Topic 7: Drainage System — Patterns & Himalayan Rivers

A country's rivers are the master key to its physiography, agriculture and civilisation. This chapter builds the concepts first — drainage, basins, watersheds and the drainage patterns (dendritic, trellis, radial, rectangular) plus antecedent vs consequent rivers — then contrasts India's two great families of rivers (Himalayan vs Peninsular). It then follows the three mighty Himalayan systems in detail: the Indus and its Punjab tributaries (with the Indus Waters Treaty), the Ganga from its Bhagirathi–Alaknanda headstreams through the Yamuna, Chambal, Ghaghara, Gandak, Kosi and Son, and the braided Brahmaputra (Tsangpo–Siang, Majuli). With labelled diagrams, tables and PYQs + full model answers.

UPSC Prelims · Mains GS-I Indus · Ganga · Brahmaputra ~42 min read Drainage Patterns · Tributaries Very High Weight

1.Drainage Concepts & Patterns
2.Himalayan vs Peninsular Drainage
3.The Indus River System
4.The Ganga River System
5.Ganga Tributaries in Detail
6.The Brahmaputra River System
7.Antecedent Rivers & River Capture
8.River Regimes, Importance & Interlinking
9.River Pollution & Namami Gange
10.Significance & GS-I Synthesis
11.Current Affairs Link
12.Prelims PYQs
13.Mains PYQs + Model Answers
★15-Minute Revision Box

Conceptual Clarity — Why this Chapter Matters

Rivers are one of the densest scoring areas in Prelims (source, tributary, confluence, order) and a rich Mains theme (water, floods, interlinking). Sort your prep three ways:

Definitional / static: drainage patterns (dendritic = uniform rock; trellis = folded/tilted; radial = dome; rectangular = jointed); antecedent (Indus, Sutlej, Brahmaputra cut across the rising Himalaya) vs consequent rivers; Himalayan (perennial, snow-fed) vs Peninsular (seasonal, rain-fed).
Statement-elimination: Ganga headstreams (Bhagirathi + Alaknanda meet at Devprayag); Yamuna = longest tributary of the Ganga; Chambal badlands; Kosi = "Sorrow of Bihar"; Brahmaputra = Tsangpo (Tibet) → Siang/Dihang (Arunachal) → Brahmaputra (Assam); Panjnad = the five Punjab rivers combined.
Applied / synthesis (Mains GS-I & GS-III): why Himalayan rivers are perennial, the flood problem of the Kosi & Brahmaputra, the Indus Waters Treaty, and the interlinking debate. Needs concept + example + judgement.

Territorial note: the upper Indus system (including rivers flowing through Gilgit-Baltistan, Ladakh and Jammu & Kashmir) lies within India's sovereign territory; the LoC and LAC are not settled international borders.

1. Drainage Concepts & Patterns

Drainage is the network of channels (rivers, streams) that carries a region's runoff. The area drained by a river and its tributaries is its basin; the boundary (usually a ridge) separating two basins is the watershed / water-divide.

Catchment / basin: the total land drained by a river system (Ganga basin is India's largest).
Watershed: the upland divide between basins (the Himalaya, Western Ghats and Aravalli act as major divides).
Stream order: a way of ranking channels by their branching hierarchy.

1.1 Drainage patterns

The pattern a river network makes reflects the underlying rock structure and slope.

Fig 7.1 — Drainage patterns and their controls: dendritic (uniform rock), trellis (folded/tilted strata), radial (dome or volcano), rectangular (jointed/faulted rock).

Pattern	Looks like	Control / example
Dendritic	Tree branches	Uniform rock, gentle slope (northern plains rivers)
Trellis	Right-angle grid	Folded/tilted rock (parts of the Himalaya)
Radial	Spokes from a centre	Dome/volcano (Amarkantak — Narmada, Son, Mahanadi radiate)
Rectangular	Right-angle bends	Jointed/faulted rock
Centripetal	Inward to a basin	Inland basins (Sambhar area)

Prelims lock: dendritic = uniform rock; trellis = folded strata; radial = dome/volcano (Amarkantak); rectangular = jointed rock; centripetal = inward-draining basin.

2. Himalayan vs Peninsular Drainage

India's rivers fall into two great families whose contrast flows from age & source — young, snow-fed Himalayan rivers vs old, rain-fed Peninsular rivers.

Feature	Himalayan Rivers	Peninsular Rivers
Source / feed	Snow & glaciers + rain → perennial	Rain only → seasonal
Age	Young, still evolving	Old, graded (near base level)
Course	Long, meandering; big deltas; erosive gorges	Shorter, fixed valleys; some rift (Narmada/Tapi)
Catchment	Very large	Smaller
Nature	Antecedent gorges; braiding	Mostly consequent; hard-rock beds
Examples	Indus, Ganga, Brahmaputra	Godavari, Krishna, Kaveri, Narmada

Why Himalayan rivers are perennial: they draw on glacial melt in summer and monsoon rain, so they flow year-round; peninsular rivers depend on the monsoon alone and shrink drastically in the dry season.

3. The Indus River System

The Indus (Sindhu) is one of the world's great rivers and India's westernmost system. It rises near Lake Mansarovar in Tibet, enters India through Ladakh, and is joined by the Punjab tributaries before flowing on to the sea.

Main stem: Indus — source near Mansarovar (Tibet) → Ladakh (India) → onward; total ~2,880 km.
Ladakh tributaries: the Zaskar, Shyok, Nubra, Gilgit join in the mountains.
The "Five Rivers" of Punjab: Jhelum, Chenab, Ravi, Beas, Sutlej — they unite as the Panjnad before meeting the Indus.
Sutlej is antecedent (also rises near Mansarovar/Rakas Tal); the Jhelum flows through the Wular lake & Srinagar; the Chenab is the largest of the five.

Punjab river	Note
Jhelum	Through Wular lake & Srinagar (Kashmir valley)
Chenab	Largest of the five; Chandra + Bhaga (Lahaul)
Ravi	Smallest; past Chamba
Beas	Wholly in India; joins Sutlej at Harike
Sutlej	Antecedent; near Mansarovar; Bhakra dam

Indus Waters Treaty (1960): under the World-Bank-brokered treaty, India has largely unrestricted use of the three eastern rivers (Ravi, Beas, Sutlej), while the three western rivers (Indus, Jhelum, Chenab) are largely allocated to Pakistan, with India permitted specified non-consumptive, run-of-river and limited storage uses. check for latest update or data

Prelims lock: the five Punjab rivers (Jhelum, Chenab, Ravi, Beas, Sutlej) combine as the Panjnad; Sutlej is antecedent; Chenab is the largest; Jhelum drains the Kashmir valley through Wular lake.

4. The Ganga River System

The Ganga is India's largest river system by basin, the lifeline of the northern plains. Its two Himalayan headstreams — the Bhagirathi (from Gangotri/Gaumukh) and the Alaknanda — unite at Devprayag to form the Ganga.

Headstreams & prayags: the Alaknanda gathers tributaries at the five prayags (Vishnuprayag, Nandaprayag, Karnaprayag, Rudraprayag, Devprayag); the Ganga proper begins at Devprayag.
Plains course: the Ganga emerges onto the plains at Haridwar, flows through UP, Bihar, and enters the Bengal delta, where it divides — the Hooghly (India) and the Padma (Bangladesh) — forming the world's largest delta with the Brahmaputra.
Left-bank tributaries (mostly Himalayan, perennial): Yamuna (joins from the right actually), Ramganga, Ghaghara, Gandak, Kosi, Mahananda.
Right-bank tributaries (mostly Peninsular, seasonal): Yamuna, Son.

Element	Detail
Headstreams	Bhagirathi (Gaumukh) + Alaknanda → unite at Devprayag
Enters plains	Haridwar
Largest tributary	Yamuna (longest tributary of the Ganga)
Delta	Sundarbans; splits into Hooghly (India) & Padma (Bangladesh)
Basin	India's largest river basin

Prelims lock: Bhagirathi + Alaknanda meet at Devprayag to form the Ganga; the Ganga hits the plains at Haridwar; the Yamuna is its longest tributary; the delta (with the Brahmaputra) is the world's largest.

5. Ganga Tributaries in Detail

The Ganga's power comes from its tributaries — Himalayan (perennial, north bank) and Peninsular (seasonal, south bank).

Tributary	Source / type	Key facts
Yamuna	Yamunotri (Himalayan)	Longest tributary; parallel to Ganga; joins at Prayagraj (Sangam); Delhi, Agra on it
Chambal	Peninsular (Malwa)	Yamuna tributary; famous ravines/badlands; Gandhi Sagar dam
Betwa & Ken	Peninsular	Yamuna tributaries; Ken–Betwa link project
Ramganga	Himalayan (Kumaon)	Joins near Kannauj
Ghaghara (Karnali)	Himalayan (Tibet/Nepal)	One of the largest tributaries by volume; joins in Bihar
Gandak	Himalayan (Nepal)	Joins at Patna; heavy silt & floods
Kosi	Himalayan (Tibet/Nepal)	"Sorrow of Bihar"; shifts course; huge silt
Son	Peninsular (Amarkantak)	Largest south-bank tributary; joins near Patna
Mahananda	Himalayan	Last major left-bank tributary (Bengal)

Yamuna: the longest and most important tributary — runs parallel to the Ganga before the Sangam at Prayagraj; its own Peninsular tributaries are the Chambal, Betwa & Ken.
Kosi & Gandak: silt-laden Himalayan rivers that flood the north Bihar plains; the Kosi's westward shifting earns it "Sorrow of Bihar."
Son: the main Peninsular (south-bank) tributary, rising with the Narmada at Amarkantak.

Prelims lock: Chambal (badlands) & Betwa & Ken join the Yamuna, not the Ganga directly; Kosi = "Sorrow of Bihar"; Son = largest south-bank tributary (rises at Amarkantak, radial pattern with Narmada & Mahanadi).

6. The Brahmaputra River System

The Brahmaputra is one of the world's largest rivers by discharge — a braided, silt-heavy giant. It changes name three times along its course.

Tibet: rises near Mansarovar as the Tsangpo, flowing east; takes the "Great Bend" around Namcha Barwa.
Arunachal Pradesh: enters India as the Siang / Dihang.
Assam: joined by the Dibang & Lohit, it becomes the Brahmaputra — a wide, braided river with the huge river-island Majuli (world's largest).
Bangladesh: becomes the Jamuna, joins the Padma (Ganga) and Meghna → the great delta.

Stretch	Name	Feature
Tibet	Tsangpo	Great Bend at Namcha Barwa
Arunachal	Siang / Dihang	Deep gorges (antecedent)
Assam	Brahmaputra	Braided; Majuli island; heavy floods
Bangladesh	Jamuna → Padma/Meghna	World's largest delta with Ganga

Why the Brahmaputra floods & braids: immense discharge + very high silt load + low Assam-valley gradient make it braid into shifting channels and flood almost annually, eroding banks and threatening Majuli. Major tributaries: Subansiri, Manas, Teesta (which joins in Bangladesh).

Prelims lock: Tsangpo (Tibet) → Siang/Dihang (Arunachal) → Brahmaputra (Assam) → Jamuna (Bangladesh); Majuli = world's largest river island; the Great Bend is around Namcha Barwa.

7. Antecedent Rivers & River Capture

Some Himalayan rivers are older than the mountains they cross — a striking proof of the Himalaya's rise.

Antecedent rivers: the Indus, Sutlej & Brahmaputra existed before the Himalaya fully rose; they cut deep gorges by down-cutting as the land uplifted, keeping their original courses across the ranges.
Consequent rivers: formed after and flow along the slope created by uplift (most peninsular rivers).
River capture (piracy): a vigorously eroding river beheads a weaker one, capturing its headwaters (common in the dissected Himalayan foothills and peninsular scarps).

Why it matters: antecedent gorges (e.g., the Brahmaputra at the Great Bend, the Indus in Ladakh) show the rivers predate the final Himalayan uplift — a favourite conceptual Prelims/Mains point on the region's geomorphic history.

8. River Regimes, Importance & Interlinking

A river's regime is the pattern of its flow through the year. Himalayan rivers have a double peak (snowmelt + monsoon); peninsular rivers have a single sharp monsoon peak and near-dry lean season.

Importance: irrigation, drinking water, hydropower, inland navigation (National Waterways), fisheries, and religio-cultural value.
Interlinking of rivers (ILR): the National Perspective Plan proposes Himalayan & Peninsular components to transfer water from "surplus" to "deficit" basins — the Ken–Betwa link is the first project under implementation.
Debate: ILR promises drought/flood relief & irrigation but raises ecological, displacement, inter-state & cost concerns.

Ken–Betwa link (MP–UP, Bundelkhand) is the flagship first river-interlinking project — often paired in exams with debates over the Panna tiger reserve and water-sharing. check for latest update or data

9. River Pollution & Namami Gange

India's rivers, especially the Ganga–Yamuna, face severe pollution from sewage, industrial effluent, idol immersion and reduced lean-season flow (aviral–nirmal deficit).

Namami Gange: the flagship integrated Ganga-rejuvenation mission (sewage treatment, riverfront, afforestation, biodiversity) under the National Mission for Clean Ganga.
Yamuna: the Delhi stretch is among the most polluted; froth & low dissolved oxygen recur.
Concept: "Aviral Dhara" (continuous flow) + "Nirmal Dhara" (clean flow) — both flow & quality must be restored.

Ganga as a living entity: conservation blends ecology (e-flows, Gangetic dolphin — the national aquatic animal), engineering (STPs) and governance (river-basin management) — a rich GS-III theme. check for latest update or data

10. Significance & GS-I Synthesis

The Himalayan rivers built the plains, feed the granary, and carry India's civilisation — but their perennial power is matched by flood and pollution challenges.

Constructive: deep renewable alluvium, assured irrigation, hydropower and navigation — the base of the northern economy.
Hazards: Kosi/Gandak/Brahmaputra floods, bank erosion & channel shifting; Himalayan-headwater glacial-lake outburst risk.
Trans-boundary: shared rivers (Indus, Ganga, Brahmaputra, Teesta) tie water security to India–Pakistan/Nepal/Bangladesh/China relations.
Ecological: pollution, e-flows, dolphins, wetlands & delta health need integrated basin management.

GS-I synthesis: Himalayan rivers are perennial because they are snow-fed and antecedent — the same youth that gives them power also gives them floods and silt. The single logic: snow + monsoon = perennial flow = fertile plains, but also floods, silt, pollution & trans-boundary dependence.

11. Current Affairs & Contemporary Relevance (2024–2026)

Rivers stay "current" through treaty disputes, interlinking, floods, GLOFs and clean-river missions — verify the latest status. check for latest update or data

11.1 Indus Waters Treaty

IWT review: India has sought renegotiation/modification of the 1960 Indus Waters Treaty; disputes over the Kishenganga & Ratle hydropower projects (Jhelum/Chenab) keep it topical. check for latest update or data

11.2 River interlinking

Ken–Betwa link: implementation of India's first river-interlinking project (Bundelkhand) advances amid ecological & Panna-reserve debates. check for latest update or data

11.3 Floods, GLOFs & clean rivers

Himalayan hazards & Namami Gange: glacial-lake outburst floods (Sikkim/Teesta, 2023), recurring Brahmaputra–Kosi floods, and progress under Namami Gange keep river management in the news. check for latest update or data

11.4 Why it matters

Development	Why it matters for UPSC
Indus Waters Treaty review	Trans-boundary water & India–Pakistan (GS-II/III).
Ken–Betwa link	First ILR project; water transfer debate (GS-III).
Teesta GLOF (2023)	Himalayan-river hazard & hydropower risk.
Namami Gange	River rejuvenation & e-flows (GS-III).

Recurring exam hooks:

Drainage patterns · antecedent rivers · tributary–confluence pairings (evergreen Prelims).
Ganga headstreams/prayags · Panjnad · Brahmaputra name changes (favourite factual sets).
IWT, interlinking, floods, Namami Gange (evergreen Mains GS-III).

12. Prelims PYQs (exam-style, high-frequency themes)

Objective questions anchored to genuinely tested UPSC themes on India's drainage and Himalayan rivers. Each carries a worked rationale.

UPSC Prelims — exam-style

Q: The Bhagirathi and Alaknanda unite to form the Ganga at:

(a) Rudraprayag
(b) Devprayag
(c) Haridwar
(d) Karnaprayag

Answer: (b) Devprayag — the Bhagirathi (Gaumukh/Gangotri) and Alaknanda meet here to become the Ganga; the river reaches the plains at Haridwar.

UPSC Prelims — exam-style

Q: The five rivers of Punjab combine to form the ____ before joining the Indus.

(a) Panchganga
(b) Panjnad
(c) Triveni
(d) Sangam

Answer: (b) Panjnad — the Jhelum, Chenab, Ravi, Beas and Sutlej unite as the Panjnad before meeting the Indus.

UPSC Prelims — exam-style

Q: A trellis drainage pattern typically develops on:

(a) Uniform, horizontally-bedded rock
(b) Folded or tilted strata of alternating hardness
(c) A volcanic dome
(d) A flat inland basin

Answer: (b) Trellis patterns form where folded/tilted strata of alternating resistance guide tributaries at right angles. Dendritic = uniform rock; radial = dome; centripetal = inland basin.

UPSC Prelims — exam-style

Q: Which of the following are antecedent rivers that predate the Himalayan uplift?

1. Indus 2. Sutlej 3. Brahmaputra

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1, 2 and 3
(d) 1 and 3 only

Answer: (c) The Indus, Sutlej and Brahmaputra are classic antecedent rivers — they cut deep gorges across the rising Himalaya, keeping their pre-uplift courses.

UPSC Prelims — exam-style

Q: The longest tributary of the Ganga is the:

(a) Yamuna
(b) Ghaghara
(c) Kosi
(d) Son

Answer: (a) Yamuna — the longest tributary of the Ganga; it runs parallel to the Ganga and joins at the Prayagraj Sangam. Its own tributaries include the Chambal, Betwa and Ken.

UPSC Prelims — exam-style

Q: In its Tibetan course, the Brahmaputra is known as the:

(a) Siang
(b) Tsangpo
(c) Dihang
(d) Jamuna

Answer: (b) Tsangpo (Tibet) → Siang/Dihang (Arunachal) → Brahmaputra (Assam) → Jamuna (Bangladesh). The Great Bend is around Namcha Barwa.

UPSC Prelims — exam-style

Q: The Chambal, Betwa and Ken rivers are tributaries of the:

(a) Ganga directly
(b) Yamuna
(c) Son
(d) Ghaghara

Answer: (b) These Peninsular rivers are tributaries of the Yamuna (not the Ganga directly). The Chambal is famous for its badlands/ravines.

UPSC Prelims — exam-style

Q: Majuli, the world's largest river island, lies in the:

(a) Ganga
(b) Brahmaputra
(c) Indus
(d) Godavari

Answer: (b) Majuli, in the braided Brahmaputra (Assam), is the world's largest river island and a centre of Vaishnavite (Satra) culture, threatened by erosion.

Prelims — anticipated themes

Likely: drainage patterns & controls · antecedent rivers (Indus/Sutlej/Brahmaputra) · Panjnad & the five Punjab rivers · Devprayag/prayags & Ganga headstreams · Yamuna longest tributary · Chambal/Betwa/Ken to Yamuna · Kosi "Sorrow of Bihar" · Son at Amarkantak · Brahmaputra name changes & Majuli · Indus Waters Treaty rivers. check for latest update or data

13. Mains PYQs + Model Answers

Genuine UPSC GS-I/GS-III themes on India's drainage and Himalayan rivers and their resource & hazard significance. Each carries a full answer skeleton — Introduction → body → Conclusion.

UPSC Mains GS-I — style 15 marks · 250 words

Q: Compare the Himalayan and Peninsular river systems of India and explain why the Himalayan rivers are perennial.

Model Answer

Introduction: India's rivers form two families whose contrast springs from their age and water source.
Himalayan rivers: young, snow-and-glacier-fed and rain-fed, hence perennial; long, meandering, antecedent gorges, large catchments and big deltas (Indus, Ganga, Brahmaputra).
Peninsular rivers: old, graded, rain-fed and therefore seasonal; shorter fixed valleys, hard-rock beds, some rift-valley courses (Narmada, Tapi).
Why perennial: Himalayan rivers draw glacial melt in summer plus monsoon rain, so they flow year-round; peninsular rivers depend on the monsoon alone and shrink in the dry season.
Conclusion: the perennial Himalayan rivers underpin northern agriculture and hydropower, while seasonal peninsular rivers demand storage — a contrast rooted in source and age.

UPSC Mains GS-I — style 15 marks · 250 words

Q: Account for the recurrent flooding of the Kosi and the Brahmaputra, and suggest management measures.

Model Answer

Introduction: the Kosi and Brahmaputra flood almost annually, a product of their Himalayan sources, high silt and low plain gradients.
Causes: heavy monsoon + snowmelt discharge, enormous silt load raising beds, low gradient causing channel-shifting (Kosi's westward migration), deforestation and embankment failure.
Impacts: loss of life, displacement, bank erosion (Majuli), waterlogging — the Kosi is the "Sorrow of Bihar."
Management: catchment afforestation, desilting, flood-forecasting, embankment maintenance, floodplain zoning, and India–Nepal/China data-sharing and reservoir coordination.
Conclusion: living with silt-laden Himalayan rivers needs an integrated basin approach — forecasting and floodplain management more than embankments alone.

UPSC Mains GS-III — style 15 marks · 250 words

Q: Critically examine the interlinking of rivers as a solution to India's water problems.

Model Answer

Introduction: the National Perspective Plan for river interlinking (ILR) proposes transferring water from surplus to deficit basins; Ken–Betwa is the first project.
Benefits: drought & flood mitigation, expanded irrigation, hydropower, navigation and drinking water for water-stressed regions.
Concerns: huge cost, ecological disruption (Panna reserve), displacement, silt/seismic risk, inter-state & international disputes, and questionable "surplus" assumptions under climate change.
Balanced view: selective, well-studied links with strong environmental & rehabilitation safeguards may help, but decentralised solutions (watershed, rainwater harvesting, efficiency) are complementary.
Conclusion: ILR is not a panacea — it must be pursued case-by-case, balancing water security with ecology and federal consensus.

UPSC Mains GS-II/III — style 15 marks · 250 words

Q: Discuss the significance of the Indus Waters Treaty and the challenges it faces today.

Model Answer

Introduction: the 1960 World-Bank-brokered Indus Waters Treaty allocates the eastern rivers (Ravi, Beas, Sutlej) largely to India and the western rivers (Indus, Jhelum, Chenab) largely to Pakistan.
Significance: it has survived wars, providing a durable water-sharing framework and a model of trans-boundary cooperation.
Challenges: disputes over Indian run-of-river hydropower (Kishenganga, Ratle), India's push for review/modification, climate-driven flow changes and rising water demand.
Way forward: technical dispute-resolution, data-sharing and updating the treaty for climate and energy realities while preserving its cooperative spirit.
Conclusion: the IWT remains vital but strained — adapting it to new hydropower and climate pressures is the central task.

UPSC Mains GS-I — style 10 marks · 150 words

Q: Explain, with examples, how drainage patterns reflect the underlying geology.

Model Answer

Introduction: the plan-shape of a river network mirrors the rock structure and slope it develops on.
Examples: dendritic (tree-like) on uniform rock; trellis (right-angled) on folded/tilted strata; radial (spokes) on a dome (Amarkantak — Narmada, Son, Mahanadi); rectangular on jointed rock; centripetal in inland basins.
Application: reading a drainage pattern lets a geographer infer the structure — a practical geomorphic tool.
Conclusion: drainage patterns are a visible signature of the hidden geology beneath.

Mains — anticipated themes

Likely: Himalayan vs Peninsular rivers & perennial flow · Kosi/Brahmaputra floods & management · interlinking debate · Indus Waters Treaty · drainage patterns & geology · Namami Gange & e-flows. check for latest update or data

15-Minute Revision Box

Must-Remember Facts — Drainage & Himalayan Rivers

Concepts:

Patterns: dendritic (uniform), trellis (folded), radial (dome/Amarkantak), rectangular (jointed), centripetal (basin)
Antecedent = older than mountains: Indus, Sutlej, Brahmaputra
Himalayan = perennial (snow+rain); Peninsular = seasonal (rain)

Indus system:

Source near Mansarovar (Tibet); via Ladakh
Five Punjab rivers → Panjnad (Jhelum, Chenab, Ravi, Beas, Sutlej)
Chenab largest; Jhelum → Wular/Srinagar
IWT: east (Ravi/Beas/Sutlej) India; west (Indus/Jhelum/Chenab) Pakistan

Ganga system:

Bhagirathi + Alaknanda → Devprayag; plains at Haridwar
Yamuna = longest tributary; Chambal/Betwa/Ken join Yamuna
Kosi = "Sorrow of Bihar"; Son = largest south-bank (Amarkantak)
Delta with Brahmaputra = world's largest (Sundarbans)

Brahmaputra:

Tsangpo → Siang/Dihang → Brahmaputra → Jamuna
Great Bend at Namcha Barwa; braided; Majuli island
Floods heavily; Subansiri, Manas, Teesta tributaries

Highest-frequency themes: drainage patterns · antecedent rivers · Panjnad · Devprayag & Ganga headstreams · Yamuna longest tributary · Chambal/Betwa/Ken to Yamuna · Brahmaputra name changes & Majuli · IWT rivers. One logic: snow+monsoon feed = perennial Himalayan rivers = fertile plains but floods, silt & trans-boundary dependence.

System	Mouth
Indus	Arabian Sea
Ganga	Bay of Bengal (delta)
Brahmaputra	Bay of Bengal (delta)

Pattern	Control
Dendritic	Uniform rock
Trellis	Folded strata
Radial	Dome
Rectangular	Jointed rock

Topic 7: Drainage System — Patterns & Himalayan Rivers

On this page

Conceptual Clarity — Why this Chapter Matters

1. Drainage Concepts & Patterns

1.1 Drainage patterns

2. Himalayan vs Peninsular Drainage

3. The Indus River System

4. The Ganga River System

5. Ganga Tributaries in Detail

6. The Brahmaputra River System

7. Antecedent Rivers & River Capture

8. River Regimes, Importance & Interlinking

9. River Pollution & Namami Gange

10. Significance & GS-I Synthesis

11. Current Affairs & Contemporary Relevance (2024–2026)

11.1 Indus Waters Treaty

11.2 River interlinking

11.3 Floods, GLOFs & clean rivers

11.4 Why it matters

12. Prelims PYQs (exam-style, high-frequency themes)

13. Mains PYQs + Model Answers

Model Answer

Model Answer

Model Answer

Model Answer

Model Answer

15-Minute Revision Box

Must-Remember Facts — Drainage & Himalayan Rivers