The 1000 MW Karcham-Wangtoo Hydroelectric Project is a run-of-the-river project consisting of four units of 250 MW each on the river Sutlej, in Kinnaur district of the State of Himachal Pradesh.

Project Features:

• Out of the 88 m height of the deepest overflow block for concrete dam, 53 m is entirely below the river bed level.
• Overall, more than 50% of the dam concrete volume is below the river bed level and hence managing de-watering of the dam pit while excavating below the river bed has indeed been a challenging job.
• Jet grouted columns up to 67 m depth in the upstream coffer dam and up to 50 m depth in the downstream coffer dam have been provided as cut-off walls to manage the seepage of water in the dam pit.
• Keeping in view the damages/outages caused due to silt to the turbines in 1500 MW Nathpa Jhakri powerhouse during monsoons, the intake level has been kept at about 15 m above the river bed level in order to utilize the top layers of water which carry less sediment.
• Further a 5.25 km long silt flushing tunnel with gravity flow for effective flushing of sediments from the sedimentation chambers has been provided which is the longest flushing tunnel in the history of hydropower plants in India.