WATER RESOURCES
Topics in the Water
Chapter → Some facts and Figures
• Dams
• Multi-purpose river projects
→ Objectives of multi-purpose river projects
→ Disadvantages of Multi-purpose river projects
→ Movements against Multi-purpose river projects
• Rainwater Harvesting
→ How Tankas works
Water Water is a renewable resource
• Three-fourth of the earth’s surface is covered with
water but only a small proportion of it accounts for
freshwater fit for use.
Some facts and 96.5 percent of the total volume of world’s water is
Figures estimated to exist as oceans and only 2.5 per cent as
freshwater.
• India receives nearly 4 percent of the global
precipitation and ranks 133 in the world in terms of
water availability per person per annum.
• By 2025, it is predicted that large parts of India will
join countries or regions having absolute water scarcity.
Water Scarcity and The lack sufficient water as compared to its demand in
need for water a region is known as Water Scarcity.
conservation and
management • Causes of Water Scarcity are:
→ over-exploitation- Overexploitation of water
is when water resources are extracted at a rate that
exceeds the rate at which they can be
replenished. This can happen when water is used for
domestic and industrial purposes, irrigation, or
when it's wasted or carelessly
used. Overexploitation can lead to water scarcity,
which can be a problem in many places.
→ excessive use and unequal access to water among
different social groups.
→ Large population
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There are many other reasons which lead to scarcity
of water:
1. Large growing population;
2.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; 3.There is
greater demand for water with growing urbanization
and industrialization; An unequal access to water
among different social groups;
4.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; and Over
exploitation of water in the urban areas.
Adverse effects of over-exploitation of ground water
resources:
• 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.
Main causes of Domestic wastes, especially urban sewers; industrial
water pollution: wastes are disposed off in the water without proper
treatment; chemical effluents from industries and from
agricultural sector; and many human activities, e.g.,
religious rituals and immersing of idols, etc. in the
water also pollute water.
Measures for water 1.Do not overdraw the ground water, recharge it by
conservation: techniques like rainwater harvesting; tapping rainwater
in reservoirs, watershed development programmes, etc.
2.Avoid wastage of water at all levels and do not
pollute the water.
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3.Adopting water conserving techniques of irrigation,
e.g., drip irrigation and sprinklers etc., especially in dry
areas.
Dams A dam is a barrier across flowing water that obstructs,
directs or retards the flow, often creating a reservoir,
lake or impoundment.
A dam is the reservoir and not the whole structure.
Multi-purpose Multi-purpose river projects large dams that serve
river projects several purposes in addition to impounding the water of
a river and used later to irrigate agricultural fields. For
example, the Sutluj-Beas river basin, the Bhakra–
Nangal project etc.
Advantages of multi-purpose river projects are:
→ Electricity generation
→ Irrigation
→ Water supply for domestic and industrial uses
→ Flood control
→ Recreation
→ Inland navigation
→ Fish breeding
Multipurpose river Jawahar Lal Nehru pro-claimed that multipurpose
valley projects — projects are ‘The Temples of Modem India’, because
’The Temples of they were thought of as the vehicle that would lead the
Modern India’: nation to development 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
industrialization and growth of the urban economy.
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;
• These projects can be used for recreation, inland
navigation and fish breeding.
Disadavantages: • Damming of rivers affects their natural flow
causing poor sediment flow;
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• Excessive sedimentation at the bottom of the
reservoir;
• Lack of sediments results in (a) rockier stream
bed and (b) poorer habitat for the rivers aquatic
life;
• The reservoirs submerge the existing vegetation
and soil, leading to its decomposition over time;
• They affect the fertility levels of the soil;
• cause large scale displacement of local
communities.
Disadvantages of It affects the natural flow of river causing poor
Multi-purpose sediment flow and excessive sedimentation at the
river projects are:
bottom of the reservoir.
→ It destroys the habitats for the rivers’ aquatic life.
→ It submerges the existing vegetation and soil if
created on the floodplains.
→ It displaces the local people of the place where it is
created.
→ These are unsuccessful in controlling floods at the
time of excessive rainfall.
→ These projects induced earthquakes, caused water-
borne diseases and pests and pollution resulting from
excessive use of water.
Movements against These projects were the cause of many new social
Multi-purpose movements like the
river projects 1. ‘Narmada Bachao Andolan’ and the
2. ‘Tehri Dam Andolan’ etc.
→ This is due to the large-scale
displacement of local communities.
3. Inter-state water disputes are also
becoming common with regard to sharing
the costs and benefits of the multi-purpose
project.
Rainwater Rainwater Harvesting refers to the practice of storing
Harvesting and using of rainwater from the surface on which it
falls.
• In hill and mountainous regions, people built
diversion channels like the ‘guls’ or ‘kuls’ of the
Western Himalayas for agriculture.
WATER RESOURCES
Kuls and guls are diversion channels built in hilly and
mountainous regions for irrigation. They are commonly
used in the state of Himachal Pradesh and the Western
Himalayas. Kuls are smaller reservoirs that provide
access to stored water for local villagers. Guls are
larger water storage systems that collect runoff from
large areas like hillsides or open spaces. The collected
water then flows into a kul.
Kuls and guls are important for agriculture, and require
special care during design and operation. For example,
in Himachal Pradesh, water from natural flowing
streams called khuds is diverted to the irrigation
channels. A kul can irrigate an area of about 20
hectares, serving up to 30 farmers at once.
• In Rajasthan, ‘Rooftop rain water harvesting’ was
commonly practised to store drinking water.
• In the flood plains of Bengal, people developed
inundation channels to irrigate their fields.
• In arid and semi-arid regions, agricultural fields were
converted into rain fed storage structures that allowed
the water to stand and moisten the soil.
• In the semi-arid and arid regions of Rajasthan, almost
all the houses traditionally had underground tanks or
tankas for storing drinking water.
Traditional 1.In mountainous areas ‘Guls’ and ‘Kuls’ the diversion
rainwater channels were built for agriculture.
harvesting
WATER RESOURCES
methods practiced 2.‘Rooftop rainwater harvesting’ was commonly
in different parts practiced to store drinking water, especially in
of the country: 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 rain fed storage structures, e.g.,
‘Khadins’ in Jaisalmer and ‘Johads’ in other parts of
Rajasthan.
5.In semi-arid and arid regions of Rajasthan,
particularly in Bikaner, Phalodi and Banner, 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.
‘Narmada Bachao Narmada Bachao Andolan or Save Narmada Movement
Andolan’: is an NGO that mobilized tribal people, farmers,
environmentalists and human rights activists against
the Sardar Sarovar Dam being built across the Narmada
river in Gujarat. The movement originally focused on
environmental issues related to submerging of trees
under the dam water. Recently its aim has been to
enable the displaced poor people to get full
rehabilitation facilities from the government.
How Tankas Tankas were connected to the sloping roofs of the
works: houses through a pipe.
→ Rain falling on the rooftops would travel down the
pipe and was stored in these underground ‘tankas’.
Answer the following questions in about 30 words.
1. Explain how Water is a renewable resource as it is renewed by water
water becomes a cycle itself, where three processes take place as
renewable resource. evaporation, condensation and precipitation. This
process of water cycle is never ending and hence, water
is a renewable resource.
2. What is water
scarcity and what Water scarcity or water stress occurs when water
are its main causes? 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.
WATER RESOURCES
3. Compare the Multipurpose river projects help in irrigation,
advantages and electricity production, flood control, inland navigation
disadvantages of and fish breeding. However, the reservoirs destroy
multi-purpose river local flora and fauna. Many native villages are
projects. submerged, and people lose their livelihood, with little
or no hope of rehabilitation.
Answer the following questions in about 120 words.
1. Discuss how 1.Houses in the semi arid regions of Rajasthan have
rainwater harvesting traditionally constructed tanks for storing drinking
in semi-arid regions water.
of Rajasthan is 2.They are big and are a part of the well-developed
carried out. rooftop rainwater harvesting system.
3.The tanks are constructed inside the main house or
the courtyard, and are connected to the sloping roofs of
the houses through a pipe.
4.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.
5.The rainwater from the subsequent spells is collected.
6.This water is used till the next rainy season, and is a
reliable source of water even after other sources have
dried up.
7.The tanks also help in cooling the houses as rooms
built around them have generally low temperatures due
to conduction.
2. Describe how 1.Traditional methods of rainwater harvesting like 'the
modern adaptations rooftop method' are becoming popular in India.
of traditional 2.In Gendathur village, Mysore, about 200 households
rainwater harvesting have adopted the rooftop rainwater harvesting method,
methods are being thereby making the village rich in rainwater.
carried out to 3.The state of Tamil Nadu has made it compulsory for
conserve and store all the houses to have rooftop rainwater harvesting
water. structures.
4.Defaulters are severely punished.
MAPWORK-Water The river and the states associated with the dams are
Resources also given here in brackets.
1. Salal (Chenab – Jammu & Kashmir)
2. Bhakra Nangal (Sutlej – Himachal Pradesh)
3. Tehri (Bhagirathi – Uttarakhand)
4. Rana Pratap Sagar (Chambal – Rajasthan)
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5. Sardar Sarovar (Narmada – Gujrat)
6. Hirakud (Mahanadi – Orissa)
7. Nagarjuna Sagar (Krishna – Telangana & A.P.)
8. Tungabhadra (Tungabhadra – Karnataka)
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