CBSE Class 10 SST: Water Resources — Geography Notes 2026

Water Scarcity in India

• India has 4% of world's freshwater but 18% of world's population; per capita water availability declining
• Water stress: <1,700 m³/person/year; water scarcity: <1,000 m³/person/year; India projected to reach scarcity level by 2025
• Reasons: population growth, urbanisation, industrial demand, groundwater depletion, pollution

Multipurpose River Projects

• Dams serve multiple purposes: irrigation, hydropower, flood control, drinking water, fisheries, recreation
• Bhakra Nangal (Sutlej, 1963): hydropower + irrigation for Punjab, Haryana; 'temple of modern India' (Nehru)
• Sardar Sarovar Dam (Narmada): provides water to Gujarat, Rajasthan, MP; displaced 100,000+ people; NBA protest

Problems with Multipurpose Projects

• Displacement: large dams displace millions; most are tribal people; inadequate rehabilitation
• Ecological damage: disrupts fish migration, reduces silt deposition downstream, alters river ecosystem
• Salinity: irrigation without drainage causes waterlogging and salinisation of farmland

Rainwater Harvesting in India

• Traditional systems: johads (Rajasthan) — earthen check dams; khadins (Jaisalmer) — farm ponds
• Bamboo drip irrigation (Meghalaya): hollow bamboo pipes divert stream water to fields
• Urban RWH: mandatory in many cities; roof-top collection → sump → groundwater recharge; Chennai model

Groundwater Over-Extraction

• Punjab, Haryana, UP, Rajasthan: extensive tube well irrigation → falling water table
• Black zone districts: water table declined 100+ metres; tube wells going deeper every year; power subsidy encourages over-extraction
• Solution: micro-irrigation (drip, sprinkler) reduces water use by 40–50%; PM Krishi Sinchayee Yojana

Water Pollution

• Ganga and Yamuna: most polluted rivers; BOD (Biochemical Oxygen Demand) far above safe levels in industrial stretches
• Point source pollution: factories, sewage plants; non-point source: agricultural runoff
• Namami Gange Programme (2014): integrated conservation; 20,000 MLD sewage treatment capacity being created

CBSE Exam Tips

• Water Resources: map-based questions common; mark major dams (Bhakra, Sardar Sarovar, Hirakud, Tehri)
• Multipurpose projects: advantages and disadvantages table; 4 marks
• Rainwater harvesting: traditional methods of any two regions; explain one method in detail