Explanation:

Tehri was a small town in Uttarakhand, located on the confluence of Bhagirathi and Bhilangna Rivers. The town got submerged in water which resulted in creation of a large catchment area. This way, the Old Tehri town became The Tehri Lake. It is the largest manmade lake in Asia. Town of Tehri was evacuated to make space for Tehri dam. It is located at an elevation of 1700 meters. It is an artificial dam reservoir that came into existence when water from Bhagirathi River was diverted to fill the Tehri dam reservoir.