Koteshwar HEP (4×100 MW), is about 22 km downstream of Tehri Dam, is an integral part of Tehri Hydro Power Complex (2400 MW). It consists of a 97.5m high concrete gravity dam across river Bhagirathi at Koteshwar and a surface power house accommodating four conventional Francis generating units of 100 MW each on the Right bank. The dam is provided with spillway having 4 bays to pass the probable max flood discharge of 13243 Cumecs. The overflow spillway and energy dissipation arrangement has been located centrally in the river course itself. It is having a live storage capacity of 35 MCM and serve as the lower balancing reservoir for Tehri PSP. This project also controls how much water is released for agriculture from the Tehri reservoir.

The work was originally awarded in November 2002 for 394 Cr and was successfully completed in 2011 for a total work value of 1050 Cr.

This project involves lining a 593 m long, 8.0 m wide horseshoe-shaped diversion tunnel and a 500 m long, 8.0 m wide D-shaped access tunnel to reach the open powerhouse. The whole project entails the excavation of it is a concrete gravity dam with a maximum height of 97.5 meters above the deepest foundation. Four spillways with four 18m x 16m radial gates make
up this dam’s four spillways. On the right bank, a power intake was built with four 6.2-meterdiameter penstocks. On the right bank, a surface powerhouse was built at the dam’s toe. Additionally, this project entails erecting civil works in the outside switch yard, such as tower basements and switch yard control rooms.

All four units (Unit-I, Unit-II, Unit-III & UnitIV) were synchronized with the Northern Grid in March’ 11, March’11, Jan’12 & Mar’12 respectively