Question map
Consider the following rivers: 1. Barak 2. Lohit 3. Subansiri Which of the above flows/flow through Arunachal Pradesh?
Explanation
The Barak originates at the Barail range south of Kohima at an altitude of 2,995 metres above the MSL and flows through South Assam.[1] The Barak river, the largest in the state, originates in the Manipur hills and is joined by tributaries such as Irang, Maku and Tuivai.[2] Therefore, the Barak River does not flow through Arunachal Pradesh; it flows through Assam and Manipur.
The Dihang is joined by the Dibang, the Lohit, and many other tributaries to form the Brahmaputra in Assam.[3] The Brahmaputra receives its main left bank tributaries, viz., Dibang or Sikang and Lohit[4] after entering India. Since these rivers join in the northeastern region and the Brahmaputra enters India west of Sadiya town in Arunachal Pradesh[4], the Lohit flows through Arunachal Pradesh.
The Subansiri which has its origin in Tibet, is an antecedent river.[4] The Subansiri is an important right bank tributary of the Brahmaputra.[4] Since it originates in Tibet and joins the Brahmaputra in Assam, it must flow through Arunachal Pradesh, which is supported by references to the Subansiri region in Arunachal.
Therefore, only rivers 2 (Lohit) and 3 (Subansiri) flow through Arunachal Pradesh.
Sources- [1] https://ncert.nic.in/pdf/publication/otherpublications/tinei101.pdf
- [2] https://ncert.nic.in/pdf/publication/otherpublications/tinei101.pdf
- [3] CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Brahmaputra River System > p. 20
- [4] INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > The Brahmaputra System > p. 23
PROVENANCE & STUDY PATTERN
Full viewThis is a classic 'Mental Map' test. While text search makes it look hard, any serious aspirant with an Oxford Student Atlas knows the 'Barak Valley' is in South Assam, separated from Arunachal by the entire Brahmaputra Valley and the Barail Range. The key is not memorizing lists, but visualizing the watershed divide.
This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.
- Explicitly states the Barak's origin and primary course as south of Kohima and through South Assam.
- If the river flows through South Assam and bifurcates near the Assam–Bangladesh border, it indicates its main course is not in Arunachal Pradesh.
- Describes the Barak as the largest river in Manipur and notes it originates in the Manipur hills.
- An origin and major basin in Manipur further support that the Barak's course is in Manipur/Assam regions, not Arunachal Pradesh.
Describes the Barak's origin (Mt. Japov, Nagaland) and course southwards through Manipur and Cachar (Silchar) before entering Bangladesh.
A student could use a map of northeastern India to trace that southward route (Nagaland → Manipur → Cachar) and note that this path does not pass through Arunachal Pradesh, which lies north of these areas.
Explains that the Brahmaputra (and its tributaries) enters India in Arunachal Pradesh, highlighting which major river system occupies Arunachal.
A student can compare river-basin maps to see Barak listed with southern NE basins while Arunachal is in the Brahmaputra basin, suggesting the Barak basin is separate from Arunachal.
States the Brahmaputra's source and its entry into India through Arunachal Pradesh (Dihang/Siang), reinforcing that Arunachal is associated with Brahmaputra headwaters.
Using this, a student could check whether Barak is a Brahmaputra tributary or a distinct southern basin — if distinct, it's less likely to flow through Arunachal.
Notes the Sankosh River forms the boundary between Assam and Arunachal Pradesh and is a Bhutan-main-river that meets the Brahmaputra, indicating which rivers touch Arunachal.
A student could locate the Sankosh and compare its position to the Barak basin; if Barak features are south of these boundary rivers, that supports that Barak does not traverse Arunachal.
Groups the Barak with Ganga and Brahmaputra as major high-precipitation river basins of India, implying distinct major basins in the region.
A student might consult basin maps to see that Barak forms a separate basin (southern NE) rather than the Brahmaputra-dominated Arunachal, helping judge whether Barak flows through Arunachal.
- Describes the Brahmaputra entering India in Arunachal Pradesh and then receiving main left bank tributaries, explicitly listing Lohit as one of them.
- Implies the Lohit is part of the river network encountered as the Brahmaputra/Dihang flows through Arunachal Pradesh.
- States that after entering India in Arunachal Pradesh (as the Dihang/Siang), the river is joined by the Dibang and the Lohit to form the Brahmaputra.
- Links the Lohit with the river system at the point of entry in Arunachal, supporting that Lohit is a tributary in that region.
- Lists a 'Subansiri Lower H.E Project' explicitly under Arunachal Pradesh projects.
- Association of the Subansiri project with Arunachal Pradesh indicates the river/river basin lies in that state.
- Refers to the 'Subansiri region' in the context of peoples and tribes of Arunachal.
- This ties the Subansiri area geographically to Arunachal Pradesh.
Identifies the Subansiri as a right-bank tributary of the Brahmaputra and states it has its origin in Tibet (an antecedent river).
A student could use a map to follow tributaries originating in Tibet and trace whether such right-bank tributaries enter the Brahmaputra within Arunachal Pradesh or downstream in Assam.
Describes where the Brahmaputra (called Dihang) enters India in Arunachal Pradesh and that it is joined there by tributaries like the Dibang and Lohit.
One can extend this pattern by checking whether other named Brahmaputra tributaries (e.g., Subansiri) join the Brahmaputra in the same Arunachal reach on a regional map.
Notes the arrangement of ranges and heavy fluvial erosion in the Eastern Himalaya along the southern border of Arunachal Pradesh, implying many Himalayan-origin rivers cross or drain this state.
Combine this general terrain pattern with the Subansiri's Himalayan/Tibet origin to assess whether its course is likely to pass through Arunachal on its way to the Brahmaputra.
Gives an example (Sankosh) of a river that forms a boundary between Assam and Arunachal Pradesh, illustrating that Brahmaputra tributaries may run along or across the Assam–Arunachal frontier.
Use this example plus a political map to locate where tributaries meet the Brahmaputra and whether the Subansiri could plausibly meet it within Arunachal or at the Assam boundary.
States several Indian rivers flow through neighbouring countries (e.g., Tibet) before entering India, showing cross-border courses are common for major tributaries.
Given Subansiri's stated origin in Tibet, consult a regional map to trace its cross-border path and determine which Indian state(s) it traverses.
- [THE VERDICT]: Sitter for map-readers, Trap for text-crammers. Source: NCERT Class XI (India Physical Environment) Ch 3 + Atlas.
- [THE CONCEPTUAL TRIGGER]: Drainage Systems of North East India. Specifically, the distinction between the Brahmaputra Basin (North) and the Barak/Meghna Basin (South).
- [THE HORIZONTAL EXPANSION]: Memorize the 'Arunachal 5': Kameng, Subansiri, Siang, Dibang, Lohit. Contrast with 'Barak System': Origin (Manipur Hills/Mt. Japvo), Course (Manipur → Mizoram border → Cachar Assam → Bangladesh). Know the watershed: The Barail Range separates these two systems.
- [THE STRATEGIC METACOGNITION]: Do not study rivers as isolated lists. Study them as 'Basins'. Ask: 'Does this river fall into the Brahmaputra from the North (Himalayas) or the South (Naga Hills)?' Barak is a distinct system that does not join the Brahmaputra within Indian territory.
Evidence identifies the Barak's origin and the states it flows through (e.g., Nagaland, Manipur, Mizoram) rather than Arunachal Pradesh.
High-yield for UPSC geography: questions often ask which states a river rises in and traverses. Mastering this helps eliminate options in MCQs and frame answers in polity/IR contexts where rivers determine boundaries and resources. Study by mapping major rivers and memorising source-to-mouth sequences.
- Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > Barak River > p. 18
References describe the Brahmaputra entering India in Arunachal Pradesh (as Dihang/Siang) and its key tributaries, highlighting how river systems are named and change across regions.
Crucial for questions on Northeast hydrography and inter-state water issues; connects to flood patterns, basin management and riverine geopolitics. Learn by clustering rivers into major basins and noting local names and entry points.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > The Brahmaputra System > p. 23
- CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Brahmaputra River System > p. 20
Evidence notes rivers (e.g., Sankosh) form boundaries between states like Assam and Arunachal Pradesh, illustrating rivers' role in political geography.
Often tested in geography and polity intersections (state boundaries, resource sharing). Understanding which rivers demarcate borders aids in answering questions on federal disputes and regional planning. Memorise notable boundary rivers and their adjoining states.
- Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 3: The Drainage System of India > The Sankosh River > p. 17
The references identify Lohit (and Dibang) as principal tributaries that join the Brahmaputra around its entry into India.
High-yield for UPSC physical geography: knowing major river systems and their tributaries helps answer questions on drainage, inter-state river flows and regional development. Connects to topics on Assam-Arunachal hydrology, flood plains and river basin management. Learn by mapping major tributaries and memorising their origins and states traversed.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > The Brahmaputra System > p. 23
- CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Brahmaputra River System > p. 20
References note the river is called Siang/Dihang on entry into India (Arunachal) and becomes the Brahmaputra after joining tributaries including Lohit.
Frequently tested: origin-to-mouth nomenclature and where name changes occur clarify questions on river identity across regions. Useful across river-origin, interstate river questions and map-based prelims; revise by tracing river courses and noting local names.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > The Brahmaputra System > p. 23
- CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Brahmaputra River System > p. 20
Evidence explicitly refers to 'main left bank tributaries' including Lohit, introducing bank-based classification of tributaries.
Understanding left/right bank distinctions aids answers on river morphology and drainage patterns; often appears in descriptive mains answers and map questions. Practice by labelling tributaries on river-flow maps and noting their relative banks.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > The Brahmaputra System > p. 23
The evidence lists the Brahmaputra's principal tributaries and explicitly names Subansiri as a major right-bank tributary.
High-yield for UPSC: questions often ask about major river systems and their tributaries. Mastering this helps answer questions on drainage patterns, river basin administrations, and inter-state water issues. Learn by mapping the main trunk (Brahmaputra) and memorising key left/right-bank tributaries, their origins, and confluence zones.
- INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.) > Chapter 3: Drainage System > The Brahmaputra System > p. 23
- CONTEMPORARY INDIA-I ,Geography, Class IX . NCERT(Revised ed 2025) > Chapter 3: Drainage > The Brahmaputra River System > p. 20
The Barail Range. It is the critical geomorphic feature that acts as the water divide between the Brahmaputra valley (North) and the Barak valley (South). A future question will likely ask which range separates these two drainage systems.
Use the 'Gravity Logic'. Arunachal Pradesh is the 'Crown' of the NE (Himalayas). The Barak river flows into Bangladesh (Sea level). For a river named 'Barak' (famous in Manipur/South Assam) to flow through Arunachal, it would have to defy gravity and flow North-East uphill across the Assam plains. Impossible. Eliminate 1.
Internal Security & Connectivity: The 'Chicken's Neck' corridor is vulnerable. The Barak Valley is the sole logistical gateway to Tripura, Mizoram, and Manipur. Understanding this river's geography is essential for answering Mains GS3 questions on North-East insurgency and infrastructure (e.g., Silchar-Saurashtra Corridor).