NCERT Class 10 Geography Chapter 3: Water Resources YouTube Lecture Handouts

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NCERT Class 10 Geography Chapter 3: Water Resources

Chapter 3: Water Resources

Why? – Water Wars? ?

“Water, water everywhere nor a drop to drink”

  • 3/4th World is water – water is renewable
  • Why global water scarcity? (by 2025 – 2 billion without water)
  • 96.5 % in oceans
  • 2.5 % as freshwater – (of it 70 % in icecaps & 30 % as groundwater)
  • India gets 4 % of global rain & ranks 133 in water availability per person per annum
  • Total renewable water resources of India are estimated at 1,897 sq km per annum

Why Scarcity?

  • Not due to unequal distribution of rain (dry areas of Rajasthan)
  • Over- exploitation
  • Excessive use
  • Unequal access to water among different social groups
  • Large population – more demand for water (domestic & agri. use)
  • Scarcity even in water abundant areas (like cities)
  • Industrialization & Urbanization (ground water pumping devices)
  • Bad quality of water – polluted by chemicals, fertilizers & pesticides
  • Water stress - when water availability is less than 1,000 m3 per person per day (by Falken Mark)

Multi-Purpose River Projects & Integrated Water Resources Management

  • Historical – dams of stone, canal for irrigation
  • 1st Century B. C. : Sringaverapura near Allahabad - water harvesting system channeling the flood water of Ganga.
  • Chandragupta Maurya: Dams, lakes and irrigation systems were built.
  • Irrigation works: Kalinga, (Orissa) , Nagarjunakonda (Andhra Pradesh) , Bennur (Karnataka) , Kolhapur (Maharashtra) , etc.
  • 11th Century: Bhopal Lake - one of the largest artificial lakes of its time was built.
  • 14th Century: Tank in Hauz Khas, Delhi was constructed by Iltutmish for supplying water to Siri Fort area.

Dams – Temples of Modern India (JL Nehru)

Dams - Temples of Modern India for Geography Image - 1

Dams Classification

  • Based on height – large, medium, small
  • Based on material - timber, embankment or masonry
Dams Classification for Geography Image - 2

Limitations of Damming

  • Poor sediment flow
  • Excessive sedimentation at the bottom of the reservoir - rockier stream beds and poorer habitats for the rivers՚ aquatic life.
  • Fragment rivers – migration of aquatic fauna & spawning gets difficult
  • Reservoirs on floodplains - submerge existing vegetation and soil leading to its decomposition
  • Farmers move to water intensive crop – salinization
  • Rising gap b/w rich and poor
  • Gives rise to inter-state disputes (allowing Cauvery water/Indus water)
  • Displacement of local people
  • Narmada Bachao Andolan & Tehri Dam Andolan
Multipurpose for Geography Image - 3

Ironical Situation

  • Made to control floods – but increased floods by sedimentation
  • Situation of Gujarat & Maharashtra in 2006 – devastates property & soil erosion
  • Sedimentation - flood plains were deprived of silt, natural fertilizer, further adding on to the problem of land degradation.
  • Induced earthquakes
  • Caused waterborne diseases and pests
  • Pollution resulting from excessive use of water

Alternative – Water Harvesting System

  • Hill and mountainous regions - Diversion channels like ‘guls’ or ‘kuls’ of Western Himalayas for agriculture.
  • Rooftop rain water harvesting - store drinking water in Rajasthan – to tanks/tankas (1st rain not collected) – Rainwater or Palar Pani - purest water form; also in Shillong
  • Shillong so close to Mawsynram – still acute water shortage
  • Flood plains of Bengal – Inundation channels to irrigate their fields.
  • Arid and semi-arid regions - agricultural fields were converted into rain fed storage structures – water collected and soil moistened - ‘khadins’ in Jaisalmer and ‘Johads’ in Alwar.
  • In Rajasthan – rooftop harvesting declined by Rajasthan Canal
  • Tamil Nadu - first and the only state in India to make roof top rainwater harvesting structure compulsory to all the houses across the state.

Rooftop Harvesting & Tankas

Rooftop Harvesting & Tankas for Geography Image - 4
Rooftop Harvesting & Tankas for Geography Image - 5

Bamboo Drip Irrigation System

  • 18 - 20 liter water enter bamboo pipe system & reduce to 20 - 80 drops per minute
  • In Meghalaya – 200 years old technique
  • From springs on hilltop to low level by gravity
  • Fertilizers can be used with high efficiency
  • Water used at maximum level
  • Low operation cost
  • Low initial cost
  • Weed cannot absorb water
  • Maximum crop yield
  • Nutrient loss is minimized
  • Can pass through road
Bamboo Drip Irrgation System for Geography Image - 6
Bamboo Drip Irrgation System for Geography Image - 7

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