Sediment Fluxes in Coastal Areas

Abstract

The morphogenesis of the mouths and shores of the Rho ˆne river delta has been strongly influenced by changes in hydrology associated with climatic deteri- oration during the Little Ice Age (LIA). The present shape of the delta is related to two avulsions. The progradation of delta-mouth lobes, their morphology (digitated or lobate), and their reworking by marine processes are described here from ancient maps, the interpretation of which has been comforted jointly by the critical view- point of the historian and input from previous geomorphic studies. The impacts of climatic oscillations proper to the LIA are analysed and confronted with other factors implied in deltaic morphogenesis such as sediment transfers, accommoda- tion space, marine processes and human interventions, notably from an engineering perspective. The successive metamorphoses of the Rho ˆne delta are, thus, seen to be related to the conjunction of some or all of these factors, depending on the time frame under consideration.