Class 10 Social Science Notes Chapter 3 (Water resources) – Contempory India Book
Alright class, let's begin our detailed study of Chapter 3: Water Resources from your 'Contemporary India II' textbook. This chapter is vital not just for your understanding of geography but also holds significant weight for various government examinations. Pay close attention to the facts, concepts, and examples.
Chapter 3: Water Resources - Detailed Notes for Exam Preparation
1. Introduction: Water - A Vital Resource
- Three-fourths of the earth's surface is covered with water, but only a small proportion accounts for freshwater fit for use.
- Sources of freshwater: Surface runoff (rivers, lakes) and groundwater (continuously renewed through the hydrological cycle).
- Water is a renewable resource, yet its scarcity is a major global issue.
2. Water Scarcity and the Need for Water Conservation and Management
- Water Scarcity: Shortage of water. It can be:
- Quantitative Scarcity: Insufficient physical availability of water in a region compared to its demand.
- Qualitative Scarcity: Water is available but is polluted or contaminated, making it unfit for human consumption or other uses.
- Causes of Water Scarcity:
- Growing Population: Increased demand for domestic use, food production (irrigation).
- Commercial Agriculture: Water-intensive crops, over-exploitation of groundwater via wells and tubewells by farmers.
- Industrialisation: Heavy water usage, discharge of untreated effluents polluting water bodies.
- Urbanisation: High population density in cities, increased water and energy requirements, over-exploitation of groundwater resources.
- Unequal Access: Variation in rainfall, over-exploitation in certain areas leads to unequal distribution among different social groups.
- Pollution: Domestic waste, industrial effluents, pesticides, fertilisers contaminate surface and groundwater.
- Need for Conservation and Management:
- To safeguard ourselves from health hazards.
- To ensure food security (agriculture depends heavily on water).
- To prevent degradation of our natural ecosystems.
- To ensure sustainable development and prevent ecological crises.
3. Historical Context: Water Conservation Structures
- India has a long history of sophisticated hydraulic structures:
- 1st Century B.C.: Sringaverapura near Allahabad had water harvesting systems channeling flood water of the Ganga.
- Chandragupta Maurya's time: Dams, lakes, and irrigation systems were extensively built.
- Kalinga (Odisha), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra): Evidence of sophisticated irrigation works.
- 11th Century: Bhopal Lake, one of the largest artificial lakes of its time.
- 14th Century: Hauz Khas tank in Delhi built by Iltutmish for supplying water to Siri Fort area.
4. Multi-purpose River Projects and Integrated Water Resources Management
- Dams: Barriers across flowing water that obstruct, direct, or retard the flow, often creating a reservoir, lake, or impoundment. Traditionally built to impound river and rainwater for later irrigation.
- Multi-purpose Projects: Modern dams built for integrated water resource management, serving several purposes simultaneously:
- Irrigation
- Electricity generation (hydropower)
- Water supply for domestic and industrial uses
- Flood control
- Recreation
- Inland navigation
- Fish breeding
- Jawaharlal Nehru: Proclaimed dams as the 'temples of modern India' as they were seen as vehicles for national development, agriculture, and village economy growth integrated with rapid industrialisation and urban growth.
- Criticisms and Disadvantages of Dams:
- Impact on River Ecology: Affect natural flow, cause excessive sedimentation at the reservoir bottom, resulting in rockier stream beds and poorer habitat for aquatic life. Affect migration and spawning of aquatic fauna.
- Submergence: Reservoirs submerge existing vegetation and soil, leading to decomposition over time.
- Displacement: Large-scale displacement of local communities, loss of livelihoods and culture, inadequate rehabilitation.
- Ecological Damage: Deforestation, loss of biodiversity.
- Induced Seismicity: Potential to trigger earthquakes in seismically sensitive zones.
- Water-borne Diseases & Pests: Reservoirs can become breeding grounds.
- Salinisation: Excessive irrigation in command areas can lead to soil salinisation.
- Inter-state Water Disputes: Sharing costs and benefits often leads to conflicts (e.g., Krishna-Godavari dispute).
- Failure in Objectives: Dams built for flood control have sometimes triggered floods due to sediment deposition in reservoirs and heavy rainfall releases. Example: Floods in Maharashtra and Gujarat (2006).
- Social Movements Against Dams:
- Narmada Bachao Andolan (NBA): A movement against the Sardar Sarovar Dam on the Narmada River. Initially focused on environmental issues, later on rehabilitation of displaced people.
- Tehri Dam Andolan: Against the Tehri Dam on the Bhagirathi River in Uttarakhand.
5. Rainwater Harvesting
- A technique of collection and storage of rainwater for reuse on-site, rather than allowing it to run off.
- Seen as a viable alternative, both socio-economically and environmentally, to large multi-purpose projects.
- Traditional Rainwater Harvesting Methods in India:
- 'Guls' or 'Kuls': Diversion channels built in hilly/mountainous regions (Western Himalayas) for agriculture.
- Rooftop Rainwater Harvesting: Common in semi-arid/arid regions (Rajasthan) and also in areas with sufficient rain but needing storage (Shillong, Meghalaya).
- Inundation Channels: Used in flood plains (e.g., Bengal) to irrigate fields.
- 'Khadins' (Jaisalmer) and 'Johads' (other parts of Rajasthan): Rain-fed storage structures allowing water to stand and moisten the soil for agriculture.
- 'Tankas' / 'Tanks': Underground tanks/cisterns for storing drinking water, particularly in arid/semi-arid Rajasthan (Bikaner, Phalodi, Barmer). Often connected to sloping roofs. Rainwater is called 'Palar Pani' in these regions.
- Bamboo Drip Irrigation System: Practiced in Meghalaya. Bamboo pipes transport stream/spring water over hundreds of meters, reducing 18-20 litres per minute entering the pipe system to 20-80 drops per minute at the plant site.
- Modern Relevance:
- Gendathur Village (Mysuru, Karnataka): Households have installed rooftop rainwater harvesting systems. Has the distinction of being rich in rainwater.
- Tamil Nadu: The first and only state in India which has made rooftop rainwater harvesting structures compulsory for all houses across the state. Legal provisions exist to punish defaulters.
- Shillong: Faces acute water shortage despite being near Cherrapunji/Mawsynram (highest rainfall). Rooftop harvesting is practiced by nearly 15-25% of households.
6. Conclusion
- Water scarcity is a significant challenge driven by both natural factors and human activities.
- While multi-purpose projects have benefits, they also have considerable social and environmental costs.
- Rainwater harvesting offers a decentralized, community-managed, and environmentally sound approach to water conservation.
- Integrated water resource management considering all sources and involving local communities is crucial for sustainable development.
Multiple Choice Questions (MCQs) for Practice:
-
Which one of the following is NOT a major cause of water scarcity?
(a) Growing Population
(b) Industrialisation
(c) Afforestation
(d) Unequal access to water resources -
Who proclaimed dams as the 'temples of modern India'?
(a) Mahatma Gandhi
(b) Jawaharlal Nehru
(c) Sardar Vallabhbhai Patel
(d) B.R. Ambedkar -
The Narmada Bachao Andolan (NBA) is primarily associated with which type of project?
(a) Thermal Power Project
(b) Multi-purpose Dam Project
(c) Nuclear Power Project
(d) Rainwater Harvesting Project -
'Guls' or 'Kuls', traditional water harvesting systems, are commonly found in which region of India?
(a) Deccan Plateau
(b) Western Himalayas
(c) Flood plains of Bengal
(d) Arid regions of Rajasthan -
Which state in India has made rooftop rainwater harvesting structures compulsory for all houses?
(a) Kerala
(b) Karnataka
(c) Tamil Nadu
(d) Rajasthan -
The primary disadvantage of multi-purpose river projects related to river ecology is:
(a) Increased fish breeding
(b) Enhanced natural flow of the river
(c) Excessive sedimentation and impact on aquatic life
(d) Reduced risk of water-borne diseases -
'Tankas' are traditional water storage structures predominantly found in which state?
(a) Gujarat
(b) Maharashtra
(c) Rajasthan
(d) Madhya Pradesh -
Which of the following is NOT a purpose served by multi-purpose river valley projects?
(a) Irrigation
(b) Electricity generation
(c) Increasing groundwater levels naturally
(d) Flood control -
The bamboo drip irrigation system is prevalent in which Indian state?
(a) Assam
(b) Meghalaya
(c) Mizoram
(d) Arunachal Pradesh -
Qualitative aspect of water scarcity refers to:
(a) Shortage of water quantity in a region
(b) Water pollution making it unfit for use
(c) Unequal distribution of water among users
(d) Over-exploitation of groundwater
Answer Key for MCQs:
- (c) Afforestation (planting trees generally helps conserve water)
- (b) Jawaharlal Nehru
- (b) Multi-purpose Dam Project (specifically Sardar Sarovar Dam)
- (b) Western Himalayas
- (c) Tamil Nadu
- (c) Excessive sedimentation and impact on aquatic life
- (c) Rajasthan
- (c) Increasing groundwater levels naturally (Dams primarily manage surface water; rainwater harvesting helps recharge groundwater)
- (b) Meghalaya
- (b) Water pollution making it unfit for use
Study these notes thoroughly. Remember the specific examples, names, and locations as they are often targeted in objective-type questions in government exams. Good luck!