Chapter Notes – Water Resources

• India receives nearly 4 percent of the global precipitation and ranks 133 in the world in terms of water availability per person per annum.

• Causes of Water Scarcity are:

→ over-exploitation

→ excessive use and unequal access to water among different social groups.

→ Large population
Dams
• A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment.

Advantages of multi-purpose river projects are:

→ 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 Mult-purpose river projects
• These projects cause of many new social movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan’ etc.
→ This is due to the large-scale displacement of local communities.
• Inter-state water disputes are also becoming common with regard to sharing the costs and benefits of the multi-purpose project.
Rainwater Harvesting
• Rainwater Harvesting refers to the practice of storing and using of rainwater from the surface on which it falls.

• 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.