Previous Year Question
Assertion (A): The rivers of West Coast of India do not form delta.
Reason (R): They flow through short courses on relatively harder rocks.
Choose the correct answer using the codes given below:
Both (A) and (R) are correct and (R) is the correct explanation of (A).
Both (A) and (R) are correct, but (R) is not the correct explanation of (A).
(A) is true, but (R) is false.
(A) is false, but (R) is true.
Correct Answer: A
Detailed Solution
The western coastal plain of India is comparatively narrow, and the Western Ghats lie quite close to the coast at many places. Therefore, most west-flowing rivers originating in the Western Ghats have a short course and steep gradient before reaching the sea.
A large part of their course passes over the old and relatively hard rocks of Peninsular India. Because of their short courses and hard-rock terrain, these rivers generally carry less sediment than the large east-flowing river systems.
Moreover, owing to their steep gradient, west-flowing rivers reach the Arabian Sea relatively rapidly. Since sufficient sediment is not deposited at their mouths, large deltas generally do not develop.
In contrast, the eastern coastal plain is broad and has a comparatively gentle slope. Long east-flowing rivers such as the Mahanadi, Godavari, Krishna and Kaveri carry large quantities of sediment and form extensive deltas along the Bay of Bengal.
A useful distinction is that the major west-flowing rivers Narmada and Tapi also form estuaries rather than deltas.