The Bléone river, about 67km long, drains a catchment area of 905km² between its source under the Tête de l'Estrop mountain and its confluence with the Durance river.

The foothills valley of the Bléone river, dominated by the Liman Ridge to the west, spreads a wide bed of pebbles revealing its torrential flow, with a succession of natural terraces indicating the former levels of the river at the time of the great glaciations.

Between the river and the hamlet of Villard, three natural terraces are clearly visible, separated by pine woods. The upper natural terrace corresponds to the Mindel glaciation (50,000 years ago), the middle terrace to the Riss glaciation (35,000 years ago) and the lower terrace to the Würm glaciation (15,000 years ago).

The Bléone river is a braided river characterised by a very wide main river-bed where the flow is divided into various channels separated by areas of gravel that are mobile according to the intensity of the waterflow and floods. These areas of gravel, or braid bars, ensure the temporary storage of the sedimentary load. This type of river, which used to be very common, is now in decline as a result of the development of waterflow and watercourse regulations and techniques. Between La Javie and Marcoux, the Bléone river is almost completely undeveloped : wild and natural.