The construction work of Diversion Tunnel, Dam, Intakes and Desilting chamber including associated Hydro-Mechanical works was awarded to M/s Larsen & Toubro Limited, India.
The MC-1 package consists of following components:
- 2 Nos. of Diversion Tunnel of 11 m dia. each & lengths 1,427 m & 1,296 m.
- 4 Desilting Chamber each of 330 m x 18 m x 24 m.
- U/s & D/s CofferDam.
- 4 Nos. of Intake tunnel each of 6 m dia. & total length of 1,477 m.
- Concrete Dam of 136 m height and 239 m length, 70 m deep below river bed level.
Special Measure Features / Uniqueness of the Package adopted
- 2 m wide, 137 m Long, 92.0 m deep (varies from 40 m to 92.5 m) plastic concrete cut-off wall have been constructed below upstream Coffer Dam first time in the Subcontinent
- conventional vibrated concrete (Quantity 1.6 million Cum.appox.)
- 791 Nos. of 325 mm dia. Micro piles, of total drilling depth of 66,735 m has been carried out, first time in Bhutan
- Consolidation Grouting drilling depth – 37,103 m.
- 50 m to 92 m deep, 491 Nos. Cable anchors, having total drilling depth of 29,778m carried out first time in Bhutan
- 229 Nos. of 2 m dia. RCC piles, 50 to 65 m deep in rocks is being carried out as slope stabilization measures and part Dam foundation first time.