Nicola Corradi

The evolution of the dune fields of Platamona-Marritza (northern Sardinia) : Application of remote-sensing methods

The littoral of Platamona–Marritza is an example of a Mediterranean coastal environment with a marked heterogeneous dune system. Morphological studies, based on remote-sensing methods and on field surveys, have been carried out in order to trace the diachronic evolution of the aeolian deposits and to understand the current condition of this area. Aerial photographs have allowed us to analyse the evolution of the coastline, the dune fields and the anthropic development of the coastal strip over the period 1955–2002. The field surveys were undertaken in September 2003 and September 2004 to verify the data acquired by the elaboration of the aerial photographs and to identify and map the vegetation of the dune belt. A relationship between vegetative species found on the Platamona–Marritza dune field and the retreat of the coastline was then established.

Late Quaternary deposits from the Ligurian continental shelf (NW Mediterranean): A response to problems of coastal erosion

The Ligurian continental shelf is a terrigenous platform characterized by variable extension and subsidence of the continental margin and thick accumulation of sediments originated by repeated sea-level oscillations. Its genesis and evolution occurred during the Plio-Quaternary, even if early erosive modelling in some sectors has been dated to the Late Miocene. The present morphology of the shelf is the result of transgressive–regressive Quaternary cycles. Using a high-resolution seismic grid of more than 1000 km, we have been able to define the seismostratigraphic characteristics of the Ligurian Sea shelf. On the basis of our studies, it has been possible to describe in detail the seismostratigraphy of the Late Quaternary and Holocene sediments that cover the shelf to various depths, in terms of sedimentary sources, for the purpose of distinguishing ‘relic’ deposits suitable for nourishing beaches undergoing erosion. From this detailed study of the evolution of the most superficial deposits, it is possible to distinguish between different sedimentary bodies deposited during a transgressive phase and located at a water depth ranging between 20 and 70 m; they are represented by relic sands cropping out at the sea bottom due to a relatively thin Holocene drape and could be explored for beach nourishment programmes.

Discovery of Versilian deposits suitable for beach nourishment on the continental shelf of Western Liguria

In this paper we present the results of a study conducted in collaboration with the Ligurian Region, in the framework of the E.U. Beachmed-e Interreg IIIc Project, to distinguish relic coastal deposits on the continental shelf, suitable for beach nourishment. These deposits are related to transgressive-regressive sedimentary cycles, and they are due to Quaternary glacio-eustatic sea level variations. In fact, during the sea level low stand associated with the last glacial maximum (c.18–20,000 yBP) the sea level was 110–120 m lower than its present level and the continental shelf was exposed. During the Versilian Transgression the coastline migrated from the shelf break to its present position. This migration was not continuous and conspicuous sediment bodies, associated with deltaic or littoral systems, were deposited during static periods. The results of a marine geology campaign with seismostratigraphic and sedimentological analyses enabled us to distinguish gravelly and sandy littoral deposits at depths of 20–40 m near the coast and 60–80 m on the outer shelf, in areas with only a thin Holocene mud cover (high stand deposits).

Evaluation of the effectiveness of a seasonal nourishment programme of the pocket beaches of the city of Genoa

The aim of the study was to monitor several beaches of the city of Genoa following artificial nourishment programmes carried out in 2003. The programmes, which involved depositing fluvial material from the Bisagno Torrent in the swash zone, were carried out as part of the seasonal nourishment of the beaches of Boccadasse, Bagnara and Caprafico to the east of Genoa, which are subject to intense erosion. The study provided for a preliminary survey in April 2003, before the nourishment, and three other surveys were subsequently carried out to evaluate the effectiveness of the intervention through the evolution of the beach. The morphological and sedimentological surveys were carried out in July and November 2003 and April 2004 to evaluate the development of the beach in both high and low energy situations. The suitability of the material was evaluated using the method proposed by Hobson. From the data obtained from the field studies it was possible to demonstrate that the interventions had only partially counteracted the annual sedimentary losses of the beaches. The quantities of material deposited were inadequate to enable the beaches to re-equilibrate their compromised morphodynamic profiles and adapt to the wind-wave conditions. Therefore, we consider it essential to undertake the reconstruction of the beaches and not simply try to maintain them in this way. The use of greater quantities of material would permit not only the widening of the backshore but also the creation of more stable morphodynamic profiles that would last longer.

Evaluation of a nourishment programme with a webcam: the case of Levanto (La Spezia, Italy)

This paper presents the results of a monitoring programme of the littoral of the town of Levanto (La Spezia) to evaluate the efficiency of a nourishment project carried out on a gravel beach. The study was carried out with a webcam, one of the most innovative techniques for monitoring coastal evolution. This technique makes it possible to automatically obtain a continuous, real-time set of images of high quality that can then be processed with dedicated software to provide information on the morphodynamic conditions of the beach. The image processing technique, [based on the studies carried out by the Coastal Imaging Laboratory of Oregon State University to develop the Argus System], was developed by the Dipartimento per lo Studio del Territorio e delle sue Risorse (Dip.Te.Ris.) and the Dipartimento di Matematica (Di.Ma.) of the University of Genoa. The research was focused on studying the variations in the shoreline following a nourishment programme as revealed by a comparison of the processed images, which made it possible to reconstruct the evolution of the beach in the short- and medium-term and thereby evaluate the efficiency of the intervention.

Storm Hazard Assessment for Urban Areas

Storm surges are one of the most significant threats for coastal urban areas. In view of finding a way to minimize sea storm damages to anthropic structures, this paper focuses on the analysis of storm hazard investigation methods and on coastal control line definition. Generally, coastal control lines are identified through Run up equations proposed by Mase (1989). Applicability of Van der Meer equations (1998), usually employed for beach profile analysis, will be assessed here as an alternative to Mase equations. Three urban beaches on Genoa coast are considered: Voltri beach, Pegli beach and Vernazzola beach. The analysis takes into account sea and weather condition data collected during three major storm surges in the aforementioned littoral areas. Empirical data gathered in field surveys during storms were subsequently examined in order to analyze seaside area response. Collected data were compared with theoretical computations. Results show a greater significance of data obtained through the application of Van De Meer (1998) equation than Mase equation data (1989). In conclusion, Van De Meer (1998) equation could provide information about coastal control lines on urban gravel beaches. Such information would then be useful to locate high hazard areas and act accordingly.