| Pracana Dam | |
| Name Official: | Barragem de Pracana |
| Location Map: | Portugal |
| Coordinates: | 39.5649°N -7.8122°W |
| Country: | Portugal |
| Location: | municipality Mação, Santarém District |
| Purpose: | Power |
| Status: | O |
| Construction Began: | 1947 |
| Opening: | 1950 |
| Owner: | Companhia Portuguesa de Produção de Electricidade |
| Operator: | Energias de Portugal |
| Dam Type: | Concrete buttress dam |
| Dam Crosses: | Ocreza |
| Dam Height Foundation: | 60m (200feet) |
| Dam Length: | 245.5m (805.4feet) |
| Dam Elevation Crest: | 115m (377feet) |
| Dam Volume: | 144000m2 |
| Spillway Type: | Shaft and chute spillway |
| Spillway Capacity: | 2560m3/s |
| Res Capacity Total: | 111900000m2 |
| Res Capacity Active: | 69000000m2 |
| Res Surface: | 5.5km2 |
| Res Elevation: | 114m (374feet) |
| Plant Operator: | Energias de Portugal |
| Plant Commission: | 1951 |
| Plant Hydraulic Head: | 57m (187feet) (max) |
| Plant Turbines: | 2 x 8 MW, 1 x 25 MW Francis-type |
| Plant Capacity: | 41 MW |
| Plant Annual Gen: | 63.8 GWh |
Pracana Dam (Portuguese: Barragem de Pracana|links=no) is a concrete buttress dam on the Ocreza, a right (northern) tributary of the Tagus. It is located in the municipality Mação, in Santarém District, Portugal.
Construction of the dam began in 1947. The dam was completed in 1950. It is owned by Companhia Portuguesa de Produção de Electricidade (CPPE). The dam is used for power generation.
Pracana Dam is a 60 m tall (height above foundation) and 245.5 m long buttress dam with a crest altitude of 115 m. The volume of the dam is 144,000 m³. There is one shaft spillway on the right side of the dam and a chute spillway on the left side. The combined maximum discharge is 2,560 m³/s. There is also a bottom outlet which can discharge up to 52 m³/s.
At full reservoir level of 114 m the reservoir of the dam has a surface area of 5.5 km² and a total capacity of 111.9 mio. m³. The active capacity is 69 (95.6 or 102) mio. m³. Minimum operating level is 97 m. With the 95.6 mio. m³ 9.8 GWh can be produced.
The hydroelectric power plant was commissioned in 1951 (1950). It is operated by EDP. The plant has a nameplate capacity of 41 (14,7 or 40) MW. Its average annual generation is 63.8 (41, 61.8, or 53) GWh.
The power station contains 3 Francis turbine-generators in a surface powerhouse located at the toe of the dam. The first 2 units were commissioned in 1951, the third in 1993. The minimum hydraulic head is 28 m, the maximum 57 m.
| Unit | Commission date | Turbine (MW) | Generator (MVA) | Rotation | Flow (m³/s) |
|---|---|---|---|---|---|
| 1 | 1951 | 8 | 9.68 | 375 | 18 |
| 2 | 1951 | 8 | 9.68 | 375 | 18 |
| 3 | 1993 | 25 | 28.5 | 272.7 | 52 |