 nakthan hep nakthan hep gayathri mon 6192023 1149 nakthan hep is being conceived as a runofriver project on tosh nallah parbati river a left bank tributary of beas river in kullu district of himachal pradesh the project envisages the construction of the diversion barrages across parbati river and tosh nallah conveying the water so diverted through two independent hrts to meet at a common point followed by a single hrt of bigger diameter terminating into an underground surge shaft which conveys water through pressure shaft two vertical limbs to facilitate the construction thus utilising a gross head of approximately 69775 m and feeding underground power house having four machines with total installed capacity of 4600 mw 4 x 1150 mw the discharge from the power house is conveyed through tail race tunnel trt into the parbati river the project is expected to generate 154831mu of electricity in 90 dependable year capacity 460mw design energy in 90 dependable year 153511 mu gross head 69608 m barrages parbati tosh height above deepest foundation 15m length of barrage at top 44m height above deepest foundation 17m length of barrage at top 20m penstock pressure shaft 420m diameter 184838m long 4 no unit pressure shaft 21m diameter length ps1 ps2 ps3 ps4 55723454371371 head race tunnel parbati tosh 50m diameter 7472m long 31m diameter 2896m long power house underground power house cavern incl service bay 1320 l x205 w x455 h village nihare thach wanshil thach tehsil bhunter district kullu state himachal pradesh nearest access nearest airport bhunter kullu nearest railhead kiratpur nearest highway nh 21 under investigation preconst clearances stage 1325 mw  beas parbati tosh kullu hp 460 mw  