• The drainage system is an integrated system of tributaries and a mainstream that collects and funnel surface water to the sea, lake or some other water bodies. The total area that contributes water to a single drainage system is known as a drainage basin

Introduction to Drainage

• The movement of water along well-defined channels is referred to as drainage, with these channels carving out distinct paths in various directions. Drainage is influenced by factors such as the nature and structure of rocks, geology, slope, topography, velocity, etc.
• A watershed denotes a smaller land area that directs water flow towards a particular stream, lake, or wetland.
• A river basin encompasses multiple watersheds, and these watersheds serve as boundaries that separate one drainage basin from another.
• The catchment area is where water accumulates before being directed by the river. 

Drainage pattern of Rivers

• Drainage basins represent regions where a large river, along with its tributaries, collects and discharges all its water.
• The arrangement formed by the river and its tributaries from the origin of the river to its mouth is termed a drainage pattern.

Following are the major drainage patterns

Drainage Pattern of Rivers

Drainage system 

• A drainage system refers to a network of defined channels, categorized into two parts based on slope and geological structure:

Sequent Drainage System

• Consequent Stream: Develops in accordance with the initial slope, present in the area. Examples include Godavari, Krishna, Kaveri, etc.
• Subsequent Stream: Develops after the consequent stream and joins it at a right angle. Examples include Chambal, Sindh, Betwa, etc.
• Obsequent Stream: Moves in the opposite direction to the consequent stream but joins it at a right angle.
• Resequent Stream: Moves in the direction of the master stream but joins it at a right angle.

Insequent Drainage System

• Antecedent Stream: Maintains its original course and pattern despite changes in underlying rock topography. Examples include Indus, Brahmaputra, Sutlej, etc.
• Superimposed Stream: Does not follow the slope of the landmass. Examples include Son, Chambal, Banas, etc.

Drainage System of Indian Rivers:

• The drainage system of Indian rivers can be divided into the Himalayan drainage system and the Peninsular drainage system.

The Himalayan Drainage System

• The Himalayan drainage system comprises all the international rivers of India, i.e., the Indus, the Ganga and the Brahmaputra,
• Most of these rivers and their major tributaries are perennial in character, obtaining their water from the glaciers, springs and rains.
• These rivers are in their youthful stage carving out a number of erosional landforms like Waterfalls, cataracts, rapids, gorges, steep-sided valleys, alluvial fans and river terraces.
• The regimes of these rivers exhibit wide seasonal fluctuations, causing devastating floods, especially during the season of general rains.
• Most of the rivers, which rise in the Himalayas are antecedent in nature
• These antecedent rivers existed and flowed before the Himalayas were formed.

Ganga River System

• The Ganga originates as the Bhagirathi from the Gangotri glacier. Before it reaches, Devprayag in the Garhwal Division, the Mandakini, Pindar, Dhauli Ganga and the Bishen Ganga rivers merge into the Alaknanda and the Bheling drain into the Bhagirathi.
• The Pindar river rises from East Trishul and Nanda Devi unites with the Alaknanda at Karnaprayag. The Mandakini meets at Rudraprayag
•  The water from both Bhagirathi and the Alaknanda flows in the name of the Ganga at Devprayag

Panch Prayag

• Vishnuprayag Where the river Alaknanda meets river Dhauli Ganga.
• Nandprayag Where river Alaknanda meets river Nandakini.
• Karnaprayag Where river Alaknanda meets river Pindar.
• Rudraprayag Where river Alaknanda meets riverMandakini.
• Devprayag Where river Alaknanda meets river Bhagirathi Ganga.

The Ganga System

Doab of Ganga River System

Government Initiatives for Ganga Conservation

Several government initiatives aimed at the rejuvenation of the Ganga river include

• Namami Ganga Programme: Launched in 2014, this flagship program under the Ministry of Jal Shakti focuses on the effective abatement of pollution and the conservation and rejuvenation of the National River Ganga.
• Smart Ganga City: Introduced in 2016 by the Ministry of Water Resources, River Development, and Ganga Rejuvenation, in collaboration with the Ministry of Urban Development, the Smart Ganga City scheme targets ten major cities along the banks of the Ganga, including Haridwar, Rishikesh, Mathura-Vrindavan, Varanasi, Kanpur, Allahabad, Lucknow, Patna, Sahibgunj, and Barrackpore.
• Chitale Committee: Constituted in July 2016 by the Ministry of Water Resources, River Development, and Ganga Rejuvenation, the Chitale Committee was tasked with preparing guidelines for the desolation of the Ganga river from Bhimgauda (Uttarakhand) to Farakka (West Bengal).

The Indus River System

• The Indus, also known as Sindhu, boasts one of the world's largest river basins, covering an area of 1,165,000 sq km. With a total length of 2,880 km (1,114 km in India), it originates from a glacier near Bokhar Chu in the Tibetan region, within the Kailash mountain range.
• Cutting across the Ladakh range, the Indus forms a gorge near Gilgit in Jammu and Kashmir, with major tributaries including Shyok, Gilgit, Zanskar, Nubra, Shigar, and Dras in the upstream region. It then flows southward, receiving the Panjnad above Mithankot, which comprises the five rivers of Punjab: Sutlej, Beas, Ravi, Chenab, and Jhelum.
• Finally, the Indus discharges into the Arabian Sea east of Karachi, with its presence in India limited to the Leh district in Jammu and Kashmir.
• Notable tributaries like Beas, Jhelum, Chenab, Ravi, and Sutlej contribute to the overall flow of the Indus, each originating from different regions and adding to the river's vast and intricate system.

The Brahmaputra River System 

• The Brahmaputra River System Eastward direction. When it Heches Namcha Barwa.
•  It flows parallel to the Himalayas in the Fate of Arunachal Pradesh. Here, it is known as the Dihang River.
• In India, it flows through the states of Arunachal Pradesh and Assam and is connected by several

The Brahmaputra System (Brahmaputra and its Tributaries)

• Sankosh River serves as a significant North bank tributary to the Brahmaputra, establishing the boundary between Assam and West Bengal.
• Teesta River, a tributary of the Brahmaputra (known as Jamuna in Bangladesh), flows through India and Bangladesh. Its source lies in the Himalayas near Chunthang, Sikkim, and it courses southward through West Bengal before entering Bangladesh.
• Rangit River, a tributary of the Teesta, holds the distinction of being the largest river in Sikkim, originating within the state. Notably, it is renowned for various water sports activities.

The accurate descending order of the rivers of India by length is as follows:

• Ganga
• Indus
• the Godavari
• Krishna
• the Brahmaputra
• Mahanadi

Major dams Related to Himalaya Rivers

The Peninsular Drainage System

• The Peninsular drainage system comprises the Mahanadi, the Godavari, the Krishna, the Kaveri and other numerous West flowing rivers.
• The drainage of Peninsular India is much older than that of the Himalayan drainage system. They are mostly seasonal. Their erosional and carrying capacity is low. Their channels are more defined and are close to the base level.
• There are many small rivers in the coastal areas and called coastal rivers. These flow towards the Arabian Sea in the West and towards the Bay of Bengal in the East.
• The major West flowing rivers are Shetrunji, Kalindi, Sharavati, Bhadra, Mandavi, Zuari, Bharathapuzha, Pamba, Periyar, etc. The major east-flowing rivers are Vamsadhara, Brahmani, Baitarani, Subarnarekha, Penneru, Palar, Tamrapani and Vaigai, etc.

The Peninsular River System

Differences Between the Himalayan and Peninsular Rivers

List of Major Rivers of India

Major Towns Situated on the Banks of Rivers

Inland Drainage

• Some rivers in India don't reach the sea or ocean; instead, they discharge water into lakes or inland seas, constituting inland drainage. 
• These rivers are mostly found in the drier regions like Western Rajasthan, Ladakh, and Aksai Chin. The Chaggar River serves as a significant example of inland drainage, acting as a seasonal stream flowing on the ancient dried bed of River Saraswati. It forms a boundary between Punjab and Haryana, eventually getting absorbed in the Rajasthan desert.
• Another instance of inland drainage is the River Luni, which rises from the lower slopes of the Himalayas, draining the steep North-West of Aravalli hills, and joining the Rann of Kutch in the left side. Its entire catchment area falls within Rajasthan.

River Regimes

• River regime refers to the annual variation in a river's discharge—the amount of water flowing through it and how this changes throughout the year. Factors influencing river regimes include changes in the water cycle, temperature, and the characteristics of the drainage basin. Examples of river regimes can be observed in the two Himalayan rivers (Ganga and Jhelum) and two Peninsular rivers (Narmada and Godavari).

Inter-State River Water Disputes

• Despite India's abundant water resources, the distribution is uneven. Himalayan rivers are large, perennial, and glacier-fed, while Peninsular rivers are seasonal. 
• The overwhelming demands of riparian states during dry seasons lead to disputes due to excessive demand, inadequate water supply, and varied utilizations like irrigation and hydropower projects. The Inter-State River Water Disputes (ISRWD) Act of 1956 was enacted by Parliament for adjudication of such disputes.

Major Inter-State River Disputes

National Water Grid

• The National Water Grid, proposed by Dr. KL Rao in 1972, aims to interlink rivers for irrigation and hydro projects. If implemented, it would connect major Himalayan and Peninsular rivers through a network of canals.
• The project involves linking 37 rivers with 30 different canals to redistribute surplus water from Himalayan rivers to water-deficient Peninsular regions. However, environmental concerns and political difficulties pose challenges to the project.

National River Linking Project Plan

The National River Linking Project plans to redistribute river water from surplus to deficit basins. It comprises two components:

• Himalayan Component: Includes 14 projects to link various Himalayan rivers like the Ghaghara-Yamuna link (feasibility study complete).(Feasibility study complete), Yamuna-Rajasthan link, Rajasthan-Sabarmati link, Kosi-Ghaghara link, Kosi-Mechi link, Manas-Sankosh-Tista-Ganga link, Jogighopa-Tista-Farakka link, Ganga-Damodar-Subarnarekha link, Subarnarekha-Mahanadi link, Farakka-Sunderbans link, Gandak-Ganga link, Chunar-Son Barrage link, Son dam-Southern tributaries of Ganga link.
• Peninsular Component Under this segment, 16 projects are enlisted to link various peninsular rivers, including inter-linking Mahanadi-Godavari-Krishna-Palar-Pennar-Kaveri, inter-linking West flowing rivers (North of Mumbai and South of Tapi), inter-linking Ken with Chambal, and diversion of water from West flowing rivers.

Lakes

• A lake is defined as an area of variable size, filled with water, localized in a basin, surrounded by land, without any other rivers or outlets surrounding it.

Lakes can be classified as

• Tectonic Lakes: Formed due to fractures and faults in the Earth's crust, e.g., Nainital, Bhimtal, Wular, Dal Lake, etc.
• Crater Lakes: Formed when craters and calderas are filled with water, e.g., Lonar Lake in Buldhana.
• Glacial Lakes (Tarns): Resulting from glacial erosion, e.g., Gangabal Lake in Kashmir.
• Fluvial Lakes: Formed by rivers through erosional and depositional work, such as Ox-bow lakes, e.g., in the upper, middle, and lower courses of the Ganga and Brahmaputra rivers, and Kolleru Lake in Andhra Pradesh.
• Aeolian Lakes: Small depressions on wind-blown sand surfaces, e.g., Sambhar and Panchbhadra lakes.
• Lagoons: Formed by depositions of sand bars along the sea coast, e.g., Vembanad, Asthamudi, Kayals of Kerala, and Lake Chilika of Odisha.

Important Lakes in India

Waterfalls

• A waterfall is an area where water flows over a vertical drop or a series of steep drops in the course of a stream or river.
• In India, waterfalls are mostly formed in the upper course of a river where lakes flow into valleys in steep mountains.

List of Major waterfalls in India

Prelims Facts

• The Western part of Teesta river is known as?

- Terai /WBCS (Pre) 2019]

• Punarbhava and Atrai are the distributaries of which Rivers?

- Teesta [WBCS (Pre) 2020]

•  The Confluence of Bhagirathi and Alakananda is located at

- Devprayaga [WBCS (Pre) 2021]

• River Beas, flowing from Himachal Pradesh and Punjab, joins the river

- Sutlej [UPPSC (Pre) 2015]

• Geomorphologists opine that change of the course of the Kosi river resulted in

- Ganga river flowing through Padma in Bangladesh [WBCS (Pre) 2017]

•  Baspa, Spiti and Beas are the tributary of the river

- Sutlej [UKPSC (Pre) 2022]

•  The Main purpose of 'Ganga Action Plan' project, launched in 1985 was to

- Make it water pollution free [UPPSC (Pre) 2022]

•  'Moribund delta' is a subdivision of which delta

- Bengal Delta [UPPSC (Pre) 2019]

• In Bangladesh, the Ganga is know by the name of

- Padma [UKPSC (Pre) 2005, UPPSC (Mains) 2016]

• From which place the Bhagirathi river originates?

- Gaumukh [CGPSC (Pre) 2011, MPPSC 2013)

•  The Tributaries of river Yamuna from West to East are

- Chambal-Sindh-Betwa-Ken [UPPSC (Pre) 2020]

•  Which valley is known for its deep ravine?

- Chambal [MPPSC (Pre) 2019]

•  Which range acts as a water divide between Yamuna and Son?

- Kaimur IMPPSC (Pre) 2016]

•  Which river joins the Ganga at Fatuha?

- Punpun [BPSC (Pre) 2017]

•  What is the Indian name of the Yarluny Zangbo river?

- Brahmaputra [BPSC (Pre) 2015]

•  The river Manas is the tributary of river

- Brahmaputra [BPSC (Pre) 2000]

•  Rivers like Dibang, Kameng and Lohit are tributaries of

- Brahmaputra [IAS (Pre) 2016]

•  The most important reason for the construction of the Farakka Barrage was

- Raise the Lower Ganges flow [UPPSC (Pre) 2005]

•  What is the name of those two rivers which do not form delta?

- Narmada and Tapi [MPPSC (Pre) 2013]

• The river Ganga flows into the Bay of Bengal through

- A Triangular Delta [WBCS (Pre) 2012)

Self-Check

1. When the rivers discharge their water from all directions in a lake or depression, the pattern is known as

(a) trellis

(b) dendritic

(c) radial

(d) centripetal

2. The rivers of South India mainly have which of the following drainage patterns?

UPPSC (Pre) 2014

(a) Radial

(b) Intermittent

(c) Dendritic

(d) Trellis

3. Among the following tributaries, which one is the part of the Ganga river basin?

BPSC (Pre) 2019

(a) Sankh

(b) North Koel

(c) South Koel

(d) Barakar

4. Which river flows through the valley of Kashmir? WBCS (Pre) 2013

(a) Sutlej

(b) Ravi

(c) Chenab

(d) Jhelum

5. Which of the following is not a tributary of Brahmaputra river?

Manipur PSC (Pre) 2016

(a) Kolong

(b) Sankosh

(c) Kopili

(d) Dhaleshwari

6. Identify the only tributary of river Ganges which rises in the plains.

(a) Son

(b) Sharda or Saryu

(c) Gomati

(d) Ramganga

7. Consider the following tributaries of river Yamuna and arrange them from West to East.

1. Betwa
2. Ken
3. Sindh
4. Chambal

Codes

(a) 4, 3, 1, 2

(b) 1, 2, 3, 4

(c) 3, 2, 1, 4

(d) 2, 3, 1, 4

8. Four rivers have been mentioned below. What will be the decreasing order of these rivers in length (starting from the longest to the shortest)? HPSC (Pre) 2022

1. Mahanadi
2. Krishna
3. Godavari
4. Narmada

Codes

(a) 4, 1, 2, 3

(b) 2, 3, 1, 4

(c) 1, 2, 4, 3

(d) 3, 2, 4, 1

9. Dubbed as the Dakshin Ganga (the Ganges of the South), the largest river of South India is

WBCS (Pre) 2021

(a) The Godavari

(b) The Kaveri

(c) The Penganga

(d) The Mahanadi

10. Consider the following rivers.

IAS (Pre) 2015

1. Vansadhara
2. Indravati
3. Pranahita
4. Pennar

Which of the following above are tributaries of Godavari?

(a) 1, 2 and 3

(b) 2, 3 and 4

(c) 1, 2 and 4

(d) 2 and 3

11. Consider the following rivers.

IAS (Pre) 2015

1. Brahmani
2. Nagavali
3. Subarnarekha
4. Vamsadhara

Which of the above rise from the Eastern ghats?

(a) 1 and 2

(b) 2 and 4

(c) 3 and 4

(d) 1 and 3

12. Which of the following characteristic feature is appropriate for Narmada river ?

JPSC (Pre) 2021

(a) Wind origin

(b) Structural origin

(c) Glacial origin

(d) Volcanic origin

13.  The following characteristic are of which river?

1. Originates from the Aravallis near the fort of Kumbhalgarh.
2. Flows through the Mewar plain.
3. Bedach, Kothari and Morel are its tributaries.

Codes

(a) Champal

(b) Mahi

(c) Banas

(d) Luni

14. The source of Kaveri river lies in UPPSC (Mains) 2011

(a) Sahyadri

(b) Brahmagiri hills

(C) Gavaligarh hills

(d) Amarkantak

15. Kolleru lake is located between WBCS (Pre) 2019,2021

(a) Godavari and Kaveri

(b) Godavari and Krishna

(c) Krishna and Kaveri

(d) Mahanadi and Godavar

16. Which of the following statements is correct?

UPPSC (Pre) 2023

1. Ram Ganga river joins the Ganga at Kannauj.
2. River Betwa joins the Yamuna near Prayagraj

Codes

(a) Only 2

(b) Neither 1 nor 2

(c) Only 1

(d) Both 1 and 2

17. Chilika Lake is a

WBCS (Pre) 2018

(a) saltwater lake

(b) freshwater lake

(c) freshwater lake in the monsoon season

(d) saltwater lake in summer season

18. Hundru fall is formed on

BPSC (Pre) 1994

(a) Indravati

(b) Kaveri

(c) Subarnarekha

(d) None of these

19. Consider the following statements

TAS (Pre) 2023

1. Jhelum river passes through Wular Lake.
2. Krishna river directly feeds Kolleru Lake.
3. Meandering of the Gandak River formed Kanwar Lake.

How many of the statements given above are correct?

(a) Only one

(b) Only two

(c) All three

(d) None of these

Know Right Answer

1 (d)

2 (c)

3 (b)

4 (d)

5 (d)

6 (c)

7 (a)

8 (d)

9 (a)

10 (d)

11 (b)

12 (b)

13 (c)

14 (b)

15 (b)

16 (c)

17 (d)

18 (c)

19 (a)