This is very useful ppt for students like us

3.  FRESHWATER
 WATER SCARCITY
* Causes of water scarcity
* Needs to conserve water
 WATER FACTS
 TEMPLES OF MODERN INDIA
 MULTIPURPOSE RIVE PROJECTS
 CLASSIFICATION OF DAMS
 DAMS IN INDIA (MAP)
 DISADVANTAGES OF DAMS
 RAINWATER HARVESTING
* Methods of rainwater harvesting
 TEST YOUR BRAIN
* MCQ
* Short Questions

4. Three - fourth of the earth surface is covered with water but
only less percentage of it is accounted by freshwater. This
freshwater can be mainly obtained by precipitation, surface
run off and ground water that is continually being renewed
and recharged through the hydrological cycle ensuring that
water is a renewable resource.
The shortage of water as compared to its demand is known as
water scarcity.
• Causes of water scarcity
Quantitative aspects
1. Variation in seasonal and annual precipitation
2. Over exploitation of water resources

5. 3. Excessive use of water
4. Unequal access to water among
different social groups.
Qualitative aspects
1. Bad quality of water.
2. Population growth
3. Commercialisation of agriculture
4. Industrialisation
5. Urbanisation
• Needs to conserve water resources
 Water is necessary for life on earth. It is believed that life
first originated in water before it invaded land. Water is in fact
a pre-condition of life.
Industrial waste in
water

6.  Cultivation of crops depends on
water. As India is a agricultural country,
so availability of water is must.
 Water is also essential for drinking
and other domestic works.
 It is also used in industries.
• 96.5% of water is exist as oceans and 2.5% as freshwater.
• Nearly 70% of the freshwater is in the form of ice sheets and glaciers,
while a little less than 30% is stored as groundwater.
• India receives 4% of global precipitation and ranks 133 in the world in
terms of water availability per person per annum.
• The total renewable water resources of India is estimated 1,897sq km
per annum.
• By 2025, large parts of India will join countries having absolute water
scarcity.

7. Pandit Jawaharlal Nehru proclaimed the dams as “temples of modern India” as
they were thought of as the vehicle that would lead the nation to development
and progress. They would integrate development of agriculture and the village
economy with rapid industrialization and growth of urban economy.
What is a dam?
Dam is a barrier across flowing water that obstructs, directs or retards the flow
often creating a reservoir, lake or impoundment.

8. Multipurpose river projects
Dams are considered as a multipurpose river project because
they can be used for many purposes as:
• irrigation
• electricity generation
• water supply for domestic and industrial uses
• flood control
• recreation
• inland navigation
• fish breeding
Example :
1. Bhakra Nangal project in Satluj-Beas basin is used both for
hydel power production and irrigation.
2. Hirakud project in Mahanadi basin integrates conservation
of water by flood control.

9. Basedon structure and material used:
• timber dams
• embankment dams
• masonry dams
Basedon height:
• low dams
• medium height dams
• high dams
Classification of dams
Dams can be classified based on their
structure, intended purpose or height :

11. • Adverse effect on aquatic life:
Regulating & 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 river’s aquatic life.
• Adverse effect on soil fertility:
Due to dams, there are no annual floods in the rivers
and so the soil of the downstream region do not nutrient rich
silt which decreases the fertility of soil.
• Displacement of local communities:
The building of large dams results in displacement of
local communities because the local people often give up
their land and livelihood and their control over resources for
greater food of the nation.

12. • Adverse impact on migration of aquatic life:
Dams also fragment rivers making it difficult for
the aquatic fauna to migrate, especially for spawning.
• Change in cropping pattern:
The multipurpose river projects are responsible
for providing assured means of irrigation to farmers. Due to
this, most of the farmers have changed the cropping pattern
shifting to water intensive and commercial crops. This has
led to salinisation of soil leading to ecological imbalance.
• Cause of disputes:
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
multi-purpose project.

13. • Water harvesting is a very cheap and affordable method of
conservation of water.
• Indian people have in-depth knowledge of rainfall regime and soil
type. They have developed techniques to harvest rainwater
groundwater and flood water in keeping with the local ecological
conditions and their water needs.
• Rainwater harvesting techniques are more environmental friendly
as compared to multipurpose river projects.
Water harvesting systems are considered
a variable alternative both socially and
environmentally in a country like India
because :

14. In hill and mountainous regions , people built diversion
channels like the “guls”, or “kuls” of the Western Himalayas
for agriculture.
Rooftop rainwater harvesting was commonly practised to
store drinking water particularly in Rajasthan.
In flood plains of Bengal, people built inundation channels
to irrigate their fields.

15. In arid and semi-arid regions, agricultural fields were
converted into rain fed storage structures that allowed the
water to stagnant and moisten the soil like the “khadins” in
Jaisalmer and the “johads” in other parts of Rajasthan.
In the semi-arid and arid regions of Rajasthan almost all the
houses had underground tanks or tankas for storing drinking
water.
Bamboo drip irrigation system is also being used in some
states.

16. Rainwater harvesting by making tanks
• In Rajasthan rainwater harvesting is carried out by making
tanks or tankas which are connected to the sloping roofs of the
houses.
• Rain falling on the rooftop would travel down the pipe , and
was stored in these tanks.
• The first spell of rain is usually not collected, as this would
clean the roofs and pipes. The rainwater from the subsequent
showers are then collected.
• Water is used immediately or else stored in wells which
recharges the groundwater.

17. 1. Who proclaimed the dams as the temples of modern India?
a. Mahatma Gandhi
b. Jawaharlal Nehru
c. Indira Gandhi
d. Dr. A.P.J Abdul Kalam
2. What are the underground tanks for storing drinking water?
a. Kul
b. Canal
c. Tankas
d. PVC Pipes

18. 3. Sardar Sarovar Project is based in the state of:
a. Gujarat
b. Madhya Pradesh
c. Rajasthan
d. Maharashtra
4. The Koyna Dam is being constructed on the river :
a. Kaveri
b. Yamuna
c. Bhagirathi
d. Krishna
5. Tanka is water harvesting technique associated with which of the
following states:
a. Tamil Nadu
b. West Himalayas
c. Gujarat
d. Rajasthan

19. 6. Bhakra Nangal multipurpose project is constructed on the river:
a. Satluj
b. Mahanadi
c. Ganga
d. Chenab
7. In which of the following states people developed inundation channels to
irrigate their fields?
a. Rajasthan
b. West Bengal
c. Punjab
d. Haryana
Answers
1. (b) 5. (d)
2. (c) 6. (a)
3. (a) 7. (b)
4. (d)

20. 1. How is freshwater obtained?
2. How is freshwater being renewed?
3. Mention any two regions which are expected to face water
shortage?
4. What is a dam?
5. What are multipurpose projects?
6. What is the need of rainwater harvesting?
7. What is water scarcity? Mention the responsible factors.
8. Name any two social movements which have been launched
against multipurpose river projects.
9. How do people harvest water in the flood plains of Bengal?
10. What was the main purpose of launching multi-purpose
project in India after independence?