Ralco RCC dam, 155m high, was constructed in the southern wet and very cold winter region of South America under the most adverse conditions yet encountered by any other RRC dam of it size and importance. Its1.6million m3 of RCC was placed in 20 months, through rainfall and snowfall conditions and ambient temperatures whilst RCC was being placed ranging from -6 °C to plus 35 °C. The RCC placing surface was overtopped by floods exceeding the diversion tunnel capacity (1 in 20 year) on at least 2 occasions as well as the 50m high embankment upstream cofferdam being overtopped and breaching at the start and requiring re construction with a new 'overtoppable' section in RCC incorporated into the earthfill cofferdam.
The project is owned by Empresa Nacional de Electricidad S.A ENDESA CHILE.
