The Departmental Council of Cantal wishes to undertake restoration work of a road structure combining restoration work of ecological continuity (fish, semi-aquatic mammals and sediments) on the Petite-Rhue (affluent of the Rhue / Dordogne basin) at the level of Chapsal (communes of Riom-ès-Montagnes and Saint-Saturnin). The objectives of this work are to guarantee the sustainability of the development and in particular of the debark which will host the environmental developments dedicated to the restoration of ecological continuities and allow a reconnection over nearly 11 kilometers upstream on the Petite-Rhue. The project is part of the Green and Blue Contract of the Volcanoes PNR, Action E25 - Restoration of ecological continuity at the right of the bridge of Chapsal on the Petite-Rhue.