NCERT Solutions for Class 11th: Ch 3 Drainage System Indian Physical Environment
Exercises
Page No: 30
1. Choose the right answer from the four alternatives given below.
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
(b) The Son
(a) The Gandak
(b) The Son
(c) The Kosi
(d) The Damodar
► (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
► (c) The Ganga
(iii) Which one of the following rivers is not included in ‘Panchnad’?
(a) The Ravi
(b) The Chenab
(c) The Indus
(d) The Jhelum
► (c) The Indus
(iv) Which one of the following rivers flows in a rift valley?
(a) The Son
(b) The Narmada
(c) The Yamuna
(d) The Luni
► (b) The Narmada
Page No: 31
Page No: 31
(a) Vishnu Prayag
(b) Rudra Prayag
(c) Karan Prayag
(d) Deva Prayag
► (d) Deva Prayag
2. State the differences between the following.
(i) River Basin and Watershed
(ii) Dendritic and Trellis drainage pattern
(iii) Radial and Centripetal drainage pattern
(iv) Delta and Estuary
(iii) Radial and Centripetal drainage pattern
(iv) Delta and Estuary
Answer
(i) River Basin and Watershed
River Basin
|
Watershed
|
| The catchments of large rivers are called river basins. | The catchments of small rivulets and rills are often referred to as watersheds. |
| These are larger in the area. | These are small in area. |
(ii) Dendritic and Trellis drainage pattern
(iii) Radial and Centripetal drainage pattern
(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?
Answer
The socio-economic advantages of inter-linking of rivers in India are:
• The problems of floods and drought will get solved as excess water from an area can be transferred to water deficit areas.
• The inland waterway transportation will improve which will make the transportation of materials across the country easier.
• It will also help in imporving irrigational facilities which will increase the productivity.
• It will provide various opportunities such as hydro-electricity and fisheries activities.
(ii) Write three characteristics of the Peninsular river.
Answer
Three characteristics of the Peninsular river are:
• These rivers originate in Peninsular plateau and central highland.
• These are seasonal and dependent on monsoon rainfall.
• These rivers are smaller having fixed course with well adjusted valleys.
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?
Answer
The important characteristic features of north Indian rivers are:
• They originate in Himalayan mountain covered with glaciers.
• These rivers are perennial in nature because they receive water from glacier and rainfall.
• These rivers form deep gorges and V-shaped valleys in mountainous areas.
• It has long course, flowing through the rugged mountains experiencing headward erosion and river capturing.
• These rivers are young and youthful, active and deepening in the valleys.
These are different from peninsular rivers because of these reasons:
• The north Indian rivers have very large basins while peninsular rivers have relatively smaller basin.
• The north Indian rivers are perennial as they receive water from glaciers and rainfall while peninsular rivers receive their water only from monsoon rains.
• The north Indian rivers are antecedent and consequent leading to dendritic pattern in plains while peninsular rivers are super imposed, rejuvenated resulting in trellis, radial and rectangular patterns.
• The north Indian rivers are young and youthful, active and deepening in the valleys while peninsular rivers are old with graded profile, and have almost reached their base levels.
(ii) Suppose you are travelling from Haridwar to Siliguri along the foothills of the Himalayas. Name the important rivers you will come across. Describe the characteristics of any one of them.
Answer
If we are travelling from Haridwar to Siliguri along the foothills of the Himalayas we will come across Gomti, Ramganga, Rapti, Gandak, Kosi, Kamla, Saryu, Sharda, Ghaghra, Mahanadi and Ganga.
The characteristics of Gandak:
• It rises in the Nepal Himalayas between the Dhaulagiri and Mount Everest and drains the central part of Nepal
• It comprises two streams, namely Kaligandak and Trishulganga
• It enters the Ganga plain in Champaran district of Bihar and joins the Ganga at Sonpur near Patna.
• Its length is 630 Km.
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Dendritic drainage pattern
|
Trellis drainage pattern
|
| The drainage pattern resembling the branches of a tree is known as dendritic. | 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. |
| The drainage pattern of Northern plain is the example of such pattern. | The drainage pattern of Himalayan mountain is the example of such pattern. |
(iii) Radial and Centripetal drainage pattern
Radial drainage pattern
|
Centripetal drainage pattern
|
| When the rivers originate from a hill and flow in all directions, the drainage pattern is known as ‘radial’. | When the rivers discharge their waters from all directions in a lake or depression, the pattern is known as ‘centripetal’. |
| The rivers originating from the Amarkantak range is the example of such pattern. | Sambhar Lake of Rajasthan is the example of such pattern. |
(iv) Delta and Estuary
Delta
|
Estuary
|
| A Delta is a triangular landmass formed at the mouth of the river. | An Estuary is a funnel shaped formed at the mouth of the river. |
| It is formed in the regions of low tides and coastal plains. | It is formed in the regions of high tides and rift valleys. |
| These are extremely fertile and support agriculture. | They provide fishing ground and support inland transportation. |
| The rivers like Ganga and Brahmaputra form deltas. | The rivers like Narmada and Tapi form estuaries. |
3. Answer the following questions in about 30 words.
(i) What are the socio-economic advantages of inter-linking of rivers in India?
Answer
The socio-economic advantages of inter-linking of rivers in India are:
• The problems of floods and drought will get solved as excess water from an area can be transferred to water deficit areas.
• The inland waterway transportation will improve which will make the transportation of materials across the country easier.
• It will also help in imporving irrigational facilities which will increase the productivity.
• It will provide various opportunities such as hydro-electricity and fisheries activities.
(ii) Write three characteristics of the Peninsular river.
Answer
Three characteristics of the Peninsular river are:
• These rivers originate in Peninsular plateau and central highland.
• These are seasonal and dependent on monsoon rainfall.
• These rivers are smaller having fixed course with well adjusted valleys.
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?
Answer
The important characteristic features of north Indian rivers are:
• They originate in Himalayan mountain covered with glaciers.
• These rivers are perennial in nature because they receive water from glacier and rainfall.
• These rivers form deep gorges and V-shaped valleys in mountainous areas.
• It has long course, flowing through the rugged mountains experiencing headward erosion and river capturing.
• These rivers are young and youthful, active and deepening in the valleys.
These are different from peninsular rivers because of these reasons:
• The north Indian rivers have very large basins while peninsular rivers have relatively smaller basin.
• The north Indian rivers are perennial as they receive water from glaciers and rainfall while peninsular rivers receive their water only from monsoon rains.
• The north Indian rivers are antecedent and consequent leading to dendritic pattern in plains while peninsular rivers are super imposed, rejuvenated resulting in trellis, radial and rectangular patterns.
• The north Indian rivers are young and youthful, active and deepening in the valleys while peninsular rivers are old with graded profile, and have almost reached their base levels.
(ii) Suppose you are travelling from Haridwar to Siliguri along the foothills of the Himalayas. Name the important rivers you will come across. Describe the characteristics of any one of them.
Answer
If we are travelling from Haridwar to Siliguri along the foothills of the Himalayas we will come across Gomti, Ramganga, Rapti, Gandak, Kosi, Kamla, Saryu, Sharda, Ghaghra, Mahanadi and Ganga.
The characteristics of Gandak:
• It rises in the Nepal Himalayas between the Dhaulagiri and Mount Everest and drains the central part of Nepal
• It comprises two streams, namely Kaligandak and Trishulganga
• It enters the Ganga plain in Champaran district of Bihar and joins the Ganga at Sonpur near Patna.
• Its length is 630 Km.
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