## 2 Study Area  
With more than 7900 km of coastline, Italy encompasses several coastal areas potentially vulnerable to inundation from RSLR in the coming decades [16; 18]. The present research focuses on five of these areas (Figure 1), characterized by significant environmental and economic value. The first two sites, Marina di Campo and Piombino-Follonica, are located in the Tus-cany Region (central Italy). The coastal areas of Tuscany host about 13% of the population of the region, along with significant touristic activities that leverage the rich environmental and cultural local resources [21; 80]. The Gulf of Follonica includes almost 35 km of fine sandy coast that has experienced considerable erosion rates in the past decades, leading to shoreline retreat in many segments [80; 81], while coastal processes have been deeply affected by anthropogenic sediment management [82; 83; 84; 21]. Tuscany also includes a group of stunning small islands that constitute the Tuscan Archipelago. These islands are mainly characterized by high and rugged coastlines, including some sandy beaches, such as the one facing the Gulf of Marina di Campo on Elba Island, which is about 2 km long. As for the oceanographic context, it is noted that during autumn and winter, the main feature of marine surface circulation along the Italian western coast is the northern current, which flows cyclonically from the southern Tyrrhenian to the Latium coasts [85]. However, at about 42\({}^{\circ}\)N, after bordering the Bonifacio cyclone, the current moves away from the coast, heads towards the Corsica Strait (west of Elba), and then crosses it to merge with the wide cyclonic cell of the Liguro-Provencal basin. Thus, the coasts of Tuscany are not directly exposed to this current, but are subject to coastal circulations induced by it, and by the presence of numerous islands (see [PERSON] et al., 2022 [86]). The current stops in spring, and in summer an anticyclonic circulation typically develops in the Corsica Strait area,  
Figure 1: Locations of the study areas in Italy: Piombino-Follonica, Marina di Campo (Tuscany), Alghero-Fertilia (Sardinia), Rome (Fiumicino-Ostia) and Latina-Sabaudia (Lazio). which basically separates the Northern Tyrrhenian from the Ligurian Sea [87; 88], and may extend into the coastal region of Tuscany. The third site that we consider is the Alghero-Fertilia lititoral, located in the bay of Alghero, on the northwestern coast of Sardinia. It is characterised by a 4 km sandy shore forming an arc with an NNW-SSE orientation. The bay is bounded by the harbour of Alghero to the south and by the smaller Fertilia harbour, at the inlet of Calich Lagoon, to the north [89]. The lagoon of Calich is fed by three small rivers, it has been partially reclaimed for agricultural use, and its connection to the sea has been armoured by the harbour of Fertilia. Detailed studies of emerged and submerged beach and seafloor habitat mapping have been conducted by the University of Sassari, highlighting complex feedback mechanisms controlling the evolution of coastal geomorphology and the relevance of anthropogenic impacts [89; 90]. The extension of the lagoon was further reduced in the late 1980s. The northwestern part of Sardinia is exposed to persistent systems of waves of considerable energy, which could be suitable for the deployment of wave energy converters [91]. However, the strong indentation of the coast to the southeast of Capo Caccia provides a very good shelter for the Gulf of Alghero-Fertilia, preventing wave propagation from the dominant south-eastward direction into the Gulf, where very low wave energy flux is typically observed. The fourth and fifth study areas are the coastal stretches of Rome (Ostia--Fiumicino) and Latina-Sabaudia, part of the Pianura Pontina (Pontina coastal plain). The Pontina coastal plain has a length of about 50 km and a width of about 20 km from the foot of the Lepine ridges to the Tyrrhenian Sea.