Water Resources

The situations can be classified as follows:

- (a) Region with high annual rainfall — not suffering from water scarcity
- (b) Region having high annual rainfall and large population — suffering from water scarcity
- (c) Region having high annual rainfall but water is highly polluted — suffering from water scarcity
- (d) Region having low rainfall and low population — suffering from water scarcity

High rainfall alone does not always ensure enough usable water. Scarcity can also happen because of large population, unequal access, over-exploitation, or polluted water.

The statement that is not an argument in favour of multi-purpose river projects is (c), because it states a disadvantage. The other options give reasons in support of such projects: water supply in scarcity areas, flood control, and electricity generation.

The corrected statements are:

- (a) Multiplying urban centres with large and dense populations and urban lifestyles have added to water and energy requirements and have aggravated the problem.
- (b) Regulating and damming of rivers affect the river's natural flow, causing poor sediment flow and excessive sedimentation at the bottom of the reservoir.
- (c) Today in Rajasthan, the practice of rooftop rainwater harvesting has declined because plenty of water is available due to the perennial Indira Gandhi Canal, though some houses still maintain the tankas.

Water becomes a renewable resource because it is always moving within the hydrological cycle. It is not used up permanently; instead, it is continuously renewed and recharged by precipitation, surface run-off and groundwater recharge.