Tehri Hydro Development Corporation Ltd.
The river diversion works for construction of earth and rockfill dam at Tehri, comprise the construction of a cofferdam and four nos. diversion tunnels of 11.0 m dia. In view of site topography and economy in construction cost, the cofferdam was planned so as to be an integral part of main dam and is, therefore, also referred to as the 1st stage Dam. All the four diversion tunnels were constructed by March, 1988. Cofferdam was raised from deepest foundation level i.e. El. 596.0 (+/−) m in working season 1989–90. Further raising of coffer dam could not be done due to various reasons. It was subsequently, planned to implement the raising of cofferdam in working season 1994–95.
This paper presents an account of river diversion scheme as adopted and a brief account of the studies carried out for fixing the height of cofferdam and proposed sequence of closure of diversion tunnels.
