Koteshwar Dam

The Koteshwar Dam is a gravity dam on the Bhagirathi River, located 22 km downstream of the Tehri Dam in Tehri District, Uttarakhand, India. The dam is part of the Tehri Hydropower Complex and serves to regulate the Tehri Dam's tailrace for irrigation and create the lower reservoir of the Tehri Pumped Storage Power Station. In addition, the dam has a 400 MW (4x100 MW) run-of-the-river power station. The project was approved in 2000 and its first generator was commissioned on 27 March 2011, the second on 30 March 2011. The construction site had been inundated in September 2010 by floods. The diversion tunnel was later blocked heaving/collapse of the hill in December 2010. The spillway was commissioned in Jan, 2011. The last two generators were made operational in March 2012.

Design
The dam is 97.5 m tall and 300 m long. It has a structural volume of 560000 m3 and its crest lies at an elevation of 618.5 m above sea level. The dam's spillway consists of four 18 m wide and 16 m tall radial gates. When the reservoir is at flood level, the spillway has a discharge capacity of 13240 m3/s. Receiving water from Tehri Dam and collecting it from an overall 7691 km2 catchment area, the dam creates a reservoir with a 88900000 m3 capacity, of which 35000000 m3 is active (or "useful"). The reservoir's surface area is 29 km2 and at full pool, it lies at an elevation of 612.5 m. The dam's power station is a run-of-the-river type and uses the active storage in the reservoir which can draw the lake down 30 m from full pool. The power house is located on the right bank of the river below the dam and contains 4 x 100 MW Francis turbine-generators. The height of the dam allows for a maximum 75 m of hydraulic head.