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values of geographic fetch are Research & development

comprised in the directional

sectors 150-190°N and 260-290°N.

A rose plot of the offshore

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.

FIGURE 14 a) Positions of the real and virtual stations used for geographical Considering the coastline
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 d50 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 d50 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 4HPUVɈZOVYL^H]LJSPTH[LWHYHTL[LYZ

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.

:DYHFOLPDWHDQGFRDVWDOK\GURG\QDPLFV FIGURE 15 9VZLWSV[ZVMLZ[PTH[LKVɈZOVYLHUU\HS^H]LJSPTH[L
In Figure 14, the positions of Mazara del Vallo wave and wave climate obtained by simulation of wave
buoy and Favignana virtual buoy used for geographic propagation at Cala Azzurra and Lido Burrone sites
transposition of wave data are plotted. In the same (reference depth 15 m)
Figure, polar graphs of geographic and effective
fetches estimated at virtual buoy are shown; the highest

55EAI Energia, Ambiente e Innovazione 4/2015