Revision Notes for Chapter 3 Water Resources Class 10 Geography
CBSE NCERT Revision Notes1
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• Water is a renewable resource
• Three-fourth of the earth’s surface is covered with water but only a small proportion of it accounts for freshwater fit for use.
Some facts and Figures
• 96.5 percent of the total volume of world’s water is estimated to exist as oceans and only 2.5 per cent as freshwater.
• India receives nearly 4 percent of the global precipitation and ranks 133 in the world in terms of water availability per person per annum.
• By 2025, it is predicted that large parts of India will join countries or regions having absolute water scarcity.
Water Scarcity and need for water conservation and management
• The lack sufficient water as compared to its demand in a region is known as Water Scarcity.
• Causes of Water Scarcity are:
→ over-exploitation
→ excessive use and unequal access to water among different social groups.
→ Large population
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→ Electricity generation
→ Irrigation
→ Water supply for domestic and industrial uses
→ Flood control
→ Recreation
→ Inland navigation
→ Fish breeding
Disadvantages of Multi-purpose river projects are:
→ It affects the natural flow of river causing poor sediment flow and excessive sedimentation at the bottom of the reservoir.
→ It destroys the habitats for the rivers’ aquatic life.
→ It submerges the existing vegetation and soil if created on the floodplains.
→ It displaces the local people of the place where it is created.
→ These are unsuccessful in controlling floods at the time of excessive rainfall.
→ These projects induced earthquakes, caused water- borne diseases and pests and pollution resulting from excessive use of water.
Movements against Multi-purpose river projects
• These projects cause of many new social movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan’ etc.
• Inter-state water disputes are also becoming common with regard to sharing the costs and benefits of the multi-purpose project.
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• In hill and mountainous regions, people built diversion channels like the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture.
• In Rajasthan, ‘Rooftop rain water harvesting’ was commonly practised to store drinking water.
• In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
• In arid and semi-arid regions, agricultural fields were converted into rain fed storage structures that allowed the water to stand and moisten the soil.
• In the semi-arid and arid regions of Rajasthan, almost all the houses traditionally had underground tanks or tankas for storing drinking water.
→ Tankas were connected to the sloping roofs of the houses through a pipe.
→ Rain falling on the rooftops would travel down the pipe and was stored in these underground ‘tankas’.
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