QA Water Resources

 

Water Resources

Q. What is water scarcity? Write the main reasons for water scarcity.

Answer:

Water scarcity means shortage of water. It is usually associated with regions having low rainfall or drought prone areas. There are many other reasons which lead to scarcity of water.

These are:

1 Large growing population—means more water required for domestic use and also to produce more food.

In the agricultural sector, water resources are being over-exploited to expand irrigated areas and dry-season agriculture.

2 More water required for irrigation purposes to facilitate higher food production, i.e., for doing multiple cropping and for HYV seeds.

There is greater demand for water with growing urbanisation and industrialisation.

3 An unequal access to water among different social groups.

4 The quality of water is deteriorating, i.e., getting polluted by domestic and industrial wastes, chemical fertilizers and pesticides used in agriculture.

5 Excessive use of water by industries which also require water to generate hydro-electric power to run them.

Over exploitation of water in the urban areas. Housing societies and colonies have their own ground-water pumping devices. This causes depletion of fragile water resources in the cities.

Q. Write the adverse effects of over-exploitation of ground water resources.

Answer:

1 Pumping out more water from under the ground may lead to falling ground water levels.

2 It will adversely affect water availability.

3 This, in turn, will affect our agriculture and food security of the people.

4 Impoverishment of water resources may adversely affect the ecological cycle.

Q Write the main causes of water pollution.

Answer: Water gets polluted by:

1 Domestic wastes, especially urban sewers.

2 Industrial wastes are disposed off in the water without proper treatment.

3 Chemical effluents from industries and from agricultural sector.

4 Pesticides and fertilisers used in agriculture may get washed into rivers by rain-water and may pollute the water by enriching it with minerals.

5 Many human activities, e.g., religious rituals and immersing of idols, etc. in the water also pollute water.

Q How intensive industrialisation and urbanisation have posed a great pressure on existing fresh water resources in India? 

Explain with two examples for each. 

Answer:

Intensive industrialisation 

1 With the ever growing number of industries, the demand for water has grown tremendously:

2 Industries are heavy users of fresh water as water is required for cooling the machines as well as for the processing of goods.

3 Also the machines run on the power supplied by the hydel power plants. 22 percent of the total electricity is hydro-electric power.

4 Rapid urbanisation has led to expansion of industries which increased the requirement of water.

5 The untreated industrial effluents which are discharged into water bodies are polluting the water and making it hazardous for human consumption. This is responsible for creating water scarcity.

Urbanisation:

Large urban populations and

urban lifestyles have not only added to water and energy requirements 

2 Water needs for domestic purposes such as cleaning, cooking, washing, etc.

3 Water resources are being over-exploited which has caused their depletion in several cities.

Q What is the need for conservation of water resources? 

Answer:

1 Our water resources are limited and our requirements are increasing day by day. 

2 The water resources are unevenly distributed.

3 Most of our resources especially in the cities and urban areas are polluted and unsuitable for drinking and other purposes.

4 To safeguard ourselves from health hazards.

5 We need to conserve water for the continuation of our livelihoods and to prevent degradation of our natural ecosystem. 

6 To ensure food security and for continuation of our livelihoods.

7 For productive activities of the nation.

8 To prevent degradation of our natural ecosystem

Q What is a dam? Describe the functioning of dams? On what basis are dams classified into different types?

Answer:

A dam is a barrier across flowing water that obstructs, directs or retards the flow, creating a reservoir, lake or impoundment.

A dam is the reservoir and not the whole structure.

Functioning:

Most dams have a section called spillway or weir over which or through which, water will flow intermittently or continuously.

Classification:

Dams are classified according to structure, intended purpose or height.

According to structure and materials used, they are classified as timber dams, embankment dams or masonry dams.

According to height, they are classified as large and major dams, low dams, medium height dams and high dams.

Q Why are multipurpose river valley projects called ‘The Temples of Modern India’? Who first made this statement?

Answer:

Jawahar Lai Nehru proclaimed that multipurpose projects are ‘The Temples of Modern India’, because they were thought of as the vehicle that would lead the nation to development and progress.

He believed that these projects with their integrated water resource management approach would integrate development of agriculture and the village economy with rapid industrialisation and growth of the urban economy.

Dams or multipurpose river valley projects have the following advantages:

1 They bring water to those areas which suffer from water scarcity and also provide water for irrigation.

2 These projects generate electricity for industries and our homes.

3 They help in controlling floods by regulating the water flow.

4 These projects can be used for recreation, inland navigation and fish breeding.

Q ‘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 at the bottom of the reservoir.

Lack of sediments results in

rockier stream bed and

poorer habitat for the river’s aquatic life.

3 Dams also fragment rivers, making it difficult for acquatic fauna to migrate, especially for spawning.

4 The reservoirs submerge the existing vegetation and soil, leading to its decomposition over time.

5 Flood plains are deprived of silt and khadar, affecting the fertility levels of the soil.

6 Construction of dams also faces resistance because of large scale displacement of local communities.

Q Multipurpose projects and dams have been the cause of many new social movements. Name two such social movements and write the underlying causes for these movements.

Answer:

Resistance to these projects came from social movements, e.g.,

‘Narmada Bachao Andolan’ and

‘Tehri Dam Andolan’.

Their major concerns were as follows:

1 Initially the environmental concerns were of utmost importance.

2 Dams have resulted in large-scale displacement of local communities.

3 Local people have to give up their land and livelihood.

4 Local people do not benefit from such projects as they are even deprived of the local sources on which they have little control.

5 Many settlements and agricultural lands are submerged under water.

6 Rehabilitation of the displaced persons is now the prime concern of these movements.

Q Explain any three problems faced by local communities due to the construction of large dams.

Answer:

Problems faced by local communities due to the construction of large dams:

1 Dams have resulted in large-scale displacement of local communities.

2 Local people have to give up their land and livelihood.

3 Local people do not benefit from such projects as they are even deprived of the local resources on which they have little control.

4 Many settlements and agricultural lands are submerged under water.

Q Describe the traditional method of rainwater harvesting adopted in different parts of India.

Answer:

In ancient India, people developed wide-ranging techniques to harvest rainwater.

1 In mountainous areas ‘Guls’ and ‘Kuls’ the diversion channels were built for agriculture.

2 ‘Rooftop rainwater harvesting’ was commonly practised to store drinking water, especially in Rajasthan.

3 Inundation channels for irrigation were developed in the flood plains of West Bengal.

In arid and semi-arid regions, agricultural fields were converted into rainfed storage structures, eg. ‘Khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.

4 In semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, all the houses had underground tanks or ‘tankas’ built inside the house for storing drinking water. They were a part of the well-developed rooftop rainwater harvesting system.

 Q What is the need for conservation of water resources? 

Answer:

1 Our water resources are limited and our requirements are increasing day by day. 

2 The water resources are unevenly distributed.

3 Most of our resources especially in the cities and urban areas are polluted and unsuitable for drinking and other purposes.

4 To safeguard ourselves from health hazards.

5 We need to conserve water for the continuation of our livelihoods and to prevent degradation of our natural ecosystem. 

6 To ensure food security and for continuation of our livelihoods.

7 For productive activities of the nation.

8 To prevent degradation of our natural ecosystem

Q.Explain the various types of water harvesting techniques existed in olden days.

Answer

·        In hill and mountainous regions, people built diversion channels like the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture. ‘

·        Rooftop rainwater harvesting’ was commonly practised to store drinking water, particularly in Rajasthan.

·         In the flood plains of Bengal, people developed inundation channels to irrigate their fields. In arid and semi-arid regions, agricultural fields were converted into rain fed storage structures that allowed the water to stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.

·        In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or tankas for storing drinking water.

·        Rainwater, or palar pani, as commonly referred to in these parts, is considered the purest form of natural water. Many houses constructed underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool.