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. Power Purchase Agreement was done on 21, Magsir,2069 with Nepal Electricity Authority with RCOD of 1, Aswin,2074.
Salient Features
| Project | Middle Modi Hydroelectric Project |
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LOCATION
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| 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 |
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HYDROLOGY
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| Catchment Area at Intake | 488 km2 |
| Design Discharge | 25 m3/s |
| 90% Annual Dependable Flow | 7.31m3/s |
| Compensation Flow | 0.72m3/s |
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FLOOD
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| 1 in 100 years Design Flood at Weir | 972.9 m3/s |
| 1 in 200 years Design Flood at Weir | 1084.5 m3/s |
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ACCESS ROAD
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| Access Road to HW | Existing Nayapul – Birethanti Road |
| Access Road to PH | 700m from Pokhara-Baglung Highway |
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DIVERSION WEIR
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| 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 |
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INTAKE
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| 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 |
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GRAVEL TRAP
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| 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 |
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APPROACH BOX CULVERT
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| Canal Type | Double Box Culvert |
| Length of Canal | 83m |
| Size of Canal | 3.2m x 3.4m (H x W) |
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SIDE SPILLWAY
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| Length | 27m |
| Discharge Capacity | 117.3 m3/sec |
| Location | At Side Wall of Combined Box Culvert |
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SETTLING BASIN
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| 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 |
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HEADPOND
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| 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 |
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HEADRACE TUNNEL
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| 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) |
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SURGE TANK
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| Type | Surface and near HRT outlet portal |
| Finish Diameter | 9m |
| Height | 33.49m |
| USWL | EL. 1024.57 masl |
| DSWL | EL. 1000.18 masl |
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PENSTOCK
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| Material | Steel |
| Diameter | 3.2m |
| Length | 147m |
| Thickness | 10, 12 and 16 mm |
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POWERHOUSE
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| 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 |
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TAILRACE
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| Type | Concrete Box Culvert |
| Length | 77m |
| Size | 4m x 3.6m |
| Outlet Tail water Level | EL. 940.42 masl |
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TURBINES
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| Type of Turbine | Francis (Vertical Axis) |
| No. of Units | Two |
| Rated Net Head | 69.78m |
| Unit Discharge | 12.50m3/s |
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TRANSMISSION LINE
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| Voltage | 132kV |
| Length | 4km |
| Connection | NEA Sub-station at Patichaur, Parbat |
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POWER AND ENERGY GENERATION
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| 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 |
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TARGET COMPLETION DATE: July 2014
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