About This Section
This section collects previous-year Board examination questions (CBSE and State Boards) from Chapter 3, with model answers, to show the pattern and depth expected in the exam.
Board PYQ — Very Short Answer (1 mark)
Q1. Name one multi-purpose project and the river on which it is built. Ans. Bhakra-Nangal project on the Sutlej-Beas (or Hirakud on the Mahanadi).
Q2. What is a dam? Ans. A barrier across flowing water that obstructs, directs or slows the flow, usually creating a reservoir.
Q3. Name a traditional water-harvesting structure of the Western Himalayas. Ans. Guls or kuls (diversion channels).
Board PYQ — Short Answer (3 marks)
Q4. Which statement is NOT an argument in favour of multi-purpose projects: (a) they bring water to scarcity areas, (b) they control floods, (c) they cause large-scale displacement, (d) they generate electricity? Explain. Ans. Statement (c) — 'they cause large-scale displacement and loss of livelihood' — is not an argument in favour; it is a problem/disadvantage of multi-purpose projects. The others (bringing water, flood control, electricity) are benefits.
Q5. Compare the roles of the Bhakra-Nangal and Hirakud projects. Ans. The Bhakra-Nangal project (Sutlej-Beas) uses its water for both hydel power and irrigation. The Hirakud project (Mahanadi) integrates the conservation of water with flood control. Both are multi-purpose projects that integrate several uses of the impounded water.
Board PYQ — Short Answer (3 marks)
Q6. 'Rooftop rainwater harvesting has declined in western Rajasthan.' Give the reason. Ans. In western Rajasthan the practice of rooftop rainwater harvesting has declined because plenty of water is now available from the perennial Indira Gandhi Canal. However, some households still maintain their tankas because they prefer the taste of stored rainwater to tap water.
Q7. Identify and correct the mistake: 'Regulating and damming of rivers does not affect the river's natural flow and its sediment flow.' Ans. The statement is false. Correct version: 'Regulating and damming of rivers affects the river's natural flow, causing poor sediment flow and excessive sedimentation in the reservoir.'
Board PYQ — Long Answer (5 marks)
Q8. Explain how water scarcity is caused by human factors. Ans. Water scarcity is caused largely by human factors: a growing population needing more water and food; over-exploitation of groundwater for irrigated agriculture (the largest water consumer) through wells and tube-wells; industrialisation (heavy water use plus power needs); and urbanisation, with cities and colonies pumping groundwater. Poor water quality (pollution) and unequal access add to the scarcity.
Q9. Assess the disadvantages of multi-purpose river projects. Ans. Multi-purpose projects disturb the natural flow of rivers, causing sedimentation, rockier beds and loss of aquatic habitats; they fragment rivers, hindering fish migration; they submerge vegetation and displace large populations; they have triggered floods and deprived floodplains of fertile silt; and they can induce earthquakes and cause water-borne diseases. These led to movements like the Narmada Bachao Andolan.