Key Concepts: Water Resources | Social Studies (SST) Class 10 PDF Download

1. Earth's Water Composition

• 71% of Earth’s surface is covered with water.
• Of this: 97% is saltwater, unsuitable for direct human use.
• Only 3% is freshwater, available in limited forms like glaciers, groundwater, and surface water.

2. Sources and Cycle of Freshwater

• Freshwater comes primarily from surface runoff and groundwater—both part of the hydrological cycle.

• The hydrological cycle is a continuous process: Water evaporates from oceans and lakes. Forms clouds, falls as precipitation, and returns to surface or underground sources. This makes water a renewable resource.
  
  Hydrological Cycle

3. Water Scarcity: Causes and Challenges

Despite abundance, water scarcity persists due to:

• Unequal access, overuse, and pollution rather than just natural shortages.
• Regions like Rajasthan experience both low rainfall and overexploitation.
• Growing population and industrialization have amplified demand for water.

Key Issues:

• Overuse in agriculture, especially irrigated farming.
• High water demand from industries and urban areas.
• Pollution from domestic and industrial waste, pesticides, and fertilizers.
• Quality issues make even available water unsafe for consumption.

4. Government Initiatives

Jal Jeevan Mission (JJM)

• Aims to provide 55 litres/person/day of clean piped water to every rural household.
• Focuses on: Quality and regular supply of water. Reducing health hazards from polluted water.

Pradhan Mantri Krishi Sinchayee Yojana (PMKSY)

• Improve irrigation infrastructure.

• Promote water-use efficiency ("more crop per drop").

• Encourage sustainable farming and water-saving technologies.

5. Traditional & Modern Water Management Systems

A. Ancient Hydraulic Structures

Historical records show water systems like:

• Dams, lakes, and canals in Mauryan and Sultanate periods.
• Bhopal Lake, Hauz Khas tank, and systems in Kalinga and Kolhapur.

B. Dams as Multi-Purpose Projects

Dams serve for:

• Irrigation
• Hydroelectric power
• Water supply (domestic and industrial)
• Flood control, navigation, and recreation

Examples:

• Bhakra–Nangal Project: irrigation + electricity
• Hirakud Dam: flood control + conservation

Disadvantages of Dams:

• Sedimentation, disrupted aquatic life, displacement of people.
• Ecological imbalance from commercial crops.
• Social disputes and inter-state conflicts.
• Sometimes fail in flood control during extreme rainfall.

C. Cropping Pattern Shift

Irrigation encourages water-intensive commercial crops.

Leads to:

• Soil salinisation
• Social inequality (rich landowners vs. landless poor)
• Increased water stress

6. Water Conservation Techniques

A. Rainwater Harvesting (RWH)

• Involves collecting rainwater from rooftops or other surfaces.
• Stored in underground tanks, cisterns, or aquifers.
• Effective in both urban and arid rural areas.

Case Studies:

• Rajasthan: Underground tankas used to store drinking water.
• Shillong: Despite heavy rainfall nearby, faces shortages—houses use rooftop RWH.
• Gendathur (Karnataka): Community harvesting yields 1,00,000 litres annually.
• Tamil Nadu: First state to make RWH legally mandatory in all homes.

B. Bamboo Drip Irrigation (Meghalaya)

• Traditional system using bamboo pipes to channel spring water to crops.
• Water-saving and eco-friendly; supplies precise water drops directly to plant roots.

Conclusion

While Earth's water seems abundant, freshwater availability is limited and threatened by human activities. Sustainable management through:

• Government initiatives
• Technological solutions
• Traditional practices
  is essential to ensure equitable and long-term access to water for all.