NCERT Class 9 Solutions: Drainage (Contemporary India-I) Chapter 3– Part 1

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Q-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?

  1. Radial

  2. Centripetal

  3. Dendritic

  4. Trellis

Answer: (c)

Explanation: The river system of an area along with all its’ tributaries and distributaries is called the drainage of that region. The area covered by a single river system is called the drainage basin.

Based on land, structure and patters drainage basin are arranged in following four pattern:

  1. Dendritic Drainage Pattern:

    • When the river channel follows the slope of the land, it develops dendritic pattern.

    • The stream resemble the branches of a tree and so it is called dendritic pattern.

      Dendritic Drainage Pattern along the slope of a plane

      Dendritic Drainage Pattern

      Dendritic Drainage Pattern along the slope of a plane

  2. Trellis Drainage Pattern:

    • In trellis pattern, other streams are flowing parallel to the main river and join the river at almost right (or sharp) angles.

    • Trellis pattern develops where hard and soft rocks exist parallel to each other. So that the river has to follow a specific path by cutting soft rocks.

    Trellis drainage pattern where stream follows the soft valley

    Trellis Drainage Pattern

    Trellis drainage pattern where stream follows the soft valley

  3. Rectangular Drainage Pattern:

    • When rocks are strongly joined, then rectangular pattern develops.

    • The rivers and streams now flow along the rectangular rifts and cracks in the rocks

    Rectangular Drainage Pattern along the jointed bedrock

    Rectangular Drainage Pattern

    Rectangular Drainage Pattern along the jointed bedrock

  4. Radial Drainage Pattern:

    • When the streams flow in different directions from a central peak or dome like structure, a radial pattern is developed.

    Radial drainage from a volcano and peak

    Radial Drainage

    Radial drainage from a volcano and peak

  5. Centripetal

When the streams are flowing inwards towards a central lowland (enclosed basin) centripetal pattern is developed.

Centripetal drainage to a low lying basin where drainage happens to a central point

Centripetal Drainage to a Low Lying Basin

Centripetal drainage to a low lying basin where drainage happens to a central point

View the following video for detailed explanation

Watch video lecture on YouTube: Restless Rivers - Stream Types, River Capture and Drainage Patterns

Restless Rivers - Stream Types, River Capture and Drainage Patterns

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