NCERT Class 11 Geography India Physical Environment: Chapter 3 — C H A P T E R
This chapter, "Drainage System," from NCERT's India Physical Environment for Class 11, introduces the concept of drainage as the flow of water through well-defined channels and the network of these channels as a drainage system. It explains that the drainage pattern is influenced by geological time, rock structure, topography, slope, and water flow. The chapter defines a river's catchment area and discusses four primary drainage patterns: dendritic (like tree branches, common in northern plains), radial (flowing in all directions from a hill, like Amarkantak range), trellis (parallel primary tributaries joining at right angles), and centripetal (discharging into a lake or depression from all directions). Understanding these patterns is crucial for comprehending India's physical geography and water resources within the CBSE curriculum.
Quick info
| Board | CBSE / NCERT |
|---|---|
| Class | Class 11 |
| Subject | Geography |
| Book | India Physical Environment |
| Chapter | Chapter 3 — C H A P T E R |
| Language | English |
| PDF type | NCERT Textbook |
| Session | CBSE 2026 |
| Reading time | 2 minutes |
| Word count | 383 |
Learning outcomes
- Define drainage and drainage system.
- Identify factors influencing drainage patterns.
- Describe and differentiate between dendritic, radial, trellis, and centripetal drainage patterns.
- Understand the concept of a catchment area.
- Relate drainage patterns to geological and topographical features.
Vocabulary
| Word | Meaning |
|---|---|
| Drainage | The flow of water through well-defined channels. |
| Drainage System | The network of channels through which water flows. |
| Catchment Area | The specific area from which a river drains its water. |
| Dendritic | A drainage pattern resembling the branches of a tree. |
| Radial | A drainage pattern where rivers flow in all directions from a central high point. |
| Trellis | A drainage pattern with parallel primary tributaries joining at right angles. |
| Centripetal | A drainage pattern where rivers flow from all directions into a central depression or lake. |
| Perennial | A river that has water throughout the year. |
| Ephemeral | A river that has water only during the rainy season. |
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Practice questions
- What is drainage? Answer: Drainage is the flow of water through well-defined channels.
- What is a catchment area? Answer: A catchment area is the specific region from which a river collects and drains its water.
- Name the four main drainage patterns discussed in the chapter. Answer: The four main drainage patterns are dendritic, radial, trellis, and centripetal.
- Which drainage pattern resembles the branches of a tree? Answer: The dendritic drainage pattern resembles the branches of a tree.
- Give an example of a region with a radial drainage pattern. Answer: The rivers originating from the Amarkantak range present a good example of a radial drainage pattern.
Practice MCQs
Q1. The network of channels through which water flows is known as:
Explanation: A drainage system refers to the entire network of channels that drain an area.
Q2. Which drainage pattern is characterized by rivers flowing in all directions from a central elevated area?
Explanation: Radial drainage patterns occur when rivers originate from a hill or mountain and flow outwards in all directions.
Q3. The rivers of the northern plain in India typically exhibit which drainage pattern?
Explanation: The dendritic pattern, resembling tree branches, is common in areas with uniform rock structure and gentle slopes, like the northern plains.
Q4. What is an area drained by a river and its tributaries called?
Explanation: A catchment area is defined as the specific region from which a river collects and drains its water.
Q5. In which drainage pattern do primary tributaries flow parallel to each other and join secondary tributaries at right angles?
Explanation: The trellis pattern is characterized by a rectangular network of streams, formed by parallel main tributaries and perpendicular secondary tributaries.
Q6. A river that has water only during the rainy season is called:
Explanation: Ephemeral rivers are those that flow only during periods of rainfall and may be dry for the rest of the year.
Frequently asked questions
What is the definition of drainage?
Drainage is defined as the flow of water through well-defined channels.
What determines the drainage pattern of an area?
The drainage pattern is determined by the geological time period, nature and structure of rocks, topography, slope, and the amount and periodicity of water flow.
What is the difference between a perennial and an ephemeral river?
A perennial river has water throughout the year, while an ephemeral river has water only during the rainy season and may be dry otherwise.
Where is the dendritic drainage pattern commonly found in India?
The dendritic drainage pattern is commonly found in the rivers of the northern plains of India.
What is a catchment area?
A catchment area is the specific region from which a river collects and drains its water.
Can you give an example of a radial drainage pattern?
Rivers originating from the Amarkantak range in India are a good example of a radial drainage pattern.
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NCERT Class 11 Geography — India Physical Environment — Chapter 3 — C H A P T E R. Verified by NCERT Help Editorial Team. Reviewed on 29 Jul 2026. Last updated 10 Aug 2026.