Chapter 3- Water Resources
1. (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.
Answer
(a) Not suffering from water scarcity
(b) Suffering from water scarcity
(c) Suffering from water scarcity
(d) Not suffering from water scarcity
(ii) Which one of the following statements is not an argument in favour of multi-purpose river projects?
(a) Multi-purpose projects bring water to those areas which suffer from water scarcity.
(b) Multi-purpose projects by regulating water flow help 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.
(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 water harvesting has gained popularity despite high water availability due to the Rajasthan Canal.
Answer
(a) Multiplying urban centres with large and dense populations and urban lifestyles have caused the over exploitation of water resources.
(b) Regulating and damming of rivers affect their natural flow and causes the sediment to settle at the bottom of the reservoir.
(c) 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 is on the decline due to the Rajasthan canal.
2. 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.
Answer
(i) Water is a renewable resource as it is renewed by water cycle itself, where three processes take place as evaporation, condensation and precipitation. This process of water cycle is never ending and hence, water is a renewable resource.
(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, growing demand for water, and unequal access to it.
(iii) Multipurpose river projects help in irrigation, electricity production, flood control, inland navigation and fish breeding. However, the reservoirs destroy local flora and fauna. Many native villages are submerged, and people lose their livelihood, with little or no hope of rehabilitation.
3. 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.
Answer
(i) Houses in the semi arid regions of Rajasthan have traditionally constructed tanks for storing drinking water. They are big and are a part of the well-developed rooftop rainwater harvesting system. The tanks are constructed inside the main house or the courtyard, and are connected to the sloping roofs of the houses through a pipe. The rain falling on the rooftop travels down and is stored in the tanks. The first spell of rain is not collected as this water cleans the roof and the pipes. The rainwater from the subsequent spells is collected. This water is used till the next rainy season, and is a reliable source of water even after other sources have dried up. The tanks also help in cooling the houses as rooms built around them have generally low temperatures due to conduction.
(ii) Traditional methods of rainwater harvesting like ‘the rooftop method’ are becoming popular in India. In Gendathur village, Mysore, about 200 households have adopted the rooftop rainwater harvesting method, thereby making the village rich in rainwater. The state of Tamil Nadu has made it compulsory for all the houses to have rooftop rainwater harvesting structures. Defaulters are severely punished.
Question-1
What is the situation regarding water scarcity in post independent India?
Solution:
Post-independent India witnessed intensive industrialisation and urbanisation, creating vast opportunities for us. Today, large industrial houses are as common placeas the industrial units of many MNCs(Multinational Corporations). The ever-increasing number of industries has made matters worse by exerting pressure on existing freshwater resources. Industries, apart from being heavy users of water, also require power to run them. Much of this energy comes from hydroelectric power. Today, in India hydroelectric power contributes approximately 22 per cent of the total electricity produced. Moreover, multiplying urban centres with large and dense populations and urban lifestyles have not only added to water and energy requirements but have further aggravated the problem. If you look into the housing societies or colonies in the cities, you would find that most of these have their own groundwater pumping devices to meet their water needs.
Question-2:
What are the causes of water scarcity in available areas?
Solution:
This scarcity may be due to bad quality of water. Lately, there has been a growing concern that even if there is ample water to meet the needs of the people, much of it may be polluted by domestic and industrial wastes, chemicals, pesticides and fertilisers used in agriculture, thus, making it hazardous for human use.
Question-3:
Give a short note on Multi-purpose projects In India.
Solution:
Multi-purpose projects, launched after Independence with their integrated water resources management approach, were thought of as the vehicle that would lead the nation to development and progress, overcoming the handicap of its colonial past. Jawaharlal Nehru proudly proclaimed the dams as the ‘temples of modern India’; the reason being that it would integrate development of agriculture and the village economy with rapid industrialisation and growth of the urban economy.
Question-4:
What were the different methods of traditional rain-water harvesting?
Solution:
There existed an extraordinary tradition of water-harvesting system. People had in-depth knowledge of rainfall regimes and soil types and developed wide ranging techniques to harvest rainwater, groundwater, river water and flood water in keeping with the local ecological conditions and their water needs. In hill and mountainous regions, people built diversion channels like the ‘guls’or ‘kuls’ of the Western Himalayas for agriculture.
‘Rooftop rain water 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 an 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.
Question-5:
Give a short note on Rooftop rainwater harvesting.
Solution:
Rooftop harvesting was common across the towns and villages of the Thar. Rainwater that falls on the sloping roofs of houses is taken through a pipe into an underground tanka (circular holes in the ground).It is built in the main house or in the courtyard. Water can be taken from a neighbour’s roof through a long pipe. A hole is made through which rainwater flows down into an underground tanka.
Question-6:
State two objectives of rainwater harvesting?.
Solution:
1.It reduces run-off of potable water back into the sea.
2.It prevents water –logging in roads during rainy season.
Question-7:
What are two measures of conservation of water resources?
Solution:
Rainwater harvesting.
Transfer of water from flood prone basins to drought prone basins.
Question-8:
Give four major uses of water.
Solution:
Drinking and domestic consumption like washing clothes.
2.Irrigation of farm lands.
3.Generation of Hydro-electricity.
4.Cooling at home and in industrial establishments.
Question-9:
What do you understand by underground water? Mention two areas where underground water is abundant.
Solution:
Water resources that lie beneath the surface of the earth is called underground water resources. These come into existence due to the seepage of ground water during rainy spells. Northernplains and coastal regions have abundant underground water. This is because the plains are flat and the rock strata are permeable.
Question-10:
Name any Multi-purpose projects In India and give three contributions of that project.
Solution:
The Damodar Valley Project offers the following advantages:
1) Power station under that project provides 104 MW of Hydro electricity.
2.The project provides 136 km of inland waterways through reservoirs and canals.
Its canals irrigate 4,50,000 hectares of agricultural land.
Question-11:
What is a Multi-purpose project? State two purposes, which are fulfilled by multi-purpose projects.
Solution:
Multi-purpose projects comprises of one or more dams erected to contain the free flow of water, storage of water in artificially created reservoirs, power house for generation of Hydro-electricity and feeder canals for irrigation.
1) They are designed to generate Hydro-electricity.
2) Store water for feeding irrigation channels.
Question-12
Give two reasons why precipitation is called primary source of water on earth.
Solution:
Precipitation causes rains. The rainwater flow into rivers that are one of the primary sources of water.
Rainwater made available by precipitation seeps into ground creating ground water reserves.
Question-13:
Give 2 examples of over-exploitation of water resources.
Solution:
Mineral water bottling plants and deep bore wells are two examples of over-exploitation of water resources.
Question-14:
How much of the world’s water exist as fresh water?
Solution:
2.5 % of the world’s water exists as fresh water.
Question-15:
Identify the sources of fresh water supply?
Solution:
Precipitation, surface run-off and ground water are sources of fresh water supply.
Question-16:
How has industrialisation affected the quality of river waters?
Solution:
Discharges of untreated effluents in the river by industrial units have polluted river water.
Question-17:
What are the social consequences of building big dams?
Solution:
Big dam projects cause large scale displacement of people. The displaced people have to give up their homes and their lands. The displaced people do not get the compensation they are promised by the government and are put to a lot of hardship. The advantages of the dam, such as better irrigation facilities, electricity and industrialisation are enjoyed by others, were as the displaced people are left defenceless.
The dams have caused conflict between people who have been displaced and those who have benefited.
Tribal people and farmers are involved in the Narmada Bachao Andolan and Tehri Dam Andolan seeking justice for displacement.
Question-18
What is the situation regarding water scarcity in post independent India?
Solution:
Post-independent India witnessed intensive industrialisation and urbanisation, creating vast opportunities for us. Today, large industrial houses are as common placeas the industrial units of many MNCs(Multinational Corporations). The ever-increasing number of industries has made matters worse by exerting pressure on existing freshwater resources. Industries, apart from being heavy users of water, also require power to run them. Much of this energy comes from hydroelectric power. Today, in India hydroelectric power contributes approximately 22 per cent of the total electricity produced. Moreover, multiplying urban centres with large and dense populations and urban lifestyles have not only added to water and energy requirements but have further aggravated the problem. If you look into the housing societies or colonies in the cities, you would find that most of these have their own groundwater pumping devices to meet their water needs.
Question-19
What were the different methods of traditional rain-water harvesting?
Solution:
There existed an extraordinary tradition of water-harvesting system. People had in-depth knowledge of rainfall regimes and soil types and developed wide ranging techniques to harvest rainwater, groundwater, river water and flood water in keeping with the local ecological conditions and their water needs. In hill and mountainous regions, people built diversion channels like the ‘guls’or ‘kuls’ of the Western Himalayas for agriculture.
‘Rooftop rain water 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 an 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.
Question-20:
What is a multi-purpose project? Name any one and give 3 contributions of that project.
Solution:
The Damodar Valley Project offers the following advantages:
1) Power station under that project provides 104 MW of Hydro electricity.
2.The project provides 136 km of inland waterways through reservoirs and canals.
Its canals irrigate 4,50,000 hectares of agricultural land.
Multi-purpose projects comprises of one or more dams erected to contain the free flow of water, storage of water in artificially created reservoirs, power house for generation of Hydro-electricity and feeder canals for irrigation.
1) They are designed to generate Hydro-electricity.
2) Store water for feeding irrigation channels.