I.  Main Civil Works/Packages Including Hydro-Mechanical (HM) Works

C-1 DAM

Contract Package # C-1 :-Construction of Diversion Tunnel, Dam, Intake and Desilting Arrangement including Hydro-Mechanical works and Highway Tunnel

The construction work of Diversion Tunnel, Dam, Intake and Desilting Arrangement including Hydro-Mechanical works and Highway Tunnel was awarded to M/s Jaiprakash Associates Ltd. on June 26, 2011.

The Contract Package C-1 consists of following components:

• 1 No. Diversion Tunnel of 12 m dia., 877.46 m length & 1118 Cumec. Design Discharge
• Concrete Gravity Dam of 91 m height & 223.8 m length
• U/s Coffer Dam of 168.75 m length & 22 m height
• D/s Coffer Dam of 102.02 m length & 13.5 m height
• Chute with Gates type Auxiliary Spillway with 1 No. gate
• Sluice Spillway with 7 Nos. Gate, each of  8 m x 13.20 m
• 4 Nos. Intake Tunnels each of 6.4 m dia. & total length of 1926.78 m
• 4 Nos. underground Desilting Chambers each of 420 m (L) x 17/19 m (W) x 24.74 m (H)
• Silt Flushing Tunnel(D-shaped) of size 3.6 m (W) x 2.96 m (H) to 8.6 m (W) x4.675 m (H), 495 m length
• Highway Tunnel of 11 m dia., 1522 m length

Special Features / Uniqueness of the Package

• Diversion Tunnels (with 12 M dia) constructed is the largest in the sub-continent.
• Desilting Chambers are the biggest in size in the country.
• First ever Highway Tunnel (1.5 KM) constructed in Bhutan on the National Highway.