The Drainage System of India

The Drainage System of India

Definition

The flow of water through well-defined channels is known as 'drainage', and the network of such channels is called a 'drainage system'. The drainage pattern of an area is the outcome of the geological period, nature and structure of rocks, topography, slope, amount of water flowing, and the periodicity of the flow.

Important Drainage Patterns

Dendritic Pattern

• The drainage pattern resembling the branches of a tree is known as "dendritic", and examples of this are the rivers of the northern plain.

Radial Pattern

• When the rivers originate from a hill and flow in all directions, the drainage pattern is known as 'radial'. The rivers originating from the Amarkantak range present a good example of it.

Trellis Pattern

• When the primary tributaries of rivers flow parallel to each other and secondary tributaries join them at right angles, the pattern is known as 'trellis'.

Centripetal Pattern

• When the rivers discharge their waters from all directions into a lake or depression, the pattern is known as 'centripetal'.

Classification of the Indian Drainage System

Indian drainage system may be divided on various bases. Based on discharge of water (orientations to the sea), it may be grouped into:

1. The Arabian Sea drainage, and,

2. The Bay of Bengal drainage.

Nearly 77% of the drainage area consists of the Ganga, the Brahmaputra, the Mahanadi, the Krishna, etc. It is oriented towards the Bay of Bengal, while 23% comprises the Indus, the Narmada, the Tapi, the Mahi, and the Periyar systems discharge their waters in the Arabian Sea.

The Himalayan Drainage

The Himalayan drainage system mainly includes the Ganga, the Indus, and the Brahmaputra river basins. Since these are fed by both the melting of snow and precipitation, the rivers of this system are perennial.

River Kosi, also known as the 'sorrow of Bihar', has been notorious for frequently changing its course. The Kosi brings a huge quantity of sediments from its upper reaches and deposits them in the plains. The course gets blocked, and consequently, the river changes its course.

The River Systems of the Himalayan Drainage

The Indus System

• It is one of the largest river basins of the world, covering an area of 11,65,000 sq. km (in India it is 321,289 sq. km) and a total length of 2,880 km (in India 1,114 km).

• The Indus, also known as the Sindhu, is the westernmost of the Himalayan rivers in India.

• It originates from a glacier near Bokhar Chu (31°15’ N latitude and 81°40' E longitude) in the Tibetan region at an altitude of 4,164 m in the Kailash Mountain range. In Tibet, it is known as 'Singi Khamban' or Lion's mouth.

• It enters Pakistan near Chilas in the Dardistan region.

• Find out the area known as Dardistan.

• The Indus receives several Himalayan tributaries such as the Shyok, the Gilgit, the Zaskar, the Hunza, the Nubra, the Shigar, the Gomshing, and the Dras. It finally emerges out of the hills near Attock, where it receives the Kabul River on its right bank.

• Other important tributaries joining the right bank of the Indus are the Khurram, the Tochi, the Gomal, the Viboa, and the Sangar. They all originate in the Sulaiman ranges.

• The river flows southward and receives 'Panjnad' a little above Mithankot. The Panjnad is the name given to the five rivers of Punjab, namely the Satluj, the Beas, the Ravi, the Chenab, and the Jhelum. It finally discharges into the Arabian Sea, east of Karachi.

• The Indus flows in India through Ladakh.

The Jhelum

• Rises from a spring at Verinag, situated at the foot of the Pir Panjal in the south-eastern part of the valley of Kashmir.

• It flows through Srinagar and the Wular lake before entering Pakistan.

• It joins the Chenab near Jhang.

The Chenab

• The largest tributary of the Indus.

• Formed by two streams, the Chandra and the Bhaga, which join at Tandi near Keylong in Himachal Pradesh.

• Also known as Chandrabhaga.

• Flows 1,180 km before entering Pakistan.

The Ravi

• Rises west of the Rohtang Pass in the Kullu hills of Himachal Pradesh.

• Flows through the Chamba valley, enters Pakistan, and joins the Chenab near Sarai Sidhu.

The Beas

• Originates from Beas Kund near Rohtang Pass at an elevation of 4,000 m.

• Flows through Kullu valley, forms gorges at Kati and Largi, and meets the Satluj near Harike.

The Satluj

• Originates in the Rakas lake near Mansarovar at 4,555 m in Tibet, known as Langchen Khambab.

• Passes through Shipki La, enters the Punjab plains, and is an antecedent river.

• Important for the Bhakra Nangal project.

The Ganga System

The Ganga is the most important river of India from both basin and cultural significance points of view. Rises in the Gangotri glacier near Gaumukh (3,900 m) in the Uttarkashi district of Uttarakhand. Known here as the Bhagirathi.

The Ganga Basin

The most populous basin in the world, with more than 400 million people.

Accounts for:

• 28% of India's water resources

• 26% of the landmass

• 43% of the population

• Traverses Uttarakhand, U.P., Bihar, Jharkhand, and West Bengal, covering 2,525 km.

[Source: India 2022]

• At Devprayag, the Bhagirathi meets the Alaknanda – hereafter known as the Ganga.

• The Alaknanda has its source in the Satopanth glacier above Badrinath, and is formed by Dhauli and Vishnu Ganga (meet at Joshimath/Vishnu Prayag).

Other tributaries:

• Pindar joins Karna Prayag

• Mandakini (Kali Ganga) joins at Rudra Prayag

The Ganga enters the plains at Haridwar, then splits into Bhagirathi and Hugli.

Shared by:

• Uttarakhand: 110 km

• Uttar Pradesh: 1,450 km

• Bihar: 445 km

• West Bengal: 520 km

Covers 8.6 lakh sq. km.

Tributaries of the Ganga

Right Bank Tributary

• Son

Left Bank Tributaries

• Ramganga, Gomati, Ghaghara, Gandak, Kosi, Mahananda

Discharges into the Bay of Bengal near Sagar Island.

The Yamuna

The westernmost and longest tributary of the Ganga. Originates from the Yamunotri glacier on the Banderpunch range (6,316 m). Joins the Ganga at Prayag (Allahabad).

Right Bank Tributaries (Peninsular origin):

• Chambal, Sind, Betwa, Ken

Left Bank Tributaries:

• Hindan, Rind, Sengar, Varuna

The Chambal

• Rises near Mhow in the Malwa plateau, flows through Kota, Bundi, Sawai Madhopur, and Dholpur.

• Famous for badland topography or Chambal ravines.

The Gandak

• Formed by Kaligandak and Trishulganga, rises in the Nepal Himalayas, enters Champaran (Bihar), and joins the Ganga at Sonpur.

The Ghaghara

• Originating in the Mapcha-chungo glacier, joined by Tila, Seti, and Beri, and cuts a gorge at Shishapani.

• Joined by Sarda (Kali/Kali Ganga) in the plains before meeting Ganga at Chhapra.

The Kosi

• An antecedent river, source north of Mount Everest.

• Mainstream Arun, joined by Son Kosi and Tamur Kosi to form Sapt Kosi.

The Ramganga

• Rises in the Garhwal hills near Gairsain, enters the plains near Najibabad, and joins the Ganga near Kannauj.

The Damodar

• Flows through a rift valley on the Chotanagpur Plateau, joining the Hugli. Known as the 'sorrow of Bengal', now controlled by the Damodar Valley Corporation.

• Major tributary: Barakar.

The Sarda (Saryu)

• Rises in the Milam glacier, known as Goriganga, along the Indo-Nepal border, called Kali/Chauk, join the Ghaghara.

The Mahananda

• The last left-bank tributary of the Ganga in West Bengal originates in the Darjeeling hills.

The Son

• A large south bank tributary originates in the Amarkantak plateau, forms waterfalls, and joins the Ganga near Arrah, west of Patna.

The Brahmaputra System

• Originates in the Chemayungdung glacier of the Kailash range near Mansarovar Lake.

• Flows eastward through Tibet as Tsangpo (meaning 'the purifier').

Rango Tsangpo

• A major right bank tributary in Tibet.

• Carves a deep gorge near Namcha Barwa (7,755 m), emerges as Siang or Dihang.

• Enters India near Sadiya (Arunachal Pradesh), receives Dihang and Lohit, then called Brahmaputra.

Subansiri

• The antecedent river originates in Tibet.

• Brahmaputra enters Bangladesh near Dhubri, flows southward.

• Joined by Teesta (right bank), known as Jamuna, merges with Padma, and falls into the Bay of Bengal.

Major Water Channels of India

Final Thoughts

India's drainage system is a vital part of its geography, shaped by geological, climatic, and topographical factors. It is broadly categorized into the Himalayan and Peninsular systems, with major rivers like the Ganga, Indus, and Brahmaputra forming the backbone of the Himalayan drainage. These rivers are perennial, fed by both snowmelt and rainfall.

The Ganga basin is the most densely populated and significant, culturally and agriculturally. Drainage patterns such as dendritic, radial, trellis, and centripetal reflect the diversity of India’s terrain.

While 77% of rivers drain into the Bay of Bengal, 23% flow towards the Arabian Sea. Understanding these systems is crucial for managing water resources, planning irrigation, and preventing floods in the region.