Water ResourcesClass 10 Geography NCERT Solutions
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Solution 1 of 3
Q1Exercises
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.
(b)
Region having high annual rainfall and large population.
(c)
Region having high annual rainfall but water is highly polluted.
(d)
Region having low rainfall and low population.
(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.
(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.
(b)
Regulating and damming of rivers does not affect the river's natural flow and its sediment flow.
(c)
Today in Rajasthan, the practice of rooftop rainwater water harvesting has gained popularity despite high water availability due to the Indira Gandhi Canal.
Solution
(i) Classification of situations:
- (a) Region with high annual rainfall: Not suffering from water scarcity.
- (b) Region having high annual rainfall and large population: Suffering from water scarcity. As the chapter states, water scarcity can be an outcome of a large and growing population leading to greater demands for water.
- (c) Region having high annual rainfall but water is highly polluted: Suffering from water scarcity. The chapter explains that scarcity can occur when ample water is available but is polluted by wastes and chemicals, making it hazardous for human use.
- (d) Region having low rainfall and low population: Suffering from water scarcity. Regions with low rainfall are naturally prone to water shortages.
(ii) Which statement is not an argument in favour of multi-purpose projects?
- The correct answer is (c) Multi-purpose projects lead to large scale displacements and loss of livelihood. This is a major disadvantage and an argument against such projects, not in favour of them.
(iii) Corrected Statements:
- (a) Multiplying urban centres with large and dense populations and urban lifestyles have led to the over-exploitation of water resources and have aggravated the problem of water scarcity.
- (b) Regulating and damming of rivers affects their natural flow and causes poor sediment flow and excessive sedimentation at the bottom of the reservoir.
- (c) Today in Rajasthan, the practice of rooftop rainwater harvesting is on the decline as plenty of water is available due to the perennial Indira Gandhi Canal.
Q2Exercises
Answer the following questions in about 30 words.
(i)
Explain how water becomes a renewable resource.
(ii)
What is water scarcity and what are its main causes?
(iii)
Compare the advantages and disadvantages of multi-purpose river projects.
Solution
(i) How water becomes a renewable resource:
Water is considered a renewable resource because it is continuously renewed and recharged through the hydrological cycle. In this cycle, water evaporates, condenses into clouds, and falls back to the Earth as precipitation. This water replenishes surface water bodies and groundwater, ensuring a continuous supply.
(ii) Water scarcity and its main causes:
Water scarcity is a situation where there is a shortage of water to meet the demands of a region. The main causes include:
- Over-exploitation and excessive use by a growing population, for intensive agriculture, and by industries.
- Unequal access to water among different social groups.
- Pollution of water bodies by domestic and industrial waste, which makes the available water unfit for use.
(iii) Advantages and disadvantages of multi-purpose river projects:
Advantages:
- They provide water for irrigation.
- They generate electricity (hydel power).
- They help in controlling floods.
- They supply water for domestic and industrial use.
- They can be used for recreation, inland navigation, and fish breeding.
Disadvantages:
- They cause large-scale displacement of local communities.
- They negatively affect the natural flow of rivers and aquatic ecosystems.
- They lead to excessive sedimentation in reservoirs and soil erosion.
- They can induce earthquakes and cause water-borne diseases.
Q3Exercises
Answer the following questions in about 120 words.
(i)
Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
(ii)
Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
Solution
(i) Rainwater harvesting in semi-arid regions of Rajasthan:
In the semi-arid regions of Rajasthan, traditional rainwater harvesting is a time-tested method to combat water scarcity. The most common practice is rooftop rainwater harvesting using underground tanks called 'tankas'.
These tankas are large, underground structures built inside the main house or courtyard. They are connected to the sloping roofs of the houses with a pipe. When it rains, the water from the roof travels down the pipe and is stored in the tanka. The first spell of rain is usually not collected, as it serves to clean the roof and the pipes. The rainwater collected subsequently, known as 'palar pani', is considered the purest form of natural water and provides a reliable source of drinking water until the next rainfall, especially during the dry summer months.
Other traditional structures like 'khadins' in Jaisalmer and 'Johads' were also used. These were rain-fed storage structures built in agricultural fields to allow water to stand and moisten the soil for cultivation.
(ii) Modern adaptations of traditional rainwater harvesting:
Modern adaptations of traditional rainwater harvesting methods are being successfully implemented across India to conserve and store water. These methods are environmentally friendly and promote community participation.
-
Rooftop Rainwater Harvesting: This traditional technique is being adapted in many rural and urban areas. For instance, in Gendathur, a village in Karnataka, about 200 households have installed rooftop systems to meet their water needs. The state of Tamil Nadu has made it compulsory for all houses to have rooftop rainwater harvesting structures.
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Groundwater Recharge: Rainwater is now being used to recharge groundwater. This is done by diverting it into structures like abandoned dug wells, hand pumps, and percolation pits. This helps to raise the water table.
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Bamboo Drip Irrigation: In Meghalaya, a 200-year-old system of using bamboo pipes to tap stream and spring water for drip irrigation is still in use. This ancient technique efficiently transports water over long distances directly to the roots of plants, minimizing wastage.
These modern adaptations combine traditional knowledge with contemporary techniques to ensure sustainable water management for the future.