Class X NCERT - CBSE Solutions for Social Science (Geography)
WATER RESOURCES (Chapter 3, Contemporary India - II)
NCERT (CBSE) Textbook Exercise Answers
Q.1 (iii): Here are some false statements. Identify the mistakes and rewrite them correctly.
(a) Multiplying urban centers with large and dense populations with urban lifestyles have helped in proper utilizations 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 practice of rooftop rainwater harvesting has gained popularity despite high water availability due to Rajasthan Canal.
Ans: (a) Multiplying urban centers with large and dense populations with urban lifestyles have added to the water and energy requirements and thus, caused the over exploitation of water resources.
(b) Regulating and damming of rivers affect their natural flow and causes the sediment to settle at the bottom early.
(c) In Gujarat, the Sabarmati basin farmers agitated over the higher priority given to water supply in urban areas, particularly during droughts.
(d) Today in Rajasthan, the practice of rooftop rainwater harvesting is on decline as plenty of water is available due to Rajasthan Canal.
Q.2: answer the following questions in about 30 words.
(i) Explain how water becomes a renewable resource.
(ii) What is water scarcity and what are its main causes?
(iii) Compare the advantages and disadvantages of multipurpose river projects.
(i) 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.
(ii) Scarcity of water means shortage of water, an imbalance between demand and supply. Causes or the factors responsible for water scarcity are as follows:
1. growing population which is the main cause of water scarcity.
2. urbanization and industrialization which have increased the consumption of water.
3. wastage and injudicious use of water.
4. over-exploitation and mismanagement of water resources.
5. unequal access to water resources.
6. in post green revolution era, the commercial crops which are grown more, consume more water.
(iii) The various advantages and disadvantages of multipurpose river projects can be compared as follows:
b. Electricity generation
c. Water supply for industrial and domestic purposes
d. Flood control
f. Inland navigation
g. Fish breeding
a. Natural flow of river is affected causing poor flow of sediments also
b. Excessive sedimentation of the reservoir
c. Stream beds become rockier
d. Dam fragments a river thus making it difficult for aquatic fauna to migrate, and for spawning
e. Reservoirs submerge the existing vegetation and soil leading to its decomposition over time.
f. Deforestation and displacement of local people.
Q.3: Answer the following questions in about 120 words.
(i) Discuss how rainwater harvesting in semi arid regions of Rajasthan is carried out.
(ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
(i) In semi arid regions of Rajasthan rainwater harvesting is carried out in their own manner. Houses have traditionally constructed underground tanks or ‘tankas’ for storing rainwater which they use for drinking and other purposes. These are big and are a part of well-developed rooftop rainwater harvesting system. These 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 through the pipe and is stored in the tanks (tankas). The first spell of rain is not collected as this water cleans the roof and pipes.
During summer when all other sources of water dry up, these tanks remain the best source of water. The water is sweet and cool here and also help in keeping the houses cool due to conduction.
(ii) Rainwater harvesting means capturing rain when it falls. It is done to meet the increasing demand of water as also to recharge the ground water. People living in urban areas have realized the importance of traditional rainwater harvesting methods like the rooftop storing method. The level of underground water in most of the urban areas has gone down much because of the increasing population, industrialization etc.
In Gendathur village, Mysore, about 200 households have adopted the rooftop rainwater harvesting method, thereby making village rich in rainwater. The Tamil Nadu government has made it compulsory for all the houses to have rooftop rainwater harvesting structures.
Further study –
Contemporary India - II, Chapter 3 Water Resources | NCERT - CBSE Class X Geography | Important Questions [Read]