CBSE Class 10 Social Science Water Resources Important Questions Set 03

Question 1. ‘Multi-purpose projects and large dams have come under great scrutiny.’ Identify the problems caused by the setting up of these projects and dams.
Answer:
Problems caused by setting up of multi-purpose projects and large dams:
(1) Regulating and damming of rivers affects their natural flow, causing poor sediment flow.
(2) Dams fragment rivers.
(3) It becomes difficult for aquatic fauna to migrate.
(4) Existing vegetation gets submerged.
(5) This leads to decomposition of the submerged vegetation and soil.
(6) Large-scale displacement of local communities.

Teacher's Note:
a) Six distinct problems here — group them as ecological (1-5) and social (6).
b) This same list recurs through the chapter; learn it once and reuse it.

Question 2. What is the meaning of rain-water harvesting? State any four points that should be kept in mind for efficient management of water.
Answer:
Water harvesting is a technique of increasing the recharge of groundwater by capturing and storing rainwater.
Points to keep in mind for efficient management of water:
(1) There should be no wastage of drinking water.
(2) Common people should take an active part in water conservation and proper management of water.
(3) Any chemical or other source which pollutes the water should be checked.
(4) The government should register all water extraction points.

Teacher's Note:
a) Define rainwater harvesting first, then list the management points — two-part questions need both parts answered.
b) This question and the one on 'techniques of water conservation' overlap; revise together.

Question 3. An area or region may have ample water resources but it may still face water scarcity. Give four reasons for such a situation. (Or: explain any four reasons responsible for water scarcity in India.)
Answer:
(1) A large and growing population leads to greater demand for water for domestic purposes.
(2) A huge population requires more food. To produce more foodgrain, water resources are over-exploited to expand irrigated areas and dry-season agriculture.
(3) Most farmers have their own wells and tube-wells at their farms for irrigation to increase their produce. This leads to falling groundwater levels, adversely affecting water availability.
(4) The ever-increasing number of industries exerts pressure on existing freshwater resources. Industries are heavy users of water and also require power to run them, which comes from hydroelectric power.

Teacher's Note:
a) Key idea: water scarcity is about over-use and quality, not just the total amount available.
b) Four causes: population, irrigation demand, falling groundwater, industrial demand.

Question 4. It is said that by 2025, about two billion people will face severe water scarcity. Do you agree? Discuss.
Answer:
Yes, by 2025 about two billion people will face severe water scarcity.
(1) Due to expansion of irrigated areas, water resources are being over-exploited. Farmers install tube-wells on their farms to increase produce, leading to falling groundwater levels.
(2) Rapid industrialisation exerts pressure on water resources. Industries demand heavy amounts of water and also require power, generated from hydroelectric sources.
(3) Huge amounts of polluted water and chemicals are discharged into rivers. Pesticides and fertilisers used in agriculture also pollute fresh water resources, making the water hazardous for human use.
(4) Multiplying urban centres with dense populations and an urban lifestyle have added to water and energy requirements, further aggravating the problem.

Teacher's Note:
a) This is an opinion/discussion question from the NCERT chapter — ‘Yes’ with reasons is the expected approach.
b) Four causes to remember: irrigation over-use, industrial demand, pollution, urbanisation.

Question 5. Mention the major reasons for water scarcity in urban areas.
Answer:
(1) Multiplying urban centres with large populations has added to water and energy requirements.
(2) Housing societies or colonies in cities have their own groundwater pumping devices to meet their water needs, so water resources are being over-exploited.
(3) Bad quality of water also leads to water scarcity. Water gets polluted due to domestic and industrial wastes, and chemicals, pesticides and fertilisers used in agriculture.

Teacher's Note:
a) Urban scarcity is both quantitative (not enough water) and qualitative (poor quality water) — mention both.
b) Private groundwater pumps by housing societies is a specific, exam-friendly point.

Question 6. How have industrialisation and urbanisation aggravated water scarcity in India? (Or: what is meant by water scarcity, and give any two causes.)
Answer:
Shortage of water as compared to its demand is known as water scarcity.
Causes: Industries are heavy users of water. They also require energy to run them.

Teacher's Note:
a) A short, one/two-mark version of the fuller industrialisation-urbanisation answer above.
b) Define ‘water scarcity’ precisely — it's about demand exceeding supply, not just low rainfall.

Question 7. What is a multipurpose project?
Answer:
A multipurpose project is a scheme which serves several purposes at the same time — for example, irrigation, generation of power and flood control.
River valley projects which serve a number of purposes simultaneously are known as multipurpose projects. Because of their many uses, they are rightly called the ‘temples of modern India’.
(1) Irrigation: they help in storing water for irrigation — for example, the Rajasthan Canal utilises the water of the Satluj river to irrigate the parched land of Rajasthan.
(2) Flood control: for example, the Damodar river was known as the ‘river of sorrow’ in West Bengal, but after constructing the Damodar Dam, floods have been checked.
(3) Afforestation: multi-purpose projects provide facilities for large-scale afforestation in the catchment area of the reservoirs.
(4) Hydro-electricity: they store water in the rainy season so electricity can be produced throughout the year, and water is a renewable, non-polluting resource for this purpose.
(5) Navigation: under favourable conditions, canals are also used for navigation.
(6) Fishing: reservoirs are used as good fishing grounds.

Teacher's Note:
a) ‘Temples of modern India’ is a Jawaharlal Nehru quote worth remembering as a direct exam reference.
b) Six purposes here — irrigation and flood control are the two most commonly tested.

Question 8. Explain two techniques of water conservation.
Answer:
(a) Rainwater Harvesting: a technique of capturing and storing rainwater by constructing reservoirs, ponds, tanks, dug-wells and dams. It helps recharge groundwater.
Rainwater harvesting helps to: (i) meet the increasing demand for water; (ii) reduce run-off water; (iii) avoid flooding of roads and lanes; (iv) increase the water-table and recharge groundwater; (v) reduce water pollution and improve the quality of groundwater; (vi) supplement domestic water requirements during summer and long dry spells.
(b) Rooftop rainwater harvesting: simple and cheap techniques include construction of percolation pits, digging of dug-wells and trenches, and refilling of dug-wells.

Teacher's Note:
a) Two named techniques: rainwater harvesting generally, and rooftop harvesting specifically.
b) The six benefits list is useful for a longer answer on 'why harvest rainwater'.

Question 9. Name two multi-purpose river projects. Why have they been under great scrutiny and opposition in recent years? Give three reasons.
Answer:
Two multi-purpose river projects: the Bhakra-Nangal Project and the Hirakud Project.
(1) Due to the construction of dams, the natural flow of rivers gets affected. Excessive sediment accumulates at the bottom of the reservoir, making stream beds shallow and rocky, and poor habitats for the river's aquatic life.
(2) Dams also split rivers into narrow streams, making it difficult for aquatic fauna to migrate and spawn.
(3) Reservoirs made on floodplains submerge vegetation and soil, leading to their decomposition over time.
(4) Construction of dams also leads to large-scale displacement of local communities, who often have to give up their land and livelihood.

Teacher's Note:
a) Bhakra-Nangal and Hirakud are the two named projects to remember for this question.
b) Four reasons for opposition: sediment, river fragmentation, submergence, displacement.

Question 10. Do you agree that multi-purpose projects failed to achieve the purpose for which they were built? Discuss.
Answer:
Yes, in several respects multi-purpose projects have not fully achieved their purpose.
(1) The dams were built to control floods, but sedimentation in the reservoirs has in some cases contributed to flooding instead.
(2) At times of heavy rainfall, water released from the dams can cause floods in adjacent areas.
(3) Such floods also cause extensive soil erosion.
(4) Due to sedimentation, the flood plains are deprived of silt (a natural fertilizer), adding to land degradation.
(5) Large dams also increase the possibility of reservoir-induced seismic activity.

Teacher's Note:
a) This is a discussion/opinion question from the NCERT chapter — both a ‘yes’ and a balanced ‘yes, but with benefits too’ answer can score well.
b) Point (5), on earthquakes, refers to reservoir-induced seismicity, a recognised but less commonly cited risk.

Question 11. What is a multipurpose river valley project? Give any four objectives of multipurpose river valley projects.
Answer:
Dams are referred to as multi-purpose projects where many uses of the impounded water are integrated with one another — built not just for irrigation but also for electricity generation, water supply, flood control, recreation, etc.
Main objectives:
(1) Hydro-electric power generation.
(2) Irrigation.
(3) Domestic/industrial supply of water.
(4) Navigation.
(5) Flood control.
(6) Fishing.

Teacher's Note:
a) Same six objectives as the 'multipurpose project' question above, listed more briefly — good for a shorter-mark answer.

Question 12. Write a short essay on the Narmada Bachao Andolan (Save Narmada Movement).
Answer:
The Narmada Bachao Andolan (Save Narmada Movement) is a Non-Government Organisation (NGO) that mobilised tribal people, farmers, environmentalists and human rights activists against the Sardar Sarovar Dam being built across the Narmada river in Gujarat.
It originally focused on the environmental issues related to trees that would be submerged under the dam water.
More recently it has refocused on enabling the poor citizens, especially the oustees (displaced people), to get full rehabilitation facilities from the government.

Teacher's Note:
a) Key facts: NGO, Sardar Sarovar Dam, Narmada river, Gujarat.
b) Note the shift in focus over time — from environment to rehabilitation of displaced people.

Question 13. How is hydro-electricity better than thermal power? Explain.
Answer:
(1) Thermal power: electricity generated by burning coal, petroleum or natural gas. Its production is costly, it comes from non-replenishable resources, and it creates pollution. As coal and petroleum reserves diminish, emphasis on thermal power is decreasing.
(2) Hydro power: produced by the motive power of falling water. Its production is comparatively cheap, water is a replenishable resource with no fear of exhaustion, and hydro-electricity is free from pollution.

Teacher's Note:
a) Three points of comparison: cost, resource type (replenishable or not), pollution.
b) Water is renewable; coal and petroleum are not — the core distinction examiners test.

Question 14. What are the factors responsible for the scarcity of water in India? (Or: why is the scarcity of water increasing day by day in India? Explain any three reasons.)
Answer:
(1) Growing population: one of the basic factors responsible for water scarcity.
(2) Commercialisation of agriculture: after the success of the Green Revolution, farmers produce commercial crops that need more water and other inputs.
(3) Urbanisation: another factor responsible for the scarcity of water.
(4) Over-exploitation and mis-utilisation of water: many states, like Punjab and Haryana, have overutilised their water resources, lowering the water table.
(5) Pollution: pollution of water resources, from domestic and industrial wastes, is another factor responsible for scarcity.

Teacher's Note:
a) Punjab and Haryana are the two named states to remember as over-exploitation examples.
b) Five factors here — pick the number the question's marks require.

Question 15. Multi-purpose projects and large dams have been the cause of many new social movements. Give two examples of such movements. What are the reasons and purposes of these movements?
Answer:
(1) Examples: (i) Narmada Bachao Andolan, (ii) Tehri Dam Andolan.
(2) Reasons for these movements:
(i) Large-scale displacement of local communities, who had to give up their agricultural land and became devoid of their houses.
(ii) Labourers became jobless.
(iii) Since more land is required for dams, forests are damaged enormously.
(iv) During heavy rainfall, water released from dams leads to floods in adjacent areas, or forests get submerged.
(v) The construction of huge reservoirs increases the risk to surrounding ecosystems and communities.

Teacher's Note:
a) Two named movements: Narmada Bachao Andolan and Tehri Dam Andolan.
b) This question overlaps heavily with the Narmada Bachao Andolan essay question — revise together.

Question 16. ‘Construction of dams on rivers has caused environmental degradation.’ Give reasons to support this statement.
Answer:
(1) Damming of rivers affects their natural flow, causing poor sediment flow.
(2) Excessive sedimentation occurs at the bottom of the reservoir.
(3) Lack of sediment downstream results in (a) a rockier stream bed and (b) a poorer habitat for the river's aquatic life.
(4) Dams also fragment rivers, making it difficult for aquatic fauna to migrate, especially for spawning.

Teacher's Note:
a) Four linked points, each building on the previous one — present them in this cause-and-effect order.
b) This is the ecological half of the 'why dams face opposition' question seen earlier in this set.

Question 17. Explain three reasons for multi-purpose projects and large dams coming under great scrutiny and opposition.
Answer:
(1) Local communities have been displaced from their original settlement areas, with consequent loss of livelihood and income.
(2) These projects create conflicts between people wanting to avail benefits from the same water resources, leading to unsettled disputes.
(3) Objections have been raised about sedimentation of the reservoirs leading to floods in nearby areas, causing land degradation by depriving the land of silt (a natural fertiliser), and other consequent problems.

Teacher's Note:
a) Three distinct angles: social (displacement), political (conflicts over resources), ecological (sedimentation and floods).
b) A compact 3-mark version of the longer 'problems caused by dams' answer at the top of this set.

Question 18. On which of the following rivers is the Sardar Sarovar Dam built: (a) River Kaveri (b) River Krishna (c) River Narmada (d) River Satluj?
Answer:
(c) River Narmada — the Sardar Sarovar Dam is built on the Narmada river.

Teacher's Note:
a) Sardar Sarovar Dam is built on the Narmada river.
b) It was the focus of the Narmada Bachao Andolan protest movement.

Question 19. What is the traditional system of rainwater harvesting used in Rajasthan?
Answer:
Tankas — underground tanks traditionally used in Rajasthan for storing rainwater for drinking purposes.

Teacher's Note:
a) Tankas are Rajasthan's traditional underground rainwater-storage tanks.
b) They were historically present in almost every house in the region.

Question 20. How has the ever-increasing number of industries in India put pressure on existing fresh water resources? Explain.
Answer:
After independence, industries increased rapidly and put pressure on existing fresh water resources; fresh water is limited, though renewable, and over-exploitation and mismanagement by industries aggravates water stress day by day.
Industries, especially heavy industries, use huge amounts of fresh water, while also polluting and wasting a large amount of it.
These industries often depend on hydroelectric projects, generated through damming rivers upstream, so the river almost dries up in the lower stream areas.
Industries dump chemical waste in rivers and lakes, dangerously polluting the water; these wastes also contaminate groundwater through seepage, so the growing number of industries exerts ever more pressure on existing fresh water resources.

Teacher's Note:
a) Industries use huge amounts of fresh water and also pollute and deplete it.
b) Hydroelectric damming and chemical waste discharge both intensify pressure on existing water resources.

Question 21. “Water scarcity is increasing day by day.” Justify the statement, citing three reasons.
Answer:
Seasonal and annual variation in precipitation.
Unequal access to water resources.
Over-exploitation of water resources or fresh water bodies.
A large and growing population, resulting in greater demand for water, particularly in cities — more water is needed both for domestic use and for higher foodgrain productivity, leading to over-exploitation of water resources to expand irrigated areas, especially for dry-season agriculture, and to falling groundwater levels.
Multiplying urban areas, with dense population and modern lifestyles, create an ever-increasing demand for water and energy resources.
Pollution of water bodies from industrial effluents, pesticides, insecticides and fertilisers makes river water hazardous for human consumption.

Teacher's Note:
a) Water scarcity results from rainfall variation, unequal access, over-exploitation, population growth and pollution combined.
b) Growing cities and rising food demand both intensify pressure on limited fresh water.

Question 22. Explain the working of underground tanks as part of the rooftop rainwater harvesting system practised in Rajasthan.
Answer:
In the semi-arid and arid regions of Rajasthan, almost all houses traditionally had underground tanks for storing drinking water; these are an extremely reliable source of drinking water when other sources dry up, since rainwater is considered the purest form of natural water.
The tanks could be as large as big rooms.
They were part of a well-developed rooftop rainwater harvesting system.
The tanks were built inside the main house or courtyard, giving a cooling effect to the rooms in summer.
They were connected to the sloping roofs of the houses by a pipe.
Rain falling on these rooftops would travel down the pipe and get stored in the underground tanks.
Usually, the first rainwater is not collected, as it cleans the rooftop and the pipe first.

Teacher's Note:
a) Rajasthan's underground tanks (tankas) collect rooftop rainwater via connecting pipes.
b) They also keep rooms cool and provide reliable drinking water when other sources run dry.

Question 23. “In recent years, multipurpose projects and large dams have come under scrutiny and opposition.” Explain why.
Answer:
They affect the natural flow of running water, causing excessive sedimentation at the bottom of the reservoir, rockier stream beds, and fragmenting rivers, making it difficult for aquatic fauna to migrate, especially for breeding.
They affect natural vegetation and soil: reservoirs created on floodplains submerge existing vegetation and soil, causing decomposition over time, and deprive floodplains of silt, a natural fertiliser, worsening land degradation.
They create conflicts between people wanting different uses and benefits from the same water resources, including inter-state water disputes over sharing costs and benefits.
They have caused many social movements, like the Narmada Bachao Andolan and the Tehri Dam Andolan.
They cause large-scale displacement of local communities, who often give up land and livelihood for the project, widening the social gap without benefiting from it.
Dams built to control floods have often triggered floods due to sedimentation and excessive rainfall, and have also been linked to earthquakes and waterborne diseases.
Availability of irrigation has changed cropping patterns towards water-intensive, commercial crops, causing ecological consequences like soil salinisation and widening the social gap between richer landowners and the landless poor.

Teacher's Note:
a) Dams disrupt river flow, vegetation and soil, while causing displacement and social conflict.
b) They've also driven major protest movements like the Narmada Bachao Andolan and Tehri Dam Andolan.

Question 24. Describe the procedure for rooftop rainwater harvesting.
Answer:
Rooftop rainwater is collected using a PVC pipe.
The collected water is filtered using sand and bricks.
An underground pipe is used to take the water to the tank for immediate usage.
Excess water from the tank is taken to the well.
This recharges the groundwater through the well.

Teacher's Note:
a) Rooftop rainwater is piped, filtered through sand/bricks, and stored underground.
b) Any excess is sent to a well to recharge groundwater.