Fluvial morphogenesis evolution of a mediterranean river: The example of the Durance fluvial system (south-eastern France).

Based on stratigraphical and sedimentological analysis of floodplain sediments, aerial photographies, ancient maps and texts preserved in local archives, the historical evolution of the Durance fluvial system (south-eastern France) is reconstructed. The amount of data allows to suggest a "model" of the evolution of the river during the 19th and the 20th centuries (decrease of floods frequency, reduction of fluvial bed, incision). Before these periods of time morphological and hydrological crisis (the end of the 14th century, 16th-19th centuries) may have alternate with period more quiet (15th century, as in the 20th century), althought the braided pattern never disappeared. This study stresses the originality of the evolution of a mediterranean and mountainous river, and, in this context, the importance of climatic fluctuations on the fluvial system evolution.