Consider the following statements: 1. River Kaveri has well developed valley 2. Valley of River Alakananda is still growing 3. River Krishna is largest east flowing peninsular river Which of the statements given above is/are correct?

Correct — B, 1 and 2. Statement 1 holds: the Kaveri drains the ancient, stable Deccan block, has long been graded, and flows through a broad, mature valley with a wide flood plain and a large delta at its mouth. Statement 2 holds for the opposite reason: the Alakananda is a Himalayan headstream of the Ganga, rising at the Satopanth and Bhagirath Kharak glaciers and joining the Bhagirathi at Devprayag, and it flows through mountains that are still rising, so it is still cutting down and eating headward — its valley is a young, deep gorge that is actively growing. Statement 3 fails on a single fact: the largest east-flowing peninsular river is the Godavari, not the Krishna. The Godavari runs about 1,465 kilometres and drains roughly 3.1 lakh square kilometres, which is why it is called the Dakshin Ganga; the Krishna is the second largest of the group.

• (a)1 only — It drops the Alakananda. A river in a mountain range that is still being uplifted is the standard textbook case of a valley in the youthful stage, actively deepening and extending.
• (c)2 and 3 — It keeps the one false statement and drops a true one. The Krishna is not the largest east-flowing peninsular river; the Godavari is.
• (d)2 only — It rejects the Kaveri statement, which is straightforwardly true — a peninsular river on an old, tectonically quiet plateau is the classic example of a well-developed, graded valley.

Indian rivers split into two families that behave differently. The Himalayan rivers are young, perennial, fed by snow and rain, and flow through mountains still rising, so they cut down hard and their valleys are deep gorges in the making. The peninsular rivers run across one of the oldest and most stable land surfaces on Earth, have largely finished their downcutting, and flow in shallow, broad, graded valleys. The Alakananda and the Kaveri are the two families' textbook representatives.

The item mixes a process claim with a size claim, and the size claim is where candidates fall. Rank the east-flowing peninsular rivers once — Godavari, then Krishna, then Mahanadi, then Kaveri — and statement 3 becomes automatic. The other useful ordering is west-flowing: the Narmada and the Tapi are the two large ones, and they run in rift valleys rather than building deltas, which is why they are the exceptions in every question on peninsular drainage.

• The Godavari is the largest peninsular river, about 1,465 km long and draining roughly 3.1 lakh sq km — the Dakshin Ganga.
• The Krishna is the second largest east-flowing peninsular river, after the Godavari and before the Mahanadi.
• The Alakananda rises at the Satopanth and Bhagirath Kharak glaciers and meets the Bhagirathi at Devprayag to form the Ganga.
• Himalayan rivers flow through actively rising mountains, so they are still downcutting and extending headward.
• Peninsular rivers such as the Kaveri run over an old, stable shield and have broad, graded valleys with large deltas.

• Ranking the Krishna above the Godavari because its basin spans more states in the news.
• Assuming a river with a famous delta must be the largest of its group.
• Treating 'valley still growing' as a defect rather than as the signature of a young, uplifting mountain range.

Asked as a three-statement item combining geomorphology with a ranking, so one recalled number decides the whole answer.

• practice — not a real PYQ

  The Alakananda joins the Bhagirathi to form the Ganga at

  • (a)Rudraprayag
  • (b)Karnaprayag
  • (c)Devprayag
  • (d)Vishnuprayag

  Answer(c) Devprayag — the confluence below which the river is called the Ganga.

• practice — not a real PYQ

  Which one of the following is the largest river of peninsular India?

  • (a)Krishna
  • (b)Godavari
  • (c)Mahanadi
  • (d)Kaveri

  Answer(b) Godavari — about 1,465 km long, and known as the Dakshin Ganga.