Class 10 chapter 3 Water Resources - dams and multipurpose river valley project

Water resources are the title of the chapter 3 in the textbook Geography of Social Studies for class 10. In the chaper Water Resources, various topics related to water as a resource are dealt with which include the meaning of freshwater, water conservation and management, dams and multipurpose valley projects, their merits and demerits, water disputes, water scarcity and rain water harvesting methods.

Umiam Dam in Shillong  |  image: Wikimedia

Following are questions and answers from this chapter. Good luck.

Q. What is freshwater?

Water obtained from surface runoff and groundwater is termed freshwater.

Q. How is water distributed on earth?

ANS. About 95.5% of the total volume of water in the world lies in oceans. Only 2.5% of water is freshwater existed in different forms. 70% of all the freshwater occurs as ice and glaciers in different parts of the world. The remaining 30% of freshwater is stored underground.

Q. How much is India received of the global precipitation?

ANS. India received about 4% of all the precipitation around the globe. In terms of the per capita availability of water per annum, India ranks 133rd.

Q. What is the total volume of renewable water available in India?

ANS. The renewable water available in India is about 1897 square kilometres per year.

Q. What are the causes of water scarcity?

ANS. Water availability is not uniform everywhere in the world. Water scarcity is felt even in places which otherwise have ample water resources. Three reasons that caused water scarcity. These are -

1. Population growth which leads to increasing demands for water resources.

2. Unequal access to water.

3. Poor quality of water due to pollution.

Dams and multipurpose river valley project

Q. What is a dam?

ANS. A dam is a reservoir, lake or impoundment created by a barrier built across the flowing water. A dam obstructs, retards or directs the flow of water.

Q. Classify dams

AND. Dams are classified in two ways:-

Based on the materials that are used to make, dams are of two types - timber dams and embankment dams.

Based on height or purpose, dams are classified into three categories - high dams, medium height dams and low dams.

Q. What are the merits or advantages of dams?

ANS. Advantages or the merits of a dam are given below:-

1. The dam helps in the impoundment of rivers and storing rainwater.
2. Dam water can be used to irrigate agricultural lands.
3. Dam water can be used for drinking and domestic purposes. 
4. The construction of dams serves the purpose of flood control and checking soil erosion.
5. Dam water can be used for electricity.
6. In addition, a dam can be used to generate electricity, inland navigation and recreational purposes.

Q. Who called 'the multipurpose river valley project the temple of Modern India? Why?

ANS. Pandit Jawaharlal Nehru once said that the multipurpose river valley projects are like "temples" of Modern India. He called so because these projects were a unique blend and integration of the development of Agriculture and village economy with industrialisation and development of the urban economy.

Q. Why is the dam called the multipurpose river valley project?

ANS. A dam is an impoundment of water which serves many purposes such as generating hydroelectricity, for checking flood and soil erosion. Dam water can also be used to supply water to villages and towns for drinking and domestic uses. Also, dam water is used for irrigation of agricultural lands. Besides, the dams have now become a hub for various recreational activities and navigation. Hence, dams are also known as the multipurpose river valley projects.

Q. What are the disadvantages or demerits of a dam (or multipurpose river valley projects)?

OR

State 4 harmful effects of large dams.

ANS. The construction of dams or the multipurpose projects may lead to several challenges which are listed below:-

1. Sedimentation of dams - over the years huge amount of silts and other effluents get accumulated at the base of the dam which leads eventually leads to frequent water release and flood.
2. Large dams are known to trigger earthquakes.
3. Excessive use of dam water leads to water pollution which then makes it a breeding spot of harmful waterborne disease-causing agents.
4. Aggravation of flood situation during heavy rainfall due to releasing of water from the dam.

Q. What is rainwater harvesting?

For answers relating to rainwater harvesting read here

Q. What is the purest form of water?

ANS. Rainwater is known as the purest form of water.

Q. Name the river on which the Sardar Sarovar dam has been built.

ANS. Narmada river.

Q. Name the river on which Nagarjuna Sagar Dam has been built.

ANS. Krishna river

Q. List two major reasons for water scarcity in India.

ANS. two major reasons for water scarcity in India are 

1. Population growth and,
2. unequal access to water.

Q. What was the main purpose of launching the multipurpose project in India after Independence?

ANS. The main purpose of launching the multipurpose project in India after Independence was to generate electricity to catch up with the growing demand for energy in the country.