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2) Explain the concept of discordant drainage? Do structure and lithological aspects always control drainage systems? Explain with examples. (250 words)

Topic: Salient features of world’s physical geography.

2) Explain the concept of discordant drainage? Do structure and lithological aspects always control drainage systems? Explain with examples. (250 words)

 

Why this question:

The question is based on the concept of types of drainage system and role of structure and lithological aspects as a control factor on them.

Key demands of the question:

The answer must provide for a brief discussion on what is meant by Discordant drainage system with examples and then evaluate the role of structure and lithological aspects as a control factor on the formation of a drainage system.

Directive word

Explain – Clarify the topic by giving a detailed account as to how and why it occurred, or what is the  particular context. You must be defining key terms where ever appropriate, and substantiate with relevant associated facts.

Structure of the answer:

Introduction

Start by definition of a drainage system.

Body

Discuss the following aspects in the answer:

  • What is a Discordant drainage system? – The river follows its initial path irrespective of the changes in topography i.e. it does not correlate to the topology [surface relief features] and geology [geological features based on both Endogenetic movements and exogenetic movements] of the area.
  • Explain the types : Discordant drainage patterns are classified into two main types: antecedent and superimposed.
  • Factors otherwise Influencing drainage patterns  – Topography, Geology, landforms etc.
  • Then move on to explain role of structure and lithology ; explain how these factors do not control the patter in case of Discordant drainage pattern.
  • Substantiate your answer with examples and suitable diagrams wherever necessary.

Conclusion

Conclude with significance of controlling factors in formation of a drainage pattern.