RRC promove visita tecnica à barragem Ribeiradio-Ermida


RRC promotes a technical visit to Ribeiradio-Ermida dam

These works, located between the districts of Aveiro and Viseu, are divided into three main groups: Ribeiradio dam, Ermida dam and the access roads to the dams.

RRC promotes a technical visit to Ribeiradio-Ermida dam


Concrete dam, circular layout, 262 m at the top level, with a maximum height of 74 m, with a spillway composed of three spans 13 x 13 m long, with segment-type (Taintor) gates and bottom outlet 2.5 m in diameter. The hydro plant, built in a shaft, has a single generator and is powered by an underwater water circuit (water intake, supply gallery 20.5 m x 5.5 m in diameter and replacement). Includes an access road to the plant and to the building housing the observation and control post, with a total length of 1.6 km.

Main characteristics:

  • 300,000 m3 of hydraulic concrete in the body of the dam
  • Width at top of dam = 9 m; at base of dam = 55m
  • Joints positioned every 17 m
  • Central spillway
  • Land-consolidation treatments
  • River diversions coordinated with the concrete-pouring plan for the body of the dam


Concrete dam, straight, 175.1 m at the top, with a maximum height of 35 m. The power plant will be equipped with two generators powered by separate water circuits crossing the body of the dam. Includes access roads to the plant and the right bank from the EM-569 road.

Main characteristics:

  • 75,000 m3 of concrete in the body of the dam
  • Top width = 4 m; width at the base of the dam = 26.65 m
  • Central spillway
  • Joints positioned every 16.4 m

Access roads to Ribeiradio dam and replacement of main access roads:

The access roads to Ribeiradio run for 1,340 m along the right bank and 1,000 m along the left bank, with an average slope of 10% and a mountain-road layout.

The replacement of the EM569 road, on the right bank of Ermida dam, will be nearly 2.35 km long, including the building of a bridge over the banks of the river Salgueira.


As these are works with major impact on the community, a set of measures were implemented to minimise and regularly monitor environmental impact during the construction phase.

Environmental characterisation:

  • RAN classified area: 409,000 m2
  • REN classified area: 3,256,400 m2
  • Length of water lines affected: 20,000 m
  • Public Water Domain (DPH) area affected: 661,000 m2

Monitoring programmes:

Some of the measures applied were established in the environmental-impact assessment (EIA), while other were applied in order to comply with legal requirements imposed during the construction phase.

Monitoring programmes and sub-programmes in the EIA:

  • Monitoring programme for ecological water quality:
    • Physical and chemical characterisation.
    • Hydromorphological characterisation (hydrology + morphology).
    • Biological characterisation.
  • Monitoring programme for ecological systems:
    • Monitoring wildlife on land: mammals, reptiles and amphibians.
    • Monitoring underwater wildlife: water plans, freshwater species, migratory species, European eel, Grela transposition, on the upper reaches of the river Vouga, conditioning of the ecological flow.
  • Socio-economic monitoring programme:
    • Control of compulsory purchases.
    • Air quality.
    • Noise.

Monitoring programmes to meet legal requirements:

  • Wastewater drainage
  • Groundwater capture.