Due to its mid-mountain terrain, its abundant rainfall, and the absence of deep water infiltration, the Morvan Regional Nature Park is characterized by a dense and complex hydrographic network. The innumerable glens that cut into it as well as its main valleys (Yonne, Cure, Cousin, Ternin Alène) are fed by a multitude of small streams. The omnipresent water and the varied wetlands (peat bogs, para-peat meadows, wet meadows, etc.) allow a dispersed habitat, play an important role in the water supply of the populations, and participate in the supply of the two large watersheds of the Seine and the Loire. As for the more than 3,450 bodies of water (ponds and lakes), they are all artificial and were, for the most part, created on the minor bed of watercourses initially for the floating of wood and, for about sixty years, for leisure.