CDS (I) 2020 General Knowledge · Question 109 of 120

Correct — A, Volga. The Volga is Europe's longest river, about 3,530 kilometres from the Valdai Hills to a delta below Astrakhan, and that delta opens into the Caspian Sea, not the Black Sea. Because the Caspian has no outlet to any ocean, the Volga belongs to an inland drainage basin — it is the largest river in the world that ends in a closed sea. The other three all reach the Black Sea. The Danube crosses or touches ten countries and enters through a delta on the Romanian and Ukrainian border; the Dnieper runs down through Belarus and Ukraine past Kyiv; and the Don flows into the Sea of Azov, which connects to the Black Sea through the Strait of Kerch, so it drains into the Black Sea system.

• (b)Dnieper — Rises in Russia, flows through Belarus and Ukraine past Kyiv and Dnipro, and enters the Black Sea through a liman below Kherson. It is the fourth-longest river in Europe.
• (c)Don — Reaches the Sea of Azov at Rostov-on-Don, and the Sea of Azov opens into the Black Sea through the Strait of Kerch. A candidate who treats the Azov as a separate sea can be tempted here, but hydrologically the Don is in the Black Sea basin.
• (d)Danube — The classic Black Sea river — the second-longest in Europe, rising in the Black Forest, passing Vienna, Bratislava, Budapest and Belgrade, and reaching the sea through the Danube Delta shared by Romania and Ukraine.

River questions of this kind are really questions about drainage basins. A river's mouth is fixed by the basin it belongs to, and the useful distinction in Eurasia is between rivers that reach an ocean-connected sea and rivers that end in a closed basin. The Caspian Sea is the world's largest inland water body with no outlet, and the Volga together with the Ural and the Kura empties into it. The Black Sea, by contrast, is connected to the Mediterranean through the Bosporus, the Sea of Marmara and the Dardanelles.

The Don is the option that separates a careful candidate from a lucky one. Its mouth is in the Sea of Azov, and unless you know that the Azov is a northern arm of the Black Sea joined by the Strait of Kerch, the Don looks like the odd one out. Fix the four mouths as a set — Volga to the Caspian, Danube and Dnieper to the Black Sea, Don to the Azov and so to the Black Sea — and the item is safe in either direction. It is worth carrying the neighbouring facts too, since the same map is asked about repeatedly: the Rhine reaches the North Sea, the Rhone the Mediterranean, and the Loire the Bay of Biscay.

• The Volga, about 3,530 kilometres long, is Europe's longest river and drains into the Caspian Sea.
• The Caspian Sea has no outlet to any ocean, so the Volga belongs to an inland drainage basin.
• The Danube is Europe's second-longest river and enters the Black Sea through a delta on the Romanian and Ukrainian border.
• The Dnieper flows through Russia, Belarus and Ukraine and enters the Black Sea below Kherson.
• The Don empties into the Sea of Azov, which is joined to the Black Sea by the Strait of Kerch.

• Treating the Sea of Azov as unconnected to the Black Sea and marking the Don as the answer.
• Assuming the Volga must reach an ocean because it is the longest river in Europe; it ends in a closed sea.
• Confusing the Dnieper with the Dniester, a shorter river that also reaches the Black Sea.

As a river-to-sea match, as an odd-one-out, or as a pairs item mixing rivers from several continents.

• practice — not a real PYQ

  Which one of the following seas has no outlet to any ocean?

  • (a)Black Sea
  • (b)Caspian Sea
  • (c)Sea of Azov
  • (d)Adriatic Sea

  Answer(b) Caspian Sea — the largest inland water body in the world, into which the Volga, the Ural and the Kura drain.

• practice — not a real PYQ

  The Sea of Azov is connected to the Black Sea by

  • (a)the Strait of Kerch
  • (b)the Bosporus
  • (c)the Dardanelles
  • (d)the Strait of Otranto

  Answer(a) the Strait of Kerch — which is why the Don, whose mouth is in the Azov, counts as a Black Sea basin river.