Which of the following three rivers of the peninsula India have the Amarkantak region as their source ?

1. Introduction to Peninsular Drainage Systems (basic)

Welcome to our journey through the Peninsular Drainage System. To understand India's rivers, we must first recognize that the Peninsular system is far older than its Himalayan counterpart. While the Himalayan rivers are "youthful" and aggressive, Peninsular rivers are mature. This maturity is visible in their broad, largely-graded shallow valleys and the fact that most have reached their base level of erosion INDIA PHYSICAL ENVIRONMENT, Chapter 3, p.23. Unlike the perennial Himalayan rivers fed by melting glaciers, Peninsular rivers are primarily seasonal, relying almost entirely on monsoon rainfall CONTEMPORARY INDIA-I, Chapter 3, p.17.

The current geography of these rivers was shaped by three major geological events in the distant past:

• Subsidence of the Western Flank: During the early Tertiary period, the western side of the Peninsula subsided and submerged below the sea. This disturbed the original symmetrical drainage plan of the region.
• Himalayan Upheaval: As the Himalayas rose, the northern part of the Peninsular block underwent subsidence and trough faulting. This created the rift valleys through which the Narmada and Tapi flow today. Because they flow through these hard-rock cracks, they lack significant alluvial deposits INDIA PHYSICAL ENVIRONMENT, Chapter 3, p.23.
• Slight Tilting: The entire Peninsular block tilted slightly from the northwest to the southeast. This tilt explains why the vast majority of major rivers—like the Godavari, Krishna, and Kaveri—flow toward the Bay of Bengal.

A fascinating feature of this system is the Western Ghats, which act as the primary water divide. Most major rivers originate here and flow east. However, certain regions like the Amarkantak Plateau in Central India act as a unique hydrological hub. Here, we see a radial drainage pattern where rivers like the Narmada (flowing west), the Son (flowing north to join the Ganga), and the Mahanadi (flowing southeast) originate in close proximity but head in completely different directions Geography of India, Chapter 3, p.20.

Feature	Himalayan Rivers	Peninsular Rivers
Age	Geologically young	Very old, stable landmass
Valley Shape	V-shaped, deep gorges	Broad, shallow, and graded
Nature of Flow	Perennial (Rain + Snow)	Seasonal (Mainly Rain)

Sources: INDIA PHYSICAL ENVIRONMENT, Chapter 3: Drainage System, p.23; CONTEMPORARY INDIA-I, Chapter 3: Drainage, p.17; Geography of India, Chapter 3: The Drainage System of India, p.20

2. East-Flowing vs. West-Flowing Rivers (basic)

To understand the drainage of Peninsular India, we must first look at the 'tilt' of the land. The Peninsular plateau is one of the oldest and most stable landmasses on Earth, with a general elevation that slopes from the west toward the east. This structural tilt is the primary reason why the majority of major rivers flow toward the Bay of Bengal INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Chapter 3, p.12. The Western Ghats, running close to the western coast, act as the primary water divide. While most rivers follow the plateau's natural slope eastward, a few notable exceptions like the Narmada and Tapi flow westward through rift valleys, which are structural depressions formed by tectonic activity rather than simple surface erosion.

One of the most distinct differences between these two systems lies in the landforms they create at their mouths. East-flowing rivers, such as the Mahanadi, Godavari, Krishna, and Kaveri, travel long distances over gentler slopes, carrying significant amounts of sediment. By the time they reach the coast, they slow down and deposit this silt, forming expansive deltas CONTEMPORARY INDIA-I, Geography, Class IX (NCERT 2025 ed.), Chapter 3, p.21. In contrast, west-flowing rivers are generally shorter and flow with higher velocity down steeper gradients. Because they flow through hard rock rift valleys, they carry less sediment and reach the sea with enough force to prevent large-scale deposition, forming estuaries instead of deltas.

Feature	East-Flowing Rivers	West-Flowing Rivers
Examples	Godavari, Krishna, Kaveri, Mahanadi	Narmada, Tapi, Periyar, Sharavati
Mouth Landform	Deltas (e.g., Sundarbans, Godavari Delta)	Estuaries (deep, narrow submerged mouths)
Slope & Path	Longer path, gentler slope	Shorter path, steeper slope (often in rift valleys)
Drainage Area	Larger basins	Relatively smaller basins

Finally, we must note the unique Amarkantak Plateau in central India. It acts as a hydrological hub where a radial drainage pattern is observed. From this highland, the Narmada flows west, while the Son flows northeast toward the Ganga, and the headwaters of the Mahanadi system originate nearby, showing how a single highland can distribute water in entirely different directions Geography of India, Majid Husain, Chapter 3, p.20.

Sources: INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Structure and Physiography, p.12; CONTEMPORARY INDIA-I, Geography, Class IX (NCERT 2025 ed.), Drainage, p.21; Geography of India, Majid Husain (9th ed.), The Drainage System of India, p.20

3. Radial and Dendritic Drainage Patterns (intermediate)

A drainage pattern is the geometric arrangement of a river and its tributaries from source to mouth. It is never accidental; rather, it is a signature of the underlying geology, the slope of the land, and the nature of the rocks Majid Husain, Geography of India, Chapter 3, p.1. Understanding these patterns allows us to "read" the history of a landscape simply by looking at a map of its rivers.

The Dendritic pattern is the most common arrangement you will encounter. The word comes from the Greek 'dendron', meaning tree. Just like the branches of an oak tree, the tributaries join the main river at acute angles. This pattern develops where the underlying rock is uniform in its resistance to erosion (homogeneous), allowing the slope of the land to be the primary director of water flow. While famous in the Indo-Gangetic plains, it is also extensively seen in the flatter parts of the Peninsular plateau Majid Husain, Geography of India, Chapter 3, p.3.

In contrast, the Radial pattern occurs when rivers originate from a central high point, such as a volcanic cone or a structural dome, and flow outward in all directions—much like the spokes of a wheel. In the context of the Peninsular drainage system, the Amarkantak Plateau is the most iconic example of this. From this central highland hub, the Narmada flows west, the Son flows north toward the Ganga, and the Mahanadi (originating in the nearby Chhattisgarh highlands) flows toward the southeast Majid Husain, Geography of India, Chapter 3, p.3, 20.

Feature	Dendritic Pattern	Radial Pattern
Visual Appearance	Tree-like branching	Spokes of a wheel
Geological Trigger	Uniform rock resistance/flat terrain	Central dome or volcanic peak
Indian Example	Indo-Gangetic Rivers	Amarkantak (Narmada, Son), Girnar Hills

Sources: Geography of India, Chapter 3: The Drainage System of India, p.1, 3, 20

4. Rift Valley Topography and West-Flowing Rivers (intermediate)

To understand why certain Peninsular rivers flow West, we first need to look at the 'unusual' topography they inhabit. Most Peninsular rivers, like the Godavari and Krishna, flow East because the Indian Plate is tilted from West to East. However, the Narmada and Tapi are exceptions because they do not follow the general slope of the land; instead, they occupy Rift Valleys (or troughs) created by geological faulting during the Himalayan upheaval Geography of India, Physiography, p.55. These rift valleys act like pre-defined geological pipes that force the rivers to flow West toward the Arabian Sea. The Narmada River flows through a structural rift valley between the Vindhya Range to the North and the Satpura Range to the South. Parallel to it, the Tapi River rises in the Satpura ranges of the Betul district and flows through a more constricted rift valley between the Satpura and the Ajanta Range Geography of India, The Drainage System of India, p.20. Because these rivers flow through hard rock and confined channels, they carry relatively little silt compared to Himalayan rivers. This lack of sediment, combined with the high velocity of the water as it nears the coast and the very narrow coastal plains, prevents these rivers from forming deltas; instead, they form estuaries at their mouths Contemporary India-I, Drainage, p.21. Another fascinating feature of this region is the Amarkantak Plateau. This plateau acts as a major hydrological hub exhibiting a radial drainage pattern, where rivers flow in different directions from a central high point. From this single region, the Narmada flows West, while the Son River (a tributary of the Ganga) flows Northeast, and the headwaters of the Mahanadi originate nearby to the Southeast Geography of India, Physiography, p.55.

Feature	Narmada River	Tapi River
Location	Between Vindhyas and Satpuras	South of Satpuras (between Satpura & Ajanta)
Origin	Amarkantak Plateau (MP)	Betul District (MP)
Length	Longer (~1,312 km)	Shorter (~700 km)

Sources: Geography of India, Physiography, p.55; Geography of India, The Drainage System of India, p.20; Contemporary India-I, Drainage, p.21

5. South Bank Tributaries of the Ganga System (exam-level)

The Ganga river system is a massive network that receives water from two distinct geological regions: the snow-capped Himalayas to the north and the ancient Peninsular plateau to the south. The south bank (or right bank) tributaries are particularly fascinating because they are primarily non-perennial, meaning they depend on monsoon rains rather than melting glaciers. The most significant direct right-bank tributary is the Son River, which originates from the Amarkantak Plateau in the Maikal Hills Geography of India, Majid Husain, Chapter 3, p.16. The Amarkantak region is a unique hydrological hub exhibiting a radial drainage pattern; while the Son flows northeast to join the Ganga, the Narmada flows west towards the Arabian Sea Geography of India, Majid Husain, Chapter 3, p.20.

While the Yamuna is the longest right-bank tributary, it serves as a massive collector for other peninsular rivers. Rivers like the Chambal, Betwa, and Ken originate from the Malwa Plateau and Vindhyan ranges, flowing northwards to join the Yamuna before it eventually merges with the Ganga at Prayag (Allahabad) INDIA PHYSICAL ENVIRONMENT, Class XI, Chapter 3, p.22. Further east, the Damodar River joins the Hugli (a distributary of the Ganga); it was historically known as the 'Sorrow of Bengal' due to its devastating floods INDIA PHYSICAL ENVIRONMENT, Class XI, Chapter 3, p.25.

Comparing these rivers helps clarify their diverse origins and paths:

River	Source Region	Confluence Point
Son	Amarkantak Plateau	Directly joins Ganga near Patna
Chambal	Malwa Plateau (Vindhyas)	Joins Yamuna
Betwa	Bhopal (Vindhyas)	Joins Yamuna
Damodar	Chota Nagpur Plateau	Joins Hugli (Ganga Distributary)

Sources: Geography of India, Majid Husain, Chapter 3: The Drainage System of India, p.16, 20, 47; INDIA PHYSICAL ENVIRONMENT, Geography Class XI (NCERT 2025 ed.), Chapter 3: Drainage System, p.22, 25; CONTEMPORARY INDIA-I, Geography, Class IX (NCERT 2025 ed.), Chapter 3: Drainage, p.20

6. The Amarkantak Plateau: A Hydrological Hub (exam-level)

The Amarkantak Plateau, nestled in the Maikal Hills of eastern Madhya Pradesh and Chhattisgarh, is one of India's most fascinating geographical features. It acts as a primary water divide and a central 'hydrological hub.' Physically, the Maikal Range serves as a vital link connecting the Vindhyan and Satpura mountain systems Geography of India, Physiography, p.54. Its unique elevation and structure make it the starting point for rivers that travel to completely different corners of the subcontinent.

The defining characteristic of this plateau is its radial drainage pattern. In this system, rivers originate from a central highland and flow outwards in different directions, much like the spokes of a bicycle wheel. This is distinct from the dendritic (tree-like) or trellis patterns seen elsewhere in the Peninsular plateau INDIA PHYSICAL ENVIRONMENT, Drainage System, p.24. The three major river systems emerging from this region include:

• The Narmada: Rising from the western flank, it flows westward through a rift valley formed by faulting, eventually reaching the Arabian Sea Contemporary India-I, Drainage, p.21.
• The Son: This river flows northeast, cutting through the Kaimur hills to eventually join the Ganga as one of its major south-bank tributaries.
• The Mahanadi: While its primary source is in the Sihawa highlands of Chhattisgarh, its headwaters are traditionally associated with the broader Amarkantak watershed, from where it drains southeast toward the Bay of Bengal.

Understanding the Amarkantak Plateau is essential because it contrasts sharply with other peninsular sources. For instance, while the Western Ghats (home to the Godavari and Krishna) slope gently eastward, the Amarkantak region forces water to flow in three different cardinal directions—West, North, and Southeast—creating a unique triple-drainage divide in the heart of India Contemporary India-I, Physical Features of India, p.12.

Sources: Geography of India (Majid Husain), Physiography, p.54; INDIA PHYSICAL ENVIRONMENT (NCERT 2025), Drainage System, p.24; Contemporary India-I (NCERT 2025), Drainage, p.21; Contemporary India-I (NCERT 2025), Physical Features of India, p.12

7. Solving the Original PYQ (exam-level)

Now that you have mastered the radial drainage pattern and the physiography of the Peninsular Plateau, this question serves as the perfect application of those building blocks. In your previous lessons, we identified the Maikal Hills as a critical hydrological hub. As explained in NCERT Class XI India Physical Environment, the Amarkantak Plateau acts as the center of a "spoke-and-wheel" system, where gravity sends water in diverging directions. To solve this, you must recall which rivers "radiate" from this specific central point: the Narmada flows westward into a rift valley, the Son travels north-east to meet the Ganga, and the Mahanadi originates from the adjacent highlands of the same watershed system, making (B) Son, Mahanadi, Narmada the correct choice.

Why is this a classic UPSC-style question? It tests your ability to differentiate between the various "water towers" of India. Options (A) and (C) are common traps because they feature the Godavari, Krishna, and Cauvery. While these are major peninsular rivers, your conceptual maps—and Majid Husain’s Geography of India—show they originate much further west in the Western Ghats (specifically Nasik, Mahabaleshwar, and the Brahmagiri hills). Similarly, option (D) lists the Chambal and Betwa, which belong to the Malwa Plateau and the Vindhyan range. By systematically eliminating rivers based on their specific mountain origins, you can confidently arrive at the correct answer even if the Mahanadi’s precise source (Sihawa) is slightly south of the Amarkantak peak, as they are traditionally grouped within the same drainage region.