Hydrodynamic modeling of the final reach of the Misa River (Senigallia, Italy): the role of sea action and bed forms

The work carried out within the framework of this thesis deals with the hydrodynamic modeling regarding the final stretch of the Misa River (Senigallia, Italy) using the HEC-RAS software with particular emphasis on the effect brought by the tidal action and some riverbed forms existing at the estuary. Initially, a characterization of the estuarine environments is performed, focusing successively on the description of the Misa River microtidal estuary. This is defined as a salt-wedge estuary marked by an upper freshwater layer that overrides the denser marine saltwater layer without mixing one another. Afterwards, an overall picture on the river bars is presented. Specifically, the river-mouth bars are taken into account given that an emerged bar intermittently shows up and moves close to the Misa River mouth, depending on the river discharge, tides and sea waves. Then, following a brief overview of the Misa River site, which is featured by a marked torrential regime, data from Marche Region Civil Protection, field surveys and hydrodynamic data regarding the final reach of the river are used with the aim of making unsteady simulations of the final reach of the Misa River extending for about 10km. The HEC-RAS modeling makes use of the data collected by two hydrometers (property of the Civil Protection), a river gauge (installed within the framework of the international MORSE project) and several surveys of the river bed. After the model calibration (carried out in a companion thesis work), unsteady simulations of events recorded in 2014, 2019, 2020 and 2021 are performed, with the main purpose of understanding the tide effect along the investigated river reach and the influence of the river-mouth bar on the water elevation along the river during different flow regimes.