Question

Which of the following rivers makes an estuary?
a.Cauvery
b.Krishna
c.Narmada
d.Ganga

Answer 1

Hint: Estuary is an area of brackish water which is the tidal mouth of a large river. It refers to the meeting point of the tide and the stream.

Complete answer:The rivers of India have been divided into East flowing rivers and west-flowing rivers. The east-flowing rivers are the Godavari, Krishna, Cauvery, Mahanadi and the Narmada and Tapi form the west-flowing rivers.

The east-flowing rivers drain into the Bay of Bengal and they form huge deltas. Whereas, the west-flowing rivers drain into the Arabian Sea and do not form deltas.
The west-flowing rivers form estuaries instead of Delta because,
-The Deccan plateau has an eastward sloping which makes it more elevated than that of the eastern coast. Hence, there is no ground available for the formation of Delta.
-Since most of the west-flowing rivers originate in Western ghat, their travel distance is lesser as compared to the east-flowing rivers before getting into the sea.
-The west-flowing rivers flow through hard rocks on their way and are unable to collect silt. These hard rocks prevent the west-flowing rivers from widening their mouths into the sea. Hence, they form estuaries.

Looking at the options given:

Option a: The Cauvery river forms a wide delta which is known as the “garden of southern India". This is an incorrect option.

Option b: The Krishna River along with the delta formed by the Godavari River is called the Rice Granary of South India. This is an incorrect option.

Option c: The Narmada is a west-flowing river which forms estuaries. Hence, this is the correct option.

Option d: The Ganga river forms the largest delta along with the Brahmaputra river. This is an incorrect option.

Option 'c' is correct.

Note: Basically, estuaries are formed by rising sea levels. India has 14 major, 44 medium and 162 minor estuaries. The major estuaries drain into the Bay of Bengal.