This is Lake Serre-Ponçon (Lac de Serre-Ponçon) in the southerneast French Alps and yes it really is this gorgeous turquoise colour. It is one of the largest artificial lakes in western Europe. The lake gathers the waters of the Durance and the Ubaye rivers, flowing down through the Hautes-Alpes and the Alpes du Sud to the Rhône River. The waters are dammed by the Barrage de Serre-Ponçon, a 123 m high earth core dam.
As well as water control, sixteen hydroelectric plants use the water and the lake provides irrigation to 1,500 km² of land.
It’s one of the biggest artificial lakes in Europe and very popular with holiday makers.
The lake was created to control water flow after disastrous floods caused severe damage and loss of life in 1843 and 1856. First proposed in 1895, construction started in 1955 and was completed by 1961.
During construction of the lake, approximately 3 million m3 of material was moved. The dam was constructed and the valley slowly became a lake, flooding some villages in the process. This flooding is the subject of Jean Giono’s movie Girl and the River, starring Guy Béart.