Q.1 Explain how water becomes a renewable resource?
Answer:

• Fresh water is mainly obtained from surface run off and ground water. This is continually being renewed and recharged through the hydrological cycle.
• All the water moves within the hydrological cycle making water a renewable resource.

Q.2 What were the different types of hydraulic structures constructed in Ancient India? Give examples.
Answer:
The different types of hydraulic structures were:

• Dams built of stone rubble e.g., during Chandragupta Maurya’s time, dams, lakes and irrigation systems were extensively built.
• Reservoirs or lakes like the Bhopal lake of the 11th century which was one of the largest artificial lakes of its time.
• Embankments and canals for irrigation. Sophisticated irrigation works have been found in Kalinga (Orissa), Kolhapur (Maharashtra), Nagarjunakonda (Andhra Pradesh) etc.
• Many tanks were built to store rainwater e.g., the tank in Huaz Khas in Delhi was built in 14th century to supply water to Siri Fort area.

Q.3 Describe the traditional method of rainwater harvesting adopted in different parts of India.
Answer:
In ancient India, people developed wide-ranging techniques to harvest rainwater.

1. In mountainous areas ‘Guls’ and ‘Kuls’ the diversion channels were built for agriculture.
2. ‘Rooftop rainwater harvesting’ was commonly practised to store drinking water, especially in Rajasthan.
3. Inundation channels for irrigation were developed in the flood plains of West Bengal.
4. In arid and semi-arid regions, agricultural fields were converted into rainfed storage structures, eg. ‘Khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.
5. In semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, all the houses had underground tanks or ‘tankas’ built inside the house for storing drinking water. They were a part of the well-developed rooftop rainwater harvesting system.

Q.4 What is water scarcity? Write the main reasons for water scarcity. (2015)
Answer:
Water scarcity means shortage of water. It is usually associated with regions having low rainfall or drought prone areas. There are many other reasons which lead to scarcity of water.
These are:

1. Large growing population—means more water required for domestic use and also to produce more food.
2. In the agricultural sector, water resources are being over-exploited to expand irrigated areas and dry-season agriculture.
3. More water required for irrigation purposes to facilitate higher food production, i.e., for doing multiple cropping and for HYV seeds.
4. There is greater demand for water with growing urbanisation and industrialisation.
5. An unequal access to water among different social groups.
6. The quality of water is deteriorating, i.e., getting polluted by domestic and industrial wastes, chemical fertilizers and pesticides used in agriculture.
7. Excessive use of water by industries which also require water to generate hydro-electric power to run them.
8. Over exploitation of water in the urban areas. Housing societies and colonies have their own ground-water pumping devices. This causes depletion of fragile water resources in the cities.

Q.5 Write the adverse effects of over-exploitation of ground water resources.
Answer:

1. Pumping out more water from under the ground may lead to falling ground water levels.
2. It will adversely affect water availability.
3. This, in turn, will affect our agriculture and food security of the people.
4. Impoverishment of water resources may adversely affect the ecological cycle.

Q6 .
Write the main causes of water pollution.
Answer:
Water gets polluted by:

1. Domestic wastes, especially urban sewers.
2. Industrial wastes are disposed off in the water without proper treatment.
3. Chemical effluents from industries and from agricultural sector.
4. Pesticides and fertilisers used in agriculture may get washed into rivers by rain-water and may pollute the water by enriching it with minerals.
5. Many human activities, e.g., religious rituals and immersing of idols, etc. in the water also pollute water.

Q.7 How was water conserved in ancient India? Give any four examples in support of your answer. (2012)
Answer:
Archaeological and historical records show that from ancient times India has been constructing sophisticated hydraulic structures like dams, reservoirs, embankments and canals for irrigation.

1. For example, in the first century B.C., Allahabad had sophisticated water harvesting system channelling the flood water of the river Ganga.
2. During the time of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.
3. Sophisticated irrigation works have been found in Kalinga in Odisha, Nagarjunakonda in Andhra Pradesh, Bennur in Karnataka and Kolhapur in Maharashtra.
4. Bhopal lake, built in the 11th century, was one of the largest artificial lakes of its time.
5. In the 14th century, Iltutmish constructed a tank in Hauz Khas, Delhi for supplying water in Siri Fort area.

Q.8 What is the main difference between traditional dams and modern dams?
Answer:
Traditionally dams were built to impound rivers and rainwater that could be used later to irrigate the agricultural fields.

Today, dams are referred to as multipurpose projects where many uses of the impounded water are integrated with one another. The main purposes served by these projects are irrigation, electricity generation, flood control, water supply for domestic and industrial use, fish breeding and tourism

Q.9 What are the social consequences of multipurpose projects?
Or
Multipurpose projects have transformed the social landscapes. Explain.
Answer:

1. Local people, especially the landless people, did not gain from these projects.
2. It led to displacement of people which deprived the people of their land and livelihood.
3. It has increased the social gap between the richer landowners and the landless poor.
4. Dams created conflicts between people wanting different uses and benefits from the same water resources.
5. Inter-state water disputes are also becoming common with regard to sharing the costs and benefits of the multipurpose projects.

Q.10 Explain how rooftop rainwater harvesting in semi-arid regions of Rajasthan is carried out. (2012)
Or
Write the features of the ’tankas’ built in the houses of Bikaner, Phalodi and Barmer.
Answer:
‘Rooftop rainwater harvesting’ was commonly practiced to store drinking water, especially in semi-arid and arid regions like Bikaner, Phalodi and Barmer in Rajasthan.

1. In semi-arid and arid regions, all the houses had underground tankas or ‘tankas’ for storing drinking water built inside the house. They were the part of the well-developed rooftop rainwater harvesting system.
2. The tankas could be as large as a big room. One household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres long and 2.44 metres wide.
3. The tankas were built inside the main house or the courtyard.
4. The tanks were connected to the sloping roofs of the houses through a pipe. The falling rain would travel down the pipes and get stored in the underground ‘tankas’. The first spell of rain would not be collected as it cleaned the roof and pipes. The rainwater from subsequent showers was collected.
5. Many houses constructed underground rooms adjoining the tanka to beat the summer heat as it would keep the room cool.

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