NCERT Solutions for Class 10 Social Science Water Resources

Q1. 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) Region with high annual rainfall.
(b) Region having high annual rainfall and large population.
(c) Region having high annual rainfall but water is highly polluted.
(d) Region having low rainfall and low population.

(ii) Which one of the following statements is not an argument in favour of multi-purpose 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.

(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 practice of rooftop rainwater water harvesting has gained popularity despite high water availability due to the Rajasthan Canal.

(i)

(a) Not suffering from water scarcity
(b) Suffering from water scarcity
(c) Suffering from water scarcity
(d) Not suffering from water scarcity

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

(iii)

(a) Multiplying urban centres with large and dense populations and urban lifestyles have 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 of the reservoir.
(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 harvesting is on the decline due to the Rajasthan canal.

Q2. 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 fresh water mainly obtained from surface run off and ground water is continually being renewed and recharged by the water /hydrological cycle itself.
In this cycle three processes take place – evaporation, condensation and precipitation. This process of the 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. A large and growing population is the main cause of water scarcity. More water is required for domestic purposes and for growing food.
2. Urbanization and industrialization have increased the consumption of water.
3. Wastage, excessive use 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, more water intensive commercial crops are grown that consume more water.
7. Pollution by domestic and industrial waste, chemicals, pesticides, fertilizers used in agriculture etc.
(iii) The various advantages and disadvantages of multi-purpose river projects can be compared as follows

Q3. 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 the following manner:

Houses have traditionally constructed underground tanks or ‘tankas’ for storing rainwater 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 these underground tanks . The first spell of rain is not collected as this water cleans the roof and pipes but rain from subsequent showers is collected.
During summer when all other sources of water dry up, these tanks remain the best source of water. Rain water/palar pani is pure and sweet. These tanks 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 and also to recharge the ground water. People living in rural and urban areas have realized the importance of traditional rainwater harvesting methods like the rooftop storing method and this has been successfully adapted to store and conserve water. The level of underground water in most urban areas has fallen because of increasing population, industrialization etc.
In Gendathur village, Mysore, about 200 households have adopted the rooftop rainwater harvesting method, making the village ‘rich in rainwater. With 80% collection efficiency each house can collect about 50,000 litres annually. The Tamil Nadu government has made it compulsory for all the houses to have rooftop rainwater harvesting structures.

It is also the most common practice in Shillong and Meghalaya.