Water Resources

Water Resources
Water Resources


1. Multiple choice questions.

(i) Based on the information given below classify each of the situations as ‘suffering from water
scarcity’ or ‘not suffering from water scarcity’.

(a) A region with high annual rainfall.

(b) A region having high annual rainfall and large population.

(c) A region having high annual rainfall but water is highly polluted.

(d) A region having low rainfall and low population.

Answer:

(a) A region with high annual rainfall. -    Not suffering from water scarcity

(b) A region having high annual rainfall and large population. -   Suffering from water scarcity

(c) A region having high annual rainfall but water is highly polluted. -   Suffering from water scarcity

(d) A region having low rainfall and low population.-   Not suffering from water scarcity



(ii) Which one of the following statements is not an argument in favour of multipurpose river
projects?

(a) Multi-purpose projects bring water to those areas which suffer from water scarcity.

(b) Multi-purpose projects by regulating water flow help to control floods.

(c) Multi-purpose projects lead to large scale displacements and loss of livelihood.

(d) Multi-purpose projects generate electricity for our industries and our homes.

Answer:

(c) Multi-purpose projects lead to large scale displacements and loss of livelihood

(iii) Here are some false statements. Identify the mistakes and rewrite them correctly.

(a) Multiplying urban centres with large and dense populations and urban lifestyles have helped

in proper utilisation of water resources.

(b) Regulating and damming of rivers does not affect the river’s natural flow and its sediment

flow.

(c) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to

water supply in urban areas, particularly during droughts.

(d) Today in Rajasthan, the practise of rooftop rainwater water harvesting has gained popularity

despite high water availability due to the Indira Gandhi Canal.

Answer:

(a) Multiplying urban centres with large and dense populations and urban lifestyles have resulted in

improper utilisation of water resources.

(b) Regulating and damming of rivers does affect the river’s natural flow and its sediment flow.

(c) In Gujarat, the Sabarmati basin farmers were agitated when higher priority was given to water

supply in urban areas, particularly during droughts.

(d) Today in Rajasthan, the practice of rooftop rainwater water harvesting popularity has declined due

to high water availability from Indira Gandhi Canal.

2. Answer the following questions in about 30 words.
(i) Explain how water becomes a renewable resource.

Answer:

Water can be considered as a renewable resource since there will be rains and surface water and

groundwater will get recharged continuously due to the 3 process involved in the hydrological cycle.

The 3 process of the hydrological cycle are

1. Evaporations

2. Condensation

3. Precipitation

(ii) What is water scarcity and what are its main causes?

Answer:

Many of our cities are such examples. Thus, water scarcity may be an outcome of large and growing

population and consequent greater demands for water, and unequal access to it. A large population

requires more water not only for domestic use but also to produce more food. Hence, to facilitate higher

food-grain production, water resources are being over-exploited to expand irrigated areas for dryseason agriculture. Irrigated agriculture is the largest consumer of water. Most farmers have their own

wells and tube-wells in their farms for irrigation to increase their produce. This has adversely affected

water availability and food security of the people.

(iii) Compare the advantages and disadvantages of multi-purpose river projects.

Answer:

Advantages:

1. Irrigation

2. Electricity generation

3. Flood control

4. Water supply for industrial and domestic purposes.

5. Tourist attraction

6. Inland navigation

Disadvantages:

1. The natural flow of water is affected

2. Aquatic life gets affected

3. Submergence of land in surrounding areas

4. Ecological consequences

5. Large scale displacement of local people.

3. Answer the following questions in about 120 words.

(i) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.

Answer:

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 for storing drinking water. The tanks could be

as large as a big room; one household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres

long and 2.44 metres wide. The tankas were part of the well-developed rooftop rainwater harvesting

system and were built inside the main house or the courtyard. They were connected to the sloping roofs

of the houses through a pipe. Rain falling on the rooftops would travel down the pipe and was stored in

these underground ‘tankas’. The first spell of rain was usually not collected as this would clean the

roofs and the pipes. The rainwater from the subsequent showers was then collected. The rainwater can

be stored in the 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 parts, is considered the purest form of natural water.

(ii) Describe how modern adaptations of traditional rainwater harvesting methods are being
carried out to conserve and store water.

Answer:

Water harvesting system is a viable alternative, both socio-economically and environmentally. In

ancient India, along with the sophisticated hydraulic structures, there existed an extraordinary tradition

of water-harvesting system. People had in-depth knowledge of rainfall regimes and soil types and

developed wide-ranging techniques to harvest rainwater, groundwater, river water and floodwater in

keeping with the local ecological conditions and their water needs. In hill and mountainous regions,

people built diversion channels like the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture. ‘Rooftop

rainwater harvesting’ was commonly practised to store drinking water, particularly in Rajasthan. In the

flood plains of Bengal, people developed inundation channels to irrigate their fields. In arid and semiarid regions, agricultural fields were converted into rain-fed storage structures that allowed the water to

stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan. In

Gendathur, a remote backward village in Mysuru, Karnataka, villagers have installed, in their

household’s rooftop, rainwater harvesting system to meet their water needs. Nearly 200 households

have installed this system and the village has earned the rare distinction of being rich in rainwater.

Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya. It is interesting

because Cherapunjee and Mawsynram situated at a distance of 55 km. from Shillong receive the 

highest rainfall in the world, yet the state capital Shillong faces acute shortage of water. Nearly every

household in the city has a rooftop rainwater harvesting structure. Nearly 15-25 per cent of the total

water requirement of the household comes from rooftop water harvesting. Tamil Nadu is the first state

in India which has made rooftop rainwater harvesting structure compulsory to all the houses across the

state