Modelling Rhodamine dispersion experiments in Fangar bay case (NW Mediterranean sea)

Fangar Bay, a semi-open bay with micro-tidal dynamics, is located in the Ebro Delta (NW Mediterranean Sea). Over the past few decades, the bay, a key area for aquaculture and rice cultivation, has been increasingly influenced by human activities and climate change. To better understand this sensitive area, we investigated the bay's hydrodynamics and the impact of freshwater discharge. Using the TELEMAC 3D model, we preliminarily included the internal and external forces affecting the bay's hydrodynamics (i.e, meteorological forcing, river fluxes, regional hydrodynamics provided by CMEMS products). For coastal semi-enclosed waters with a depth of less than 4 m, the model achieved a relatively high-resolution grid (24 m) and completed the preliminary verification of temperature and salinity in the profile, as well as the initial verification of water flow speed and direction at the bay mouth and within the bay. Collaborative efforts with UPC/LIM and IRTA included Rhodamine experiments, which support the validation of the model using a numerical conservative tracer, the comparison results between model and Drone data also show acceptable goodness of fit This study combines field campaigns and numerical modeling to propose effective strategies for the governance and optimization of the bay activities. Also, it has been verified that high-resolution numerical models are an effective technical means for studying the hydrodynamics of complex and sensitive coastal waters.