Barrage de Cize-Bolozon

At the time of the construction of the Cize-Bolozon dam, the electricity companies each had their own factories, power lines and customers. The Cize-Bolozon hydroelectric power station built on the Ain between 1928 and 1931 by the "Energie Electrique Rhône-Jura" company was intended to improve the supply of power to the metallurgical factories of Le Creusot and the coal mines of Decize, the surplus being sold to the "Compagnie Bourguignonne de Transport d'Energie" which supplied Gueugnon, Bourges, Dijon, Lyon and wanted to reinforce its outlets to the Paris region. This factory was the most important in the Ain valley. Today its production, like that of most of the other factories in the valley, is fed into the regional 63,000 V network.

The construction of the dam across a river as capricious as the Ain was at the time was only made possible by the construction of circular sheet pile enclosures.

The numerous and exceptionally violent floods of the spring and summer of 1930 repeatedly drowned the construction site, but the pugnacity of the men overcame the ravages of nature.

With its superstructures, the dam is typical of the constructions of this period. Its layout was made necessary by the type of 60-ton flat gates running on caterpillar tracks, known as "Stoney" gates.

The massive crane, now decommissioned, is used to place the concrete cofferdams stored near the bridge, which are placed one on top of the other to form a sort of arch dam in front of the gates to be repaired and thus "lifted" out of the water. This crane was also sometimes used to transfer goods or small boats on either side of the dam, as the Ain was navigable at the time