ch 3 water resoures

1 What is dam?

Ans  a barrier across the flowing water.

2 What is multipurpose?

Ans A river valley project which serves a number of purposes such as irrigation, flood control and generates hydroelectricity e.g. the Bhakra Nangal.

3 What is perennial canals ?

Canals developed by diverting water from river that flow throughout the year.

4 What is water scarcity?

 Shortage of water as compare to its demand is called water scarcity.

5 What is rainwater harvesting?

It is a technique of increasing the recharge of ground water by capturing and storing the rain water , by constructing structures such as percolating pits ,check dams ,etc.

6 What is ground water?

Water which is obtained from a depth of  more than 15 metre is known as ground water.

7  What is hydrological cycle?

The continuous movement of water on , above and below the surface of earth.

8 Name any 2 social movements which have being launched against the multipurpose project?

 ‘Narmada Bhachao Andolan’ and ‘tehri dam Andolan’.

9 What is kul?

It is a circular village tank from which water is released and taken when required.

10 What was the primary reason for launching Narmada Bhachao andolan?

Narmada bhachao andolan was launched due to the large scale displacement of local communities.

11 What is silt?

A fine soil which is formed in flood plains .

12 Name two techniques of roof top rain water harvesting?

(1) Recharge through handpump

(2) recharge through abandoned dug well.

13 Define the term Tankas?

Tankas are the under ground tanks for storing rain water.

 14. Explain how water becomes a renewable resource.

Ans 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.

15.What is water scarcity and what are its main causes?

Ans.Water scarcity or water stress occurs when water availability is not enough to match the demand for water. It is caused by an increase in population, growing demand for water, and unequal access to it.

16.Compare the advantages and disadvantages of multi-purpose river projects.

Ans. Multipurpose river projects help in irrigation, electricity production, flood control, inland navigation and fish breeding. However, the reservoirs destroy local flora and fauna. Many native villages are submerged, and people lose their livelihood, with little or no hope of rehabilitation.
17. Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
Ans. 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.

18. Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
AnsTraditional 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.