UPSC CSE Prelims
Drainage System and Rivers Previous Year Questions (PYQs)

Detailed Explanation:

Explanation:

The Sutlej River satisfies all the given conditions. It is an antecedent river, originating near Rakshastal in the Tibetan Plateau and flowing through China, India, and Pakistan.

It is an important source of irrigation in northwestern India and, unlike the Indus and Brahmaputra, does not form distributaries. Instead, it joins the Chenab before ultimately merging with the Indus system.

Therefore, Option C (Sutlej) is correct.

Detailed Explanation:

🧠 Concept First — What is Being Asked?

This question tests understanding of Pleistocene river piracy and drainage evolution in the Indian subcontinent — specifically the ancient connection between the Indus and Ganga river systems.

🌊 The Core Geological Idea

During the Pleistocene epoch, a single massive river called the Indo-Brahma (Shiwalik River) is believed to have connected modern Indus and Ganga basins. Later, tectonic uplift (Delhi Ridge) caused river avulsion — Yamuna shifted east to Ganga, Sutlej shifted west to Indus.

📋 Statement-wise Analysis

Statement 1 — Incorrect. The Nadi-Sukta (Rigveda 10.75) lists rivers east to west (Ganga, Yamuna, Sarasvati, Sutlej). It reflects Holocene human geography — NOT Pleistocene geological shifts which occurred millions of years before the Vedic period.

Statement 2 — Incorrect. Robert Bruce Foote = "Father of Indian Prehistory" — famous for discovering India's first Paleolithic handaxe at Pallavaram, Tamil Nadu (1863). His work focused on Stone Age archaeology in South India and Gujarat — NOT geological mapping of Sutlej-Yamuna shifts.

Statement 3 — Correct. The presence of closely related blind river dolphins in two completely separated basins:

• Platanista gangetica minor → Indus
• Platanista gangetica gangetica → Ganga

Same species in separated basins = biological proof of ancient river connection = primary basis of the assertion.

Detailed Explanation:

Answer: Option 2 — Gomati - Ghaghara – Gandak – Kosi

The correct sequence of Himalayan rivers joining the Ganga downstream of Prayagraj from West to East is Gomati, Ghaghara, Gandak, and Kosi. Gomati joins near Varanasi (westernmost), followed by Ghaghara at Chhapra, Gandak at Sonpur near Patna, and Kosi near Kursela in Katihar district (easternmost).

📝 Short Notes: Himalayan Tributaries of Ganga Downstream of Prayagraj

• Geographic Sequence: All four rivers originate in the Himalayas (except Gomati which is plains-fed) and join the Ganga in Bihar and eastern UP, progressively from west to east.
• Importance: These rivers are crucial for irrigation, hydropower, and navigation in the Indo-Gangetic plains, but also cause frequent flooding.
• Confluence Points: Remembering the confluence locations helps: Varanasi → Chhapra → Patna (Sonpur) → Katihar (west to east along Ganga's course).

Detailed Explanation:

Answer: Option 2 — Only two

This question tests the correct matching of waterfalls with their regions and rivers. Out of the three pairs given, two are correctly matched while one contains an error in the river name.

✅ Pair 1 – Correct: Dhuandhar waterfall is located on the Narmada River in the Malwa region (Jabalpur, Madhya Pradesh).

✅ Pair 2 – Correct: Hundru waterfall is located on the Subarnarekha River in the Chota Nagpur Plateau region (Jharkhand).

❌ Pair 3 – Incorrect: Gersoppa (Jog Falls) is located on the Sharavati River in the Western Ghats, not on the Netravati River.

📝 Short Notes: Major Waterfalls of India

Detailed Explanation:

Answer: Option 1 — Only one

This question tests knowledge of Indian rivers and their associated lakes. Out of the three statements given, only the statement about Jhelum River and Wular Lake is correct, while the other two contain factual inaccuracies regarding the formation and feeding mechanisms of the respective lakes.

✅ Statement 1 – Correct: The Jhelum River, originating from Verinag Spring in Kashmir Valley, does pass through Wular Lake (one of Asia's largest freshwater lakes) before continuing towards Baramulla.

❌ Statement 2 – Incorrect: Kolleru Lake is located between Krishna and Godavari deltas but is NOT directly fed by the Krishna River; it receives water from seasonal streams like Budameru and Tammileru, which are independent tributaries.

❌ Statement 3 – Incorrect: Kanwar Lake (Kabartal) in Bihar is an oxbow lake formed by the meandering of the Burhi Gandak River, not the main Gandak River—these are two separate river systems.

📝 Short Notes: Important Indian Lakes and Associated Rivers

Detailed Explanation:

Answer: Option 3 — Pennar

Gandikota, located in the Kadapa district of Andhra Pradesh, is famously known as the "Grand Canyon of India." This spectacular gorge was carved out over millions of years by the Pennar River, which flows from the Erramala hills. The canyon is characterized by its striking red-hued, layered, and jagged rock formations that resemble the Grand Canyon of the United States.

📝 Short Notes: Major Rivers and Geographical Features of South India

• Pennar River: Rises in the Nandi Hills of Karnataka, flows through Andhra Pradesh, and drains into the Bay of Bengal. Famous for creating the Gandikota gorge.
• Cauvery River: Originates in the Western Ghats (Talakaveri, Karnataka), flows through Karnataka and Tamil Nadu, creating the Hogenakkal Falls and Shivanasamudra Falls.
• Tungabhadra River: A tributary of the Krishna River, formed by the confluence of Tunga and Bhadra rivers, flows through Karnataka and Andhra Pradesh.
• Manjira River: A tributary of the Godavari River, originates in Maharashtra and flows through Telangana.
• Gandikota Canyon: Located near Gandikota village, Kadapa district, Andhra Pradesh; known for its red sandstone formations and steep cliffs rising up to 300 feet.

Detailed Explanation:

Answer: Option 3 — Only three pairs

Out of the four given pairs, only Gandhi Sagar Reservoir in Madhya Pradesh is correctly matched. The other three pairs are incorrectly matched: Ghataprabha is in Karnataka (not Telangana), Indira Sagar is in Madhya Pradesh (not Andhra Pradesh), and Maithon is in Jharkhand (not Chhattisgarh).

❌ Pair 1 – Incorrect: Ghataprabha Reservoir is located in Karnataka (on Ghataprabha River, a tributary of Krishna), not in Telangana.
✅ Pair 2 – Correct: Gandhi Sagar Reservoir is correctly matched with Madhya Pradesh (on Chambal River).
❌ Pair 3 – Incorrect: Indira Sagar Reservoir is located in Madhya Pradesh (on Narmada River), not in Andhra Pradesh.
❌ Pair 4 – Incorrect: Maithon Reservoir is located in Jharkhand (on Barakar River), not in Chhattisgarh.

📝 Short Notes: Major Reservoirs in India

Detailed Explanation:

Answer: Option 2 — 2 and 4

Among the given rivers, only Nagavali and Vamsadhara originate from the Eastern Ghats, while Brahmani and Subarnarekha have their sources in the Chota Nagpur Plateau of Jharkhand.

❌ Statement 1 – Incorrect: The Brahmani river is formed by the confluence of Sankh and South Koel rivers near Rourkela; these headstreams originate in the Chota Nagpur Plateau of Jharkhand, not the Eastern Ghats.

✅ Statement 2 – Correct: The Nagavali river (also known as Langulya) originates in the Eastern Ghats near Lakhbahal in the Kalahandi district of Odisha.

❌ Statement 3 – Incorrect: The Subarnarekha river originates in the Chota Nagpur Plateau near Ranchi in Jharkhand and flows through West Bengal and Odisha before entering the Bay of Bengal.

✅ Statement 4 – Correct: The Vamsadhara river originates in the Eastern Ghats near Lanjigarh in the Kalahandi district of Odisha and flows through Andhra Pradesh before joining the Bay of Bengal.

📝 Short Notes: Rivers Originating from Eastern Ghats

• Eastern Ghats: A discontinuous range of mountains running parallel to the eastern coast of India through Odisha, Andhra Pradesh, Telangana, and Tamil Nadu.
• Major Rivers from Eastern Ghats: Mahanadi, Godavari (tributaries), Krishna (tributaries), Penner, Palar, Vaigai, Nagavali, Vamsadhara, and several smaller coastal rivers.
• Nagavali River: Originates in Kalahandi district (Odisha), flows through Odisha and Andhra Pradesh, length ~256 km, enters Bay of Bengal near Kalingapatnam.
• Vamsadhara River: Originates in Kalahandi district (Odisha) near Lanjigarh, flows through Odisha and Andhra Pradesh, length ~254 km, meets Bay of Bengal near Kalingapatnam.
• Chota Nagpur Plateau Rivers: Brahmani, Subarnarekha, Damodar, and other rivers originate from this plateau in Jharkhand, not from the Eastern Ghats.
• Coastal Drainage: Rivers from Eastern Ghats typically have shorter courses and form smaller drainage basins compared to peninsular rivers originating from the Western Ghats.

Detailed Explanation:

Answer: Option 4 — Sutlej

The Sutlej is the river that joins the Indus directly after receiving the collective drainage of the other three rivers. The Jhelum and Ravi rivers merge with the Chenab, and the Chenab subsequently joins the Sutlej in Pakistan. The Sutlej then flows into the Indus a few kilometres above Mithankot, making it the final conduit for the combined waters before their confluence with the Indus.

📝 Short Notes: Indus River System

• Five Major Tributaries: The Indus river system comprises five major tributaries known as the Panjnad (five rivers): Jhelum, Chenab, Ravi, Beas, and Sutlej.
• Confluence Pattern: Jhelum joins Chenab near Jhang in Pakistan; Ravi joins Chenab near Sidhnai; Beas joins Sutlej at Harike in Punjab, India; Chenab joins Sutlej near Panjnad in Pakistan.
• Final Confluence: The Sutlej (carrying waters of all other tributaries) joins the Indus directly near Mithankot in Pakistan.
• Origin: All five rivers originate in the Himalayas; Sutlej originates from Rakas Lake near Mansarovar in Tibet.
• Geographical Significance: The Indus system drains parts of India, Pakistan, China, and Afghanistan, making it one of the longest rivers in Asia (approximately 3,180 km).

Detailed Explanation:

Answer: Option 4 — Saline lakes

Didwana, Kuchaman, Sargol, and Khatu are saline lakes located in Rajasthan, India. These salt lakes are significant for salt production and are characteristic of the arid and semi-arid regions of Rajasthan where high evaporation rates lead to salt concentration in water bodies.

📝 Short Notes: Saline Lakes of Rajasthan

• Sambhar Lake: The largest saline lake in India, located in Rajasthan between Jaipur and Ajmer; a Ramsar site and major source of salt production.
• Didwana Lake: Located in Nagaur district; known for high salt concentration and commercial salt extraction.
• Kuchaman Lake: Saline lake in Nagaur district; supports salt industry and seasonal water body.
• Pachpadra Lake: Another important saline lake in Barmer district known for salt production.
• Formation: These lakes are formed in inland drainage basins where high evaporation exceeds precipitation, leading to salt accumulation.
• Economic Significance: These lakes contribute significantly to India's salt production, supporting local economy and employment.

Detailed Explanation:

Answer: Option 1 — 1, 2 and 4

This question tests knowledge of major Himalayan glaciers and their associated river systems. The correctly matched pairs are Bandarpunch-Yamuna, Bara Shigri-Chenab, and Siachen-Nubra, making option 1 the correct answer.

✅ Pair 1 – Bandarpunch : Yamuna – Correct: Bandarpunch glacier in the Garhwal Himalayas of Uttarakhand is one of the principal sources of the Yamuna River.

✅ Pair 2 – Bara Shigri : Chenab – Correct: Bara Shigri is the second-longest glacier in the Himalayas (after Gangotri) and feeds the Chenab River through its tributary system.

❌ Pair 3 – Milam : Mandakini – Incorrect: Milam Glacier in Uttarakhand feeds the Gori Ganga River (tributary of Kali River), not Mandakini. Mandakini originates from Chorabari Glacier near Kedarnath.

✅ Pair 4 – Siachen : Nubra – Correct: Siachen Glacier in the Karakoram Range is one of the world's longest mountain glaciers and is the source of the Nubra River, which later joins the Shyok River.

❌ Pair 5 – Zemu : Manas – Incorrect: Zemu Glacier in Sikkim feeds the Teesta River, not the Manas River. Manas originates in Bhutan and flows through Assam.

📝 Short Notes: Major Himalayan Glaciers and Their Rivers

Detailed Explanation:

Answer: Option 1 — 1 and 2 only

This question tests the knowledge of famous places in India and the rivers associated with them. Out of the three pairs given, only pairs 1 and 2 are correctly matched.

✅ Pair 1 – Correct: Pandharpur is a renowned pilgrimage town located on the banks of the Chandrabhaga River (also known as Bhima River) in Solapur district, Maharashtra.

✅ Pair 2 – Correct: Tiruchirappalli (Trichy) is situated along the banks of the Cauvery River in Tamil Nadu, which is one of the major rivers of South India.

❌ Pair 3 – Incorrect: Hampi, a UNESCO World Heritage Site in Karnataka, is located on the banks of the Tungabhadra River, not the Malaprabha River.

📝 Short Notes: Important Rivers and Associated Cities in India

• Chandrabhaga River: Also known as Bhima River; Pandharpur (Maharashtra) is located on its banks; it is a tributary of Krishna River.
• Cauvery River: Major river of South India; flows through Karnataka and Tamil Nadu; important cities include Tiruchirappalli, Srirangapatna, and Thanjavur.
• Tungabhadra River: Formed by confluence of Tunga and Bhadra rivers; flows through Karnataka and Andhra Pradesh; Hampi is located on its banks.
• Malaprabha River: A tributary of Krishna River; flows through Karnataka; does not pass through Hampi.
• Krishna River: One of the longest rivers in India; flows through Maharashtra, Karnataka, Telangana, and Andhra Pradesh; receives tributaries like Bhima (Chandrabhaga) and Tungabhadra.

Detailed Explanation:

Answer: Option 2 — 2 only

Only statement 2 is correct regarding river Teesta. Statement 1 incorrectly claims that Teesta and Brahmaputra have the same source, while statement 3 incorrectly states that Teesta flows into the Bay of Bengal at the India-Bangladesh border.

❌ Statement 1 – Incorrect: River Teesta originates from Pahunri glacier and Tso Lhamo Lake in North Sikkim, while Brahmaputra originates from Angsi Glacier in the Kailash range of Tibet; their sources are entirely different.

✅ Statement 2 – Correct: River Rangeet originates from the Rathong Glacier in West Sikkim and is the largest tributary of river Teesta, joining it at Melli near the Sikkim-West Bengal border.

❌ Statement 3 – Incorrect: River Teesta does not flow directly into the Bay of Bengal; instead, it joins the Brahmaputra River (Jamuna) at Fulchhari in Bangladesh, and then flows into the Bay of Bengal through the Brahmaputra system.

Detailed Explanation:

Answer: Option 2 — Godavari and Krishna

The Godavari-Krishna river linking project was recently undertaken through the Pattiseema Lift Irrigation Scheme in Andhra Pradesh. This project lifts flood water from the Godavari River and pumps it through the Polavaram right canal, which empties into the Krishna River near Vijayawada. This was a significant step in India's ambitious river interlinking program aimed at creating a national water grid for better water resource management and distribution.

Detailed Explanation:

Answer: Option 4 — 1, 2 and 3

✅ Statement 1 – Correct: Dibang is a major left-bank tributary of the Brahmaputra that flows through the Mishmi Hills in Arunachal Pradesh before joining the main river near Pasighat.

✅ Statement 2 – Correct: Kameng is a significant right-bank tributary originating in the Tawang district of Arunachal Pradesh that flows through Assam and joins the Brahmaputra downstream of Tezpur.

✅ Statement 3 – Correct: Lohit is an important left-bank tributary originating in eastern Tibet (China) that flows through the Mishmi Hills of Arunachal Pradesh and merges with the Dibang to form the Brahmaputra in the Assam plains.