Abstract:
Climate change represents a potential threat for estuaries, via potential landward intrusion
of saltwater, inundation of low-lying areas, acceleration in the nutrients cycling and disruption of
aquatic ecosystems. The Tagus estuary, one of the largest estuaries in Europe, holds a major natural
reserve and supports diverse activities, some of which may be negatively affected by the landward
intrusion of saltwater (e.g. agriculture). In this study, a new three-dimensional hydrodynamics
baroclinic model is implemented and validated in the Tagus estuary. A preliminary analysis of the
salinity distribution relative to different river flows and sea level rise is also performed. Results show
that the model adequately represents the main patterns observed, with significant improvements from
previous applications. The classification of the estuary, based on the Venice system, shows
contrasting situations regarding the salinity distribution for extreme river flows, and the progression
further upstream of the saltwater due to mean sea level rise.
