[Extract] Estuaries and coastal ecosystems are transitional between terrestrial and ocean environments, and this is the reason why they are highly dynamic ecosystems. Being situated at the lower point of the river basins, estuaries and coastal ecosystems are highly dependent on all the factors, processes, and uses directly or indirectly related with water over the entire river basin. Finding sustainable solutions to reverse the degradation and restore estuarine and coastal ecosystems requires a profound knowledge about the processes occurring at different spatial and temporal levels, and understanding of the need for a transdisciplinary approach to water issues in estuarine and coastal environments