Indian River System

• Most rivers in India flow into the Bay of Bengal, while some flow into the Arabian Sea.
• Inland drainage is found in the northern parts of the Aravalli range, some parts of Ladakh, and arid regions of the Thar Desert.
• The three main watersheds that major rivers in India originate from are: the Himalaya and Karakoram range, the Chota Nagpur plateau and Vindhya and Satpura range, and the Western Ghats.

Classification of Drainage Systems of India

• Drainage Systems Based on the Size of the Catchment Area

Division	Size of catchment area in sq km
Major river	20,000
Medium river	20,000 – 2,000
Minor river	2,000 and below

• Drainage Systems Based on Origin
  • The Himalayan Rivers: Perennial rivers: Indus, the Ganga, the Brahmaputra, and their tributaries.
  • The Peninsular Rivers: Non-Perennial rivers: Mahanadi, the Godavari, the Krishna, the Cauvery, the Narmada, and the Tapi and their tributaries.
• Drainage Systems Based on the Type of Drainage
  • The river systems in India can be categorized into four groups:
  • Himalayan rivers, Deccan rivers, and Coastal rivers that drain into the sea.
  • Rivers of the inland drainage basin, such as Sambhar in western Rajasthan, which are mostly seasonal and drain into inland basins and salt lakes.
  • The Luni river is the only river that flows through the salt desert in the Rann of Kutch.
• Drainage Systems Based on Orientation to the sea
  • India’s river systems can be broadly classified based on their drainage into two groups:
    • Bay of Bengal drainage, comprising of East flowing rivers
    • Arabian sea drainage, comprising of West flowing rivers
    • The Narmada and Tapti rivers, which are India’s holiest rivers, flow parallel to each other but in opposite directions, with the Narmada flowing westward and the Tapti flowing eastward.
    • The alluvial soil in the valley of these rivers is rich and the land is covered with teak forests.

The Bay of Bengal drainage	Arabian Sea drainage
Rivers that drain into Bay of Bengal	Rivers that drain into Arabian sea
East flowing rivers	West flowing rivers
~ 77 per cent of the drainage area of the country is oriented towards the Bay of Bengal	~ 23 per cent of the drainage area of the country is oriented towards the Arabian sea
The Ganga, the Brahmaputra, the Mahanadi, the Godavari, the Krishna, the Cauvery, the Penneru, the Penneiyar, the Vaigai, etc.	The Indus, the Narmada, the Tapi, the Sabarmati, the Mahi and the large number of swift flowing western coast rivers descending from the Sahyadris.

• The area covered by The Bay of Bengal drainage and Arabian Sea drainage are not proportional to the amount of water that drains through them.

Contribution of Water by Various Rivers

River	% Contribution of water
Brahmaputra	~ 40
Ganga	~ 25
Godavari	~ 6.4
Mahanadi	~ 3.5
Krishna	~ 3.4
Narmada	~ 2.9
Rest	~ 20

Major River System or Drainage Systems in India

• Himalayan River systems
  • Indus River System
  • Brahmaputra River System
  • Ganga River System
• Peninsular River Systems
  • Godavari River System
  • Krishna River System
  • Cauvery River System
  • Mahanadi River System
• West Flowing Peninsular River Systems
  • Narmada River System
  • Tapti River System
  • Sabarmati River
  • Mahi River
  • Luni River

The Indus River System

• The river originates from the northern slopes of the Kailash range in Tibet, near Lake Manasarovar.
• The river is around 2,897 km long from the source to the point where it meets the Arabian Sea in Karachi, out of which about 700 km is in India.
• It enters Indian territory in Jammu and Kashmir, forming a picturesque gorge.
• In the Kashmir region, it is joined by many tributaries, including the Zaskar, Shyok, Nubra, and Hunza rivers.
• It flows between the Ladakh Range and the Zaskar Range at Leh.
• The river crosses the Himalayas through a 5,181 m deep gorge near Attock, which is located north of Nanga Parbat.
• The major tributaries of the Indus River in India are Jhelum, Ravi, Chenab, Beas, and Sutlej.

The Brahmaputra River System

• The river originates from Mansarovar Lake, which is also a source of the Indus and Sutlej rivers.
• It is 3,848 km long, slightly longer than the Indus River, and most of its course lies outside India.
• It flows parallel to the Himalayas in an eastward direction and takes a U-turn around Namcha Barwa before entering India in the state of Arunachal Pradesh, where it is known as the Dihang River.
• The Brahmaputra passes through the states of Arunachal Pradesh and Assam in India and is connected by several tributaries.
• It has a braided channel throughout most of its length in Assam and is known for creating calamities in Assam and Bangladesh.
• The river carries a large amount of water and silt in India due to heavy precipitation in the region, while it receives less volume of water and silt in Tibet where it is known as the Tsangpo.

Ganga River System

• The Ganga river originates from the Gangotri glacier as the Bhagirathi.
• The Alaknanda river merges with the Bhagirathi to form the Ganga at Devprayag in the Garhwal Division.
• The Pindar and Mandakini rivers also merge with the Alaknanda before it reaches Devprayag.
• The Panch Prayag concept includes five sacred river confluences, including Vishnuprayag, Nandprayag, Karnaprayag, Rudraprayag, and Devprayag.
• The Ganga’s principal tributaries include Yamuna, Damodar, Sapta Kosi, Ram Ganga, Gomati, Ghaghara, and Son.
• The Ganga flows for 2525 km from its source to the Bay of Bengal.

Yamuna River System

• The Yamuna River is a large river in India.
• It is the largest tributary of the Ganga River.
• It starts at the Yamunotri glacier, located at the Bandarpoonch peak in Uttarakhand.
• Several other rivers, including the Sin, Hindon, Betwa Ken, and Chambal, join the Yamuna River.
• The Tons River is the largest tributary of the Yamuna.
• The catchment area of the river is spread across several states in India, including Delhi, Himachal Pradesh, Uttar Pradesh, Haryana, Rajasthan, and Madhya Pradesh.

The Narmada River System

• The Narmada is a river located in central India.
• It rises to the summit of the Amarkantak Hill in Madhya Pradesh state.
• It outlines the traditional frontier between North India and South India.
• It is one of the major rivers of peninsular India. Only the Narmada, the Tapti, and the Mahi rivers run from east to west.
• The river flows through the states of Madhya Pradesh, Gujarat, and Maharashtra.
• It drains into the Arabian Sea in the Bharuch district of Gujarat.

The Tapi River System

• The Tapi River runs from east to west in central India.
• It originates in the Eastern Satpura Range of southern Madhya Pradesh state.
• It flows westward and passes through important regions like Nimar in Madhya Pradesh, Vidarbha in Maharashtra, Khandesh in northwest Deccan Plateau and South Gujarat before emptying into the Gulf of Cambay in the Arabian Sea.
• The Tapi River Basin covers mostly eastern and northern districts of Maharashtra state, as well as some districts of Madhya Pradesh and Gujarat.
• The Waghur, Aner, Girna, Purna, Panzara, and Bori rivers are the main tributaries of the Tapi River.

The Godavari River System

• The Godavari River is the second-longest river in India with brownish water.
• It is also known as the Dakshin (South) Ganga or Vriddh (Old) Ganga.
• The river is seasonal and dries up during summers, but widens during monsoons.
• It originates from Trimbakeshwar, near Nasik in Maharashtra, and flows east for 1,465 kilometres (910 mi).
• The river drains states of Maharashtra (48.6%), Telangana (18.8%), Andhra Pradesh (4.5%), Chhattisgarh (10.9%), and Odisha (5.7%), before draining into the Bay of Bengal.
• The river forms a fertile delta at Rajahmundry.
• The banks of the river have many pilgrimage sites, including Nasik (MH), Bhadrachalam (TS), and Trimbak.
• Some of its tributaries include Pranahita (Combination of Penuganga and Warda), Indravati River, Bindusara, Sabari, and Manjira.
• The river is home to Asia’s largest rail-cum-road bridge, which links Kovvur and Rajahmundry.

The Krishna River System

• Krishna is a long river in India.
• It originates from Mahabaleshwar in Maharashtra.
• The river flows through the states of Maharashtra, Karnataka, Telangana, and Andhra Pradesh.
• It drains into the Bay of Bengal.
• Tungabhadra is its main tributary, formed by the Tunga and Bhadra rivers in the Western Ghats.
• Dudhganga Rivers, Koyna, Bhima, Mallaprabha, Dindi, Ghataprabha, Warna, Yerla, and Musi are some of its other tributaries.

The Cauvery River System

• The Cauvery is also known as the Ganges of South India.
• It originates from Talakaveri in the Western Ghats.
• It is a famous pilgrimage and tourist place in Karnataka’s Kodagu district.
• The river flows through Karnataka and Tamil Nadu.
• The river drains into the Bay of Bengal.
• The river supports irrigation for agriculture and is important for the ancient kingdoms and modern cities of South India.
• The river has many tributaries including Arkavathy, Shimsha, Hemavati, Kapila, Honnuhole, Amaravati, Lakshmana Kabini, Lokapavani, Bhavani, Noyyal, and Tirtha.

The Mahanadi River System

• The Mahanadi originates from the Satpura Range of central India and it is a river in eastern India.
• It flows east to the Bay of Bengal. The river drains of the state of Maharashtra, Chhattisgarh, Jharkhand, and Orissa.
• The largest dam, the Hirakud Dam is built on the river.