El Chocón Hydroelectric Power Plant

    Around the year 1969 an old dating Argentine project started to take place with the initial works of El Chocón Dam and Power Plant, which form part of the Hydroelectric group Cerros Colorados,an important energy supplier for a big part of the country.
    Construction was finished in 1973. It was built with loose materials of different qualities and textures overlapped, what constitutes a strong and modern design.
    El Chocón is a dam made of graded materials with a flood drain, an embankment over Limay river and a Hydroelectric Plant at the foot of the dam fed by six tunnels originated in the imput structure upstream from the dam.
    The dam is made of earth and has a waterproof clay nucleous. These materials were obtained from neighbouring deposits.
    The upper part in contact with the water is protected by basalt blocks and a concrete retaining wall to protect the road running on top of the dam, which links the provinces of Neuquén and Río Negro.
    The dam is 2500 m. long and 95 m. high. Its maximum width is 380m. and minimum is 10m.

The embankment formed by the dam originates the artificial lake Ramos Mejía, with a capacity of 20.000 cubic hectometers.
The surface of the lake is 816 km2, a surface broader than lake Nahuel Huapi.

    The lateral drain floods when excessive rain from the Andes increments its flow towards the embankment, which has a capacity of 8.000 m3/s.
    Water gets into the collecting pipes through a grid in tunnels excavated in the rock, coated in concrete with a metal blindage in most of its extension, and after acting on the turbines, it is restituted to the river through a discharging conduct.

Tunnels in each turbine are 225 m. long and have an internal diameter of 10 m.
The plant Chocón-Cerros Colorados has an energy production capacity to cover 25 % of the total supply of the country.