WATER RESOURCES NOTES

1. Explain how water becomes a renewable resource?

Ans:
Fresh water is mainly obtained from surface run off and ground water. This
is continually being renewed and recharged through the hydrological cycle.
Water moves within the hydrological cycle making water a renewable
resource.
2. What is water scarcity? Write the main reasons for water scarcity.
Ans:
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.
• Large growing population—means more water required for domestic
use and also to produce more food.
• In the agricultural sector, water resources are being over-exploited to
expand irrigated areas and dry-season agriculture.
• More water required for irrigation purposes to facilitate higher food
production, i.e., for doing multiple cropping and for HYV seeds.
• There is greater demand for water with growing urbanisation and
industrialisation.
• An unequal access to water among different social groups.
• The quality of water is deteriorating, i.e., getting polluted by domestic
and industrial wastes, chemical fertilizers and pesticides used in
agriculture.
 • Excessive use of water by industries which also require water to
generate hydro-electric power to run them.
• 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.

3. How intensive industrialisation and urbanisation have posed a great

pressure on existing fresh water resources in India? Explain with two
examples for each.
Ans:
Intensive industrialisation and urbanisation have put greater pressure on
existing fresh water resources. With the ever-growing number of industries, the
demand for water has grown tremendously:
• Industries are heavy users of fresh water as water is required for
cooling the machines as well as for the processing of goods.
• Also, the machines run on the power supplied by the hydel power
plants.
• 22 percent of the total electricity is hydro-electric power.
• Rapid urbanisation has led to expansion of industries which increased
the requirement of water.
• The untreated industrial effluents which are discharged into water
bodies are polluting the water and making it hazardous for human
consumption. This is responsible for creating water scarcity.

Large urban population and urban lifestyles have not only added to water
and energy requirements but also aggravated the problem by over-
drawing the groundwater by using their own groundwater pumping
 devices for meeting their water needs for domestic purposes such as
cleaning, cooking, washing, etc.

4. Write the adverse effects of over-exploitation of ground water resources.

Ans:
• Pumping out more water from under the ground may lead to falling
ground water levels.
• It will adversely affect water availability.
• This, in turn, will affect our agriculture and food security of the
people.
• Impoverishment of water resources may adversely affect the
ecological cycle.
5. Write the main causes of water pollution.
Ans:
Water gets polluted by:
• Domestic wastes, especially urban sewers.
• Industrial wastes are disposed of in the water without proper
treatment.
• Chemical effluents from industries and from agricultural sector.
• Pesticides and fertilisers used in agriculture may get washed into
rivers by rain-water and may pollute the water by enriching it with
minerals.
• Many human activities, e.g., religious rituals and immersing of idols,
etc. in the water also pollute water.
6. Water conservation is the need of the hour. Justify.
Ans: Conservation of water is the need of the hour because
• To safeguard ourselves from health hazards.
 • To prevent degradation of our natural ecosystem.
• To ensure food security and for continuation of our livelihoods.
• For productive activities of the nation.
• Our water resources are limited and our requirements are increasing
day by day. The water resources are unevenly distributed.
• Most of our resources especially in the cities and urban areas are
polluted and unsuitable for drinking and other purposes.

7. Write some measures adopted for conservation of water resources.

Ans:
Measures for water conservation:
• Do not overdraw the ground water, recharge the ground water by
techniques like rainwater harvesting.
• Avoid wastage of water at all levels.
• Do not pollute the water.
• Increasing the water resources by tapping the rainwater in reservoirs,
watershed development programmes, etc.
• Adopting water conserving techniques of irrigation, e.g., drip
irrigation and sprinklers etc., especially in dry areas.
8. What were the different types of hydraulic structures constructed in
Ancient India? Give examples.
Ans:
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.
.
9. What is a dam? On what basis are dams classified into different types?
Ans:
A dam is a barrier across flowing water that obstructs, directs or retards the
flow, creating a reservoir, lake or impoundment. A dam is the reservoir and not
the whole structure.
Classification:
• Dams are classified according to structure, intended purpose or height.
• According to structure and materials used, they are classified as
timber dams, embankment dams or masonry dams.
• According to height, they are classified as large and major dams, low
dams, medium height dams and high dams.
10.What is the main difference between traditional dams and modern dams?
Ans:
• 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.
11.Why are multipurpose river valley projects called ‘The Temples of Modern
India’? Who first made this statement?
Or
• Jawahar Lal Nehru proudly proclaimed the ‘dams as the temples
of modern India’. Analyze this statement.
Ans:
Jawahar Lal Nehru proclaimed that multipurpose projects are ‘The
Temples of Modern India’, because they were thought of as the
vehicle that would lead the nation to develop and progress.
• He believed that these projects with their integrated water resource
management approach would integrate development of agriculture
and the village economy with rapid industrialisation and growth of the
urban economy.
12.Explain the advantages of multipurpose river valley projects .
Multipurpose river valley projects have the following advantages:
• They bring water to those areas which suffer from water scarcity and
also provide water for irrigation.
• These projects generate electricity for industries and our homes.
• They help in controlling floods by regulating the water flow.
• These projects can be used for recreation,
• These projects help in inland navigation and fish breeding.
13. ‘Construction of dams on rivers has caused environmental degradation.’
Give reasons to support this statement.
 Ans:
• Damming of rivers affects their natural flow causing poor sediment
flow.
• Excessive sedimentation at the bottom of the reservoir.
• Lack of sediments results in
o rockier stream bed and
o poorer habitat for the river’s aquatic life.
• Dams also fragment rivers, making it difficult for aquatic fauna to
migrate, especially for spawning.
• The reservoirs submerge the existing vegetation and soil, leading to its
decomposition over time.
• Flood plains are deprived of silt and khadar, affecting the fertility
levels of the soil.
• Construction of dams also faces resistance because of large scale
displacement of local communities.
• Multipurpose projects and dams have been the cause of many new
social movements. Name two such social movements and write the
underlying causes for these movements.
Ans:
‘Narmada Bachao Andolan’ and Tehri Dam Andolan’.‘

Their major concerns were as follows:

• Initially the environmental concerns were of utmost importance.
• Dams have resulted in large-scale displacement of local communities.
• Local people have to give up their land and livelihood.
 • Local people do not benefit from such projects as they are even
deprived of the local sources on which they have little control.
• Many settlements and agricultural lands are submerged under water.
• Rehabilitation of the displaced persons is now the prime concern of
these movements.
14.What are the social consequences of multipurpose projects?
Or
Multipurpose projects have transformed the social landscapes. Explain.
Ans:
• Local people, especially the landless people, did not gain from these
projects.
• It led to displacement of people which deprived the people of their
land and livelihood.
• It has increased the social gap between the richer landowners and the
landless poor.
• Dams created conflicts between people wanting different uses and
benefits from the same water resources.
• Inter-state water disputes are also becoming common with regard to
sharing the costs and benefits of the multipurpose projects.

15.Name two multipurpose projects and the rivers on which they are
respectively situated.
Ans:
• Hirakud Project is situated on river Mahanadi in Orissa
 • Bhakra Nangal Project is situated on river Sutlej.
16.Give an example of an inter-state water dispute.
Ans:
Krishna-Godavari dispute. The Karnataka and Andhra Pradesh Governments
objected to the diversion of more water at Koyna by the Maharashtra
government for a multipurpose project as this results in reduction of
downstream flow to Karnataka and Andhra Pradesh adversely affecting
agriculture and industry in these States.
17.Describe the traditional method of rainwater harvesting adopted in
different parts of India.
Ans:
• In ancient India, people developed wide-ranging techniques to harvest
rainwater.
• In mountainous areas ‘Guls’ and ‘Kuls’ the diversion channels were
built for agriculture.
• ‘Rooftop rainwater harvesting’ was commonly practised to store
drinking water, especially in Rajasthan.
• Inundation channels for irrigation were developed in the flood plains
of West Bengal.
• 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.
• 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.
18.Explain how rooftop rainwater harvesting in semi-arid regions of
Rajasthan is carried out.
Or
Write the features of the ’tankas’ built in the houses of Bikaner, Phalodi
and Barmer.
Ans:
‘Rooftop rainwater harvesting’ was commonly practiced to store drinking
water, especially in semi-arid and arid regions like Bikaner, Phalodi and Barmer
in Rajasthan.
• 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.
• The tankas were built inside the main house or the courtyard.
• 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.
• Many houses constructed underground rooms adjoining the tanka to
beat the summer heat as it would keep the room cool.
19. Write how modem adaptations of traditional rainwater harvesting
methods are being carried out to conserve and store water.
Ans:
 • In modem times, rainwater harvesting is done in both rural and urban
areas to recharge the groundwater by capturing and storing rainwater
by constructing structures, e.g., dug wells, percolation pits, digging
trenches around fields, etc.
• Rooftop rainwater harvesting structures are a common practice in
many cities. Rain-water is collected using a PVC pipe and is filtered
using sand and bricks.
• This water can be stored to meet the household needs through storage
in tanks. This water is readily available for immediate usage.
• Excess water or a pipe can be connected to an underground reservoir
which may recharge the ground-water through hand-pump or through
abandoned dug well. Later, this water can be drawn for varied uses.
• Storage tanks/reservoirs are built to store rainwater which is later used
for irrigation purposes.
20.Which village in Karnataka has earned the distinction of being rich in
rainwater?
Ans:
In Gendathur in Mysore, Karnataka, nearly 200 households have installed
rooftop rainwater harvesting system.
21.Name the state which has made rooftop rainwater harvesting compulsory.
Ans:
Tamil Nadu has made rooftop rainwater harvesting structure compulsory for all
houses across the state.
22.Name the unique irrigation system prevalent in Meghalaya.
Ans:
Bamboo Drip Irrigation System.
23.Name two states where rooftop rainwater harvesting is common practice.
Ans:
Rajasthan and Meghalaya.
24.What is the present condition of Indian rivers?
Ans:
India’s rivers, especially the smaller ones have turned into toxic streams. Even
the bigger ones like the Ganga and Yamuna are slowly getting polluted.
25.What is JJM? What are its goals?
Ans: Jal Jeevan Mission is a programme announced by the government of India
to improve the quality of life and enhance ease of living of the people of rural
areas.
The main goal of JJM is to enable every rural household to get assured supply
of portable piped water at a service level of 55 liters per day regularly on a
long-term basis.