Recent changes in the morphodynamic of the Ebro river mouth (NW Mediterranean Sea)

The Ebro River Delta, as one of the largest river deltas in the NW Mediterranean region, is a lobate fluvial-wave dominated delta with a principal freshwater discharge channel (order of 102 m3/s of regular conditions). The lowest part of the delta and the river mouth has suffered natural-induced shifting configuration in the last century. Recent morphologic changes on the Ebro River mouth has lead to a formation of an island and tomobolo with a consequent deviation of the main channel of the freshwater discharge southwards. Field survey carried out of November 2023 has suggested a shifting of the preferential freshwater discharge from North mouth to an incipient North-East mouth. This investigation pursue to identify the main reason of this morphological changes and discern the eventual perpetuity of the new configuration. The analyses combine the use of satellite images to identify the shoreline modifications, jointly with “in situ” data of bathymetry, waves and currents. Likely the island formation and subsequent tombolo is due to the recent absence of NE storms combined with extremely low river discharge (including regulated floods) due to the drought conditions that is suffering the Ebro river basin during the last years.