RAS question
Which river is known as 'Sorrow of Bihar'?
Correct answer: (A) Kosi.
The Kosi River is known as the Sorrow of Bihar because of its frequent, destructive floods and its tendency to shift course.
Explanation
Kosi is the river known as the Sorrow of Bihar. The India-WRIS Ganga Basin Report describes the Kosi as formed by the Sun Kosi, Arun Kosi and Tamur Kosi, all rising in the Himalayan region of Nepal and Tibet, and calls it notorious for frequent and disastrous floods and shifting courses. In the flood section, the report again identifies the Kosi as the Sorrow of Bihar and says it is the most treacherous north Bihar river for floods. Himalayan rivers bring large quantities of water and silt during the monsoon, lose slope on entering the plains, spill over their banks and shift their courses. That is why the epithet fits Kosi, not a more stable river.
Why the other options are wrong
- (B) Ghaghara is named among flood-causing Ganga tributaries, but it does not have the specific epithet Sorrow of Bihar.
- (C) Gandak has a serious flood problem in the Ganga basin, yet the Sorrow of Bihar label is reserved for Kosi.
- (D) Son is not identified as Sorrow of Bihar; it is a right-bank tributary with a relatively stable course.
Concept
This tests river behaviour in the Ganga basin, especially flood-prone Himalayan tributaries in the plains. RAS repeats such epithets because they connect physical geography with disaster risk and regional planning.