Ribeiradio and Ermida Dams

Hydroelectric operation project in Portugal

The Ribeiradio and Ermida project consists of the accesses to the Ribeiradio Dam and the re-establishment of the EM 569 highway on the River Vouga near Aveiro, some fifty kilometres north of Coimbra in Portugal.

The "Aproveitamento Hidroelectrico Ribeiradio–Ermida " is an EDP (Electricidad de Portugal) project consisting of the execution of two hydraulic jumps, with eight-kilometre spacing, the Ribeiradio and Ermida Dams. The objective of this hydroelectric operation is essentially the generation of hydroelectric power, although it is also intended for flood abatement and water storage.

The works are divided into three parts: The Ribeiradio and Ermida Dams and their accesses.

Ribeiradio Dam: This is an arch-gravity dam, with a circular arch axis of 262 metres. With crest development and 83 metres maximum height and roller-bucket spillway consisting of three 13 x 13-metre long spans, with gates and bottom drains in 2.5-metre diameter piping. As a singular element, the hydraulic circuit is noteworthy. which consists of a hydroelectric power station, constructed in a pit, with a single 72-MW reversible generator set that is fed by an underground hydraulic circuit (water collection tower, abduction gallery in a 205-metre long tunnel having a 5.5 metre diameter and water return to the river). It also includes the power station accesses (1.6 kilometres) and those to the Observation and Control building (POC).

  • 320,000 m3  of concrete  in the dam body
  •  Crest width is nine metres and dam base width is eighty metres.
  •  Joints every seventeen metres
  • Central spillway is the roller-bucket type, with sluice gates.
  • Ground consolidation treatment using injections executed from the main drainage gallery in the dam body.
  • River diversion through a gallery in the dam body and coffer dams along the river
  • Reservoir capacity 135 cubic hectometres

Ermida Dam: This is a concrete gravity dam, with a straight axis (175.1 metres at the crown) and maximum height of 38 metres, with a fixed-lip spillway, 1.2 x 1.5-metre bottom drain and 30-metre stilling basin. The hydroelectric power station incorporates two 3.3 MW generator sets that are fed by two independent hydraulic circuits that cross the dam body and is located next to the dam body downstream between the spillway and the dam abutment with the ground, It includes the accesses to the power station and the right bank from the EM-569 highway.

  • 90,000 m3 of vibrated concrete in the dam body.
  • Crest width is four metres and dam base width is 26.65 metres.
  • Central spillway  without sluice gates
  • Joints every 16.40 metres.
  • Reservoir capacity 3 hm3
  • Execution percentage Dam and hydroelectric power station, 35%.

Accesses to the Ribeiradio Dam and the re-establishment of the EM 569 highway: The Ribeiradio Dam accesses are 1 kilometre long on the right bank and 1.2 kilometres on the left bank, with a mean slope of 10%.

The re-establishment of the EM 569 highway on the right bank of the Ermida Dam is approximately 2.35 kilometres. It includes the construction of a bridge over the River Salgueira. 


Cost: 107.0 M€

Client: Energías de Portugal (EDP)

Start date: 2011

End date: 2014