Hydrologie du Dévoluy : La Souloise, les Gillardes et le puits des Bans

Abstract

Hydrology of Dévoluy (French PreAlps) : Souloise river, Gillardes springs and puits des Bans Dévoluy is a karstic system in the French Alps with a size of 165 km2. The basin is drained by a surface river, the Souloise, and an underground collector, reappearing at the springs of Gillardes. A cave, the puits (shaft) des Bans, situated 200 m higher, is an overflow spring of the underground system. We studied the discharge of the surface river and the spring as well as the flooding heights in the Puits des Bans during a year. The linear correlation between the spring discharge at Gillardes and the water elevation in the puits des Bans is surprising for a karstic flow. We propose a hydrologie model of two basins with a narrow link and laminar flow, of which the common spring is Gillardes. The obstacle is localised near the important geologic structure named Digne thrust. Some hydrologie properties are developed : hydrologie connections, hydraulic transmissivity, and storage volumes during floods.