RAS question
The Tehri Dam, one of the tallest dams in the world, is built on which river?
Correct answer: (C) Bhagirathi.
The Tehri Dam is built on the Bhagirathi River near Tehri in Uttarakhand.
Explanation
Tehri Dam is not on the Ganga's main channel; it is on the Bhagirathi River near Tehri in Uttarakhand. The National Portal of India describes it as a multi-purpose rock-and-earth-fill embankment dam and links it with irrigation, municipal water supply and hydroelectric generation. Bhagirathi is one of the source streams of the Ganga: it meets the Alaknanda at Devprayag to form the Ganga. The dam's precise river is Bhagirathi, even though the project is often discussed in the wider Ganga-basin context.
Why the other options are wrong
- (A) Alaknanda is a tributary/source stream in the Ganga system, but the Tehri Dam is at Tehri on the Bhagirathi, not on the Alaknanda.
- (B) Yamuna is a different Himalayan river system, while the Tehri Dam is specifically located on the Bhagirathi River near Tehri in Uttarakhand.
- (D) Bhagirathi later joins the Alaknanda at Devprayag to form the Ganga, so calling the dam's river the Ganga main channel misses the pre-confluence location.
Concept
Indian drainage and multipurpose river-valley projects require a clear distinction between Himalayan source streams and the named main channel. RAS repeatedly links dams with rivers, states, irrigation and hydropower in one compact geography fact.