Shoreline Historical Evolution (1956-2015) of Beaches of Menorca (Balearic Islands)

Shoreline evolution of 52 beaches from the island of Menorca (Balearic Islands) has been analyzed from 1956 to 2015 using 9 orthophotos. The analysis was done with the GIS tool Digital Shoreline Analysis System (DSAS). The statistical parameters used are Weighted Linear Regression (WLR), the distance in m/y by plotting the shoreline positions with respect to time, Net Shoreline Movement (NSM), the distance between the oldest and the most recent coastlines in meters and Shoreline Change Envelope (SCE), the distance between the furthest coastlines in meters. The result is a medium setback of 4.8 m at a speed of -0.1 m/y. The behavior of the coastline according the typology of the beach has been analyzed, being the most erosive type A (urban beaches), followed by type B (non-urban beaches with vehicle accessibility), with less erosive C-type beaches (non-urban beaches only accessibility on foot). Also the behavior of the coastline has also been analyzed with regard its geographical location and its physiography. Highlights include the beaches of Ponent with strongest erosion processes, followed by the beaches of Migjorn. In contrast, those of Tramuntana are the least erosive. Finally, an Principal Components Analysis (PCA) has been used to analyze the behavior of the coastline using a matrix of 7 variables with 52 observations. The two first factors explain 66.77 % of the variance, where F1 is positively correlated with NSM and WLR, while F2 is correlated with dunar system and foredune. With regard SCE, is negatively correlated with F1, which can be interpreted that high value of SCE are correlated with high erosive value and vice versa.