CBSE Class 11 India Physical Environment Chapter 3: Drainage System NCERT Solutions

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NCERT Solutions PDF Class 11 PDF

This section provides detailed NCERT Solutions for Class 11 India Physical Environment, focusing on Chapter 3: Drainage System. It covers key concepts such as the definition and distinction between river basins and watersheds, and the characteristics of different drainage patterns like dendritic and trellis. The solutions also address specific rivers and their significance, including identifying rivers known for causing floods and those flowing through rift valleys. This resource is designed to help students grasp the fundamental aspects of India's drainage systems, understand geographical features, and prepare effectively for their examinations by offering clear explanations and accurate answers to all exercise questions.

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BoardCBSE
ClassClass 11
SubjectIndia Physical Environment
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 3

Chapter summary

Chapter 3 of the NCERT textbook for Class 11 India Physical Environment delves into the Drainage System of India. The exercises in this chapter focus on understanding the concepts of river basins and watersheds, differentiating between them, and identifying various drainage patterns like dendritic and trellis. It also tests knowledge about specific rivers, their geographical significance, and their role in shaping the landscape, including identifying rivers associated with floods and those flowing through unique geological formations like rift valleys.

Learning outcomes

  • Understand the concept of a river basin and its distinction from a watershed.
  • Identify and differentiate between dendritic and trellis drainage patterns.
  • Recognize rivers known for causing significant floods in India.
  • Identify rivers that flow through rift valleys.
  • Locate the confluence points of major rivers.
  • Understand the geographical significance of various Indian rivers.

Topics covered

Paper topics

  • Drainage System of India
  • River Basin
  • Watershed
  • Dendritic Drainage Pattern
  • Trellis Drainage Pattern
  • Rivers of India
  • Sorrow of Bengal
  • Rift Valley Rivers
  • Confluence of Rivers
  • Alaknanda River
  • Bhagirathi River
  • Ganga River

Important topics

  • River Basin vs. Watershed
  • Dendritic and Trellis Drainage Patterns
  • Rivers flowing through Rift Valleys
  • Confluence points of major rivers
  • Significance of the Ganga River basin

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Questions and Solutions

Question 1(i)

Which one of the following rivers was known as the 'Sorrow of Bengal'?

Options:

  • The Gandak
  • The Son
  • The Kosi
  • The Damodar
Solution: The correct option is The Damodar. The Damodar River has historically been prone to severe flooding, causing widespread devastation and economic hardship in the Bengal region. This recurring problem led to it being known as the 'Sorrow of Bengal'.

Question 1(ii)

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

Options:

  • The Indus
  • The Brahmaputra
  • The Ganga
  • The Krishna
Solution: The correct option is The Ganga. The Ganga River basin is the largest in India in terms of area, covering a significant portion of the northern plains and supporting a very large population.

Question 1(iii)

Which one of the following rivers is not included in 'Panchnad'?

Options:

  • The Ravi
  • The Chenab
  • The Indus
  • The Jhelum
Solution: The correct option is The Indus. The 'Panchnad' refers to the confluence of the five major rivers of the Punjab region: the Jhelum, the Chenab, the Ravi, the Sutlej, and the Beas. The Indus River is a separate, larger river system that these five rivers eventually join.

Question 1(iv)

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

Options:

  • The Son
  • The Narmada
  • The Yamuna
  • The Luni
Solution: The correct option is The Narmada. The Narmada River flows through a rift valley, which is a geological depression formed by tectonic forces. It flows westward between the Vindhya and Satpura mountain ranges.

Question 1(v)

Which one of the following is the place of confluence of the Alaknanda and the Bhagirathi?

Options:

  • Vishnu Prayag
  • Rudra Prayag
  • Karan Prayag
  • Deva Prayag
Solution: The correct option is Deva Prayag. Deva Prayag is a significant pilgrimage town where the Alaknanda River and the Bhagirathi River meet. After their confluence, the combined river is known as the Ganges (Ganga).

Question 2(i)

State the differences between the following: River Basin and Watershed
Solution: The key differences between a River Basin and a Watershed are:
  • Meaning: A river basin refers to the entire area of land drained by a large river and its tributaries. A watershed refers to the area of land drained by a smaller stream, creek, or rivulet and its tributaries.
  • Scale: River basins are generally much larger in geographical extent compared to watersheds. Watersheds are smaller units within a larger river basin.
  • Hierarchy: A large river basin can be subdivided into several smaller watersheds.

Question 2(ii)

State the differences between the following: Dendritic and Trellis drainage pattern
Solution: The differences between Dendritic and Trellis drainage patterns are:
  • Dendritic Pattern: This pattern resembles the branches of a tree. Tributaries join the main river at acute angles, forming a pattern that is widespread in areas with uniform rock structure and gentle slopes, like the plains of North India.
  • Trellis Pattern: This pattern forms when tributaries flow parallel to each other for some distance before joining the main river, often at right angles. It typically develops in regions where the geology consists of folded or faulted rocks, with the main river following a strike valley and tributaries joining from the dip slopes.

Common mistakes

  • Confusing river basins with watersheds due to similar functions.
  • Difficulty in distinguishing between different drainage patterns.
  • Incorrectly identifying rivers based on their geographical characteristics or historical significance.
  • Misremembering the confluence points of major river systems.

Revision tips

  • Create a map of India and mark the major river basins and their corresponding rivers.
  • Draw simple diagrams to illustrate dendritic and trellis drainage patterns for better recall.
  • Focus on the 'Sorrow of Bengal' and rivers flowing through rift valleys as these are common exam topics.
  • Review the definitions of river basin and watershed to ensure clear understanding of their differences.

Practice MCQs

Q1. Which river is historically known as the 'Sorrow of Bengal' due to its devastating floods?

Q2. Which of the following rivers possesses the largest river basin in India?

Q3. The term 'Panchnad' refers to the confluence of five major rivers in the Punjab region. Which of these is NOT part of the Panchnad?

Q4. Which river is known for flowing through a rift valley in India?

Q5. The confluence point where the Alaknanda and Bhagirathi rivers meet to form the Ganges is known as:

Frequently asked questions

What is the main focus of Chapter 3: Drainage System for Class 11 India Physical Environment?

Chapter 3 focuses on understanding the various drainage systems in India, including concepts like river basins, watersheds, and different types of drainage patterns such as dendritic and trellis.

How do these NCERT Solutions help students prepare for exams?

These solutions provide clear, step-by-step answers to all exercise questions, helping students understand complex concepts, revise key geographical features, and practice identifying specific rivers and patterns, thereby boosting exam preparation.

What is the difference between a river basin and a watershed?

A river basin is the larger area drained by a major river and its tributaries, while a watershed is a smaller area drained by a stream or a system of streams; river basins are generally larger in area than watersheds.

Which river is famously known as the 'Sorrow of Bengal' and why?

The Damodar River is known as the 'Sorrow of Bengal' due to its history of causing severe floods that have historically devastated the region.

Can you identify a major Indian river that flows through a rift valley?

Yes, the Narmada River is a prominent example of a major Indian river that flows through a rift valley.

Important links

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