WATER RESOURCES 10 (NCERT) NOTES

 WATER RESOURCES 10 (NCERT) NOTES

Water Scarcity Demystified:

Abundance vs. Usable Freshwater:

Earth is mostly water, 

• but a small part is usable freshwater.

Freshwater comes from 

• surface run-off and 
• groundwater.

The Hydrological Cycle:

Water constantly cycles, renewing through 

• evaporation and 
• precipitation.

This cycle makes water a renewable resource.

Paradox of Water Scarcity:

• Despite water’s presence (three-fourth of the world) , regions face scarcity.
• 2025 prediction: 2 billion people in severe water scarcity.

WATER SCARCITY AND THE NEED FOR WATER CONSERVATION AND MANAGEMENT

Understanding Water Scarcity:

Abundance vs. Scarcity:

Water seems abundant and renewable.

• Hard to imagine water scarcity exist.

Scarcity Linked to Perception:

 Think of low rainfall (dry regions) or drought-prone places.

Example: 

• Deserts, like Rajasthan, come to mind.
• Women used 'matkas' for: 
• Collecting and 
• Storing water and 
• Travelling long distances to get water. 

Real Cause of Scarcity:

Water availability varies over: 

• space and 
• time, 

Why:

Due to the variations in 

• seasonal and 
• annual precipitation

  

Real Reasons for Scarcity:

• Over -exploitation, 
• Excessive use and 
• Unequal access to water among different social groups.

Where is then water scarcity likely to occur? 

Water - hydrological cycle - freshwater obtained directly from:

• Precipitation, 
• Surface runoff and 
• Groundwater.

Can water abundant areas still face water scarcity?

Yes: Examples:

• Many of our cities 

Quantitative aspects of water scarcity

Water Scarcity Causes and Solutions:

1. Population and Demand:

   - Growing population demands more water.

   - Unequal access adds to scarcity.

2. Water for Food Production:

• More people need more water for food.
• Irrigated agriculture requires water.

3. Over-Exploitation for Agriculture:

• Water overused for expanding farmland.
• Irrigation consumes the most water.

Solution:

Need for Change:

• Adapt agriculture for water scarcity.
• Develop drought-resistant crops.

Modernizing Agriculture:

• Shift to dry farming methods.
• Address water-intensive practices.

Impact of Agriculture and Industry on Water:

1. Farming Practices:

   - Farmers use wells and tube-wells for irrigation.

   - Overuse: 

• Falling groundwater levels 
• Adversely affecting water availability
• food security.

2. Industrial Growth Post-Independence:

India witnessed intensive: 

• Industrialisation and 
• Urbanisation, 
• Creating vast opportunities for us. 

3. Emergence of Big industries and MNCs are common.

• Strain on freshwater resources.

How?

Industry's Dual Demand:

• Heavy users of water, 
• Also require power to run them. 

4. Hydroelectric power

Much of this energy comes from 

• hydroelectric power. 

Today, in India hydroelectric power contributes approximately 22 percent of the total electricity produced. 

5. Urban Expansion:

• More cities, more people, more needs.
• Urban lifestyle adds to water and energy needs.
• Intensified Water Scarcity

Example: 

Housing societies or colonies in the cities

• own groundwater pumping devices

Results: 

• over-exploitation
• Water table depletion

Qualitative aspects of water scarcity. 

Beyond Quantity: Water Quality Matters:

Sufficient but Scarce:

• Even with enough water, areas can face scarcity.
• Why? Due to bad water quality.

Reasons for Bad Water Quality?

Water can be polluted by: 

• Domestic and industrial wastes, 
• chemicals, 
• pesticides and 
• fertilisers used in agriculture

Makes water hazardous to consume.

India's Jal Jeevan Mission

Government priority:

• To improve the quality of life and 
• Enhance ease of living especially rural people 

India's Jal Jeevan Mission 

prioritizes water quality.

Aim: 

• Piped potable water to every rural households.

Mission's Goal:

• Ensure safe water access
• 55 litres per capita per day 
• Regularly on a long-term basis by ensuring functionality of the tap water connections.

(Source: Economic Survey 2020–21, p.357)

Conclude:

Urgent need to conserve and manage our water resources, 

Why?

• To safeguard ourselves from health hazards, 
• To ensure food security, 
• Continuation of our livelihoods and productive activities and 
• To prevent degradation of our natural ecosystems. 
• Over exploitation and mismanagement of water resources impoverish this resource and 
• Cause ecological crisis - impacted our lives as well.

MULTI-PURPOSE RIVER PROJECTS AND INTEGRATED WATER RESOURCES MANAGEMENT

But, how do we conserve and manage water? 

From ancient times People construct: 

• sophisticated hydraulic structures like: 
• dams built of stone rubble, 
• reservoirs or lakes, 
• embankments and 
• canals for irrigation. 

Modern India continued building dams - our river basins.

Hydraulic Structures in Ancient India

• In the first century B.C., Sringaverapura near Allahabad had a sophisticated water harvesting system channelling the flood water of the river Ganga.

• During the time of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.

Evidence Of Sophisticated Irrigation Works have also been found in Kalinga, (Odisha), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra), etc.

• In the 11th Century, Bhopal Lake,one of the largest artificial lakes of its time was built.

• In the 14th Century, the tank in Hauz Khas, Delhi was constructed by Iltutmish for supplying water to Siri Fort area.

Source: Dying Wisdom, CSE, 1997.

What are dams and how do they help us in conserving and managing water? 

Dams traditionally built: 

• to impound rivers and 
• rainwater 

Used later to irrigate agricultural fields. 

Utility of Today dams: 

• Irrigation 
• Electricity generation, 
• water supply for domestic and industrial uses, 
• flood control, 
• recreation, 
• inland navigation and 
• fish breeding. 

⬇️⬇️⬇️⬇️⬇️

Dams referred - multi-purpose projects 

For example, 

For hydel power production and irrigation.

Sutluj-Beas river basin, 

The Bhakra – Nangal project 

For conservation of water with flood control.

The Hirakud project in the Mahanadi basin 

Jawaharlal Nehru - dams as the ‘temples of modern India’; 

launched after Independence - 

• Integrated water resources management 
• Vehicle for national development and progress, 
• overcoming the handicap of its colonial past. 
• Integrate development of agriculture and the village economy 
• Rapid industrialisation and growth of the urban economy.

Definition:

A dam is a barrier across flowing water that:

• obstructs, 
• directs or 
• retards the flow, 

often creating a reservoir, lake or impoundment. 

“Dam” refers to the reservoir rather than the structure. 

Characteristics of Dam:

Spillway or weir: 

over which or through which it is intended that water will flow either intermittently or continuously. 

Classification of Dam:

According to: 

• Structure, 
• Intended purpose or 
• Height. 

Dams classification (structure and the materials used)

• Timber dams, 
• Embankment dams or 
• Masonry dams, 

with several subtypes. 

Dams classification (height):

• large dams and 
• major dams or 
• alternatively as low dams, 
• medium height dams and 
• high dams.

Criticism of multi-purpose projects and large dams 

1. Altered Natural Flow:

   - Regulating and damming rivers disrupt their natural flow.

   - Causes poor sediment flow in the river.

2. Excessive Sedimentation:

   - Reservoirs lead to excessive sediment accumulation.

   - Result: Rockier stream beds and degraded habitats for aquatic life.

3. Aquatic Fauna Migration:

   - Dams fragment rivers, obstructing fish migration.

   - Migration challenges, especially for spawning fish.

4. Vegetation and Soil Submergence:

   - Reservoirs created on floodplains cover existing vegetation and soil.

   - Submerged vegetation decomposes gradually.

5. Environmental Movements:

  Examples: 

• 'Narmada Bachao Andolan' and 
• 'Tehri Dam Andolan'. 

Why?

Resistance due to: 

• The large-scale displacement of local communities. 

Local people lost: 

land, 

livelihood and 

Lost Limited control over resources for national benefit.

If locals don't benefit, who gains?

• The landowners and 
• large farmers, 
• industrialists and 
• Few urban centres. 

Effects of Irrigation and Water Management:

1. Cropping Pattern Changes:

Farmers shift to: 

• water-intensive and 
• commercial crops due to irrigation.

Ecological Consequences:

Ex: Soil salinization occurs due to excessive irrigation.

Social Consequences:

Social gap between the richer landowners and the landless poor. 

2. Conflicts within people:

Dams caused conflicts among people with different needs for the same water resources.

Ex:

Sabarmati-Basin Case:

(Agitation and riot situation)  in Gujarat over urban water supply priority during droughts.

3. Inter-state Water Disputes:

Conflicts arise over: 

• Sharing costs and 
• Benefits of multi-purpose projects.

Example::

Krishna-Godavari dispute 

Objections raised by Karnataka and Andhra Pradesh governments? 

Reason:

Diversion of more water at Koyna by the Maharashtra government for a multipurpose project. 

Problem:

Reduce downstream flow in their states with adverse consequences for: 

• Agriculture and 
• Industry.

source Page: 23 Narmada Bachao Andolan or Save Narmada Movement is a Non Governmental Organisation (NGO) that mobilised tribal people, farmers, environmentalists and human rights activists against the Sardar Sarovar Dam being built across the Narmada river in Gujarat. It originally focused on the environmental issues related to trees that would be submerged under the dam water. Recently it has re-focused the aim to enable poor citizens, especially the oustees (displaced people) to get full rehabilitation facilities from the government. People felt that their suffering would not be in vain... accepted the trauma of displacement believing in the promise of irrigated fields and plentiful harvests. So, often the survivors of Rihand told us that they accepted their sufferings as sacrifice for the sake of their nation. But now, after thirty bitter years of being adrift, their livelihood having even being more precarious, they keep asking: “Are we the only ones chosen to make sacrifices for the nation?” Source: S. Sharma, quoted in In the Belly of the River. Tribal conflicts over development in Narmada valley, A. Baviskar, 1995. Case-Based MCQs: 1. What is the main objective of the Narmada Bachao Andolan (Save Narmada Movement)?    a) Promoting tourism along the Narmada river    b) Advocating for increased industrial development    c) Mobilizing tribal people for religious activities    d) Opposing the construction of the Sardar Sarovar Dam    e) Supporting urban development projects 2. What was the original focus of the Narmada Bachao Andolan regarding the Sardar Sarovar Dam?    a) Ensuring proper irrigation management    b) Addressing concerns about river pollution    c) Securing land for industrial development    d) Highlighting issues related to submerged trees    e) Advocating for fishery rights 3. Why did the Narmada Bachao Andolan shift its focus recently?    a) To promote environmental conservation    b) To support industrial growth near the dam    c) To advocate for dam construction acceleration    d) To help displaced people get rehabilitation    e) To establish a religious sanctuary near the river 4. Who are some of the key stakeholders that the Narmada Bachao Andolan mobilized?    a) Urban professionals and entrepreneurs    b) Tourists interested in river exploration    c) Scientists studying aquatic life    d) Tribal people, farmers, and activists    e) Foreign investors in energy projects 5. What is the central dilemma faced by the displaced people, as mentioned in the passage?    a) The struggle to find enough food    b) The challenge of finding employment    c) The decision to sacrifice for the nation    d) The uncertainty of proper rehabilitation    e) The difficulty of obtaining education One-marker Questions: 1. What was the primary aim of the Narmada Bachao Andolan? 2. How did the Narmada Bachao Andolan shift its focus in recent times? 3. What was the significance of the Sardar Sarovar Dam in relation to the Narmada river? 4. Why did displaced people initially accept their suffering during the Narmada movement? 5. Besides environmental concerns, what were the other issues raised by the Narmada Bachao Andolan? Answers: Sure, here are the answers: Case-Based MCQs: 1. Answer: d) Opposing the construction of the Sardar Sarovar Dam 2. Answer: d) Highlighting issues related to submerged trees 3. Answer: d) To help displaced people get rehabilitation 4. Answer: d) Tribal people, farmers, and activists 5. Answer: d) The uncertainty of proper rehabilitation One-Sentence Questions: 1. Answer: The primary aim of the Narmada Bachao Andolan was to oppose the construction of the Sardar Sarovar Dam. 2. Answer: The Narmada Bachao Andolan recently shifted its focus to help displaced people get proper rehabilitation from the government. 3. Answer: The Sardar Sarovar Dam holds significance as a contentious project built across the Narmada river, leading to displacement and environmental concerns. 4. Answer: Displaced people initially accepted their suffering as a sacrifice for the nation's greater good. 5. Answer: Along with environmental concerns, the Narmada Bachao Andolan raised issues related to displacement, rehabilitation, and human rights.

Issues with Dam Projects:

1. Purpose Failure Objections

• Projects didn't meet their intended goals.

2. Flood Control Irony:

• Dams built for flood control triggered floods due to sedimentation in the reservoir. 

3. Ineffective Flood Control:

Large dams unsuccessful in controlling floods at the time of excessive rainfall. 

Ex: 2006 Maharashtra and Gujarat floods.

4. Flood Consequences:

• devastated life and 
• property 
• caused extensive soil erosion. 

Consequences of Sedimentation:

• Flood plains were deprived of silt, a natural fertiliser, 
• Problem of land degradation. 

Multi-purpose projects induced 

• Earthquakes, 
• Water-borne diseases and 
• Pests and pollution 

Due to excessive use of water.

RAINWATER HARVESTING

Why? Multi- purpose projects:

• Disadvantages and 
• Rising resistance 

Viable alternative

water harvesting system 

Why?

Because it is socio-economically and environmentally friendly.

Origin:

In ancient India, 

Sophisticated hydraulic structures: Showcase the 

extraordinary tradition of the water-harvesting system. 

In-depth knowledge of: 

• Rainfall and 
• Soil types 
• Techniques to harvest: 

• rainwater, 
• groundwater, 
• river water and 
• flood water 

According to: 

• local ecological conditions and 
• their water needs. 

In hill and mountainous regions, 

Diversion channels like: 

• the ‘guls’ or ‘kuls’ of the Western Himalayas used for agriculture. 

Bengal Flood Plains:

• People developed inundation channels to irrigate their fields. 

In arid and semi-arid regions, 

• Agricultural fields were converted into: 
• Rain fed storage structures 
• Hold water + moisten soil 

Ex; 

• ‘khadins’ in Jaisalmer and 
• ‘Johads’ in other parts of Rajasthan.

‘Rooftop rainwater harvesting’ -

• Particularly in Rajasthan
• Practiced to store drinking water

 

In the semi-arid and arid regions 

In Rajasthan, particularly in: 

• Bikaner, 
• Phalodi and 
• Barmer, 

All the houses for storing drinking water built:

• Underground tanks or 
• Tankas for storing drinking water. 

The tanks - large as a big room; 

Ex:

One household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres long and 2.44 metres wide. 

How Tankas Water Harvesting Works:

The tankas part of - rooftop rainwater harvesting system 

• Built inside the main house or the courtyard. 

Connected to the sloping roofs of the houses through a pipe. 

Rain falling on the rooftops would travel down the pipe and was stored in these underground ‘tankas’. 

The first spell of rain was usually not collected as this would clean the roofs and the pipes. 

The rainwater from the subsequent showers was then collected.

The rainwater can be stored in the tankas till the next rainfall making it an extremely reliable source of: 

• drinking water (in Summers)
• when all other sources are dried up,

Rainwater, or palar pani, as commonly referred to in these parts, is considered the purest form of natural water. 

Many houses constructed underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool.

In western Rajasthan, 

Rooftop rainwater harvesting declines: 

• Due to available canal water. 
• Some homes retain tankas for better-tasting water.

Rooftop rainwater harvesting in rural and urban India, 

• Used to store and conserve water. 

Ex: In a remote Mysuru village, Gendathur, rainwater harvesting on rooftops fulfills villagers' water needs. 

Read: 

See Fig. 3.6 for a better understanding of the rooftop rainwater harvesting system which is adapted here. Gendathur receives an annual precipitation of 1,000 mm, and with 80 per cent of collection efficiency and of about 10 fillings, every house can collect and use about 50,000 litres of water annually. From the 200 houses, the net amount of rainwater harvested annually amounts to 1,00,000 litres.