Excellence in Construction since 1978
An Iso 9001:2008 Certified Company

Middle Modi Hydroelectric Project (15 MW)



Middle Modi Hydroelectric Project (15 MW) Middle Modi Hydroelectric Project (MMHP) is located about 40 km north-west of Pokhara in Kaski and Parbat Districts, Gandaki Zone of Western Development. The project lies in the Bhuktangle, Deupur and Tilhar VDCs of Parbat District and Salyan and Lumle VDCs of Kaski District. The headworks is located at Birethanti village. At present there is about 1.5km long earthen road access to the headworks area from Nayapul bazaar which is the nearest point with all year road access along the Pokhara – Baglung highway. The powerhouse lies opposite to the Pokhara – Baglung highway at the right bank of the Modi with waterway alignment located at the right bank of Modi Khola.

This project is a simple Run-of-River scheme that utilizes the flow in Modi Khola. Modi Khola is one of the major tributaries of the Kaligandaki River of the Gandaki basin. The proposed project has installed capacity of 15MW, design discharge of 25m3/sec and net head of 70m. The diversion weir across the Modi Khola diverts the water into the side intake. A gravel trap of length 15m settles gravels coming through the six orifices of the intake and settling basin with four parallel settling chambers of length 166m settles sediment particles larger than 0.2mm and passes water into the headrace tunnel. The headrace tunnel of length 2840m of finished diameter of 3.6~4.4m and steel penstock pipe of diameter 3.2m and length 147m feed water to the two units of Vertical Axis Francis Turbines installed in the semi-surface powerhouse to generate 15MW power. The water will then be discharged back into the Modi Khola through 77m long concrete tailrace box culvert. A semi-underground surge tank is provisioned at the end of the headrace tunnel.

The electricity generated from this plant will be connected to the National Grid at the Modi Khola Power Plant Sub Station at Patichaur through 4km long 132kV single circuit transmission line. The total net energy production will be 79.12GWh annually.

Salient Features

Project Middle Modi Hydroelectric Project
LocationOCATION
Type of Project Run-of-River
Village Development Committee Bhuktangle, Lumle, Deupur, Salyanand Tilhar VDCs
Districts Kaski and Parbat
Zone Gandaki and Dhaulagiri
Development Region Western Development Region
Headworks Area Bhuktangle/Birethanti village
Powerhouse Area Dhaba, Just U/S of Modi HEP (NEA)
River Modi Khola
Hydrology
Catchment Area at Intake 488 km2
Design Discharge 25 m3/s
90% Annual Dependable Flow 7.31m3/s
Compensation Flow 0.72m3/s
Flood
1 in 100 years Design Flood at Weir 972.9 m3/s
1 in 200 years Design Flood at Weir 1084.5 m3/s
Access Road
Access Road to HW Existing Nayapul – Birethanti Road
Access Road to PH 700m from Pokhara-Baglung Highway
Diversion Weir
Type of Weir Concrete Gravity with Uncontrolled Spillway
Crest Length of Spillway 32m
Weir Crest Level EL. 1014.5 masl
Height of Weir 5 m from river bed
Flood Level at 1 in 200 years Flood EL. 1021.85 masl
Under-sluice gate 2 x 3m wide x 4m high
Invert Level of Undersluice EL. 1010.20 masl
Intake
Type of Intake Side Intake, Orifice Type
No. of Intake Openings Six (1.2m x 3m each)
Invert Level of Sill EL. 1012.80 masl
Design Flow 28.75 m3/s
No. of Gates Six
Gate Size 1.5m x 3m each
Gravel Trap
Size 15m x 23~7m x 10m (L x B x H)
Flushing Conduit 1m x 1.5m Box, 30m Length
Top Level EL. 1019.7~1021.93 masl
Approach Box Culvert
Canal Type Double Box Culvert
Length of Canal 83m
Size of Canal 3.2m x 3.4m (H x W)
Side Spillway
Length 27m
Discharge Capacity 117.3 m3/sec
Location At Side Wall of Combined Box Culvert
Settling Basin
No. of Basins Two
No. of Chambers Four
Nominal Size of Trapped Particle 0.20mm
Trap Efficiency 90%
Transition Section 52m length
Parallel Section Size 114m(L)x7m(W)x8.94~11.22m (H) each including bottom hopper
Flushing Gates Four (1m x 1m)
Outlet Orifice Submerged, 8 Nos, 1.25m x 2.5m
Headpond
Capacity 1200m3
Size 28m (L) x 12m (W) x 2.5m (H)
Side Spillway 22m Length
Discharge Capacity 25 m3/sec
Normal Water Level EL. 1013.41 masl
Headrace Tunnel
Section Type Inverted-D
Finish Diameter 3.6 ~4.4m
Finish Area 12.02~15.21m2
Length 2840m
Support Fully Concrete Lined (160m) and Shotcrete Lining in Wall and Crown, Concrete Lining in Invert (2680m)
Surge Tank
Type Surface and near HRT outlet portal
Finish Diameter 9m
Height 33.49m
USWL EL. 1024.57 masl
DSWL EL. 1000.18 masl
Penstock
Material Steel
Diameter 3.2m
Length 147m
Thickness 10, 12 and 16 mm
Powerhouse
Type Semi – Surface
Dimension 30m (L) x 13.5m (W) x 24m (H)
Turbine Axis Level EL. 938.30 masl
Floor Level EL. 944.60 masl
Tail Pond Level EL. 940.50 masl
Tailrace
Type Concrete Box Culvert
Length 77m
Size 4m x 3.6m
Outlet Tail water Level EL. 940.42 masl
Turbines
Type of Turbine Francis (Vertical Axis)
No. of Units Two
Rated Net Head 69.78m
Unit Discharge 12.50m3/s
Transmission Line
Voltage 132kV
Length 4km
Connection NEA Sub-station at Patichaur, Parbat
Power and Energy Generation
Gross Head 72.91m
Net Head 69.78m
Installed Capacity 15MW
Annual Net Energy 79.124GWh
Dry Season Energy 12.198GWh
Wet Season Energy 66.925GWh
Target Completion Date: July 2014