Project Layout

The headworks comprises of a boulder lined broad crested weir. The weir has crest length of
43.5 m, 8.83 m height (from the foundation level) and its crest elevation is 867.50 m amsl. The
intake is constructed in combined arrangement together with undersluice, power-intake and
trash-passage provisioned for floating debris. After intake, a short curved inlet canal conveys
water into the gravel trap. Approach culvert joins the gravel trap with two separate settling basins
having two chambers each. From the end of the settling basin, the water is conveyed to the
headpond. A pressurized flow starts immediately after the outlet of the headpond where the inlet
portal stands. The headrace tunnel is 3578.26 m long and the cross section is inverted Ushaped.
An off set surge-shaft is located at chainage 3+930 m along the tunnel measured from
the inlet portal and is exposed to the surface. The height of the surge-shaft is 46.24 m and the
finish diameter are 6.0 m and 6.65 m for concrete lined section and shotcreted section
respectively. A single surface penstock pipe of 694.46 (401+293.46) m length conveys the water
further and bifurcates before feeding to two generating units accommodated in the semi surface
powerhouse. About 40 m long tailrace culvert conveys the water from powerhouse and
discharges into Hewa Khola back again.

The generated power is evacuated through a 132 kV single circuit transmission line of 4 km
length. The transmission line connects to the national grid at the Phidim substation.