3. WATER RESOURCES
1. Water as a Renewable Resource
Water covers about three-fourths of the Earth’s surface, but only a small proportion is
available as freshwater for human use. Freshwater is obtained mainly from:
·
Precipitation
(rainfall)
·
Surface
runoff
·
Groundwater
Water is considered a renewable resource because it is continuously renewed
through the hydrological
cycle. In this
cycle, water evaporates from oceans, rivers, and lakes, condenses into clouds, falls
as precipitation, and replenishes surface and groundwater sources.
Despite being renewable and
abundant, many regions face severe water scarcity due to overuse, pollution,
and unequal distribution.
2. Water Scarcity
Meaning
Water scarcity refers to a situation
where the available water is insufficient to meet the needs of people.
Water scarcity does not always occur
in low-rainfall regions. Even areas with high rainfall may experience water
scarcity due to pollution, over-exploitation, or large populations.
Example
Many Indian cities receive adequate
rainfall but still face water shortages because of excessive demand and poor
management.
3. Causes of Water Scarcity
A. Increasing Population
A growing population requires more
water for:
·
Drinking
·
Cooking
·
Washing
·
Agriculture
·
Industries
As population increases, pressure on
water resources also increases.
B. Expansion of Irrigated
Agriculture
Agriculture is the largest consumer
of water.
To increase food production, farmers
increasingly depend on:
·
Wells
·
Tube
wells
·
Canal
irrigation
Excessive extraction of groundwater
leads to:
·
Falling
water table
·
Groundwater
depletion
·
Threat
to food security
Important Fact
Irrigated agriculture is the largest
consumer of water in India.
C. Industrialisation
After Independence, rapid industrial
growth increased water demand.
Industries use water for:
·
Manufacturing
·
Cooling
machinery
·
Cleaning
·
Processing
raw materials
Industries also require electricity,
much of which comes from hydroelectric projects.
D. Urbanisation
Rapid growth of cities has increased
demand for:
·
Water
·
Energy
·
Sanitation
services
Many urban housing colonies use
private borewells and groundwater pumps, causing depletion of groundwater
reserves.
E. Water Pollution
Even when water is available, it may
not be usable.
Water pollution occurs due to:
·
Domestic
sewage
·
Industrial
wastes
·
Chemical
effluents
·
Fertilisers
·
Pesticides
Polluted water becomes unsafe for
human consumption and creates water scarcity.
4. Need for Water Conservation and
Management
Water conservation has become
essential because:
·
Water
resources are being over-exploited.
·
Groundwater
levels are declining.
·
Water
pollution is increasing.
·
Population
is growing rapidly.
·
Food
security depends on water availability.
If water resources are not managed
properly:
·
Ecological
imbalance may occur.
·
Agriculture
may suffer.
·
Human
health may be affected.
·
Economic
activities may decline.
5. Government Initiatives
Jal Jeevan Mission (JJM)
The Government of India launched the
Jal Jeevan Mission to improve rural water supply.
Objective
Provide:
·
Safe
drinking water
·
Functional
household tap connections
·
55
litres per capita per day
to every rural household on a
long-term basis.
Importance
·
Improves
quality of life
·
Enhances
health standards
·
Reduces
burden on rural women
Atal Bhujal Yojana (Atal Jal)
Implemented in:
·
Gujarat
·
Haryana
·
Karnataka
·
Madhya
Pradesh
·
Maharashtra
·
Rajasthan
·
Uttar
Pradesh
Coverage
·
8220
water-stressed Gram Panchayats
·
229
blocks
·
80
districts
Main Objective
To bring behavioural change from:
Consumption → Conservation
and promote smart groundwater
management.
6. Multipurpose River Projects
Meaning
Multipurpose river projects are
projects in which water stored behind dams is used for multiple purposes.
Uses
·
Irrigation
·
Hydroelectricity
generation
·
Flood
control
·
Domestic
water supply
·
Industrial
water supply
·
Inland
navigation
·
Fish
breeding
·
Recreation
7. Dams
Definition
A dam is a barrier built across a
river to obstruct or regulate the flow of water and create a reservoir.
Components
Most dams contain a:
·
Spillway
·
Weir
through which excess water flows.
Classification of Dams
Based on Materials
1.
Timber
dams
2.
Embankment
dams
3.
Masonry
dams
Based on Height
1.
Low
dams
2.
Medium
dams
3.
High
dams
8. Ancient Water Management Systems
India has a long history of water
conservation.
Examples
Sringaverapura (1st Century BC)
·
Near
Allahabad
·
Floodwater
harvesting from River Ganga
Mauryan Period
Under Chandragupta Maurya:
·
Dams
·
Lakes
·
Irrigation
systems
were extensively developed.
Other Irrigation Centres
·
Kalinga
(Odisha)
·
Nagarjunakonda
(Andhra Pradesh)
·
Bennur
(Karnataka)
·
Kolhapur
(Maharashtra)
Bhopal Lake
Built in the 11th century.
One of the largest artificial lakes
of its time.
Hauz Khas Tank
Built in Delhi during Alauddin
Khalji's reign.
Supplied water to Siri Fort.
9. Major Multipurpose Projects
Bhakra-Nangal Project
River Basin
Sutlej-Beas
Uses
·
Irrigation
·
Hydroelectric
power generation
Hirakud Project
River
Mahanadi
Uses
·
Flood
control
·
Water
conservation
·
Irrigation
Sardar Sarovar Project
River
Narmada
States Covered
·
Gujarat
·
Rajasthan
·
Madhya
Pradesh
·
Maharashtra
Benefits
·
Irrigation
for drought-prone regions
·
Drinking
water supply
·
Agricultural
development
Important Fact
Provides irrigation to:
·
18.45
lakh hectares in Gujarat
·
2.46
lakh hectares in Rajasthan
10. Jawaharlal Nehru's View
Jawaharlal Nehru called dams:
"The Temples of Modern
India"
because they promoted:
·
Agricultural
development
·
Industrial
growth
·
National
progress
11. Advantages of Multipurpose
Projects
1.
Provide
irrigation facilities.
2.
Generate
hydroelectric power.
3.
Control
floods.
4.
Supply
drinking water.
5.
Support
industries.
6.
Encourage
inland navigation.
7.
Promote
fish breeding.
8.
Boost
regional development.
12. Disadvantages of Multipurpose
Projects
Environmental Problems
·
Disturb
natural river flow.
·
Reduce
sediment flow.
·
Cause
sedimentation in reservoirs.
·
Damage
aquatic ecosystems.
·
Block
migration of fish.
Social Problems
·
Displacement
of people.
·
Loss
of livelihood.
·
Submergence
of forests and villages.
Other Problems
·
Floods
due to sedimentation.
·
Soil
erosion.
·
Earthquakes
in some regions.
·
Water-borne
diseases.
·
Salinisation
of soil.
13. Pradhan Mantri Krishi Sinchayee
Yojana (PMKSY)
Objectives
Har
Khet Ko Pani
Provide irrigation facilities to
every farm.
Per
Drop More Crop
Increase water-use efficiency.
Sustainable
Water Conservation
Promote water-saving technologies
and practices.
Importance
·
Reduces
wastage of water
·
Increases
agricultural productivity
·
Promotes
rural prosperity
14. Rainwater Harvesting
Meaning
Rainwater harvesting is the
collection and storage of rainwater for future use.
It is considered an environmentally
friendly and economically viable alternative to large dams.
15. Traditional Rainwater Harvesting
Systems
A. Guls and Kuls
Region
Western Himalayas
Purpose
Divert mountain streams for irrigation.
B. Inundation Channels
Region
Flood plains of Bengal
Purpose
Irrigate agricultural fields.
C. Khadins
Region
Jaisalmer, Rajasthan
Purpose
Store rainwater in agricultural fields.
D. Johads
Region
Rajasthan
Purpose
Collect and conserve rainwater.
16. Tankas of Rajasthan
Tankas are underground water storage
tanks.
Features
·
Built
in houses or courtyards.
·
Connected
to sloping roofs through pipes.
·
Store
rainwater collected from rooftops.
Importance
·
Supply
drinking water during summers.
·
Remain
functional when all other sources dry up.
·
Store
pure rainwater called Palar
Pani.
Additional Benefit
Underground rooms near tankas remain
cool during summer.
17. Rooftop Rainwater Harvesting
Process
1.
Rainwater
falls on rooftops.
2.
Water
moves through pipes.
3.
Water
is filtered using sand and bricks.
4.
Stored
in tanks or underground sumps.
5.
Excess
water recharges groundwater.
Benefits
·
Conserves
water
·
Recharges
groundwater
·
Reduces
dependence on external sources
18. Gendathur Village (Karnataka)
Located in:
Mysuru District
Villagers installed rooftop
rainwater harvesting systems.
Results
·
Around
200 households adopted the system.
·
Each
house collects about 50,000 litres annually.
·
Village
became self-sufficient in water.
19. Tamil Nadu's Achievement
Important Fact
Tamil Nadu became the first state in India to make rooftop rainwater
harvesting compulsory.
Legal provisions exist against
defaulters.
This is one of the most frequently
asked factual questions.
20. Bamboo Drip Irrigation System
Location
Meghalaya
Age
Around 200 years old.
Working
·
Bamboo
pipes transport water from hilltop springs.
·
Water
flows through gravity.
·
Flow
is controlled by adjusting bamboo pipes.
·
Water
finally reaches plant roots drop by drop.
Advantages
·
Saves
water
·
Low-cost
technology
·
Environment
friendly
·
Suitable
for hilly regions
Important Fact
18–20 litres of water entering the
system finally reduce to about 20–80 drops per minute near the plant roots.
******
Exercise Answers
1. Multiple Choice Questions
(i) Classify the situations
|
Situation |
Classification |
|
(a)
Region with high annual rainfall |
Not suffering
from water scarcity |
|
(b)
Region having high annual rainfall and large population |
Suffering from
water scarcity
(high demand and pressure on resources) |
|
(c)
Region having high annual rainfall but water is highly polluted |
Suffering from
water scarcity
(water not fit for use) |
|
(d)
Region having low rainfall and low population |
Not necessarily
suffering from water scarcity
(low demand may balance low supply) |
(ii) Which statement is NOT an
argument in favour of multipurpose river projects?
Answer: (c) Multi-purpose projects lead
to large scale displacements and loss of livelihood.
This is a disadvantage, not an
advantage.
(iii) Identify the mistakes and
rewrite correctly
(a)
Incorrect:
Multiplying urban centres with large
and dense populations and urban lifestyles have helped in proper utilisation of
water resources.
Correct:
Multiplying urban centres with large
and dense populations and urban lifestyles have increased the demand for water
and led to over-exploitation of water resources.
(b)
Incorrect:
Regulating and damming of rivers
does not affect the river’s natural flow and its sediment flow.
Correct:
Regulating and damming of rivers
affect the river’s natural flow and reduce sediment flow.
(c)
Incorrect:
Today in Rajasthan, the practice of
rooftop rainwater harvesting has gained popularity despite high water
availability due to the Indira Gandhi Canal.
Correct:
Today in Rajasthan, the practice of
rooftop rainwater harvesting is declining because adequate water is available
through the Indira Gandhi Canal.
2. Answer the Following Questions
(30 Words Each)
(i) Explain how water becomes a
renewable resource.
Water becomes a renewable resource
because it is continuously renewed through the hydrological cycle. Evaporation,
condensation, precipitation, and groundwater recharge ensure the constant
circulation and replenishment of water.
(ii) What is water scarcity and what
are its main causes?
Water scarcity is the shortage of
usable water to meet human needs. Its main causes are over-exploitation of
water resources, population growth, urbanisation, industrialisation, pollution,
and unequal access to water.
(iii) Compare the advantages and
disadvantages of multipurpose river projects.
Multipurpose projects provide
irrigation, hydroelectric power, flood control, water supply, navigation, and
fish breeding. However, they cause displacement, environmental degradation,
sedimentation, ecosystem damage, and may induce floods and earthquakes.
3. Answer the Following
Questions (120 Words Each)
(i) Discuss how
rainwater harvesting in semi-arid regions of Rajasthan is carried out.
In the semi-arid and arid regions of
Rajasthan, people developed traditional rainwater harvesting systems such as
tankas, johads, and khadins. Tankas are underground tanks built inside houses
or courtyards and connected to sloping rooftops through pipes. Rainwater
falling on rooftops is collected and stored in these tanks for later use. The
first rainfall is usually allowed to wash the roofs and pipes, while water from
later showers is stored. This stored water remains available throughout the
year, especially during the dry summer months when other water sources dry up.
Rainwater, locally called palar
pani, is considered pure and reliable. These systems helped people
survive in water-scarce regions and remain an important example of sustainable
water management.
(ii) Describe how modern
adaptations of traditional rainwater harvesting methods are being carried out
to conserve and store water.
Traditional rainwater harvesting
methods are being adapted in many parts of rural and urban India. Rooftop
rainwater harvesting systems collect rainwater from roofs through PVC pipes.
The water is filtered using sand and gravel before being stored in tanks or
directed to recharge wells and groundwater reserves. A notable example is
Gendathur village in Karnataka, where nearly 200 households have installed
rooftop rainwater harvesting systems. These systems help meet domestic water
needs and recharge groundwater. Several cities and states have also encouraged
or made rooftop rainwater harvesting compulsory. Tamil Nadu became the first
state to make such structures mandatory. These modern adaptations conserve
water, reduce dependence on groundwater, improve water availability, and
promote sustainable water management practices.
*********