Evaluation of the coastal erosion of the Ligurian beach

Marco Ferrari, Silvia Bolens, Alessandra Bozzano

University of Genoa - DIPTERIS (I)

Key words: coastal erosion, morpho-sedimentological index, Liguria

Abstract

In the framework of the Project Interreg Beachmed, financed by the European Union, the Ligurian regional government in collaboration with the Dip. Te. Ris (Department for the study of the territory and its resources) has been involved in a study on the Ligurian littoral to identificate and to quantify erosive phenomena.
The Ligurian coast extends for 350 kms of which 94 are beaches with principal exposure to the winds of the third quadrant; the greatest part of the beaches has the peculiar characteristic of being pocket beaches, between two rocky cliffs with short length and width, elevated slope and coarse sediment.
This morpho-sedimentological condition is not so exhaustive to evaluate the erosion of the beach only through the analysis of the shoreline variation. Thus, to evaluate the risk it has been necessary to associate this parameter to others parameters able to give information about the littoral.
The parameter considered is:
Shoreline variation
Amplitude and height of the beach in relation with the wave
Beach profile
Sedimentological index (sorting grain size and Skewness)
The investigations have interested 360 sections of the beach (graphic representation 1:25.000), where the most important quantitative and sedimentogical data have been collected.
A value index has been assigned to this morfo-sedimentary parameters, this index is a function of these parameters, then they have been elaborated through a simple computation algorithm. Thanks to the results three groups have been defined to evaluate the erosive state of the littoral.
This study represents a base to create a future coast monitoring system too.