TEXTBOOK QUESTIONS SOLVED
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.
(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.
(d 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) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to water supply in urban areas, particularly during droughts.
(d) Today in Rajasthan, the practice of rooftop rainwater harvesting has gained popularity despite high water availability due to the Rajasthan Canal.
(i) (a) Not suffering from water scarcity
(b) Not suffering from water scarcity
(c) Suffering from water scarcity
(d) Not suffering from water scarcity
(ii) (c) Mtilti-purpose projects lead to large scale displacements and loss of livelihood.
(iii) (a)Multiplying urban centres with large and dense populations and urban lifestyles have caused the overexploitation of water resources
(b)Regulating and damming of rivers affect the river’s natural flow and its sediment flow.
(c)In Gujarat, the Sabarmati basin farmers were agitated when higher priority was given to watersupply in urban areas, particularly during droughts.
(d) Today in Rajasthan, the practice of rooftop rainwater harvesting is on the decline due to the Rajasthan canal.
Q2. 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.
(i) All of our drinking water comes from two sources—groundwater (underground aquifers) and surface water (lakes, rivers, streams). These sources gel renewed through the water cycle. That is how water keeps moving between atmosphere and the earth. This is termed as hydrological cycle. The circulation and conservation of earth’s water is called the “hydrologic cycle”
(ii) Water scarcity or water stress occurs when water availability is not enough to match the demand for water. It is caused by an increase in population and consequent greater demand for water and unequal access to it. A country with a high industrial demand or which depends on large scale irrigation will therefore be more likely to experience times of scarcity than a country without such demands.
(iii) Advantages of multi-purpose river projects: They not only help in irrigation but also in electricity generation, water supply for domestic and industrial uses, flood control, recreation, inland navigation and fish breeding. For example, the Hirakud project in the Mahanadi basin integrates conservation of water with flood control.
Disadvantages: Regulating and damming of rivers affect their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers’ aquatic life. Dams also fragment rivers making it difficult for aquatic fauna to migrate, especially for spawning. Reservoirs created on the floodplains also submerge the existing vegetation and soil leading to its decomposition over a period of time.
Q3. 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.
(i) Rooftop rainwater harvesting was commonly practised to store drinking water in Rajasthan. In arid and semi-arid regions, agricultural fields were converted into rainfed storage structures that allowed the water to stand and moisten the soil like the Whadins’ in Jaisalmer and Voltads’ in other parts of Rajasthan.
In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Banner, almost all the houses traditionally had underground tanks or tankas for storing drinking water. The tanks could be as large as a big room and were built inside the main house or the courtyard. They were connected to the sloping roofs of the houses through a pipe. Rain falling on the rooftops would travel down the pipe and was stored in these underground `tankas’.
In western Rajasthan, the practice of rooftop rainwater harvesting is on decline because of the perennial Rajasthan canal. This canal provides plenty of water. Despite this, some houses stillmaintain the tankas since they do not like the taste of tap water.
(ii) Traditional methods of rainwater harvesting being carried out to conserve and store water are:
1. Roof top rainwater harvesting is the most common practice in Shillong, Meghalaya. Though Cherapunjee and Mawsynram situated at a distance of 55 km from Shillong receive the highest rainfall in the world, yet the state capital Shillong faces acute shortage of water. Nearly every household in the city has a rooftop rainwater harvesting structure.
2. Tamil Nadu is the first and the only state in India which has made roof- top rainwater harvesting structure compulsory to all the houses across the state. There are legal p’rovisions to punish the defaulters.
3. In many parts of rural and urban India, rooftop rainwater harvesting is being successfully adopted to store and conserve water. In Gendathur, a remote backward village in Mysore. Karnataka, villagers have installed in their households, rooftop, rainwater harvesting system to meet their water needs. Nearly 200 households have installed this system and the village has earned the rare dinstinction of being rich in rainwater.