NCERT Solutions for Class 9 Social Studies (Geography) Chapter 3 – Drainage

 

NCERT Solutions for Class 9 Social Studies (Geography) Chapter 3 – Drainage

Exercise Page No 23

1. Choose the right answer from the four alternatives given below.

(i) In which of the following states is the Wular lake located?

(a) Rajasthan (b) Punjab (c) Uttar Pradesh (d) Jammu and Kashmir

Answer:

Jammu and Kashmir.

(ii) The river Narmada has its source at

(a) Satpura (b) Amarkantak (c) Brahmagiri (d) Slopes of the Western Ghat.

Answer:

Amarkantak

(iii) Which one of the following lakes is a saltwater lake?

(a) Sambhar (b) Wular (c) Dal (d) Gobind Sagar

Answer:

Sambhar

(iv) Which one of the following is the longest river in Peninsular India?

(a) Narmada (b) Godavari (c) Krishna (d) Mahanadi

Answer:

Godavari

(v) Which one amongst the following rivers flows through a rift valley?

(a) Mahanadi (b) Krishna (c) Tungabhadra (d) Tapi

Answer:

Tapi

2. Answer the following questions briefly.

(i) What is meant by a water divide? Give an example.

Answer:

Any elevated area, such as a mountain or an upland, separates two drainage basins. Such an upland is known as a water divide. For example, the water divide between the Indus and the Ganga river systems.

(ii) Which is the largest river basin in India?

Answer:

Ganga River basin is the largest river basin in India.

(iii) Where do the rivers Indus and Ganga have their origin?

Answer:

Indus river origin – Near Manasarovar Lake, Tibet

Ganga River origin – Gangotri glacier in Uttaranchal

(iv) Name the two headstreams of the Ganga. Where do they meet to form the Ganga?

Answer:

The two headstreams of Ganga are Alaknanda and Bhagirathi. They both meet to form Ganga at Devprayag.

(v) Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?

Answer:

In Tibet, the river carries a smaller volume of water and less silt, as it is a cold and dry area. In India, it passes through a region of high rainfall. Hence, the river carries a large volume of water and a considerable amount of silt.

(vi) Which two Peninsular rivers flow through a trough?

Answer:

Narmada and Tapi are the two Peninsular rivers that flow through a trough.

(vii) State some economic benefits of rivers and lakes.

Answer:

Rivers have been of fundamental importance throughout human history. Water from rivers is a basic natural resource, essential for various human activities. Therefore, riverbanks have attracted settlers from ancient times. Using rivers for irrigation, navigation and hydropower generation is of special significance — particularly to a country like India, where agriculture is the major source of livelihood of the majority of its population.

3. Below are given names of a few lakes of India. Group them under two categories – natural and created by human beings. (a) Wular (b) Dal (c) Nainital (d) Bhimtal (e) Gobind Sagar (f) Loktak (g) Barapani (h) Chilika (i) Sambhar (j) Rana Pratap Sagar (k) Nizam Sagar (l) Pulicat (m) Nagarjuna Sagar (n) Hirakund

Answer:

Natural Lakes:

1. Wular
2. Dal
3. Nainital
4. Bhimtal
5. Loktal
6. Chilika
7. Pulicat
8. Sambhar
9. Barapani

Man-made lakes

1. Gobind Sagar
2. Rana Pratap Sagar
3. Nizam Sagar
4. Nagarjuan Sagar
5. Hirakud

4. Discuss the significant difference between the Himalayan and the Peninsular rivers.

Answer:

Himalayan Rivers:

1. These are perennial rivers.
2. Receive water from Rains and Snowfall.

Peninsular Rivers:

1. These are seasonal rivers
2. Dependent on rainfall. During dry seasons, the rivers get dried up.

5. Compare the east-flowing and the west-flowing rivers of the Peninsular plateau.

Answer:

West flowing rivers:

1. There are only 2 long West flowing rivers – Narmada and Tapi.
2. They flow into the Arabian Sea
3. They have a lesser number of tributaries
4. Form estuaries
5. Carry lesser sediments

East flowing rivers:

1. Many major rivers Mahanadi, Cauvery, Godavari, Krishna
2. They flow into the Bay of Bengal
3. Have many tributaries
4. Forms Deltas
5. Carry larger sediments than West flowing rivers

6. Why are rivers important for the country’s economy?

Answer:

Rivers have been of fundamental importance throughout human history. Water from rivers is a basic natural resource, essential for various human activities. Therefore, riverbanks have attracted settlers from ancient times. These settlements have now become big cities. Make a list of cities in your state which are located on the bank of a river. Using rivers for irrigation, navigation, hydropower generation is of special significance — particularly to a country like India, where agriculture is the major source of livelihood for the majority of its population.

Drainage Summary

The term drainage describes the river system of an area. The area drained by a single river basin is called a drainage basin. Chapter 3 Drainage of NCERT Class 9 Geography books – ‘Contemporary India I’ deals with the drainage system of India. The below-mentioned topics have been discussed in detail in this chapter:

1. The Himalayan Rivers

1. The Indus River System
2. The Ganga River System
3. The Brahmaputra River System

2. The Peninsular Rivers

1. Narmada Basin
2. Tapi Basin
3. Godavari Basin
4. Mahanadi Basin
5. Krishna Basin
6. Kaveri Basin

3. Lakes

4. Role of Rivers in Economy

Students will also study the causes of river pollution and how it will affect society. Also, the concerns related to the increasing river pollution will help students learn how saving resources like water bodies can help in creating a better environment to live in.