Betan Karnali Sanchayakarta Hydropower Company Limited

General

Project name	Betan Karnali PROR Hydroelectric Project
Location	Surkhet District, Karnali Province & Achham District, Sudurpaschim Province
Co-ordinates of the Project area	28°50’57” N to 28°56’04” N latitude, 81°11’43” E to 81°24’42” E longitude
Nearest highway	Karnali highway
Nearest airport	Surkhet airport – 94.25 km from project site Nepalgunj airport – 200.25 km from project site
River	Karnali
Climate	Moderate
Type of project	Peaking Run-of-River PRoR

Organization

Hydrology

Reservoir

Dam

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डाउनस्ट्रीम सर्ज शाफ्ट

ऊर्जा

Transmission Line

Developer	Betan Karnali Sanchayakarta Hydropower Company Ltd.
Consultant	NEA Engineering Company Ltd.

Catchment area	22,511.25 km2
Mean annual flow	553.92 m3/s
Maximum average monthly discharge	1609.55 m3/s
Minimum average monthly discharge	134.80 m3/s
1 in 100 years flood (Q100)	8,530.00 m3/s
1 in 1000 years flood (Q1000)	11,548.00 m3/s
1 in 10,000 years flood (Q10,000)	14,560.00 m3/s
Probable maximum flood (QPMF)	22,604.00 m3/s

Gross storage volumeGross storage volume	161.69 Mm3161.69 Mm3
Live storage volumeLive storage volume	36.19 Mm336.19 Mm3
Surface area at FSLSurface area at FSL	5.42 km25.42 km2
Length of reservoir at FSLLength of reservoir at FSL	21.93 km21.93 km
Full supply levelFull supply level	473.30 masl
Monsoon operating levelMonsoon operating level	470.00 masl
Minimum drawdown leve.	466.00 masl

Type of dam	Roller Compacted Concrete (RCC)
Location of dam	Approx. 2.00 km D/S from Malumela
Dam crest length	172.75 m
Dam height	90.00 m from riverbed
Dam height	140.00 m from foundation bed
Top width	10.00 m
Dam top elevation	480.00 masl

River Diversion Works Diversion discharge	2,400.00 m³/s
River Diversion Works Number of tunnels	2 Nos.
River Diversion Works Size and shape	9.80 m diameter horseshoe
River Diversion Works Length	584.40 m & 727.10 m
River Diversion Works Inlet and outlet level	400 masl & 394 masl (Diversion tunnel-1) 400.50 masl and 393.50 masl (Diversion tunnel-2)
River Diversion Works Lining	Reinforced concrete lining
U/S cofferdam Type & location (axis)	RCC (Permanent), 162.00 m u/s from dam axis
U/S cofferdam Height	40.96 m from existing riverbed
U/S cofferdam Crest Level	434.32 masl
D/S cofferdam Type & location (axis)	Embankment dam, 306.00 m d/s from dam axis
D/S cofferdam Height	16.50 m from existing riverbed
D/S cofferdam Crest level	406.00 masl

Main Spillway Type	Ogee and gated
Main Spillway Crest elevation	462.00 masl
Main Spillway Number and size of gates	6 nos, 11 m x 12 m (W X H)
Main Spillway Energy dissipation	Flip bucket
Sluice Spillway Type	Sluice
Sluice Spillway Crest elevation	418.00 masl
Sluice Spillway Number and Size	6 nos, 7 m x 8 m (W X H)
Auxiliary Spillway Type	Ogee and gated
Auxiliary Spillway Crest elevation	469.00 masl
Auxiliary Spillway Number and Size	1 no, 8 m x 5 m
Auxiliary Spillway Energy dissipation	Flip bucket

Main Power Intake Type of intake	Side intake
Main Power Intake Number and size of trashrack	9 nos., 5.90 m x 17.20 m (W X H))
Main Power Intake Number and size of intake gate	3 nos., 8 m x 8 m (W X H)
Main Power Intake Dry season design discharge	536.00 m³/s
Main Power Intake Wet Season design discharge	551.33 m³/s
Main Power Intake Invert level	450.00 masl
Main Power Intake Deck level	480.00 masl
Main Power Intake Trashrack	Inclined at 75º to horizontal
Intake for Dam Toe Powerhouse Type of intake	Embedded in dam
Intake for Dam Toe Powerhouse Number and size of trashrack	2 nos, 2.60 m wide up to dam deck level
Intake for Dam Toe Powerhouse Number and size of intake gates	2 nos, 1.6 m x 2 m
Intake for Dam Toe Powerhouse Invert level	460 masl
Intake for Dam Toe Powerhouse Design discharge	13.48 m³/s
Intake for Dam Toe Powerhouse Trashrack	Vertical

Headrace Tunnel Number	3 nos.
Headrace Tunnel Size and Shape	8.00 m diameter circular
Headrace Tunnel Length	2017.26 m, 2011.15 m, 2017.39 m
Headrace Tunnel Lining	450 to 300 mm thick concrete lining
Headrace Tunnel Design velocity	3.56 m/s
Headrace Tunnel Maximum velocity	3.66 m/s

Upstream Surge Shaft Type	Restricted orifice
Upstream Surge Shaft Number	3 nos
Upstream Surge Shaft Diameter	24.00 m
Upstream Surge Shaft Diameter of orifice	4.20 m
Upstream Surge Shaft Height	37.70 m

Pressure shaft Number	3 nos
Pressure shaft Orientation	Vertical and horizontal
Pressure shaft Diameter and length (concrete lined)	7.65 m circular pressure shaft of 109.80 m
Pressure shaft Diameter and length (Steel lined)	7.65 m circular pressure shaft reducing to 7m before bifurcation of 42m
Bifurcated Pipes Diameter and length	4.95 m circular bifurcating steel pipes of 79.36 and 72.74m of in each conveyance system

Main Powerhouse Coordinate	81°14’48” E, 28°55’5” N
Main Powerhouse Type	Underground
Main Powerhouse Installed capacity	430.13 MW
Main Powerhouse Powerhouse size	202.00 x 23.50 x 54.48 (L X W X H)
Main Powerhouse Number and capacity of units	6 nos x 71.68 MW
Main Powerhouse Type of turbine	Francis, Vertical Axis
Main Powerhouse Normal tail water level	374.15 masl
Main Powerhouse Gross head	99.13 m
Main Powerhouse Net head at FSL	94.13 m
Main Powerhouse Net head at MOL	90.54 m
Main Powerhouse Machine floor level	380.21 masl
Main Powerhouse Generator floor level	375.61 masl
Main Powerhouse Turbine floor level	371.85 masl
Main Powerhouse Turbine centre line level	369.17 masl
Dam Toe Powerhouse Type	Surface Toe of Dam
Dam Toe Powerhouse Installed capacity	8.77 MW
Dam Toe Powerhouse PH size	27.00 m X 15.60 m X 40.37 m (L X W X H)
Dam Toe Powerhouse Number and capacity of units	2 nos x 4.38 MW
Dam Toe Powerhouse Type of turbine	Francis, Vertical Axis
Dam Toe Powerhouse Normal tail water level	395 masl
Dam Toe Powerhouse Gross head	78.30 m
Dam Toe Powerhouse Rated net head	76.50 m

Tailrace Tunnel Number	6 nos
Tailrace Tunnel Size and shape	6.5 m diameter concrete lined tunnel
Tailrace Tunnel Length	322.49 m, 312.26 m, 302.03 m, 291.80 m, 281.57 m and 271.35 m

Downstream Surge Chamber Type	Restricted orifice
Downstream Surge Chamber Number	1 (Chamber)
Downstream Surge Chamber Orientation	Across and above 6 TRTs
Downstream Surge Chamber Size	144 m x 15 m X 19.95 m (L X W X H)
Downstream Surge Chamber Diameter of orifice	4.40 m

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