Coastal Line Changes in Mediterranean Cities: Man or Nature?

Despite being a relatively stable sea compared to the great oceans, the Mediterranean is not a risk-free place of changes in the coast, both anthropogenic and natural. The coast is home to a large part of the population and cities which are generally in constant growth due to the quality of life and the possibilities offered (i.e. tourism and other activities linked to the sea). In Mediterranean coastal cities, the first maritime line is usually the one with the highest economical value and, where the space is used intensively. For this reason, land managers have developed strategies to occupy the maximum extension of the coast. Some of these are new uses for old port areas, take advantage of coastal containment works, extending the beaches mean artificial regenerations, the construction of breakwaters and, adding waste materials in order to increment the land, gain it to the sea. So that, the urban coastal lines of Mediterranean cities have been changing a long time. This work presents these changes in the past years (last 60 years) through a methodology based on the comparison of aerial photography from different times (1956–1957 and PNOA 2014–2016) in the following settlements of the South-East of Spain: Alicante, El Campello, Santa Pola, Torrevieja, Altea and Villajoyosa). The changes have been categorized so that we can quantify the type and proportion of the changes and discriminate if those are natural or artificial. The results showed that most of the municipalities have registered changes, those were due to land reclaimed to the sea and man is the main driver of this change. These changes mask and correct those due to natural erosion, soil loss or geological changes in the coastline