

The Lac du Crachet is a glacial lake, like most of the mountain lakes. It is an oligotrophic mountain lake, that is to say, it is a stretch of clear, deep, nutrient-poor water containing very little organic matter and with a high level of dissolved oxygen. It dries out completely during periods of intense drought. The Torrent du Crachet mountain stream flows from it into the little valley which shares its name, before flowing into the Crévoux mountain stream.