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The maps of the geohazard-related features of the North Sardinia continental margin produced by the Magic project (MArine Geohazard along Italian Coasts) are here presented. The maps were created on the base of morphobathymetric data obtained by with multibeam echo sounders. ThreCoNISMa, DSCG Università degli studi di Cagliari, Cittadella Universitaria Monserrato - S.P. Monserrato-Sestu, Monserrato (CA), Italye wide canyon systems, Castelsardo to the west, Lavezzi and Caprera to the east, originate from the continental shelf between the islands of Sardinia and Corsica and run toward the Sardinia Sea and the Tyrrhenian Sea, respectively. The canyons feature very wide and articulated heads, meandered sections of the main axis. The continental shelfhosts several coastal lithotomies, genetically related to late Quaternary sea-level oscillation and coastline migration. Furthermore, in the Bonifacio Strait, several bedform fields testify to the present-day activity of strong bottom currents. The main geohazard potential from the North Sardinia is related to the retreating of Castelsardo canyon heads, in offshore of Castelsardo and Asinara, which cuts the continental shelf reaching a few kilometers from the coast. [ABSTRACT FROM AUTHOR]

This paper investigates the dynamics of the cross-shore extensions of banquettes, a sedimentary structure mostly made by rests of Posidonia oceanica (L.) Delile, in a sandy urban beach located in the Gulf of Cagliari, Italy, western Mediterranean. A video monitoring station was installed above the promontory south of the beach. We analysed a four-year image database and related these dynamics to wave and wind parameters (obtained from the Copernicus and ERA5 databases) from September 2016 to September 2020. Our results showed that banquette deposition occurred in concomitance with the presence of leaf litter in the surf zone associated with mild storm events. Erosion of the banquettes occurred during more intense storms. When leaf litter was not present in the surf zone, banquettes were not deposited even with mild storms. Wind can influence the banquette dynamics: under certain conditions of speed intensity, the banquettes may be removed offshore, supplying litter in the surf zone, or they may be covered by sediment. The permanence of the banquettes on the beaches also depended on their composition: when the banquettes were intertwined with reeds, their removal by the waves did not occur even during intense storms, and this sedimentary structure can protect the beach from flooding. [ABSTRACT FROM AUTHOR]

Simeone, S., Brambilla, W., Conforti, A., Meyer, F., Molinaroli, E., and De Falco, G., 2024. Beach shoreline trends along the western coast of Sardinia Island (western Mediterranean Sea). In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 251-255. Charlotte (North Carolina), ISSN 0749-0208. The changes in shoreline position in sandy beaches and their rates are often interpreted as indicator of coastal erosion or accretion. The retreat/accretion of the shorelines can be influenced by several factors that can influence the shoreline behaviour at different time scales. Here we present a study on shoreline trends carried out on several beaches located along the Sardinia Island, western Mediterranean Sea. The studied area includes different beach types: from large open beaches up to geologically controlled and embayed beaches. Aerial images covering a time interval of about 60 years (from 1954 to 2019) were used to investigate the trends of the shorelines. Shoreline positions were digitized from each image and trends in shoreline position were obtained by using the DSAS tools. Effect on shoreline migration caused by sea level rise has been taken into account estimating the values of migration based on the application of the Bruun formula. Migration values obtained by this application were then compared with the landward space beyond beaches. Considering the averaged values of the net shoreline movement calculated for each beach the majority of beaches experienced a little retreat, with maximum values accounted for retreat for more than 100 m in correspondence to a river mouth. Hot spot of erosion has been also found in proximity of area in which human activities are present and have modified the shoreline setting and along areas where beaches are mainly composed by reworked relict sediment and no sediment sources are active at present days. The landward migration of the shoreline was compared with the features of the back beach and the great landward migration did not interfere with physical boundaries. In some cases, also with moderate shoreline retreat the presence of human infrastructure on the back beach can influence the shoreline final position and consequently can have a role in the adaptation capacity of the beach. [ABSTRACT FROM AUTHOR]

Trogu, D.; Simeone, S.; Usai, A.; Porta, M., and De Muro, S., 2024. On the role of wood and seagrass rests in coastal flooding events in Mediterranean microtidal beaches. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 115-119. Charlotte (North Carolina), ISSN 0749-0208. In December 2019, following intense rainfall, the riverbeds of the rivers flowing into the Gulf of Cagliari (Sardinia, Italy, western Mediterranean Sea) dumped a large quantity of river reeds attributed to the species Arundo donax (Poaceae) into the sea. The concomitance of a sea storm event acting in the waters of the Gulf of Cagliari transported and allowed the deposition and sedimentation of reeds and other seagrass rests (mostly P. oceanica) on the Poetto beach (an urban microtidal beach located in the Gulf of Cagliari), for an estimated mass of over 85 tonnes. The subsequent lock-down given by the Covid-19 pandemic, and thus the absence of anthropogenic interferences, allowed the almost undisturbed interaction of beach processes with these wood and seagrass rests. This paper will describe the sedimentary structures formed on the berm, generated by the interaction between reeds, Posidonia and sediment. Subsequently, it will be analysed how these sedimentary structures protected the beach from coastal flooding during storm events which were characterised by wave parameters (significant wave height and wave peak period) with greater values than those recorded during other storm events that led to beach inundation. In detail, analyses were carried out comparing the wave data with images acquired by a coastal video monitoring system. However, this storm event caused the reeds to redistribute along the emerged beach, generating new sedimentary structures that, as a result of successive storm events from different directions, became stratified in the beach increasing its permeability. Although the beach cleaning operations often carried out with a removal of vegetal berms, the results of this study highlighted that the non-removal strategies along the foreshore and the backshore can increase the whole beach system resilience and protect the anthropic structures built in and behind the beach. [ABSTRACT FROM AUTHOR]

The expected sea level rise by the year 2100 will determine an adaptation of the whole coastal system and the land retreat of the shoreline. Future scenarios coupled with the improving of mining technologies will favour an increased exploitation of sand deposits for nourishments, especially for urban beaches and sandy coasts with lowlands behind. Objective of the work is to provide useful tools to support planning actions in the management of sand deposits located in the continental shelf of western Sardinia (western Mediterranean Sea). The work has been realized through the integration of data and information collected during several projects. Available data consist of morpho-bathymetric data (multibeam) associated with morphoacoustic (backscatter) data, collected in the depth range -25 to -700 m. Extensive coverage of high-resolution seismic profiles (Chirp 3.5 kHz) have been acquired along the continental shelf. Also surface sediment samples (Van Veen grab and box corer) and vibrocores have been collected. These data allow mapping of the submerged sand deposits with the determination of their thickness and volumes, and their sedimentological characteristics. Furthermore, it is possible to map the seabed geomorphological features of the continental shelf of western Sardinia. All the available data (doi: https://doi.pangaea.de/10.1594/PANGAEA.895430) have been integrated and organized in a geodatabase implemented through a GIS and the software suite Geoinformation Enabling Toolkit StarterKit® (GET-IT), developed by researchers of the Italian National Research Council for RITMARE project. GET-IT facilitates the creation of distributed nodes of an interoperable Spatial Data Infrastructure (SDI) and enables unskilled researchers from various scientific domains to create their own Open Geospatial Consortium (OGC) standard services for distributing geospatial data, observations and metadata of sensors and datasets. Data distribution through standard services follows the guidelines of the European Directive INSPIRE (DIRECTIVE 2007/2/EC); in particular, standard metadata describe each map level, containing identifiers such as data type, origin, property, quality, processing processes to foster data searching and quality assessment. [ABSTRACT FROM AUTHOR]