Construction under way at Ribeiradio and Ermida dams
This contract for Greenvouga (EDP), with a budget of €88.4 million and undertaken through a joint venture between FCC Construcción, Ramalho Rosa Cobetar (RRC) and OPWAY, involves the building of Ribeiradio and Ermida dams, as well as access roads to Ribeiradio dam and the replacement of the EM-569 road on the river Vouga, in the Aveiro area.
The main dam, Ribeiradio, is a gravity dam made of concrete with a circular axis, 262 m long at the top, with a maximum height of 74 m and volume of 230,000 m3. The spillway is composed of three 13 x 13 m spans, with segment-type gates and a bottom outlet 2.5 m in diameter. The impact basin is formed by a concrete counter-channel with a maximum height of 6 m, located 135 m downstream from the dam.
The hydro plant is built in a circular shaft 23 m in diameter and 36 m deep, with a single generator unit, powered via an underground water circuit, consisting of a water intake, a 205 m supply gallery, 5.5 m in diameter, and a restoration system connected to the impact basin.
Ermida dam, to generate the counter-channel, is also a concrete gravity-type structure, although its layout is straight, 175.1 m long at the top, with a maximum height of 35 m and volume of 75,000 m3. The spillway is uncontrolled, with a bottom outlet 1.2 x 1.5 m, and a 30 m impact basin. The hydro plant is equipped with two generators powered by independent water circuits crossing the body of the dam.
The access roads to Ribeiradio dam will be 1.34 km long on the right bank and 1.00 km long on the left bank, with an average slope of 10%, a mountain-road layout and a 6.5 m platform, with two 2.75 m lanes and 0.50 m kerbs. The replacement of the EM-569 road on the right bank of Ermida dam will be 2.35 km long, including the building of a bridge over the banks of the river Salgueira.
The construction of these works will require more than 570,000 m3 of excavation, 370,000 m3 of concrete and 7,700 tonnes of steel.
FCC Construcción (RRC’s principal shareholder) has vast experience of water works and is currently building more than six major dams of various types in Spain (Castrovido, 99 m high; Yesa, 117 m; Enciso, 105 m); in Mexico (El Zapotillo, 132 m) and in Bulgaria (Tsankov-Kamak, 130 m).