Answer:
(i) Water becomes a renewable resource through the hydrological cycle. Fresh water is mainly obtained from the surface run off and groundwater is continually being renewed and recharged through the hydrological cycle.
(ii) Water Scarcity Shortage of water as compared to its demand is known as water scarcity. The main causes of water scarcity are as follows—
(a) Growing Population A large population means more water requirement for cooking, washing and bathing.
(b) Industrialization The ever increasing number of industries pressure on the existing fresh water resources. Industries are heavy users of water.
(c) Commercialization of Agriculture Commercial crops need more water and other inputs. Assured means of irrigation like tube wells and canals are responsible for the falling of ground water levels.
(iii) The various advantages and disadvantages of multi-purpose river projects can be compared as given in the table below—
S.N.
Advantages
Disadvantages
1.
Irrigation of crops
Natural flow of river is affected causing poor flow of sediments also.
2.
Electricity generation
Excessive sedimentation of the reservoir.
3.
Water supply tor industrial and domestic purposes
Stream beds become rockier, affecting marine life.
4.
Flood control
Dam fragments a river thus making it difficult for aquatic fauna to migrate and spawn.
5.
Inland navigation
Reservoirs submerge the existing vegetation and soil leading to its decomposition over time.
6.
Fish breeding
Deforestation and displacement of local people.
You need to login to perform this action.
You will be redirected in
3 sec