Salient Features (Mai Cascade HP)

Project location  
Region Eastern Development Region
District Ilam
Zone Mechi
Intake site Danabari VDC
Powerhouse site Danabari VDC
Access to the project site Via. East-west highway up to Birtamode and about 25 km long blacktopped/ graveled link road north from Birtamode
Geographic Coordinates  
Longitude  87052’1.92” E to 87053’9.16” E
Latitude 27045’43.37” N to 27047’39.78” N
Altitude 155 - 200 m (amsl)
Name of the river Mai Khola
Nearest Town Birtamode Bazar         
Types of Scheme Run-of-river
Gross Head 42.65 m
Net Head 34.59 m
Installed capacity 7,000 kW
Average annual estimated energy 38,422,444 KWh
Catchment Area 589.0 km2(at MHP intake)
Average Flow 32.66 m3/s (minimum monthly flow 7.22 m3/s)
Design Flow 23.43 m3/s (40% exceedence flow)
90% Exceedence flow 7.48 m3/s
Design Flood (Q100) at MHP headworks 2070 m3/s
Name of River Mai Khola
Note: The hydrology of MCHP is same as MHP
Intake canal (Headworks)  
Type of Structure RCC rectangular canal
Water level  
Maximum 199.0 m (amsl)
Minimum 198.15 m (amsl)
Design Discharge 23.43 m3/s
Length 89.73 m
Headrace Canal/Culvert  
Total Length 3719.66 m
Size Rectangular: Height = (3.0 + 0.5) m, Width = 3.5 m, Trapezoidal: Bottom width = 2.5 m, Top width = 6.9 m, Height = (2.15+1.0) m  
Bed slope 1:1000(V:H)
HR culvert (Trapezoidal) L= 1851.66m
HR culvert (Rectangular) L= 1798.0m
HR Transition panels L=70.0m( 7 nos ,10m each)
Kholsi Crossing System  
Kholsi Crossings (With rectangular culvert)  
Crossing No-01 (Sarangi Kholsi) Span :17.00 m
Crossing No-02 (Bhimsen Kholsi) Span: 42.60 m
Crossing No-03 (Tarbare Kholsi) Span:7.60 m
Crossing No-04 (Ilame Kholsi) Span: 29.00 m
Crossing No-05 (Aaptari Kholsi) Span: 30.80 m
Kholsi Crossings (With Trapezoidal canal  
Crossing No-01 (MCHP IV Kholsi) Span: 5.63 m
Crossing No-02 ( Bhotange Kholsi) Span : 4.37 m
Crossing No-03 (Basnet Kholsi) Span :13.60 m
Kholsi Crossings (with Hume pipe arrangement)  
Crossing No-01 ( Guhe-I Kholsi) 17.5 m x 1.20m Dia ; 2 Nos
Crossing No-02 (Tukre Kholsi) 15.0 m x 1.20m Dia ; 2 Nos
Crossing No-03(Bhotange Diversion Kholsi) 20.0 m x 1.20m Dia
Crossing No-04 (Guhe-II Kholsi) 22.50 m x 0 .90m Dia
Crossing No-05 (At CH.2+510) 22.50 m x 0.90m Dia
Crossing No-06 ( At CH.2+870) 15.0 m x 1.20m Dia
Crossing -07 ( At CH.3+072) 15.0 m x 0.90m Dia
Crossing -08 ( At CH.3+143) 20.0 m x 0.90m Dia
Crossing -09 ( At CH.3+450) 17.50 m x 0.90m Dia
Crossing -10 ( At CH.3+510) 22.50 m x 0.60m Dia
Size of Forebay(Avg.) LxBxH = 60.15 m x 9.30 m x 6.44 m
Forebay Normal water level 194.544 m (amsl)
Muse Khola Spillway:  
Size of Spillway(Internal) LxBxH = 25.34 m x 8.0 m x 4.4m
Normal Water Level at U/S 197.36 m (amsl)
Normal Water Level at D/S 195.46 m (amsl)
Bhimsen Kholsi Spillway :  
Size of Spillway(Internal) LxBxH = 167.80 m x 10.0 m x 2.5 m
Types of Spillway RCC rectangular open
Exit point Lodhiya Khola
Forebay Spillway & Spillway Canal :  
Types of Spillway RCC rectangular open
Spillway size(Internal) 180 m x 10.0 m x 2.5 m
Spillway canal  
Spillway Canal length 122.24 m
 Bottom width 3.00 m
Top width 9.30 m
Height 3.15 m
Exit Point Ch. 0+084 of tailrace canal
Number  3
Diameter/Thickness 1.5 m /10-14 mm thick
Length(Total) 218.50 m
Size of Gate on Penstock in Forebay BxH = 2.42 m x 2.41 m
Type Surface
Powerhouse size  
Length 46.0 m
Width 16.62 m
Height 21.7 m
P/H Floor Level 158.30
Type-I RCC , Rectangular canal
Length 83.44 m
Width 4.60 m
Height 5.05 m
Normal tail water level EL. 155.25m
Type-II Gabion mattress lined,  trapezoidal canal
Length 128.52 m
Top width 12.30 m
Bottom width 6.0 m
Height 3.15 m
Type Francis (Horizontal axis)
Number 3
Rated output capacityEfficiency 2450 KW 92.50%
Type Electronic with PID control
Adjustment for speed drop Between 0 to 5%
Type Synchronous 3 phases
Rated output capacity per unit 2917KVA
No of units Three(3)
Power Factor 0.8
Voltage 6.3kV
Excitation system Brushless
Efficiency 96.50%
Voltage level 33 kV
No. of bays 1
At Powerhouse  
Type Three Phase
Rated Capacity 9000KVA
Voltage Ratio 33/6.3 kV
Efficiency 99.0%
At MHP  Switchyard  
Type 3-phase, two windings, oil immersed transformer with off load tap-changer
Rated Capacity 9000KVA
Voltage Ratio 132/33 kV
Efficiency 99.0%
Transmission Line  
Transmission line length 4 km
Voltage level 33 KV, single circuit
Conductor Type ACSR ”DOG”
From Powerhouse
To Switchyard of Mai Hydropower Project
Power and energy  
Installation capacity 7000 (3 x 2333.3) kW
Dry energy(annual average estimated) 6.322 GWh
Wet energy(annual average estimate) 32.099 GWh
Net Energy Output(annual average estimated) 38.422 GWh
Project Cost at completion 1,377 MNPR