Class 10th Easy Notes Geography Ch 3 WATER RESOURCES

Water Resources

• Water is a renewable resource.
• ¾th of the earth is made of water.
• 96.5% is oceanic water – 2.5% is fresh water
• 70% of freshwater occurs in ice sheets and glaciers
• 30% is ground water
• 4% rain received by India globally and ranks 133 in the world in terms of water availability per person per annum. 
• Total renewable resources of water in India are estimated at 1,897 sq. km per annum.

Water Scarcity

• Over-exploitation of resources
• Excessive use water resources
• Unequal access to water among different social groups
• People use water not only for domestic works but for agricultural activities mainly in dry season.
• Scarcity even in water abundant areas
• Industrialization and urbanization
• Water pollution due to chemicals, fertilizers and pesticides.
• When water availability is between 1,000 and 1,600 cubic meter per person per year, water stress occurs. 

Hydraulic Structures In Ancient India

• 1st century B.C. – sringverapura near Allahabad – sophisticated water harvesting system – for the river Ganga.
• Irrigation system in the time of Maurya dynasty.
• Kalinga (Odisha), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra).
• 11th century – Bhopal lake – largest artificial lake.
• 14th century – Delhi - tank in Hauz khaas – built by Iltutmish for supplying water to Siri fort area.

Multipurpose Projects

• Dam is a barrier, that stops the flow of water or underground streams. Reservoirs created by dams not only suppress floods.
• Impound water is used not just for irrigation but for electricity generation, water supply for domestic and industrial uses, recreation, flood control, inland navigation and fish breeding.

Classification Of Dams

• On the basis of height – small, medium, large
• On the basis of material – timber, embankment, masonry 

Limitation Of Damming

• It affect rivers’ natural flow causing poor sediment flow 
• Poorer habitats for the rivers’ aquatic life.
• Dams also fragments rivers, making it difficult for aquatic fauna to migrate, specifically for spawning.
• Displacement of local people.
• Soil quality decreased due to excessive commercial farming.
• Rise in inter state dispute.
• Narmada bachao Andolan & Tehri dam Andolan.

Ironic State

• The projects arose because of their failure to attain the needs for which they were built.
• The dams that were constructed to manage floods have triggered floods because of sedimentation within the reservoir.
• The big dams have often been unsuccessful in controlling floods at the time of intense rainfall.
• In 2006 Gujarat and Maharashtra, faced massive destruction of life property and this also leads to soil erosion.
• Sedimentation also meant that the flood plains were deprived of silt, a natural fertilizer, further adding on to the problem of land degradation.
• These projects induced earthquakes, caused waterborne diseases and pests, and pollution resulting from excessive use of water.

Rainwater Harvesting

• Water harvesting system is a good alternative, both socio-economically and environmentally.
• People built diversion channels, called the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture in hilly regions, 
• ‘Rooftop rainwater harvesting’ was commonly practiced to store drinkable, particularly in Rajasthan.
• In the flood plains of Bengal, people made inundation channels to irrigate their crop fields.
• Agricultural fields were converted into rain fed storage structures in arid and semi-arid regions, that allow the water to stand and humify the soil. As the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.

Bamboo Drip Irrigation System

• This is 200 yrs old system in Meghalaya.
• Through the bamboo pipe, about 18-20 liters of water, transported over many meters, and reduced to 20-80 drops per minute at the location of the plant.
• The flow of water into the pipes is managed by manipulating the pipe positions.

FOR COMPLETE EXPLANATION CLICK HERE :  https://www.youtube.com/watch?v=2fn_iL32mHs

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