Tehri Dam is the highest dam in India and fourth highest dam in the world. It is around 260.5 metre high and 592 metre long. It is part of the Tehri Dam & Hydro Power Project (the multi-purpose river valley project) taken up for construction on River Bhagirathi to tap its vast potential for irrigation and hydro-electric purposes. It is located in the Tehri district of Uttarakhand.
Tehri dam is an earth and rock fill dam. Its spillway system consists of chute spillway (consisting of three spillway radial gates) and four shaft spillways. It is designed for Probable Maximum Flood (PMF) of 15540 cumec and a drop of 220 m. The reservoir has gross storage capacity of 3540 MCM and effective storage capacity of 2615 MCM.
It consists of an underground power house housing four Turbine/ Generator sets of 250 MW each (1000 MW capacity), designed to operate with a head variation of 90 m. (4 units of 250 MW each). Construction and operation of dam & power house was taken up by Tehri Hydro Development Corporation (THDC) and was commissioned in 2006. Some of its benefits are:
The main river stream originates in the Garhwal Himalaya (300 55’ N, 7907’ E) under the name of the Bhagirathi. The river cuts its path through the Himalayas and flows a distance of about 205 Kilometers from Gaumukh and transverses through two districts of Uttarakhand state i.e. Uttarkashi and Tehri to reach Devprayg where another head stream, the Alaknanda, joins it to form Holy Ganga.