Which of the following rivers is an east flowing river?

Correct — A. Of the four rivers offered, the Godavari is the one that drains east, into the Bay of Bengal.

It rises at Trimbakeshwar near Nashik in Maharashtra and crosses the whole peninsula to a delta on the Andhra coast, which is why it is called the Dakshina Ganga.

The Narmada, the Tapi and the Mahi all run the other way, west into the Arabian Sea and the Gulf of Khambhat. The east-flowing river is option (a).

Why the others are wrong

• (b)
  Narmada river — The Narmada flows west through the rift valley between the Vindhya and Satpura ranges and empties into the Gulf of Khambhat, the opposite direction to the one asked for.
• (c)
  Mahi river — The Mahi rises in the Vindhyas and also flows west to the Gulf of Khambhat. It is remembered for crossing the Tropic of Cancer twice, not for any eastern outlet.
• (d)
  Tapi river — The Tapi runs west in its own rift valley south of the Satpura range and reaches the Arabian Sea near Surat. Like the Narmada it ends in an estuary, not a delta.

Peninsular drainage is decided by the Western Ghats watershed, which runs close to the west coast. The land therefore tilts east.

So the Mahanadi, Godavari, Krishna, Kaveri and Pennar all cross the peninsula to the Bay of Bengal and build deltas there.

The west-flowing exceptions are few, and the large ones run in rift valleys — the Narmada and the Tapi. A river confined to a fault-bounded trough carries its sediment straight out to sea, which is why these two end in estuaries while the east-flowing rivers end in deltas.

Key facts

• The Godavari rises at Trimbakeshwar in Nashik district, Maharashtra, and drains into the Bay of Bengal.
• It is the largest of the peninsular rivers and is called the Dakshina Ganga.
• The Narmada and the Tapi flow west through rift valleys and form estuaries rather than deltas.
• The Mahi crosses the Tropic of Cancer twice on its west-flowing course.

Common traps

• Assuming every large Indian river ends in the Bay of Bengal without checking the western exceptions.
• Forgetting that the Ghats watershed sits near the west coast, which is what leaves so few rivers flowing west.

No directly related past PYQ was found.