The lake's dam is one of the region's must-sees. Discover it from the heights on a hike or come and visit it on one of our guided tours.

Highlighting Brittany

The Guerlédan dam was built at the beginning of the twentieth century. Its construction, decided just after the First World War, was above all the result of the meeting of two visionary men: Joseph Ratier, sub-prefect of Pontivy, and Auguste Leson, a young electrical engineer. It was the early 1920s, when the government launched a major national electrification plan.

The works

After a decade of studies and work, the dam was built in 1929, and by the following year it was supplying electricity to a large part of Brittany. At the time, people were talking about a concrete giant that would bring the "electricity fairy" into the home.

Yohann Hamonic

Its dimensions

Building the dam was a real technical feat. It is 45 metres high and 210 metres long, making it one of the first and one of the highest dams in France at the time. The construction work was titanic for its time. It took 110,000 m3 concrete, a new material at the time.

Did you know?

The project might never have seen the light of day. Its construction came up against numerous difficulties, both technical and financial. If the project was completed, it was thanks to the determination of the players and decision-makers at the time, and to the context in which electrification was a national priority.

The construction of the dam gave rise to the Lake Guerlédan which, for around ten kilometres, winds its way through the Côtes d'Armor and Morbihan regions.

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