Drainage System – Chapter 3 Geography Class 11 NCERT Solutions

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

(i) Which one of the following rivers was known as the ‘Sorrow of Bengal’?

(a) The Gandak (c) The Kosi (b) The Son (d) The Damodar

(ii) Which one of the following rivers has the largest river basin in India?

(a) The Indus (b) The Brahmaputra (c) The Ganga (d) The Krishna

(iii) Which one of the following rivers is not included in ‘Panchnad’?

(a) The Ravi (b) The Chenab (c) The Indus (d) The Jhelum

(iv) Which one of the following rivers flows in a rift valley?

(a) The Son (c) The Yamuna (b) The Narmada (d) The Luni

(v) Which one of the following is the place of confluence of the Alkananda and the Bhagirathi?

(a) Vishnu Prayag (c) Karan Prayag (b) Rudra Prayag (d) Deva Prayag

2. State the differences between the following.

(i) River Basin and Watershed

Ans. The boundary line separating one drainage basin from the other is known as the watershed. The catchments of large rivers are called river basins while those of small rivulets and rills are often referred to as watersheds.

(ii) Dendritic and Trellis drainage pattern

Ans. The drainage pattern resembling the branches of a tree is known as dendritic” the examples of which are the rivers of northern plain. When the primary tributaries of rivers flow parallel to each other and secondary tributaries join them at right angles, the pattern is known as “trellis”.

(iii) Radial and Centripetal drainage pattern

Ans. When the rivers originate from a hill and flow in all directions, the drainage pattern is known as “radial”. The rivers originating from the Amarkantak range present a good example of it. When the rivers discharge their waters from all directions in a lake or depression, the pattern is know as “centripetal”.

(iv) Delta and Estuary

3. Answer the following questions in about 30 words.

(i) What are the socio-economic advantages of inter-linking of rivers in India?

Ans. Some of the socio-economic advantages of interlinking of rivers in India are:-
1. The rivers of India carry huge amount of water, but it is unevenly distributed. So to meet the demands of the region where water is less, linking of rivers is a good idea to provide water supply to the deficit region.
2. Interlinking of rivers is profitable for irrigation. Large agricultural area will be served and the nation will benefit from the irrigation output.
3. River interlinking is a good way to control flood, navigation, water supply, fisheries salinity and pollution. Again the idea is to reduce the supply of water to a region which may cause flood and send the surplus water to the regions that needs the most.

(ii) Write three characteristics of the Peninsular river.

Ans. Main features of the Peninsular Rivers:-

i. They flow in shallow valleys.

ii. Most of them are seasonal, not perennial.

iii. During summer there is considerable reduction in their water volume.

iv. Their erosive activity is very less.

v. They flow in straight and linear courses due to hard rocky bed and they lack in silt and sand.

4. Answer the following questions in not more than 125 words.

(i) What are the important characteristic features of north Indian rivers? How are these different from Peninsular rivers?

Ans. Difference between Himalayan Rivers and Peninsular Rivers:-

• Himalayan rivers are perennial in nature, whereas peninsular rivers are seasonal in nature and dry up in summers as they depend upon rainfall.

• Himalayan rivers cause much erosion and have great flow of water, whereas peninsular rivers create much less erosion and also have weaker flow of water.

• Himalayan rivers are meandering, whereas peninsular rivers are straight.

• Himalayan rivers create great plains suitable for agriculture, urbanization, and industrialization. These are some of the most densely populated areas in the country.

• Himalayan rivers originate in the Himalayas, whereas peninsular rivers originate in small hills and plateaus.

• Himalayan rivers are much longer and deeper than peninsular rivers.

• Basins of Himalayan rivers are much deeper than the basins of peninsular rivers.

• Himalayan rivers irrigate the northern plains, whereas peninsular rivers irrigate the Deccan Plateaus.

(ii) Suppose you are travelling from Hardwar to Siliguri along the foothills of the Himalayas. Name the important rivers you will come across. Describe the characteristics of any one of them.


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