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Thana-Plaun Hydroelectric Project conceived as a storage cum run-of-the-river scheme on Beas river in Himachal Pradesh, india, in the northwest Himalayas envisages construction of a Roller Compacted Concrete gravity dam ±107 m high and 221m long to create live storage capacity of 44.93 million cubic meter for providing 3 hours peaking during lean flow months throughout the life of the project. Water would be diverted through power intakes to two head race tunnels and steel lined pressure shafts to an underground dam toe power house housing three main generating units of 50.33 MW and two environmental units of 20 MW each with total capacity of 191 MW. For reservoir and sedimentation management, five low level under sluice spillway gates of 11 m width and 15.2 m height have been provided. Location of sluice spillways and power intakes has been optimized by carrying out two and three dimensional reservoir sedimentation studies. Reservoir would continue to serve as desanding chamber throughout life of the project, even after its sedimentation. Delineation of the project layout in order to reduce socio-economic impact, to minimize project affected families and to reduce impact on bio-diversity in the river reach downstream of the dam has been discussed.
