Page 7 - Pasanisi_alii_2015

Research & development

Results and discussion As regards Cala Azzurra, two small sandy bays can be
observed in Figure 4 (hereafter referred to as “western
Macro features of coastal morphology bay” and “eastern bay”), separated by a central rocky
and dynamics headland. Emerged beach is flat and narrow, with a
From general observation of beach morphodynamics maximum width of about 8 m at western bay and 12
at Cala Azzurra and Lido Burrone site, some qualitative m at the eastern bay. In order to reduce the risk of
differences can be noticed. landslides, the entire backshore slope is protected by
a geotextile net revetment, with a
significant reduction in sediment
supply to the beach. Moreover, at
the western bay, a quarry stone
seawall is present at the toe of the
slope, increasing wave reflection
onshore.
As historically reported and
observed during the monitoring
project, the impact of wave storms
on Cala Azzurra beach can induce
severe modifications (Figure
5), with huge coastline retreat
and, sometimes, with complete
disappearance of the emerged
beach at western bay, where
changes can take place in very
short times (days or even hours).
As regards Lido Burrone, two
coves can be distinguished just
as for Cala Azzurra (Figure 4), but
here emerged beach is present
FIGURE 5 Cala Azzurra. a) Overview of the site; the western beach on the left and the only at the south-eastern side; the
eastern bay on the right are visible in the picture. b) View of the eastern bay.
c) View of the western bay, with emerged beach (May 2012). d) View of the emerged beach is relatively flat,
western bay, with beach completely eroded (November 2012) with a width comprised between
about 10 m at ends and 30 m in
the middle. Based on historical
reports and direct observations,
the effects of coastal modelling
due to waves impact are generally
milder compared to Cala Azzurra,
with rather limited coastline
retreat and noticeable beach
width even under severe wave
conditions (Figure 6).
At both sites, sediment samples
FIGURE 6 Lido Burrone beach. Picture a was taken in late autumn (November 2012), were collected in the emerged
picture b in spring (May 2014). A huge amount of Posidonia oceanica and submerged beach. Results of
banquettes is visible at the shoreline in picture a, owing to high energy incident
waves; however, the emerged beach maintains a noticeable width grain size analysis indicate little

EAI Energia, Ambiente e Innovazione 4/2015
52