NCERT Solutions For Class 10 Geography: Water Resources

Summary of the Chapter

The chapter "Water Resources" discusses the importance of water as a vital resource and the challenges associated with its availability and management. It begins by highlighting the growing water scarcity in India and worldwide, despite three-fourths of the earth's surface being covered with water. The chapter explains the reasons for water scarcity, including over-exploitation, unequal access, and growing population.

The chapter covers various methods of water conservation and management, including traditional methods like rooftop rainwater harvesting and modern techniques like dams and multi-purpose projects. It discusses the advantages and disadvantages of large dams and the controversies surrounding them. The chapter also emphasizes the importance of rainwater harvesting and watershed management as sustainable solutions to water scarcity. Finally, it discusses the role of individuals and communities in water conservation.

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NCERT Textbook Questions and Answers

Exercises (Page 33)

Question 1: Multiple choice questions: (i) Based on the information given below, classify each of the situations as 'suffering from water scarcity' or 'not suffering from water scarcity'. (a) Region with high annual rainfall. (b) Region having high annual rainfall and large population. (c) Region having high annual rainfall but water is highly polluted. (d) Region having low rainfall and low population.

(ii) Which one of the following statements is not an argument in favour of multi-purpose river projects?
(a) Multi-purpose projects bring water to those areas which suffer from water scarcity.
(b) Multi-purpose projects by regulating water flow help to control floods.
(c) Multi-purpose projects lead to large scale displacements and loss of livelihood.
(d) Multi-purpose projects generate electricity for our industries and our homes.

(iii) Here are some false statements. Identify the mistakes and rewrite them correctly.
(a) Multiplying urban centres with large and dense populations and urban lifestyles have helped in proper utilisation of water resources.
(b) Regulating and damming of rivers does not affect the river's natural flow and its sediment flow.
(c) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to water supply in urban areas, particularly during droughts.

Answer-
(i) (a) Not suffering from water scarcity
(b) Suffering from water scarcity
(c) Suffering from water scarcity
(d) Not suffering from water scarcity

(ii) (c) Multi-purpose projects lead to large scale displacements and loss of livelihood.

(iii) (a) Corrected: Multiplying urban centres with large and dense populations and urban lifestyles have caused over-exploitation of water resources.
(b) Corrected: Regulating and damming of rivers affects the river's natural flow and its sediment flow.
(c) Corrected: In Gujarat, the Sabarmati basin farmers were agitated when higher priority was given to water supply in urban areas, particularly during droughts.

Question 2: Answer the following questions in about 30 words:
(i) Explain how water becomes a renewable resource.
(ii) What is water scarcity and what are its main causes?
(iii) Compare the advantages and disadvantages of multi-purpose river projects.

Answer-
(i) Water becomes a renewable resource through the hydrological cycle where water circulates continuously between oceans, atmosphere, and land through processes like evaporation, condensation, and precipitation. This natural process ensures that water is constantly renewed and recycled.

(ii) Water scarcity means shortage of water. Its main causes include:

• Over-exploitation of water resources
• Growing population
• Unequal access to water among different social groups
• Industrialization and urbanization
• Pollution of water bodies

(iii) Advantages of multi-purpose river projects:

• Irrigation for agriculture
• Electricity generation
• Flood control
• Water supply for domestic and industrial use

Disadvantages:

• Displacement of local communities
• Environmental degradation
• Social conflicts
• Loss of biodiversity

Question 3: Answer the following questions in about 120 words:
(i) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
(ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.

Answer-
(i) Rainwater harvesting in semi-arid regions of Rajasthan:

• Khadins: In Jaisalmer, long earthen embankments built across lower hill slopes to collect rainwater
• Tanks: Underground tanks or tankas for drinking water in Bikaner, Phalodi, and Barmer
• Rooftop harvesting: Rainwater from rooftops is collected and stored in underground tanks
• Johads: Small earthen check dams that capture and conserve rainwater
• Traditional methods: People built diversion channels like 'guls' or 'kuls' in Western Himalayas

(ii) Modern adaptations of traditional rainwater harvesting:

• Rooftop harvesting: Modern systems with filtration units and storage tanks
• Watershed management: Scientific approach to conserve water through check dams, percolation tanks, and afforestation
• Recharge shafts: Directing rainwater into ground to recharge aquifers
• Farm ponds: Constructing ponds to store rainwater for irrigation
• Drip irrigation: Efficient water use in agriculture
• Government initiatives: Programs like 'Jal Shakti Abhiyan' promoting water conservation
• Urban planning: Incorporating rainwater harvesting in building designs

Question 4: Map Skills: On an outline map of India, mark and label the following:

• Salal Dam
• Bhakra Nangal Dam
• Tehri Dam
• Hirakud Dam
• Rana Pratap Sagar Dam
• Sardar Sarovar Dam
• Nagarjuna Sagar Dam
• Tungabhadra Dam

Answer-
[Students should mark these on a map of India:
Salal Dam - Jammu and Kashmir (Chenab River)
Bhakra Nangal Dam - Himachal Pradesh (Sutlej River)
Tehri Dam - Uttarakhand (Bhagirathi River)
Hirakud Dam - Odisha (Mahanadi River)
Rana Pratap Sagar Dam - Rajasthan (Chambal River)
Sardar Sarovar Dam - Gujarat (Narmada River)
Nagarjuna Sagar Dam - Telangana/Andhra Pradesh (Krishna River)
Tungabhadra Dam - Karnataka/Andhra Pradesh (Tungabhadra River)]

Additional Questions

Question 5: What are the main causes of water scarcity in India?

Answer-
Main causes of water scarcity in India:

1.Over-exploitation: Excessive use of groundwater for agriculture and industry

2.Growing population: Increasing demand for domestic, agricultural, and industrial use

3.Unequal distribution: Some regions receive heavy rainfall while others are arid

4.Pollution: Industrial and domestic waste polluting water bodies

5.Urbanization: Rapid urban growth increasing water demand

6.Inefficient use: Wastage of water in agriculture and domestic use

7.Climate change: Changing rainfall patterns affecting water availability

8.Deforestation: Reduced groundwater recharge due to loss of forests

9.Agricultural practices: Water-intensive crops in water-scarce regions

Question 6: Compare traditional and modern water harvesting systems.

Answer-

Question 7: What are multi-purpose river projects? Discuss their advantages and disadvantages.

Answer-
Multi-purpose river projects are large dams that serve multiple purposes like irrigation, electricity generation, flood control, and water supply.

Advantages:
1.Irrigation: Provide water for agriculture in drought-prone areas
2.Hydroelectricity: Generate electricity for domestic and industrial use
3.Flood control: Regulate river flow to prevent floods
4.Water supply: Provide drinking water to cities and towns
5.Recreation: Create opportunities for tourism and water sports
6.Inland navigation: Improve water transport facilities
7.Fisheries: Support fish breeding and aquaculture

Disadvantages:
1.Displacement: Force large-scale relocation of local communities
2.Environmental impact: Submerge forests and affect biodiversity
3.Social conflicts: Create disputes over water sharing
4.Sedimentation: Reduce soil fertility in downstream areas
5.Earthquake risk: Can trigger earthquakes in seismic zones
6.Maintenance cost: Require high maintenance expenditure
7.Waterlogging: Cause waterlogging and salinity in command areas

Question 8: Explain the various methods of rainwater harvesting.

Answer-
Various methods of rainwater harvesting:

1.Rooftop harvesting: Collecting rainwater from building roofs and storing it in tanks

2.Surface runoff harvesting: Collecting rainwater from surfaces like roads and parks

3.Recharge pits: Directing rainwater into ground to recharge aquifers

4.Perculation tanks: Allowing rainwater to percolate into ground through specially designed tanks

5.Check dams: Small barriers built across streams to store water

6.Farm ponds: Constructing ponds in agricultural fields to store rainwater

7.Watershed management: Integrated approach to conserve water through various structures

8.Traditional systems: Reviving traditional methods like khadins, tankas, and johads

Question 9: What is watershed management? Why is it important?

Answer-
Watershed management is the process of creating and implementing plans, programs, and projects to sustain and enhance watershed functions that affect the plant, animal, and human communities within a watershed boundary.

Importance of watershed management:
1.Water conservation: Helps in conserving water resources
2.Soil conservation: Prevents soil erosion and maintains soil fertility
3.Groundwater recharge: Increases groundwater level
4.Biodiversity conservation: Protects flora and fauna
5.Sustainable agriculture: Supports agricultural productivity
6.Flood control: Reduces flood risks
7.Community development: Involves local communities in resource management
8.Climate resilience: Helps communities adapt to climate change

Question 10: Describe the traditional water harvesting systems in different regions of India.

Answer-

Question 11: What are the negative impacts of over-exploitation of groundwater?

Answer-
Negative impacts of over-exploitation of groundwater:

1.Depleting water table: Groundwater levels are falling rapidly

2.Land subsidence: Ground sinking due to empty aquifers

3.Saltwater intrusion: In coastal areas, seawater enters freshwater aquifers

4.Reduced stream flow: Less water available for rivers and streams

5.Water quality deterioration: Concentration of pollutants increases

6.Increased energy cost: More energy required to pump water from greater depths

7.Agricultural impacts: Affects crop production and food security

8.Ecological damage: Harms ecosystems dependent on groundwater

9.Social conflicts: Disputes over water access among users

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Important Keywords from the Chapter

• Water Scarcity: Shortage of water due to unequal access or overuse
• Multi-purpose Projects: Large dams that serve multiple purposes
• Rainwater Harvesting: Collection and storage of rainwater for future use
• Watershed Management: Scientific conservation of water within a geographical area
• Groundwater: Water found underground in soil pores and rock formations
• Aquifer: Underground layer of water-bearing permeable rock
• Drip Irrigation: Method of irrigation that saves water by dripping slowly to roots
• Hydrological Cycle: Continuous movement of water between earth and atmosphere
• Water Conservation: Practice of using water efficiently to reduce waste
• Check Dam: Small barrier built across a stream to store water
• Percolation Tank: Artificial reservoir to recharge groundwater
• Khadin: Traditional rainwater harvesting system in Rajasthan
• Tanka: Underground tank for storing drinking water
• Johad: Small earthen check dam that captures rainwater
• Bawri: Traditional stepwell used for water storage
• Water Table: Upper level of underground water
• Dam: Barrier constructed to hold back water and raise its level
• Reservoir: Artificial lake where water is stored
• Water Pollution: Contamination of water bodies with harmful substances
• Sustainable Development: Development that meets present needs without compromising future generations