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values of geographic fetch are
comprised in the directional
sectors 150-190°N and 260-290°N.
A rose plot of the offshore Research & development
annual wave climate derived
from geographic transposition
is depicted in Figure 15.
Two directional sectors for
prevailing incident waves can be
distinguished: the first comprises
the south-eastern quadrant, whilst
the second is centered on south-
western direction.
Considering the coastline
FIGURE 14 a) Positions of the real and virtual stations used for geographical
transposition of wave climate. b) Polar plots of geographic and effective geometry and orientation, it can
fetches at virtual buoy off study areas be assumed that only the waves
comprised in the sector 120-
Considering all the above considerations, for all 300°N are likely to propagate shoreward and reach
surveyed profiles, the best-fit values of scale parameters the study areas. Based on the above considerations,
A were estimated; all values correspond to ideal values the directional sector can be divided in two prevailing
of d 50 greater than that of the actual sediment (0.20 mm).
Limited to the only sections of coast where emerged
beaches are present, theoretical mean values of d 50 can
be estimated as 0.68 mm at Cala Azzurra western bay,
0.72 mm at Cala Azzurra eastern bay and 0.47 mm at
Lido Burrone beach.
Considering the minor bathymetric variations observed
during the project period, results seem to suggest TABLE 1 Main offshore wave climate parameters
an overall stability of the submerged beach profile
greater than that expected from the actual sediment
size distribution. It can be reasonably hypothesized that
this is due to presence of rock or to the stabilizing effect
of Posidonia oceanica on the sea bottom, though more
investigations are needed to confirm this hypothesis.
In particular, it should be necessary to investigate
in detail the nature of sea bottom materials and its
coverage and further extend measures in the emerged
beach and in the nearshore zone, where intense
sediment dynamics is to be expected.

Wave climate and coastal hydrodynamics
In Figure 14, the positions of Mazara del Vallo wave
buoy and Favignana virtual buoy used for geographic
transposition of wave data are plotted. In the same FIGURE 15 Rose plots of estimated offshore annual wave climate
Figure, polar graphs of geographic and effective and wave climate obtained by simulation of wave
propagation at Cala Azzurra and Lido Burrone sites
fetches estimated at virtual buoy are shown; the highest (reference depth 15 m)

EAI Energia, Ambiente e Innovazione 4/2015
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