emerge between the catchments of large rivers, termed 'river basins,' and those of smaller streams, often denoted as 'watersheds,' where river basins encompass larger territories.

Factors Influencing Drainage Patterns

The configuration of watercourses in a region, known as the 'drainage pattern,' is shaped by a multitude of factors, including geological time spans, rock attributes, topography, slope, water volume, and flow periodicity. This intricate interplay gives rise to various drainage patterns, including:

  1. Dendritic Pattern: Resembling tree branches, this pattern characterizes regions like the northern plain rivers.

  2. Radial Pattern: Origination from a central point and radiating outward, this pattern is observed in rivers originating from locations like Amarkantak.

  3. Centripetal Pattern: Rivers converge from different directions into a central lake or depression, as seen with Manipur's Loktak Lake.

  4. Trellis Pattern: Primary tributaries run parallel while secondary ones intersect at right angles, exemplified by rivers in the upper Himalayan region.

Indian Drainage System Classification

India's drainage system can be classified based on several criteria:

  1. Orientation to the Seas: The Arabian Sea and Bay of Bengal drainages are separated by geographical features like the Delhi ridge, Aravallis, and Sahyadris. Approximately 77% of the drainage area, encompassing rivers like the Ganga, Brahmaputra, and Krishna, flows into the Bay of Bengal. Meanwhile, the remaining 23%, including rivers like the Indus and Narmada, discharge into the Arabian Sea.

  2. Size of Watersheds: Indian drainage basins are categorized into three classes based on catchment area size:

    • Major River Basins: Encompassing over 20,000 sq. km, including the Ganga, Brahmaputra, Krishna, etc.

    • Medium River Basins: Ranging between 2,000-20,000 sq. km, such as the Kalindi and Periyar.

    • Minor River Basins: Covering less than 2,000 sq. km, primarily comprising rivers in low rainfall regions.

Drainage System of India

India's drainage system comprises two primary groups:

  1. Himalayan Rivers: These originate in the Himalayas and flow across northern India.

  2. Peninsular Rivers: Flowing within the Indian Peninsula, these rivers are distinct from their Himalayan counterparts.

The drainage system's dynamics involve complex interactions of geological, topographical, and hydrological elements, leading to diverse drainage patterns. India's drainage system, characterized by its Himalayan and Peninsular rivers, contributes to its diverse landscape and water distribution.

The drainage system in a region refers to the network of channels through which water flows. This network is formed based on various factors such as the geological history, rock structure, slope, topography, and water flow patterns. A drainage basin refers to the area drained by a single river system, which includes both the main river and its tributaries. A water divide is an elevated area that separates two drainage basins. In India, the drainage system can be categorized into two main systems: the Arabian Sea drainage and the Bay of Bengal drainage. These two systems are separated by geographical features like the Delhi ridge, Aravalli Range, and Sahyadri Mountains. About 77% of India's drainage flows towards the Bay of Bengal, while the remaining 23% flows into the Arabian Sea.

Different drainage patterns include:

  1. Dendritic: Resembling the branching of a tree, such as the rivers in the northern plains of India.

  2. Radial: Flowing in all directions from a central point, as seen in rivers originating from the Amarkantak range.

  3. Trellis: Primary tributaries run parallel to each other, with secondary tributaries joining them at right angles.

  4. Centripetal: Rivers discharge water from all directions into a central lake or depression.

In terms of origin and characteristics, Indian drainage can be classified into the Himalayan drainage and the Peninsular drainage:

Himalayan Rivers:

  • Mostly perennial and receive water from rain and melted snow.

  • Flow through deep gorges, V-shaped valleys, and mountainous terrain in their upper courses.

  • Form meanders, oxbow lakes, and depositional features in plains.

  • Exhibit frequent course changes due to sediment deposition.

  • Examples include the Ganga, Indus, and Brahmaputra.

Peninsular Rivers:

  • Mostly seasonal, relying on rainfall.

  • Have shorter, shallower courses compared to Himalayan rivers.

  • Flow west to east into the Bay of Bengal, with some exceptions.

  • Examples include the Godavari, Krishna, Mahanadi, and Narmada.

Indus River System:

  • Originates in Tibet and flows through India and Pakistan.

  • Major tributaries include Satluj, Beas, Ravi, Chenab, and Jhelum.

  • Indus Water Treaty divides water usage between India and Pakistan.

Ganga River System:

  • The Ganga is the largest river system in India.

  • Originates from Gangotri glacier and flows through northern India.

  • Major tributaries include Yamuna, Son, Gandak, Ghaghara, Kosi, etc.

  • Divides into distributaries in Bangladesh and forms the Sundarban Delta.

Brahmaputra River System:

  • Originates in Tibet and flows through India and Bangladesh.

  • Major tributaries include Subansiri, Kameng, and Manas.

  • Divides into distributaries in Bangladesh and flows into the Bay of Bengal.

Peninsular Rivers:

  • Narmada originates in Amarkantak and flows westward.

  • Tapi originates in Multai and also flows westward.

  • Mahi, Sabarmati, and Luni are other west-flowing rivers.

West Flowing Small Rivers

The rivers Shetrunji, Bhadra, Dhadhar, Vaitarna, Kalinadi, Bedti, Sharavati, Mandovi, Juari, Bharathapuzha, Periyar, and Pamba are important west flowing rivers originating in various regions of India.

Major East Flowing Peninsular Rivers

East flowing rivers like Mahanadi, Godavari, Krishna, and Kaveri originate in different parts of India and discharge into the Bay of Bengal.

East Flowing Small Rivers

Several small east flowing rivers, including Subarnrekha, Baitarni, Brahmani, Vamsadhara, Penner, Palar, and Vaigai, drain into the Bay of Bengal.


Lakes in India are categorized based on their origin and formation, such as tectonic, crater, glacial, lagoons, and ox-bow lakes.

Important Lakes of India

Significant lakes in different states of India include Dal Lake, Nigeen Lake, Wular Lake, Pangong Lake, Chandra Tal Lake, Loktak Lake, Chilika Lake, Vembanad Lake, and many more.


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