Water Resources

Q1. Explain how water becomes a renewable resource?

A1. Freshwater is mainly obtained from surface run off and ground water that is continually being
renewed and recharged through the hydrological cycle. All water moves within the hydrological
cycle ensuring that water is a renewable resource.

Q2. What is water scarcity and what are its main causes?

A2. Shortage of water as compared to its demand is called water scarcity.

1) The availability of water resources varies over space and time, mainly due to the variations
in seasonal and annual precipitation. Water scarcity in most cases is caused by over
exploitation, excessive use and unequal access to water among different social groups.
2) Large and growing population: - Consequent growing demands for water, and unequal
access to it. A large population means more water not only for domestic use but also to
provide more food. To facilitate higher food-grain population, water resources are being
over-exploited to expand irrigated areas and dry-season agriculture.
3) Intensive industrialisation: - The ever-increasing number of industries has made matters
worse by exerting pressure on existing freshwater resources. Industries, apart from being
heavy users of water, also require power to run them. Much of this energy comes from
hydroelectric power.
4) Urbanisation:-Multiplying urban centres with large and dense populations and urban
lifestyles have not only added to water and energy requirements but have further
aggravated the problem. Societies and colonies have their own groundwater pumping
devices to meet their water needs.
5) Pollution: - Fragile water resources are being over exploited and have caused their
depletion in several of these cities. Now, let us consider another situation where water is
sufficiently available to meet the needs of the people, but, the area still suffers from water
scarcity. This scarcity may be due to bad quality of water. It may be polluted by domestic
and industrial wastes. Chemicals, pesticides and fertilisers used in agriculture, thus, making
it hazardous for human use.

Q3. Why should we conserve water resource?

OR

Why need of the hour is to conserve and manage our water resources?

A3.

1) To safeguard from health hazards.

2) To ensure food security continuation of our livelihoods and productive activities.
SOCIAL SCIENCE NEENA VERMA 9811364727
 3) To prevent degradation of our natural ecosystems.
4) Over exploitation and mismanagement of water resources will impoverish this resource and
cause ecological crisis that may have profound impact on our lives.

Q4. What are dams and how do they help us in conserving and managing water?

A4. A dam is a barrier across flowing water that obstructs, directs or retards the flow, often
creating a reservoir, lake or impoundment.

1) Dams were traditionally built to impound rivers and rainwater that could be used later to
irrigate agricultural fields.
2) Today dams are built not just for irrigation but for electricity generation, water supply for
domestic and industrial uses, flood control, recreation, inland navigation and fish breeding.
3) Hence, dams are now referred to as multi-purpose projects where the many uses of the
impounded water are integrated with one another.

Q5. What are the disadvantages of multi-purpose project?

OR

Why multi-purpose project come under great scrutiny and opposition?

A5.

1) Regulating and damming of rivers affect their natural flow causing poor sediment flow and
excessive sedimentation at the bottom of reservoir, resulting in rockier stream beds and
poorer habitats for river’s aquatic life.
2) Dams also fragment rivers making it difficult for aquatic fauna to migrate, especially for
spawning.
3) The reservoirs that are created on the floodplains also submerge the existing vegetation
and soil leading it to its decomposition over a period of time.
4) Local people often had to give up their land, livelihood and their meagre access and control
over the resources for the greater good of the nation.
5) Irrigation has also changed the cropping pattern of many regions with farmers shifting to
water intensive and commercial crops. This has a great ecological consequence like
salinization of the soil. It has increase the social gap between the richer landowners and the
landless poor.
6) Dams did create conflict between people wanting different uses and benefits from the same
water resources.
7) Inter-state water disputes are also becoming common with regard to sharing the costs and
benefits of the multi-purpose project.
8) Dams that were constructed to control floods have triggered floods due to sedimentation in
the reservoir.

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 9) The flood plains were deprived of silt, a natural fertilizer, further adding on the problem of
land degradation.
10) The multipurpose projects induced earthquakes, caused water- borne diseases and pests
and pollution resulting from excessive use of the water.

Q6. Explain methods of rain water harvesting?

A6.

1) In the ancient India along with sophisticated hydraulic structure, there existed an extra
ordinary tradition of water harvesting system. People had in depth knowledge of rainfall
regimes and soil type and developed wide ranging technique to harvest rain water.
2) In hill and mountains regions, people built diversions channels like the ‘gulls’ or ‘kuls’ of the
western Himalayas for agriculture.
3) Rooftop rain water harvesting was commonly practiced for store drinking water, particularly
in Rajasthan.
4) In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
5) In arid areas and semi-arid regions agricultural fields were converted into rain fed storage
and structures that allowed the water to stand and moisten the soil like the ‘khadins’ in
jaisalmer and ‘johads’ in other parts of Rajasthan .
6) In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and barmer,
almost all the houses traditionally had underground tanks or tankas to store drinking water.
7) The rain water can be stored in tankas till the next rainfall making it an extremely reliable
source of drinking water when all other sources are dried up , particularly in the summers
.Rainwater or palar pani , as commonly referred to in these areas .

Q.8. Why roof top rain water harvesting is the most common practice in shillong, Meghalaya?

Ans.8 Roof top rain water harvesting is the most common practice in shillong, Meghalaya .it is
interesting because cherrapunjee and mawsynram situated at a distance of 55 km. From shillong
receive the highest rainfall in the world, yet the state capital shilling faces, acute shortage of
water. Nearly every household in the city has a roof top rain water harvesting system. Nearly 15-
25 % of total water requirement of the household comes from roof top water harvesting.

Q9.Why practice of rain water harvesting is on decline in western Rajasthan?

Ans.9. In western Rajasthan practice of rooftop rainwater harvesting is on the decline as plenty of
water is available due to the perennial Rajasthan canal, THROUGH SOME HOUSES STILL MAINTAIN
THE TANKAS SINCE THEY DO NOT LIKE THE TASTE OF tap water.

SOCIAL SCIENCE NEENA VERMA 9811364727