Q.1. How is freshwater obtained ?
Ans. The freshwater is obtained from precipitation, surface run off and groundwater that is continually being renewed and recharged through the hydrological cycle.

Q.2. What is hydrological cycle ?
Ans. The continuous movement of water on, above and below the surface of earth.

Q.3. What is the importance of hydrological cycle ?
Ans. The freshwater is mainly obtained from surface run off and groundwater that is continually being renewed and recharged through the hydrological cycle. All water moves within the hydrological cycle ensuring that .water is renewable resource. .

Q.4. What is water scarcity ? [CBSE 2014]
Ans. Water scarcity is the lack of sufficient available water resources to meet the demand.

Q.5. “The availability of water resources varies over space and time”. Give reasons.
Ans. Water resources varies over space and time due to the variation in seasonal and annual precipitation.

Q-6. What percentage of the total volume of world’s water is estimated to exist as oceans ?
Ans. 96.5%

Q.7. How much per cent of the total volume of world’s water is estimated to exist as fresh water ?
Ans. 2.5

Q.8. What are the sources of fresh water?
Ans. Precipitation, surface run off and groundwater.

Q.9. How is freshwater being renewed ?
Ans. The freshwater is being renewed through the hydrological cycle.

Q.10. Mention any two regions which are expected to face water shortage.
Ans. (i) Regions having low rainfall
(ii) Regions which are drought prone.

Q.11. What is a dam ?
Ans. ‘A dam’ is a barrier across the flowing water that obstructs dissects or retards the flow, often creating a reservoir, lake or impoundment.

Q.12. What is a multipurpose project ?
Ans. A multipurpose project is that which fulfils a . variety of purposes at the same time, for example – irrigation, generation of electricity, flood control, fish breeding, soil conservation etc.

Q.13. Who proclaimed dams as the temples of modem India ?
Ans. Jawaharlal Nehru.

Q.14. Why were the multipurpose river projects considered as temples of modem India by Jawaharlal Nehru ?
Ans. These would integrate development of agriculture and the village economy with rapid industrialisation and growth of the urban economy.

Q.15. Name any two social movements which have been launched against the multipurpose projects.
Ans. Narmada Bachao Andolan and ‘Tehri Dam’ Andolan.

Q.16. What was considered as a viable alternative to the multipurpose projects and why ? [CBSE 2013]
Ans. The. disadvantages and rising resistance against the multipurpose projects, has lead us to conclude that water harvesting system is a viable alternative, both socio-economically and environmentally.

Q.17. Irrigation has changed the cropping pattern of many regions with farmers shifting to water intensive and commercial crops”. Mention its ecological consequence.
Ans. Salinisation of the soil

Q.18. What was the primary reason for launching ‘Narmada Bachao Andolan’ ?
Ans. Narmada Bachao Andolan was launched due to the large scale displacement of local communities.

Q.19. What is silt ?
Ans. A fine soil which is formed in flood plains.

Q.20. How people used to conserve or harvest water in hills and mountainous regions ?
Ans. By building diversion channels like the ‘guts’ or ‘kuls’.

Q.21. How people used to harvest water in the flood plains of Bengal ?
Ans. By building inundation channels to irrigate their fields.

Q.22. How people harvest water in the semi- arid and arid regions of Rajasthan ?
Ans. By building underground tanks.

Q.23. Many people of arid and semi-arid regions construct under-ground rooms adjoining the water tanks. Give reason.
Ans. By beating the summer heat it would keep the room cool.

Q.24. Name two techniques of roof top rain water harvesting. [CBSE 2009(0)]
Ans. (i) Recharge through hand pump.
(ii) Recharge through abandoned dug well.

Q.25. Name any two states where roof top water harvesting is most common.
Ans. Meghalaya and Rajasthan.

Q.26. Define the term Tankas. [CBSE 2008 (F)]
Ans. Tankas are the underground tanks for storing drinking water.

Q.27. Which is the purest form of natural water ?
Ans. Rainwater

Q.28. What is Kul ?
Ans. It is a circular village tank from which water is released and taken when required.

Q.29. Name any two states which are involved in Krishna-Godavari-dispute.
Ans. Karanataka and Andhra Pradesh.

Q.30. Name the river on which the Hirakud dam is located. [CBSE 2013]
Ans. Mahanadi

Q.31. Name the river on which the Mettur dam is located.
Ans. Kaveri

Q.32. Name the river on which the Nagarjuna Sagar dam is located.
Arts. Tungabhadra

Q.33. Name the river on which the Rihand dam is located.
Ans. Son

Q.34. Name the river on which the Bhakra Nangal dam is located. [CBSE 2014]
Ans. Satluj

Q.35. Name the river on which the Koyna dam is located ?
Ans. Krishana

Q.36. Name the river on which the Sardar Sarovar dam is located.
Ans. Narmada

Q.37. What is the contribution of hydroelectricity in the total generation of electricity.
Ans. 22%