Construction began in 1937, but was delayed by World War II, and the dam did not start generating power until 1948.

The Swiss Maurice Lugeon, a specialist in large dams, refuted his arguments, declaring that the limestone would hold and calling Martel an amateur experimental geologist.

[2] There was no immediate outcome to this debate, but later Lugeon's views were confirmed by tests by the Compagnie Nationale du Rhône.

[2] The Compagnie Nationale du Rhône (CNR) was founded in 1933 to undertake construction and operation of the dam.

[4] Preliminary work began in February 1937, and official authorization to undertake the project was granted on 21 June 1938.

The diversion was opened successfully in April 1939, handling 500 cubic metres (18,000 cu ft) per second of water.

[5] Most of the concrete was poured between 1946 and 1947, using aggregate delivered by two cable cars from a gravel pit in Pyrimont, 6 kilometres (3.7 mi) downstream.