“Foča” dam and HPP are planned at the Drina River, at the chainage km 324+678, approximately 10 km downstream of the planned “Buk Bijela” HPP and approximately 1.6 km upstream of the new bridge in town. The location belongs to the municipality of Foča and the nearest town is Foča.
Basic profile hydrological properties (as given in the original technical documentation) are:
- Basin area: 4,691.8 km2,
- Mean discharge: 178 m3/s,
- Ecological flow: 27 m3/s (minimum monthly discharge with 95% availability) and
- Flood discharge referent for design of spillways: 5,600 m3/s (Q0.1).
Basic dam properties are:
- Type: gravity, concrete,
- Height: 43.4 m (construction height), 21 m (above riverbed),
- Length along the crest: 208.4 m,
- Width at the crest: 13.1 m,
- Storage evacuation structures: gated spillway, 4 fields and
- Total evacuation capacity: 5,600 m3/s.
Basic storage properties are:
- Regular water level: 403 m.a.s.l.,
- Maximum water level: 404.2 m.a.s.l.,
- Minimum operating water level: 396.0 m.a.s.l.,
- Total volume: 6.7 million m3,
- Active volume: 4.6 million m3,
- Inactive volume: 2.1 million m3,
- Ratio between active volume and mean annual inflow: 0.001,
- Length: 10 km,
- Width: approximately 170 m and
- Surface area: 0.905 km2 (at the regular water level).
The plant belongs to the non-diversion type.
Basic HPP/powerhouse properties are:
- Plant type: non-diversion,
- Unit type: 2 x bulb + 1 x “S”-type,
- Number of units: 2 + 1,
- Installed discharge: 2 x 150 + 50 = 350 m3/s,
- Tailrace water level: 387.8 m (larger units), 386.8 (smaller unit),
- Gross head: 15.2 m (larger units), 16.2 (smaller unit),
- Head loss: 1.5 m (larger units), 2.5 m (smaller unit),
- Net head: 13.7 m,
- Installed power (active): 2 x 19.3 + 1 x 6.2 = 44.8 MW,
- Installed power (apparent): 50 kVA,
- Mean annual electricity generation: 175.87 GWh and
- Connection voltage level: 110 kV.
Source: IWRM Country Report for B&H, COWI, Stucky and Jaroslav Cerni Water Institute, 2017