*4.1. Long- and Mid-Term Shoreline Changes along the Molise Coast from 1954 to 2016*

The application of the DSAS method allowed for the calculation of the long and mid-term shoreline changes of the Molise coast (see northern and southern Molise coast, Figures 4 and 5) for the periods of 1954–2004, 2004–2016, and 1954–2016 (Table 4).

**Figure 4.** Long- to mid-term annual shoreline changes along the northern Molise coast (segments S1–S5) during the periods 1954–2016, 1954–2004, and 2004–2016.

**Figure 5.** Long to mid-term annual shoreline changes along the southern Molise coast (segments S6–S9) during the periods 1954–2016, 1954–2004, and 2004–2016.


**Table 4.** Long and mid-term shoreline changes along the Molise coast.

Regarding the long-term evolution of the Molise coastline (time interval, 1954–2016), the results obtained (Figures 4 and 5, Table 4) confirm that erosion mainly affected segments S1 and S7, which underwent an overall average shoreline retreat of −132.5 m and −172.0 m, respectively (Table 4). Minor erosion areas are present in the northern part of S2, in the central and southernmost parts of S8, as well as in the northern portion of S9. However, segments S3, S4, S6, and S8 show an overall positive balance, and segments S2, S5, and S9 demonstrate substantial stability.

Shoreline changes calculated for the period of 1954–2004 obviously largely confirm this general trend, but these indicate major erosion rates for segments S1 and S7 (LRR of −2.6 m/y and −3.4 m/y, respectively; Table 4) with respect to the period of 1954–2016, thus highlighting a more intense shoreline erosion in these segments during the first 50 years of the considered time interval.

With reference to shoreline changes from 2004 to 2016, data highlight some trend inversions with respect to previous shoreline changes, from negative to positive and vice versa, which affect, for example, the northern part of S1, some parts of segments S6 and S7, as well as the two test areas. Shoreline retreat persists in segment S1, similar to the previous period (LRR of −2.1 m/y, Table 4), while the annual rates of S7 evidence a clear trend towards conditions of minor erosion (LRR of −1.2 m/y, Table 4). Furthermore, segments S2 and S9 show an overall trend towards moderate and slight shoreline retreat, respectively (LRR of −1.2 m/y and −0.5 m/y, respectively; Table 4), while the other coastal segments—and therefore also S3, where test area A is located—show an overall stability.

*4.2. Morpho-Topographic Changes of the Beach–Dune Systems in the Test Areas from 2019 to 2021*

Based on the data acquired during the UAV flights in 2019, 2020, and 2021, we produced the orthophotos and the related DEMs for test areas A and B, illustrated in Figures 6 and 7.

**Figure 6.** Orthophotos and DEM hillshades produced with the data acquired during the UAV flights in 2019 (**A**,**D**), 2020 (**B**,**E**), and 2021 (**C**,**F**) along Petacciato beach. (**A**) shows the locations of beach profiles P1–P7 extracted from the DEMs.

**Figure 7.** Orthophotos and DEM hillshades produced with the data acquired during the UAV flights in 2019 (**A**,**D**), 2020 (**B**,**E**), and 2021 (**C**,**F**) along Campomarino beach. (A) shows the locations of beach profiles C1–C5 extracted from the DEMs.

A comparison of the orthophotos and DEMs produced for test area A (Petacciato beach, Figure 6) gives evidence of the substantial stability of the dune vegetation cover and the variable coverage of vegetation debris on the beach. Slight shoreline movements are evidenced by small shoreline undulations varying from year to year, suggesting the probable role of longshore drift in local beach nourishment and erosion.

Comparing the orthophotos and DEMs obtained for test area B (Campomarino beach, Figure 7) highlights significant differences as to the morpho-topographic and vegetational features of its beach–dune system, allowing for the identification of a northern, southern, and central portion. The latter, in particular, is characterized by a larger beach and a dune front localised in a more internal position, approximately 15 m with respect to the adjacent beach portions. The comparison of recent Google Earth pictures (Figure 8) shows that the entire shoreline of test area B has undergone a more or less consistent retreat between June 2016 and July 2019 (up to approximately 30 m) despite the presence of the three breakwaters in front (but almost completely submerged, at least since 2014; Figure 8) and a groin, which was definitely detached in this period.

**Figure 8.** Evidence of shoreline and beach changes from 2016 to 2019 (Google Earth images dating back to 20 June 2016 and 20 July 2019) along the coastal stretch that includes test area B. On the Google Earth image from 2019, the white line indicates the shoreline of 2016.

Despite the fact that the entire shoreline of test area B has retreated from 2016 and 2019, the northern and southern sectors have not undergone a similar dune front retreat. This consideration, together with other observations (see below), led us to believe that the dune retreat in the central sector was not due to natural erosion but to human interventions aimed at enlarging the beach and also recovering, in this way, a part of the beach lost due to the shoreline retreat between June 2016 and July 2019 (Figure 8). In fact, this beach sector is used by the Marinelle campsite for bathing, as shown in several google earth images by the

presence of beach umbrellas and pedestrian access that cuts through the dunes, connecting the campsite directly with the beach. The latter appears clean, without vegetation debris, while the presence of several excavator footprints in the images of 2020 (Figure 7B,E), along with direct observations in the field, confirm periodic operations of cleaning, levelling, and enlargement of the beach in the pre-summer period.

For all beach profiles surveyed in the test areas in 2019, 2020, and 2021 (for location, see Figures 6A and 7A), the major morphometric features were determined.

Table 5 illustrates the major morphometric features of the beach profiles surveyed in 2019 and 2021.


**Table 5.** Comparison of main morphometric features of beach profiles in 2019 and 2021.
