Water Resources
1. Multiple choice questions.
(i) Based on the information given below classify each of the situations as ‘suffering from water scarcity’ or ‘not suffering from water scarcity’.
(a) Region with high annual rainfall.
Answer: Not suffering from water scarcity.
(b) Region having high annual rainfall and large population.
Answer: Suffering from water scarcity.
(c) Region having high annual rainfall but water is highly polluted.
Answer: Suffering from water scarcity.
(d) Region having low rainfall and low population.
Answer: Not suffering from water scarcity
(ii) Which one of the following statements is not an argument in favour of multipurpose river projects?
(a) Multi-purpose projects bring water to those areas which suffer from water scarcity.
(b) Multi-purpose projects by regulating water flow helps to control floods.
(c) Multi-purpose projects lead to large scale displacements and loss of livelihood.
(d) Multi-purpose projects generate electricity for our industries and our homes.
Answer: (c) Multi-purpose projects lead to large scale displacements and loss of livelihood.
(iii) Here are some false statements. Identify the mistakes and rewrite them correctly.
(a) Multiplying urban centres with large and dense populations and urban lifestyles have helped in proper utilisation of water resources.
Answer: False
(b) Regulating and damming of rivers does not affect the river’s natural flow and its sediment flow.
Answer: False
(c) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to water supply in urban areas, particularly during droughts.
Answer: False
Correct: In Gujarat, the Sabarmati basin farmers were agitated when higher priority was given to water supply in urban areas, particularly during droughts.
(d) Today in Rajasthan, the practice of rooftop rainwater water harvesting has gained popularity despite high water availability due to the Indira Gandhi Canal.
Answer: False
Correct: Today in Rajasthan, the practice of rooftop rainwater harvesting is on the decline due to high water availability from the Indira Gandhi Canal.
2 . Answer the following questions in about 30 words.
(i) Explain how water becomes a renewable resource.
Answer: Water keeps circulating through the hydrological cycle. It is continually renewed and recharged by precipitation, surface run-off and groundwater. Hence, water is considered a renewable resource.
(ii) What is water scarcity and what are its main causes?
Answer: Water scarcity is not only due to low rainfall but also because of large population, over-exploitation in agriculture, unequal access, industrial demand, urbanisation and pollution of water resources.
(iii) Compare the advantages and disadvantages of multi-purpose river projects.
Answer:
- Advantages – Irrigation, electricity generation, domestic and industrial water supply, flood control, navigation and fish breeding.
- Disadvantages – Alter river flow, sedimentation, harm aquatic life, submerge land and forests, displace people, cause soil salinity and lead to social conflicts.
3 . Answer the following questions in about 120 words.
(i) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
Answer: In semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost every house traditionally had underground tanks or tankas for storing drinking water. These tankas were big underground structures, sometimes as large as a room, connected to the sloping roofs of houses through pipes. Rainwater falling on the rooftops flowed into these tankas. The first spell of rain was not collected so that it could clean the roof and pipes. Later showers were stored safely. The collected water could last till the next rainfall, making it a very reliable source of drinking water in summer when all other sources dried up. Rainwater or palar pani is considered the purest form of water in this region.
(ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
Answer: In many rural and urban areas of India, rooftop rainwater harvesting is being adapted as a modern method to conserve water. In Gendathur village of Mysuru (Karnataka), nearly 200 households have installed rooftop harvesting systems to meet their needs. With about 1,000 mm of rainfall and 80% collection efficiency, each house can collect about 50,000 litres annually, making the village rich in rainwater. Similarly, in Tamil Nadu, rooftop rainwater harvesting has been made compulsory by law. In Shillong (Meghalaya), despite very high rainfall nearby, the city faces shortages, so almost every household uses rooftop harvesting to meet 15–25% of its needs. Thus, modern adaptations of traditional methods are helping conserve and store water efficiently.
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