• The Bokang-baling Hydroelectric Project is located on river Dhauliganga, a tributary of Kali (Sarda), in Pithoragarh district of Uttarakhand. Project envisages utilization of the water of the river Dhauliganga for power generation on a storage type development harnessing a head of about 500 m. The Project is approachable from Tanakpur-Khela and is located at a distance of 310 km from Tanakpur. The nearest rail head is located at Tanakpur and nearest airport is located at Delhi.
    As per Pre-feasibility studies, the proposed project involves construction of 136 m high Concrete Dam after diversion of river by constructing a 6 m dia. D-shaped Diversion Tunnel. The water conductor system consists of 1 nos. gated Power intake of size 5 m x 5 m, a 5.0 m dia., 9.4 km long & horse shoe shaped head race tunnel. The head race tunnel ends in a 140 m dia and 120 m high U/S surge shaft. Further, one no. Pressure Shaft, 4.2 m dia. is bifurcated into 3 nos. penstocks before entering the machines in the underground machine hall of size 19 m x 111 m. A Tail race tunnel of 5 m dia. and 295 m length, discharges the water back into the river.
     The project with a proposed installation of 330 MW (3 x110 MW) would afford an annual energy generation of 1124.62 GWh in a 90% dependable year. As per Pre Feasibility Report, the project is estimated to cost ` 1100.50 crores including IDC at June, 2003 price level. The first year and levellised tariff from the project would be ` 1.68 / KWh and ` 1.47/ KWh respectively.
    State Uttarakhand
    District Pithoragarh
    River Dhauliganga
    Dam Site
    Location D/S of confluence of Lassar Yankti with Dhauliganga river
    Longitude 80° 31' 58" E.
    Latitude 30° 16' 34" N.
    Nearest Rail Head Rishikesh.    
    Nearest Airport Dehradun.
    Catchment Area at Dam site 691 Sq.  Km
    Maximum average discharge at Dam site 48.64  Cumecs
    Minimum average discharge at Dam site 32.09   Cumecs
    Full Reservoir Level (FRL) El. 3280 m.
    Minimum Draw Down Level (MDDL) El. 3240 m.
    Gross Storage at FRL 50.67 MCM
    Live Storage  35.13 MCM
    Area under Submergence at FRL 132.5 ha.
    Diversion Tunnel
    Number 1
    Diameter 6.0 m
    Length 490 m.
    Diversion Discharge  205.82 Cumecs
    Type  Concrete Gravity
    Top Elevation of Dam El. 3283 m.
    Height of Dam above deepest foundation level. 136 m.
    Length of dam at top 438 m.
    River bed level EL 3162 m.
    Design Flood 3492.94 Cumec.
    Type                                                                    Sluice spillway
    Crest elevation  El.3200 m.
    Number of Bays 4
    Length of spillway 48 m
    Energy dissipation Ski jump bucket.
    Invert level EL 3227.1  m
    Number     1
    Size of Gate opening 5.0 m x 5.0 m
    Trash rack 5.5m x 13.9mx 5 no.
    Intake conduit 5.0 m dia.
    Head Race Tunnel
    Shape Horse Shoe
    Diameter 5 m
    Length 9.4 km.
    Surge Shaft
    Number 1
    Diameter 14 m.
    Height 120 m.
    Pressure Shaft
    Number 1 (Bifurcated into 2 of 2 m dia)
    Diameter 2.8  m
    Length 600 m
    Power House
    Type  Underground
    Installed Capacity 330 MW 
    Number of Units 3 x 110 MW
    Power house cavern size (main) 19 m X 111 m
    Type of Turbines Francis Vertical Axis
    E.L. of Turbines EL 2774.0 m
    Rated Head 455.2 m
    Tail Race Tunnel 
    Diameter 5.0 m dia.
    Shape D-shaped
    Length                  295.0 m
    Design discharge 78.34 Cumec
    River bed Level 2778.0 m
    Normal TWL 2783.0
    Size Gas insulated switchyard (GIS) on the floor above the transformer/s in the Transformer cavern of size 6 m x  86 m
    Power Generated  
    Installed capacity    330 MW ( 3 x 110 MW )
    Annual energy generation :  
    i) 90% dependable year 1124.62 GWH
    ii) Energy in 90% year on 95% availability 1108.38 GWH

Updated on : 19/02/2018