The powerful torrential Durance and Ubaye rivers feed Serre-Ponçon lake, which straddles the Hautes-Alpes and Alpes de Haute-Provence departments in the heart of the Southern Alps. Their tributaries provide the lake with a water particularly rich in minerals and sediments which give it that characteristic southern sea color. The exceptional sunshine of three hundred days a year in Serre-Ponçon valley further reinforces the impression of exoticism.