120 MW Rammam Hydroelectric Power Project, Stage III

The location of the project is approximately 150 km from Bagdogra / Siliguri in the Darjeeling district. The location of the dam is 3 km upstream of Lodhama, West Bengal. The Rammam project is a run-of-the-river type of hydroelectric power project. The head & discharge of the project is 481.33 & 28 cumsec. The length of the D-shaped headrace tunnel is 8.2 km & dia. is 4 m. The surge shaft is a restricted orifice type with a dia. of 14.5 m & a height of 52.5 m. The length of the pressure shaft/penstock is 1520 m with a dia. of 2.5 m. The tailrace tunnel is a cut & cover box section type with a size of (4×3 m) & its length is 740 m long. The output capacity of the project is 120 MW, i.e, (40×3 ).

Encardio-rite was awarded the sub-contract for supply, installation as well as monitoring of geotechnical instrumentation for the Barrage and headrace tunnel. The instrumentation included:

• Piezometers
• Pressure cells
• Strain meters – rosette with no stress strain meter
• Inclinometers
• Joint meters
• Borehole extensometer – multipoint 
• Automatic water level recorder
• Portable readout units
• Dataloggers
• Strong motion accelerometer