CBSE Class 10 Social Science Water Resources Important Questions Set 05

Important Questions

Question 1. 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 2. 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 3. 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 4. “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 5. 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 6. “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 7. 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.