Indian River Systems and Drainage Patterns

Rivers are the lifelines of India. The Ganga, Yamuna, Brahmaputra, Godavari, Krishna and Kaveri water our fields, supply drinking water to cities, generate electricity, carry boats and goods, and sustain forests and wildlife. Great civilisations – from the Harappan cities on the Indus to the empires of the Ganga plains – grew along their banks. The way rivers and their tributaries flow together across a region is called drainage, and the area drained by a river and all its tributaries is called its drainage basin or catchment area.

Indian rivers are among the most frequently asked topics of Indian Geography in WBCS, WBPSC Clerkship, SSC CGL, CHSL, MTS, RRB NTPC, Group D, UPSC Prelims, Police and Banking exams. Questions are asked on the origin and length of rivers, left and right bank tributaries, dams and projects, waterfalls, cities on river banks, east- and west-flowing rivers, drainage patterns and river water treaties. This guide explains every river system in simple language with clear diagrams, easy tables, memory tricks, a strong West Bengal section and 20 MCQs with answers.

➤ Two main systems: Himalayan rivers (perennial) and Peninsular rivers (mostly seasonal)
➤ Longest river in India: Ganga (about 2,525 km) · Largest river basin in India: Ganga basin
➤ Largest peninsular river: Godavari (about 1,465 km) – called "Dakshin Ganga"
➤ West-flowing rift valley rivers: Narmada and Tapi – form estuaries, not deltas
➤ Ganga is formed at: Devprayag, where the Bhagirathi and Alaknanda meet
➤ Sorrow rivers: Kosi – "Sorrow of Bihar" · Damodar – "Sorrow of Bengal"
➤ Drainage patterns: Dendritic, Trellis, Radial, Centripetal, Rectangular, Parallel

Basic Terms of Drainage

India's drainage can be divided by the direction of flow: about 77% of the drainage area drains into the Bay of Bengal (Ganga, Brahmaputra, Mahanadi, Godavari, Krishna, Kaveri and others), and about 23% drains into the Arabian Sea (Indus, Narmada, Tapi, Mahi, Sabarmati and the short Western Ghats rivers). A small area in western Rajasthan has inland drainage – rivers like the Ghaggar and Luni do not reach the sea.

Drainage Patterns

When we look at a river and its tributaries from above, they form a pattern. The pattern depends on the slope of the land, the type of rocks and the geological structure. Figure 1 shows the six main patterns found in India.

Figure 1: The six common drainage patterns (simplified sketches)

Antecedent and Consequent Rivers

An antecedent river is older than the mountain it flows through. As the Himalayas slowly rose, these rivers kept cutting downward and formed very deep gorges. The Indus, Sutlej and Brahmaputra are antecedent rivers. A consequent river follows the natural slope of the land – most peninsular rivers like the Godavari, Krishna and Kaveri flow east because the Deccan Plateau slopes towards the Bay of Bengal.

Himalayan Rivers vs Peninsular Rivers

The Indus River System

The Indus rises near Lake Mansarovar in Tibet (from the Bokhar Chu glacier in the Kailash range), at an altitude of about 4,000 metres. In Tibet it is called Singi Khamban ("Lion's Mouth"). It enters India in Ladakh, flowing between the Ladakh and Zaskar ranges, and cuts a spectacular gorge near Nanga Parbat. It then flows through Pakistan and enters the Arabian Sea near Karachi. Its total length is about 2,880 km. The Shyok, Gilgit, Hunza and Nubra join it in the mountains, and the Zaskar joins it at Nimu near Leh.

Its five famous eastern tributaries – the Jhelum, Chenab, Ravi, Beas and Sutlej – give Punjab its name ("land of five waters"). They join together and meet the Indus near Mithankot in Pakistan (Figure 2).

Figure 2: The Indus and its five Punjab tributaries – from west to east: Jhelum, Chenab, Ravi, Beas, Sutlej

Indus Waters Treaty (1960): Signed on 19 September 1960 in Karachi by Prime Minister Jawaharlal Nehru and President Ayub Khan of Pakistan, with the help of the World Bank. India got full use of the three eastern rivers (Ravi, Beas, Sutlej), and Pakistan got the three western rivers (Indus, Jhelum, Chenab), with limited rights for India to use the western rivers. In April 2025, after the Pahalgam terror attack, India announced that it was holding the treaty "in abeyance".

The Ganga River System

The Ganga is India's longest river (about 2,525 km) and has the largest river basin in the country, covering more than a quarter of India's area. It flows through Uttarakhand, Uttar Pradesh, Bihar, Jharkhand and West Bengal. On 4 November 2008, the Government of India declared the Ganga the National River, and in 2009 the Ganges river dolphin was declared India's National Aquatic Animal. The Namami Gange programme (2014) works to clean and protect the river.

Source of the Ganga and the Panch Prayag

The Bhagirathi rises from the Gangotri glacier at Gaumukh in Uttarkashi district, Uttarakhand. The Alaknanda rises from the Satopanth glacier near Badrinath. On its way down, the Alaknanda meets five rivers at five holy confluences called the Panch Prayag. At Devprayag, the Bhagirathi and Alaknanda join, and from here the river is called the Ganga. It enters the plains at Haridwar (Figure 3).

Figure 3: The Panch Prayag – five confluences on the Alaknanda; the Ganga is born at Devprayag

Tributaries of the Ganga

Rivers joining the Ganga from the north (from the Himalayas) are its left bank tributaries, and rivers joining from the south (from the Peninsular plateau) are its right bank tributaries. The Yamuna is the exception – though it comes from the Himalayas, it joins from the south side at Prayagraj, so it is a right bank tributary. Figure 4 shows the system.

Figure 4: Schematic view of the Ganga system – Himalayan tributaries from the north, peninsular tributaries from the south, and the split at Farakka (not to scale)

Lower Course – Farakka, Hooghly and the Delta

At Farakka in Murshidabad district of West Bengal, the Ganga divides. The main stream enters Bangladesh as the Padma, joins the Brahmaputra (Jamuna) and later the Meghna, and enters the Bay of Bengal. A distributary, the Bhagirathi–Hooghly, flows south through West Bengal past Kolkata to the sea near Sagar Island. The Farakka Barrage, commissioned in 1975, diverts water into the Hooghly to keep the Kolkata port navigable. The Ganga Water Treaty on sharing water at Farakka was signed between India and Bangladesh in December 1996 for a period of 30 years.

The Ganga–Brahmaputra delta is the largest delta in the world. Its southern part has the Sundarbans, the largest mangrove forest in the world and home of the Royal Bengal Tiger.

The Brahmaputra River System

The Brahmaputra rises from the Chemayungdung glacier in the Kailash range near Lake Mansarovar in Tibet, very close to the sources of the Indus and the Sutlej. In Tibet it is called the Tsangpo and flows east, parallel to the Himalayas. Near Namcha Barwa it takes a sharp U-turn, cuts a very deep gorge and enters Arunachal Pradesh as the Siang or Dihang. Near Sadiya it is joined by the Dibang and Lohit, and from here it is called the Brahmaputra. It flows west through the Assam valley and enters Bangladesh, where it is called the Jamuna. Its total length is about 2,900 km.

Peninsular River System

The Western Ghats form the main water divide of the Peninsula. Because the Deccan Plateau tilts towards the east, most big rivers – the Mahanadi, Godavari, Krishna and Kaveri – flow east into the Bay of Bengal and form fertile deltas. The Narmada and Tapi are exceptions: they flow west through rift valleys (long cracks formed by faulting) into the Arabian Sea and form estuaries. The many short rivers that rush down the western slopes of the Ghats also flow west (Figure 5).

Figure 5: Peninsular rivers – Narmada and Tapi flow west through rift valleys, while the Mahanadi, Godavari, Krishna and Kaveri flow east (schematic)

East-Flowing Peninsular Rivers

West-Flowing Peninsular Rivers

Important Waterfalls and Cities on River Banks

West Bengal Connection – Rivers of Bengal

West Bengal lies in the lower Ganga plain and the delta, and its rivers are very important for WBCS and WBPSC exams.

Rivers support grasslands, wetlands and wildlife – read more in our post on India's grassland and scrubland ecosystems. River valley projects are a big part of India's planning history; see Economic Planning: From Five-Year Plans to NITI Aayog, and how such projects are financed in World Bank, WTO and Finance Commission (the World Bank also helped negotiate the Indus Waters Treaty). For practice, try the CSIR NAL MTS Mock Test and our Static GK notes.

20 MCQs on Indian River Systems

Q1. The Ganga is formed by the confluence of the Bhagirathi and Alaknanda at:
(a) Rudraprayag
(b) Devprayag
(c) Haridwar
(d) Karnaprayag

Answer: (b) – Devprayag is the last of the Panch Prayag; from here the river is called the Ganga.

Q2. The Bhagirathi originates from:
(a) Gangotri glacier (Gaumukh)
(b) Yamunotri glacier
(c) Satopanth glacier
(d) Siachen glacier

Answer: (a) – The Alaknanda rises from the Satopanth glacier and the Yamuna from Yamunotri.

Q3. Which of the following is a right bank tributary of the Ganga?
(a) Gandak
(b) Kosi
(c) Son
(d) Ghaghara

Answer: (c) – The Son rises at Amarkantak and joins from the south; the others are Himalayan left bank tributaries.

Q4. Which river is known as the "Sorrow of Bihar"?
(a) Gandak
(b) Son
(c) Damodar
(d) Kosi

Answer: (d) – The Kosi frequently changes its course and floods; the Damodar is the "Sorrow of Bengal".

Q5. The longest tributary of the Ganga is:
(a) Yamuna
(b) Ghaghara
(c) Son
(d) Gomti

Answer: (a) – The Yamuna (about 1,376 km) joins the Ganga at Prayagraj.

Q6. The Chenab is formed by the union of:
(a) Chandra and Bhaga
(b) Bhagirathi and Alaknanda
(c) Dibang and Lohit
(d) Kali Gandaki and Trishuli

Answer: (a) – They meet at Tandi in Himachal Pradesh; the Chenab is the largest tributary of the Indus.

Q7. Under the Indus Waters Treaty (1960), India received full use of which rivers?
(a) Indus, Jhelum, Chenab
(b) Ravi, Beas, Sutlej
(c) Jhelum, Ravi, Beas
(d) Chenab, Sutlej, Beas

Answer: (b) – India got the eastern rivers; Pakistan got the western rivers (Indus, Jhelum, Chenab).

Q8. Which river enters India through the Shipki La pass?
(a) Indus
(b) Beas
(c) Sutlej
(d) Ravi

Answer: (c) – The Sutlej rises at Rakas Tal in Tibet and enters Himachal Pradesh through Shipki La.

Q9. The Brahmaputra is known as Tsangpo in:
(a) Arunachal Pradesh
(b) Assam
(c) Bangladesh
(d) Tibet

Answer: (d) – It is Siang/Dihang in Arunachal, Brahmaputra in Assam and Jamuna in Bangladesh.

Q10. Majuli, one of the world's largest river islands, is located in which river?
(a) Ganga
(b) Brahmaputra
(c) Godavari
(d) Mahanadi

Answer: (b) – Majuli in Assam became India's first island district in 2016.

Q11. Which is the largest peninsular river of India?
(a) Krishna
(b) Narmada
(c) Godavari
(d) Kaveri

Answer: (c) – The Godavari (about 1,465 km) is called "Dakshin Ganga".

Q12. The Narmada and Tapi flow westward because they flow through:
(a) Rift valleys
(b) Glacial valleys
(c) Deltas
(d) Volcanic craters

Answer: (a) – They flow in fault (rift) valleys and form estuaries in the Gulf of Khambhat.

Q13. Which river originates at Amarkantak?
(a) Tapi
(b) Mahanadi
(c) Godavari
(d) Narmada

Answer: (d) – The Narmada (and also the Son) rises at Amarkantak; the Mahanadi rises at Sihawa and the Tapi at Multai.

Q14. The Hirakud Dam is built on which river?
(a) Godavari
(b) Mahanadi
(c) Krishna
(d) Damodar

Answer: (b) – Hirakud near Sambalpur, Odisha, is one of the world's longest earthen dams.

Q15. Jog Falls is formed by the river:
(a) Kaveri
(b) Indravati
(c) Sharavati
(d) Mandovi

Answer: (c) – Chitrakote is on the Indravati, Shivanasamudra on the Kaveri and Dudhsagar on the Mandovi.

Q16. Which river crosses the Tropic of Cancer twice?
(a) Mahi
(b) Sabarmati
(c) Luni
(d) Chambal

Answer: (a) – The Mahi rises in the Vindhyas and enters the Gulf of Khambhat.

Q17. Centripetal drainage pattern in India is best seen around:
(a) Amarkantak
(b) Ganga plains
(c) Western Ghats
(d) Loktak Lake

Answer: (d) – Streams flow inward into Loktak Lake in Manipur; Amarkantak shows radial drainage.

Q18. The rivers of the northern plains, like the Ganga system, show which drainage pattern?
(a) Trellis
(b) Dendritic
(c) Radial
(d) Rectangular

Answer: (b) – Uniform alluvial land and gentle slope give a tree-like (dendritic) pattern.

Q19. The Damodar Valley Corporation was set up in 1948 on the model of:
(a) Hoover Dam Project
(b) Aswan Dam Authority
(c) Tennessee Valley Authority
(d) Three Gorges Project

Answer: (c) – DVC was independent India's first multipurpose river valley project.

Q20. The Farakka Barrage, commissioned in 1975, is located in which district of West Bengal?
(a) Malda
(b) Nadia
(c) Hooghly
(d) Murshidabad

Answer: (d) – It diverts Ganga water into the Bhagirathi–Hooghly to keep the Kolkata port navigable.

Want more practice? Try our Daily GK Quiz and Mock Tests.

Conclusion

India's rivers fall into two great families – the young, snow-fed, perennial Himalayan rivers that build vast plains and deltas, and the old, rain-fed peninsular rivers that flow over hard rock and give us waterfalls and hydroelectricity. For exams, remember the origin, length and tributaries of each major river, the left and right bank tributaries of the Ganga, the Punjab rivers in order, the different names of the Brahmaputra, the west-flowing Narmada and Tapi, dams, waterfalls, cities on river banks, the six drainage patterns, and the rivers and projects of West Bengal. Revise with the diagrams and tricks above and practise the MCQs regularly.

Reference: NCERT Geography Class IX (Contemporary India I – "Drainage"); NCERT Geography Class XI (India: Physical Environment – "Drainage System"); Ministry of Jal Shakti; Damodar Valley Corporation.