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Location: |
Danabari and Chisapani VDC, Ilam District, Eastern Development Region of Nepal |
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Purpose of Project: |
To supply hydro-electricity for domestic use by connecting to Integrated Nepal Power System (INPS) |
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Hydrology: |
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Catchment Area |
589.0 km2 |
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Average Flow |
32.66 m3/s (minimum monthly flow 7.22 m3/s) |
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Design Flow |
23.43 m3/s (40% exceedence flow) |
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90% Exceedence flow |
7.48 m3/s |
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Design Flood (Q100) |
2070 m3/s |
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1000 years Flood (Q1000) |
3007 m3/s |
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Diversion Dam: |
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Type |
Concrete gravity dam |
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Shape |
Ogee-profile |
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Crest Elevation |
321.1 m above msl |
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Crest Length |
91.12 m |
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Height |
5.1 m (from original river bed level) |
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Designed flood (Q100) level |
325.6 m above msl |
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River Diversion During Construction: |
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Alignment |
Along the river channel |
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Diversion flow |
250 m3/s |
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Coffer dams |
Two cofferdams facilitating stage1 and stage 2 concreting (Total coffer dam length = 377.5 m) |
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Intake spillway/ Undersluice: |
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Type |
Over-flow weir with under-sluice (3@2x4m width) |
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Crest Elevation |
321.1 m above msl (undersluice 314.5 m above msl) |
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Length |
111.12 mm |
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Design Flood (Q100) |
2070 m3/s |
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Intake: |
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Type |
Frontal Intake, submerged, over the undersluice |
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Number of Orifices |
3 |
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Bottom Elevation of Orifice |
317.0 m amsl |
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Top Elevation of Orifice |
320.0 m above msl |
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Length of Orifices |
20.0 m (with inner piers, clear opening of each orifice = 2.55 x 6 m width) |
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Intake canal: |
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Type |
RCC open canal |
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Maximum height |
3.0 m |
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Average Width |
6.8 m |
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Approach Culvert: |
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Type |
RCC pressurized conduit |
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Number |
2 |
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Average Height |
3.0 m (internal) |
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Average Width |
3.0 m (internal) |
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Total Length of outer branch Total length of inner branch Invert Level |
62.69 m 40.98 m 317.10 m |
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Settling Basin: |
|
|
Type |
Conventional flushing |
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Number of Chamber |
4 (four) |
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Top elevation |
322.4 m above msl |
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Normal Operation elevation |
320.50 m above msl |
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Length of the basin |
75 m (settling zone) |
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Average Height |
5.85 m |
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Bottom width per Chamber |
9.5 m c/c |
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Headrace Culvert: |
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|
Type |
RCC pressurized culvert |
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Length |
1055.69 m |
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Height |
3.3 m |
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Bottom width |
3.5 m |
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Longitudinal slope |
1:1500 (V:H) |
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Headrace Tunnel: |
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Length |
2198.0 m (incl. 66 m after surge-tank) |
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Dimensions |
Inverted D 3.8 x3.96 m, (13.1 m2-finish) |
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Discharge |
23.43 m3/s |
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Surge Shaft dimensions: |
|
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Type |
Vertical, circular section |
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Height |
35.0 m |
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Diameter |
8.0 m (finish) |
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Penstock |
|
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Length |
316.38 m (273.6 m up to bifurcation) |
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Diameter/thickness |
2.6 m to 1.5 m internal diameter/10 mm to 25 mm thickness |
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Power Facilities: |
|
|
Powerhouse Type |
Semi-surface |
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Dimensions |
36 m x 22 m |
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Gross Head |
122.1 m (321.1 – 199.0 m above msl) |
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Net Head |
108.93 m |
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Installed capacity |
22.0 MW (3x7.33 MW) |
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Dry energy |
22.11 GWh |
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Wet energy |
103.03 GWh |
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Annual Net Energy Output |
125.14 GWh |
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Tailrace Culvert: |
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|
Type |
RCC canal |
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Length |
229.5 m |
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Height |
3.3 m |
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Width |
3.5 m |
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Longitudinal slope |
1:450 (V:H) |
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Power Transformer |
|
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Type |
3-phase, two windings, oil immersed transformer with off load tap-changer; |
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Installation |
Outdoor; |
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Rated power |
10,000 kVA and 20,000 kVA; |
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Transmission Facilities: |
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Transmission line length |
11.6 km |
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Voltage level |
132 kV, single circuit |
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Project Cost at completion |
3,295 million NPR |
