CBSE Class 10 Social Science Water Resources Important Questions Set 06

Answer: A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir. It stores water for irrigation, power and other uses.

Teacher's Note:
1. Dams are classified by structure, purpose and height.
2. Mention storage as the main function.

Answer: Inundation channels are canals that divert flood water to fields during the rainy season. People in the flood plains of Bengal developed them for irrigation.

Teacher's Note:
1. They use the natural flood flow instead of pumps.
2. Link them with Bengal.

Answer: Guls or kuls are diversion channels built by people in the hills of the Western Himalayas to carry water to fields for agriculture.

Teacher's Note:
1. They suit steep terrain where rivers are far below the fields.
2. Remember the region: Western Himalayas.

Answer: The tanka is an underground tank, often built in the house courtyard, connected to the sloping roof by a pipe to collect rainwater.

Teacher's Note:
1. Tankas are common in Bikaner, Phalodi and Barmer.
2. They provided drinking water in dry months.

Answer: The Narmada Bachao Andolan, a movement of tribal communities, farmers, environmentalists and human rights activists, opposed the dam.

Teacher's Note:
1. Its main concerns were displacement and loss of livelihood.
2. It is an example of a people's movement for the environment.

Answer: Jawaharlal Nehru, India's first Prime Minister, described them this way. He believed they would integrate agriculture, industry and village economy.

Teacher's Note:
1. He saw dams as symbols of progress.
2. Connect the quote to Bhakra Nangal.

Answer: 1. They bring economic prosperity through irrigation, hydroelectricity and flood control.
2. They integrate the development of agriculture and the village economy with rapid industrialisation and growth of urban economy.
3. They promote tourism, fish breeding and inland navigation.

Teacher's Note:
1. Nehru believed they would lead the country to development.
2. Give at least three benefits of the projects.

Answer: 1. To ensure food security, since irrigation depends on water availability.
2. To check over-exploitation and mismanagement of water.
3. To protect health, as polluted water spreads disease.

Teacher's Note:
1. Per capita availability of water is falling due to rising population.
2. Link conservation with food, health and sustainability.

Answer: Dams are classified according to structure and materials as timber, embankment or masonry dams. By height they are classified as large, major or low dams.

Teacher's Note:
1. They are also classified by function, such as irrigation or power dams.
2. Mention both structure and height.

Answer: 1. The movement focused on environmental issues, mainly against the construction of the Sardar Sarovar Dam.
2. It highlighted the rehabilitation of people displaced by the project.
3. It questioned the loss of forests and farmland.

Teacher's Note:
1. It later became a symbol of environmental protest in India.
2. State displacement as the central concern.

Answer: 1. In the Western Himalayas, people built guls or kuls, diversion channels for farming.
2. In the flood plains of Bengal, inundation channels irrigated the fields.
3. In Rajasthan, rooftop rainwater was stored in underground tanks called tankas, built inside the house courtyard.

Teacher's Note:
1. Such practices are low cost and sustainable.
2. Match each practice with its region.

Answer: 1. Growing population increases demand for domestic, agricultural and industrial use.
2. Over-exploitation and unequal access to water.
3. Variation in seasonal and annual rainfall.

Teacher's Note:
1. Water scarcity is often caused more by over-use than by low rainfall.
2. Population, over-use and rainfall are the key causes.

Answer: It is a traditional system, found in Meghalaya, in which bamboo pipes carry water from hill springs to plots, dropping water near the roots. It conserves water and reduces evaporation.

Teacher's Note:
1. The method is about two centuries old.
2. Mention the state to score the example.

Answer: 1. Industrial effluents are dumped into rivers without treatment.
2. Thermal pollution occurs when hot water is released into rivers.
3. Domestic waste and sewage are drained into water bodies.
4. Oil spills from ships pollute the sea.
5. Excessive fertilisers and pesticides seep into soil and pollute groundwater.

Teacher's Note:
1. Polluted water spreads diseases and harms aquatic life.
2. Give one remedy as a closing line.

Answer: 1. They cause excessive sedimentation in reservoirs.
2. They make it hard for aquatic fauna to migrate.
3. Large-scale displacement of local communities occurs.
4. They fail to control floods during excessive rainfall, for example releases of water from dams in heavy rain.
5. They can induce earthquakes and spread water-borne diseases and pests.

Teacher's Note:
1. Dams also fragment rivers and trigger inter-state disputes.
2. Present both benefits and costs when asked to evaluate.

Answer: Advantages: irrigation, electricity generation, flood control, inland navigation, fish breeding and recreation.
Disadvantages: they fragment rivers, cause sedimentation, displace local people, affect aquatic habitats and lead to inter-state disputes.

Teacher's Note:
1. Balanced planning is needed to maximise benefits.
2. Use two columns while answering.

Answer: 1. Rainwater harvesting is capturing and storing rain to recharge groundwater, using dug wells, percolation pits and tanks.
2. It reduces dependence on rivers and dams.
3. It restores falling water tables.
4. It is cheap, and tankas, johads and khadins are traditional examples.
5. It benefits drought-prone regions like Rajasthan.

Teacher's Note:
1. Rainwater harvesting is both a traditional and a modern solution.
2. Mention at least two traditional methods.