- Water resources.
NCERT Questions:
- 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 annual rainfall and low population
Ans. Suffering from water scarcity:
b) Region having high annual rainfall and large population
c) Region having high annual rainfall but water is highly polluted
Not suffering from water scarcity:
a) Region with high annual rainfall
d) Region having low annual rainfall and low population
(ii) Which one of the following statements is not an argument in favour of multipurpose river projects?
a) Multipurpose projects bring water to those areas which suffer from water scarcity
b) Multipurpose projects by regulating water flow helps to control floods
c) Multipurpose projects lead to large scale displacement and loss of livelihood
d) Multipurpose projects generate electricity for our industries and our homes
Ans. c) Multipurpose projects lead to large scale displacement and loss of livelihood
(iii) Here are some false statements. Identify the mistake and rewrite them correctly.
a) Multiplying urban centres with large and dense population and urban lifestyles have helped in proper utilisation of water resources.
Ans. Multiplying urban centres with large and dense population and urban lifestyles have helped in improper utilization of water resources.
b) Regulating and damming of rivers does not affect the rivers natural flow and its sediment flow.
Ans. Regulating and damming of rivers affect the rivers natural flow and its sediment collect in reservoir.
c) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to water supply in urban areas, particularly during droughts.
Ans. 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 harvesting has gained popularity despite high water availability due to Rajasthan canal.
Ans. Today in Rajasthan, the practice of rooftop rainwater harvesting has gained popularity despite low water availability apart from Rajasthan canal.
- Answer the following questions in about 30 words.
(i) Explain how water becomes renewable resource.
Ans.
a) 3/4th of the Earth’s surface is covered with water, but only a small portion of it accounts for fresh water that can be put to use.
b) This fresh water is mainly obtained from surface runoff and groundwater that is continually being genuine and recharged through the hydrological cycle.
c) All water moves within the hydrological cycle and during that water is a renewable resource.
(ii) What is water scarcity and what are its main causes?
Ans.
a) Water scarcity is the shortage of water, but it is not only associated with regions having low rainfall or those that are drought prone.
b) The availability of water resources vary over space and time, mainly due to the variations in seasonal and annual precipitation.
c) But water scarcity in most cases is caused by over exploitation, excessive use and unequal access to water among different social groups.
(iii) Compare the advantages and disadvantages of multi-purpose river projects.
Ans.
a) 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.
b) Dams also fragment rivers, making it difficult for aquatic fauna to migrate especially for spawning.
c) It has great ecological consequences, like salinization of the soil.
d) At the same time, it has transformed the social landscape that is increasing the social gap between the richer landowners and the landless poor.
e) The dams that were constructed to control floods have triggered floods due to sedimentation in the reservoir.
f) Moreover, the big dams have mostly been unsuccessful in controlling floods at the time of excessive rainfall.
g) It was also observed that the multi-purpose projects induced earthquakes, caused waterborne diseases pests and pollution resulting from excessive use of water.
- Answer the following questions in about 120 words.
(i) Discuss how rainwater harvesting in semiarid regions of Rajasthan is carried out.
Ans.
a) In the semiarid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or tankas for storing drinking water.
b) The tanks could be as large as a big room. The tankas were part of the well developed rooftop rainwater harvesting system and were built inside the main house or the courtyard. They were connected to the sloping roofs of the houses through a pipe.
c) Rain falling on the roof tops would travel down the pipe and was stored in these underground tankas.
d) The first spell of rain was usually not collected as this would clean the roofs and the pipes. The rainwater from the subsequent showers was then collected.
e) The rainwater can be stored in the tankas till the next rainfall, making it an extremely reliable source of drinking water when all other sources are dried up.
f) Particularly in the summers rainwater or palar pani as commonly referred to in these parts, is considered the purest form of natural water.
g) Many houses constructed underground rooms adjoining the Tankas to beat the summer heat as it would keep the room cool.
(ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
Ans.
a) Fortunately, in many parts of rural and urban India, rooftop rainwater harvesting is being successfully adapted to store and conserve water.
b) In Gendathur, a remote backward village in Mysore, Karnataka, villagers have installed in their households rooftop rainwater harvesting system to meet their water needs.
c) Nearly 200 households have installed this system, and the village has earned the rare distinction of being rich in rainwater.
d) Rainwater harvesting is once again being conserved through modern adaptations.
e) Rain water running down from the roofs is not fed into drains. Instead, it is piped into underground reservoirs.
CBSE Questions:
(From the previous year board papers)
- Explain the term tankas. Where they were built in India?
Tankas are the underground tanks which are used to store drinking water. They are a part of well-developed rooftop rainwater harvesting and were built inside the main house or in courtyard. They could be as large as a room. They were connected to the sloping roofs of the house through a pipe. Rain falling on rooftops would travel down the pipe and was stored in these underground tanks. Tankas are exclusively built in the arid and semi-arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer.
- Suggest some ways in which water resources can be conserved.
Water resources can be conserved. In many ways:
a) Many hydraulic structures, such as dams, lakes and water harvesting systems are made to conserve water. One of the purposes which the Hirakud Dam serves is conservation of water. Jaipur City gets the water from the Bisalpur Dam. In the similar way Hussain Sagar lake in Hyderabad and Bhopal lake in Bhopal was made to store water.
b) Apart from hydraulic structure, rooftop rainwater harvesting is also widely practised in the arid regions, especially in Rajasthan. In many regions of Rajasthan, tankas are made to store the drinking water received by the rain.
c) In arid and semi-arid regions, agriculture fields were converted into rain fed storage structures that allowed water to stand and moisten the soil like ‘khadins’ in Jaisalmer and ‘johads in other parts of Rajasthan
d) Gandathur village in Mysore has well developed water harvesting system.
e) In Tamil Nadu, rooftop rainwater harvesting is made compulsory to all the houses across the state.
f) The capital of Meghalaya, Shillong suffers from acute water shortage and to meet water requirements, rooftop rainwater harvesting is commonly practiced.
g) In hills and mountainous region, people built divergent channels like the guls or kuls of western Himalayas for agriculture.
h) In the flood plains of Bengal, people develop in undulation channels to irrigate their fields.
- ‘Water can take life and give life’ support the statement.
a) Water is essential for all human beings. It is as important for us as air. We cannot survive without water, but at the same time it can also take a life.
b) If there is scarcity of water, then it will give rise to drought. This will disrupt our lives. It will obstruct the crop production and all our day to day activities.
c) If there is excessive water caused due to incessant rainfall, the floods will be harmful. For all of us as it causes a huge destruction to life and property.
d) Both of these conditions will ultimately cause destruction to life.
- What is the difference between surface runoff and underground water?
Surface runoff: Is obtained from inland drainage and rainfall such as rivers, lakes and ponds etc.
This water can be obtained directly.
It gets evaporated easily.
Underground water: It is found inside the Earth’s crust in large aquifers.
For utilising the groundwater, wells are dug and tube well system is used.
Groundwater doesn’t undergoes evaporation.
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