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Geography

Predicted Questions with Model Answers

Drainage Pattern, Rivers of India

Paper II · Unit 3 Section 9 of 11 0 PYQs 27 min
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Predicted Questions with Model Answers

Q1 (5 marks — 50 words): Name any eight tributaries of the Krishna River.

Model Answer:

The Krishna River (1,400 km; originates Mahabaleshwar, Maharashtra) has these major tributaries: (1) Bhima (861 km, right); (2) Tungabhadra (right — Hampi); (3) Ghataprabha (right); (4) Malprabha (right); (5) Musi (right — flows through Hyderabad); (6) Koyna (left — Koyna Dam); (7) Yerla (left); (8) Muneru (left). Tungabhadra is its largest tributary.

Q2 (5 marks — 50 words): Why do Narmada and Tapi flow westward unlike other peninsular rivers?

Model Answer:

Unlike other east-flowing peninsular rivers (Godavari, Krishna, Kaveri), Narmada and Tapi flow westward into the Arabian Sea because they flow through rift valleys (grabens) — tectonic fault depressions formed when the Deccan Trap basalts cracked along fault lines. Narmada flows between Vindhya and Satpura ranges; Tapi between Satpura and Ajanta. This rift prevents them from following the general eastward slope of the Deccan Plateau.

Q3 (5 marks — 50 words): What is antecedent drainage? Give two examples from India.

Model Answer:

Antecedent drainage refers to rivers that are older than the mountains they traverse — they maintained their original course by eroding downward as the mountains rose beneath them through tectonic uplift. This creates spectacular gorges where rivers cut through mountains. Examples from India: (1) Indus River — cuts through the Karakoram/Himalayas via a 5,200 m deep gorge; (2) Brahmaputra (Tsangpo) — cuts around Namcha Barwa (7,782 m), forming the world's deepest canyon.

Q4 (5 marks — 50 words): What is the Indus Waters Treaty? State its key provisions.

Model Answer:

The Indus Waters Treaty (1960) was brokered by the World Bank between India and Pakistan. It allocates the three eastern rivers (Ravi, Beas, Sutlej — ~41 BCM) exclusively to India and the three western rivers (Indus, Jhelum, Chenab — ~168 BCM) to Pakistan. India can use western rivers for non-consumptive purposes (run-of-river hydropower, irrigation up to set limits). The treaty has survived three Indo-Pak wars but faces contemporary strain.

Q5 (10 marks — 150 words): Describe the Ganga river system — its origin, tributaries, and economic significance.

Model Answer:

The Ganga (2,525 km) is India's longest, most sacred, and economically most vital river. It originates from Gangotri Glacier (Gaumukh) in Uttarakhand at 3,892 m. The Bhagirathi meets the Alaknanda at Devprayag to form the Ganga. It flows through Uttarakhand, Uttar Pradesh, Bihar, and West Bengal before forming the Sundarbans delta (world's largest mangrove forest, 10,200 sq km) in the Bay of Bengal.

Right bank tributaries: Yamuna (1,376 km — joins at Prayagraj); Son (784 km; MP-Bihar).

Left bank tributaries: Ramganga, Ghaghra/Karnali (1,080 km), Gandak, Kosi (720 km — "Sorrow of Bihar"; frequent course changes, floods).

Economic Significance:

Agriculture: Ganga basin (8.6 lakh sq km — 26% of India) supports India's food grain heartland — wheat in UP/Punjab, rice in Bihar/West Bengal, sugarcane in UP; intense Khadar cultivation in the fertile floodplains.

Industry: Major industrial cities along the Ganga — Kanpur (leather), Varanasi (textiles/handlooms), Allahabad, Patna, Kolkata (jute, engineering).

Navigation: The Ganga and its tributaries provide 1,600 km of navigable waterway (National Waterway 1 — Allahabad to Haldia).

Religion: Spiritually central to 1 billion Hindus; pilgrimage economy of Haridwar, Rishikesh, Varanasi, Prayagraj.

Challenges: Industrial effluents, sewage, religious offerings cause pollution; Namami Gange Mission (Rs 20,000 crore) addresses this through STPs, river-front development, and biodiversity conservation.

Q6 (10 marks — 150 words): Explain the Brahmaputra river system. Why does it cause frequent floods in Assam?

Model Answer:

The Brahmaputra originates as Tsangpo in Tibet (Chemayungdung glacier, 5,150 m). It flows east through Tibet for ~1,625 km, then makes a spectacular hairpin turn around Namcha Barwa (7,782 m) — cutting the world's deepest gorge (Yarlung Tsangpo Canyon, 5,382 m deep) — before entering Arunachal Pradesh as Dihang. In Assam, it is known as Brahmaputra; in Bangladesh, as Jamuna. Total length: ~2,900 km; within India: 918 km.

Major tributaries in India: Lohit, Dibang, Subansiri, Manas (right bank from Eastern Himalayas); Barak, Sankosh (left).

Why it causes frequent Assam floods:

  1. Massive discharge: Annual discharge ~585 BCM — 3rd highest in Asia; monsoon-season flow is enormous.
  2. Seismically active region: Assam lies in Zone V (highest earthquake risk); earthquakes (especially 1950 Assam earthquake, M8.6) cause landslides that constrict the riverbed, raising flood levels.
  3. Heavy sediment load: Carries ~2.2 lakh kg/second; rapid sedimentation raises riverbed, reducing channel capacity.
  4. Wide braided channel: Brahmaputra is a braided river (many intertwining channels) across a very wide floodplain — water spreads easily.
  5. Majuli Island: World's largest river island (880 sq km) is rapidly eroding — has shrunk from 1,246 sq km (1950) to ~880 sq km today.
  6. Glacial melt: Climate change accelerates Himalayan glacier melt, increasing base flow.

Mitigation: Embankments (but controversial — when breached, flooding is worse); early warning systems; Brahmaputra Board under BRBM Act 1980 for basin management.