Assignment CH: 03 WATER RESOURCES

       Assignment        CH: 03 WATER RESOURCES

Define the following:-

I. Kuls and Guls 2. Khadins or Johads 3. Water scarcity 4. Dams
(i) Explain how water becomes a renewable resource.
Water is a renewable resource as it is renewed by water cycle itself, where three processes take place as evaporation, condensation and precipitation. This process of water cycle is never ending and hence, water is a renewable resource.
(ii) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
 Houses in the semi arid regions of Rajasthan have traditionally constructed tanks for storing drinking water. They are big and are a part of the well-developed rooftop rainwater harvesting system. The tanks are constructed inside the main house or the courtyard, and are connected to the sloping roofs of the houses through a pipe. The rain falling on the rooftop travels down and is stored in the tanks. The first spell of rain is not collected as this water cleans the roof and the pipes. The rainwater from the subsequent spells is collected. This water is used till the next rainy season, and is a reliable source of water even after other sources have dried up. The tanks also help in cooling the houses as rooms built around them have generally low temperatures due to conduction.

(iii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
 Traditional methods of rainwater harvesting like 'the rooftop method' are becoming popular in India. In Gendathur village, Mysore, about 200 households have adopted the rooftop rainwater harvesting method, thereby making the village rich in rainwater. The state of Tamil Nadu has made it compulsory for all the houses to have rooftop rainwater harvesting structures. Defaulters are severely punished.

(iv) What is water scarcity and what are its main causes?

• 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

    Pollution
v) What are Multi-purpose river projects? Write their advantages.

• Multi-purpose river projects large dams that serve several purposes in addition to impounding the water of a river and used later to irrigate agricultural fields. For example, the Sutluj-Beas river basin, the Bhakra–Nangal project etc.

Advantages of multi-purpose river projects are:

→ Electricity generation

→ Irrigation

→ Water supply for domestic and industrial uses

→ Flood control

→ Recreation

→ Inland navigation 

→ Fish breeding

vi) Why the multipurpose river projects are under great scrutiny and opposition?

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.

.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.
vi) What is 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 practiced 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.

• How Tankas works:
→ 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’