


Around 4000 years ago, a rocky landslide added to an existing glacial moraine to form a natural dam capable of retaining this large volume of water. The seasonal variation of the level of the lake of 20 to 25 m is due to the permeability of the materials making the dam. In fact the lake does not have a spillway and the water infiltrates the boulders of the dam. It offers a beautiful view of the lake which infact inspired the painters at l'Abbé Guétal.