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Water Resources – Class 10 Social Science Chapter 3 Notes & NCERT PDF

Class 10Social ScienceChapter 3NCERT book: Contemporary India II (Geography) - Social Science Class 10

Notes and a simple summary of Chapter 3 of the NCERT Class 10 Social Science book, with the official chapter PDF, flashcards, an MCQ quiz and an AI tutor for your doubts.

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Chapter 3: Water Resources (Geography)

Introduction

Three-fourths of the earth's surface is covered with water, but only a small proportion is freshwater that can be used. Freshwater comes mainly from surface run-off and groundwater, continually renewed and recharged through the hydrological cycle — which makes water a renewable resource. So why do regions suffer water scarcity, and why is it predicted that by 2025 nearly two billion people will live in absolute water scarcity? This chapter answers that question and explores dams, multi-purpose projects and rainwater harvesting.

Key Concepts

Water scarcity and its causes

Availability varies over space and time due to seasonal and annual precipitation, but water scarcity in most cases is caused by:

  • over-exploitation,
  • excessive use, and
  • unequal access to water among different social groups.

    • Specific reasons given in the chapter:

  • Large and growing population needs more water for domestic use and to produce more food; water is over-exploited to expand irrigated areas for dry-season agriculture. Irrigated agriculture is the largest consumer of water.
  • Farmers' own wells and tube-wells can lead to falling groundwater levels, affecting water availability and food security.
  • Industrialisation and urbanisation — industries are heavy users of water and need power, much of it from hydroelectricity; urban housing societies pump their own groundwater.
  • Bad quality of water — even where water is ample, it may be polluted by domestic and industrial wastes, chemicals, pesticides and fertilisers.

    • Government initiatives mentioned:

  • Atal Bhujal Yojana (Atal Jal) — in 8220 water-stressed gram panchayats of 229 blocks in 80 districts of seven states (Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan, Uttar Pradesh), which account for about 37 per cent of India's water-stressed blocks; aims at behavioural change from consumption to conservation.
  • Jal Jeevan Mission (JJM) — assured supply of potable piped water to every rural household at 55 litres per capita per day.

    • Ancient hydraulic structures

  • First century B.C. — Sringaverapura near Allahabad channelled the flood water of the Ganga.
  • Chandragupta Maurya's time — dams, lakes and irrigation systems extensively built.
  • Irrigation works at Kalinga (Odisha), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra).
  • 11th century — Bhopal Lake, one of the largest artificial lakes of its time.
  • 13th–14th century — the tank in Hauz Khas, Delhi, built by Allauddin Khilji to supply water to Siri Fort.

    • Dams and multi-purpose river projects

    A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment. Most dams have a spillway or weir.

    Dams are classified by structure/materials (timber, embankment, masonry) and by height (large and major, or low, medium and high).

    Dams today serve irrigation, electricity generation, domestic and industrial water supply, flood control, recreation, inland navigation and fish breeding — hence multi-purpose projects. Examples:

  • Bhakra–Nangal project (Sutlej–Beas basin) — hydel power and irrigation.
  • Hirakud project (Mahanadi basin) — water conservation with flood control.
  • Sardar Sarovar Dam (Narmada, Gujarat) — covers Maharashtra, Madhya Pradesh, Gujarat and Rajasthan; irrigation for 18.45 lakh hectares covering 3112 villages in 15 districts of Gujarat, 2,46,000 hectares in Barmer and Jalore (Rajasthan) and 37,500 hectares in Maharashtra's tribal hilly tract.

    • Jawaharlal Nehru called dams the "temples of modern India", as they would integrate agriculture and the village economy with rapid industrialisation and urban growth. The Bhadu song of the Damodar valley calls the Damodar the "river of sorrow" for its floods.

    Opposition to large dams

  • Regulating rivers causes poor sediment flow and excessive sedimentation in reservoirs, rockier stream beds and poorer aquatic habitats.
  • Dams fragment rivers, making migration difficult for aquatic fauna, especially for spawning.
  • Reservoirs submerge vegetation and soil.
  • Dams built to control floods have triggered floods due to sedimentation; floodplains are deprived of silt, a natural fertiliser.
  • Multi-purpose projects have induced earthquakes, water-borne diseases, pests and pollution.
  • Irrigation shifted farmers to water-intensive commercial crops, causing salinisation.
  • Inter-state disputes — e.g., the Krishna–Godavari dispute, over objections by Karnataka and Andhra Pradesh to Maharashtra diverting more water at Koyna.

    • Pradhan Mantri Krishi Sinchayee Yojana aims at protective irrigation for all farms: har khet ko pani and per drop more crop.

    Rainwater harvesting

    Traditional techniques suited to local conditions:

  • Guls or kuls — diversion channels in the Western Himalayas (a kul leads to a village tank, as in Kaza village).
  • Rooftop rainwater harvesting — especially in Rajasthan, for drinking water.
  • Inundation channels — flood plains of Bengal.
  • Khadins (Jaisalmer) and johads (other parts of Rajasthan) — rain-fed storage structures in fields.
  • Tankas — underground tanks in Bikaner, Phalodi and Barmer, connected to sloping roofs by pipes. The first spell of rain is not collected, as it cleans the roof and pipes. One household in Phalodi had a tank 6.1 m deep, 4.27 m long and 2.44 m wide. Rainwater, called palar pani, is considered the purest form of natural water; rooms beside the tanka stay cool.
  • The practice is declining in western Rajasthan because of the perennial Indira Gandhi Canal, though some keep tankas as they dislike the taste of tap water.

    • Modern adaptations:

  • Gendathur (Mysuru, Karnataka) — nearly 200 households harvest rooftop rainwater; annual precipitation 1,000 mm; with 80 per cent collection efficiency, each house can collect about 50,000 litres a year.
  • Shillong, Meghalaya — faces water shortage although Cherrapunjee and Mawsynram, 55 km away, get the world's highest rainfall; nearly every household has rooftop harvesting, meeting about 15–25 per cent of household needs.
  • Tamil Nadu — the first state to make rooftop rainwater harvesting compulsory for all houses, with legal provisions to punish defaulters.
  • Bamboo drip irrigation (Meghalaya) — a 200-year-old system; about 18–20 litres of water enter the bamboo pipes and reduce to 20–80 drops per minute at the plant.

    • Map Work

    Locate on the map of India: Sardar Sarovar (Narmada), Bhakra–Nangal (Sutlej), Hirakud (Mahanadi), and the rivers and dams shown in the chapter's map.

    Board Exam Focus

  • MCQ: which statement is not an argument for multi-purpose projects — "lead to large scale displacements and loss of livelihood".
  • Correct the false statement: urban growth has not helped proper use of water; damming does affect natural flow and sediment; rooftop harvesting in Rajasthan is declining because of the Indira Gandhi Canal.
  • 3-mark: how water is renewable; what water scarcity is and its causes; advantages vs disadvantages of multi-purpose projects.
  • 5-mark: rainwater harvesting in semi-arid Rajasthan (tankas, khadins, johads); modern adaptations (Gendathur, Shillong, Tamil Nadu, bamboo drip).

    • Key Terms

  • Hydrological cycle (जल चक्र)
  • Water scarcity (जल दुर्लभता)
  • Groundwater (भौम जल)
  • Multi-purpose project (बहुउद्देशीय परियोजना)
  • Dam (बाँध)
  • Spillway (उत्प्लव मार्ग)
  • Sedimentation (अवसादन)
  • Salinisation (लवणीकरण)
  • Rainwater harvesting (वर्षा जल संग्रहण)
  • Tanka (टाँका)
  • Khadin / Johad (खडीन / जोहड़)
  • Guls or kuls (गुल / कुल)
  • Palar pani (पालर पानी)

    • Connect to Today

    Jal Jeevan Mission, Atal Jal and mandatory rooftop harvesting show a shift from big dams alone toward community and household conservation.

    Common Mistakes

  • Saying scarcity is only about low rainfall — the book stresses over-exploitation, excessive use and unequal access, and also poor water quality.
  • Writing that rooftop harvesting is growing in western Rajasthan — it is declining because of the Indira Gandhi Canal.
  • Confusing khadins (Jaisalmer) with kuls (Western Himalayas).
  • Mixing up projects and basins: Bhakra–Nangal is Sutlej–Beas; Hirakud is Mahanadi; Sardar Sarovar is Narmada.

    • 💡 Key Learning Points

    • ✓Explain why water is a renewable resource and why scarcity still occurs: over-exploitation, excessive use, unequal access and poor quality.
    • ✓Describe ancient hydraulic structures in India and the idea of dams as 'temples of modern India'.
    • ✓Evaluate the advantages and disadvantages of multi-purpose river projects with named examples.
    • ✓Describe traditional rainwater harvesting methods: guls/kuls, inundation channels, khadins, johads and tankas.
    • ✓Give modern examples of water harvesting: Gendathur, Shillong, Tamil Nadu's law and Meghalaya's bamboo drip irrigation.

    👨‍🏫 Teaching Tips

    • →Begin with the puzzle in the text: if three-fourths of the world is water and water is renewable, why is there scarcity? Collect answers before teaching.
    • →Build a 'for and against' debate on large dams using the chapter's arguments and the Sardar Sarovar figures.
    • →Draw the tanka system (roof → pipe → underground tank) on the board and explain why the first spell of rain is not collected.
    • →Mark Bhakra–Nangal, Hirakud and Sardar Sarovar on the map with their rivers.
    • →Ask students to write the short water-conservation proposal suggested in the chapter, based on their own home.
    • →Survey the school building: could rooftop rainwater harvesting work here? Estimate roof area and discuss.
    • →Enact a local water-dispute role play as the chapter suggests, to discuss unequal access.

    📋 Assessment Questions

    1. Can the student explain water scarcity and list its main causes from the chapter?
    2. Can the student compare advantages and disadvantages of multi-purpose river projects?
    3. Can the student describe how tankas work in semi-arid Rajasthan?
    4. Can the student correct the chapter's false statements about urban water use, dams and rooftop harvesting?
    5. Can the student give two modern adaptations of traditional rainwater harvesting with places?

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    Keep learning

    All chapters in Contemporary India II (Geography) - Social Science Class 10

    1. 1. Resources and Development
    2. 2. Forest and Wildlife Resources
    3. 3. Water Resources
    4. 4. Agriculture
    5. 5. Minerals and Energy Resources
    6. 6. Manufacturing Industries
    7. 7. Lifelines of National Economy