JADHGANGA H.E. PROJECT

  • The Jadhganga H.E. Project is located on Jadhganga river a tributary of Bhagirathi river joining it at Bhaironghati from the north in Uttarkashi district of Uttarakhand. The Project is approachable from Rishikesh by road (via Tehri-Uttarkashi-Gangotri highway) at a distance of 267 km up to Bhaironghati and further around 4 km to project site. The nearest rail head is Rishikesh and nearest airport is Jolly Grant, Dehradun.
    The Jadhganga H.E. project is a Run-off-the River scheme with the arrangement of gravity dam with provision of gates to create diurnal storage requirement for peaking purposes.
     
    As per Pre-feasibility studies, the proposed project involves construction of 45m high Concrete Dam after diversion of river by constructing a 5m dia. D-shaped Diversion Tunnel. The water conductor system consists of 1 nos. gated Power intake of size 3.8m x 3.8m each, a De-silting Chamber of size 10m x 17m x 220m. The de-silting chambers converges, after a smooth transition to 3.8m dia., 1.1 km long, horse shoe shaped, head race tunnel. The head race tunnel ends in a 8.0m dia. and 76m high u/s surge shaft. Further, one no. Pressure Shaft, 3.2m dia. is bifurcated into 2 nos. 2.0 m dia penstocks before entering the machines in the underground machine hall of size 59m x 20.5m x 30m. A Tail race tunnel of 4.0m dia. and 290m length, discharges the water back into the river.
     
    The project with a proposed installation of 50MW(2x25) would afford an annual energy generation of 220.88 GWh in a 90% dependable year. As per Pre Feasibility Report, the estimated cost of the project is `271.48 crores including IDC of ` 37.07crores at June, 2003 price level. The first year and levellised tariff from the project would be `2.19 / KWh and `1.91/ KWh respectively.
  • SALIENT FEATURES
    LOCATION
    State Uttarakhand
    District Uttarkashi
    River Jadhganga
     
    DAM SITE: 
    Location 100 m D/S of confluence of Gartang gad with Jadhganga river.
    Longitude     78° 53'17" E
    Latitude 31° 02'18" N
    Nearest Rail Head Rishikesh
    Nearest Airport Dehradun
     
    HYDROLOGY
    Catchment Area at Dam site 1679 Sq.km.
    Snow bound Catchment Area (including area under glacial cover)     977.0 Sq.km.
    Maximum average Discharge at Dam site 145  cumec
    Minimum average discharge at Dam site 10.7  cumec
    Average annual runoff     1607.76 Mcum
    Average monsoon runoff   1289.2 Mcum
    Average non-monsoon runoff 318.56 Mcum.
     
    RESERVOIR
    Full Reservoir Level   (FRL) El. 2802.5 m
    Maximum water level(MWL) El. 2802.5 m
    Minimum Draw Down Level (MDDL) EI. 2785.5 m.
    Gross Storage at FRL 2.28 MCM
    Live Storage  1.1MCM
    Area under submergence at FRL 8.35 ha.
     
    DIVERSION TUNNEL
    Number 1
    Diameter 5.0 m
    Length 400 m
    Diversion Discharge (assumed) 80 Cumec
     
    DAM
    Type  Concrete Gravity Dam
    Top Elevation of dam El. 2805 m.
    Height of Dam 45 m.
    Deepest foundation level.  
    Length of dam at top 110 m
    River bed level EL 2760 m.
     
    SPILLWAY
    Design Flood 6450 cumec.
    Type                                                                    Ogee
    Crest elevation    El. 2775 m.
    Number and size of Bays 3 of 14m x 13.25m
    Length of spillway   54 m
    Energy dissipation Stilling basin.
     
    INTAKE   
    Invert level        EL 2777 m
    Number 1
    Size of Gate opening               3.8 m x 3.8 m
    Trash rack      5 of 10 m x 5.5 m
    Length of intake tunnel 100 m
    Shape of tunnel            D-shaped
     
    DESILTING CHAMBERS
    Number                                        1
    Size 10m x 17m
    Length 220 m
    Design discharge 47 cumecs
    Particle size to be removed 0.2 mm & above.
    Silt Flushing discharge          8 cumec
    Silt Flushing Tunnel Size 2 m dia..
    Silt Flushing Tunnel length 180 m.
     
    HEAD RACE TUNNELS
    Number
    Shape Horse Shoe
    Diameter 3.8 m
    Length 1.1 km
    Design Discharge 39.0 cumec
     
    SURGE SHAFT
    Number 1
    Type Simple Surge Shaft
    Diameter 8 m
    Height 76 m
     
    PRESSURE SHAFT 
    Number 1(Bifurcated into 2 of 2m dia.)
    Diameter 3.2 m
    Length 210 m
     
    POWER HOUSE
    Type  Underground
    Installed Capacity 50 MW
    Number of Units 2
    Power house cavern size (main) 59m X 20.5m X 30m
    Type of Turbines Francis Vertical Axis
    C.L. of Turbines EL 2641 m
    Rated Head 142.57 m
     
    TAIL RACE TUNNEL 
    Diameter 4 m dia.
    Shape D-shaped
    Length                  290 m
    Design Discharge   39 cumec
    Maximum TWL 2649 m
    Minimum TWL     2647 m
     
    SWITCHYARD
    Size Gas Insulated switchyard on the floor above the transformer/s in P/H cavern.
     
    POWER GENERATED:
     
    Installed capacity    50MW (2 x 25 MW)
    Annual energy generation  
    i) 90% dependable year 220.88 GWH
    ii) Energy in 90% year on 95% availability 210.50 GWH
    CONSTRUCTION PERIOD 5 Years
         
     
     




Updated on : 19/02/2018