NCERT Solutions for class 9th Social-Science Geography Chapter 3 Drainage

Intext Questions

On Page 17

Question 1. Which river has the largest basin in India?

Answer: The largest basin in India is of the Ganga river with a drainage area of 8,62,769 sq km.

On Page 22

Question 1. Find out the name of the biggest waterfall in India.

Answer The highest waterfall in India is on the Varahi river in Shimoga district of Karnataka. The name of the waterfall is Kunchikal Falls and its height is 455 metres (1,493 ft)

On Page 23

Question 1. Make a list of natural and artificial lakes with the help of the atlas.


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

(i) Which one of the following describes the drainage patterns resembling the branches of a tree?

(a) Radial (b) Dendritic(c) Centrifugal (d) Trellis

Answer (b)

(ii) In which of the following states is the Wular Lake located?

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

Answer (d)

(iii) The river Narmada has its source as

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

(iv) Which one of the following lakes is a salt water lake?

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

Answer (a)

(v) Which one of the following is the longest river of peninsular India?

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

Answer (c)

(vii) Which one amongst the following rivers flow through a Rift Valley?

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

Answer (d)

Question 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 that separate two drainage basins is called a water divide. An example are the Western Ghats.

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

Answer: The Ganga Basin is the largest river basin in India.

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

Answer: The river Indus rises in Tibet, near lake Mansarowar, and the Ganga originates at the Gangotri Glacier. Both of them have their origin in the Himalayas.

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

Answer: The two headstreams of the Ganga are the Bhagirathi and Alaknanda. They meet at Devaprayag in Uttarakhand to form the Ganga.

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

Answer: In Tibet, the river Indus known as Tsang Po carries a smaller volume of water and less silt as it is a cold and dry area.

In India, the river carries a large volume of water and a considerable amount of silt because it passes through a region of high rainfall.

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

Answer: Narmada and Tapi are two peninsular rivers, which flow through a trough.

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

Answer Lakes

(a) Lakes are of great value to human beings.

(b) Lakes help to regulate the flow of rivers.

(c) Lakes help to prevent flooding during the rainy season.

(d) During the dry season, lakes help to maintain an even flow of water.

(e) Lakes can also be used for developing hydel power.

(f) They moderate the climate of the surroundings and maintain the aquatic eco-system.

(g) They enhance natural beauty help to develop tourism and provide recreation. e.g., Dal Lake and Naini Lake at Nainital.

(h) Lakes provide opportunities for fishery development.


(a) They help to develop hydel power.

(b) They provide water for irrigation, for drinking, and other requirements.

(c) They help to develop fisheries.

Question 3. Below are given names of a few lakes of India. Group them under two categories natural and created by human beings.

Question 4. Discuss the significant difference between the Himalayan and the peninsular rivers.

Answer: Differences between the Himalayas and Peninsular rivers are as follows

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

Answer: The difference between east flowing rivers and west flowing rivers are

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

Answer: Rives are important for the country’s economy because water from the rivers is a basic natural resource essential for various human activities. These are

  1. The rivers provide water for irrigation.
  2. They provide fertility to the soil.
  3. They are useful for navigation.
  4. They help to generate hydro-electricity.
  5. They help to develop tourism.
  6. They provide water for various domestic uses.
  7. They provide livelihood to fishermen.
  8. They help to moderate the climate and environment of nearby areas.

Map Skills

(i) On an outline map of India mark and label the following rivers Ganga, Satluj, Damodar, Krishna, Narmada, Tapi, Mahanadi and Brahmaputra.

(ii) On an outline map of India mark and label the following lakesChilika, Sambhar, Wular, Pulicat, Kolleru.


Solve this crossword puzzle with the help of given clauses.


  1. Nagarjuna Sagar is a river valley project, Name the river.
  2. The longest river of India.
  3. The river which originates from a place known as Beas Kund.
  4. The river which rises in the Betul district of MP and flows westwards.
  5. The river which is known as the ‘Sorrow’ of West Bengal.
  6. The river on which the reservior for Indira Gandhi Canal has been built.
  7. The river whose source lies near Rohtang Pass.
  8. The longest river of peninsular India.


9. A tributary of Indus originating from Himachal Pradesh.

10. The river flowing through fault, drains into the Arabian Sea.

11. A river of South India, which receives rain water both in summer and winter.

12. A river which flows through Ladakh, Gilgit and Pakistan.

13. An important river of the Indian desert.

14. The river which joins Chenab in Pakistan

15. A river which rises at Yamunotri Glacier.

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