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the closure depth of the site (i.e., the maximum water
depth of significant sediment transport, depending on
wave climate) is located within the headlands, long-
shore sediment exchange is negligible. In this case, the
pocket beach can be regarded as a closed sediment
cell, where sediment supply to the beach is essentially
due to shoreward cliff erosion (if comprised of soft
rock), or stream discharge (if present).
A large body of literature exists on the dynamics of pocket
beaches [3, 4, 5, 6, 7, 8]. As regards plan-view geometry, FIGURE 2 Typical features of cross-shore beach profile modelling
a number of planform parameters and ratios are used in Source: Exploring Florida. A Social Studies Resource
literature to describe and classify the coastal morphology for Students and Teachers, University of South Florida
and estimate the equilibrium status of the beach [9]. Due
to the limited sediment transport at ends, the coastline Sometimes, however, beach changes can be permanent
generally tends to align itself with prevailing incident and non-reversible. This occurs when sediment
wave fronts, assuming a typical seaward concave plan supply from the backshore is reduced or interrupted,
shape that can be approximated by a logarithmic spiral or typically for man-induced causes as land-use change,
different mathematical functions. The resulting coastline modification of hydrographic network, sediment Research & development
configuration, corresponding to ideal conditions of extraction from riverbed, destruction of dunes,
stability, is a classical and appreciated conceptual construction of seawalls and other hard structures [15,
scheme for coastal stabilization projects. The coastline 16, 17]. Other possible cases of barely reversible beach
orientation – i.e. the orientation of the line connecting changes can be due to sediment delivered by streams
the edges of the beach – is a typical parameter used to during extreme flood events, as reported for the Elba
empirically describe coastline adaptation to incident Island, [18, 19]. These are not the cases in Favignana,
waves. In general, if coastline orientation is aligned with given the absence of an organized river network.
the line connecting the headlands of the bay, a relative In the framework of a wider research program, an
stability of the beach is to be expected, while coastline extensive investigation of coastal morphology and
rotation can be regarded as a morphological response to dynamics was performed at Cala Azzurra and Lido
changes in approach angles of prevailing incident waves. Burrone sites during the period 2012-2014. First
Assuming a substantial stability in terms of long-shore results of the work, including an outline of materials
sediment processes, the dynamics of a pocket beach and methods and partial data analysis, have been
is frequently dominated by cross-shore modelling of synthetically presented in a previous paper [20].
beach profile. As well established in literature [10, 11, Besides any scientific interest, the results of the projects
12], for a given profile geometry and sediment grain will contribute to create a knowledge base aimed
size, cross-shore modelling can result in beach accretion to implement measures for sustainable tourism and
or erosion depending on incident wave conditions. In management of marine resources.
case of high energy incident waves, offshore sediment
transport (destructive forces) prevails, resulting in
coastline retreat; on the contrary, with milder wave Materials and methods
activity, the onshore transport (constructive forces)
prevails and the result is a coastline advance (Figure Hydrographic surveys
2). Cross-shore modelling processes are generally Four hydrographic surveys were performed at Cala
reversible, and the effects are alternations between Azzurra and Lido Burrone, in the following periods:
two typical beach profile shapes, referred to as November 2012 (Survey 1), July 2013 (Survey 2),
“storm”, “winter” or “bar-type” profile, and “ordinary”, September 2013 (Survey 3), and May 2014 (Survey 4).
“summer” or “berm-type” profile, respectively [13, 14]. The temporal planning of surveys was defined in order to

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