The evolution of the Adriatic Coastal zone (Italy) between the Gabicce promontory and the Tronto River mouth

摘要

Since the beginning of the 20th century, the world's coastal areas have been affected by a widespread shoreline regression that has reached the critical stage since 1950. The Italian coastal zone along the Adriatic Sea is a good example of the mentioned state of environmental destabilisation. The continuous shoreline regression from 1950 up to the present time was faced by many kinds of defence works put into operation. All these protective works, impelled by necessity at different times, were built in the course of the erosive process at enormous cost. Considering the evolutional trend of the Adriatic coastal stretch between the Oabicce promontory and the Tronto river mouth, it is possible, utilizing some geomorphological and sedimentological parameters derived from precedent studies, to show how it was possible to predict the negative evolution before it became irreversible. If this prediction was possible, even prevention would have been possible with low cost defence works and with a better chance of success at facing the shoreline regression. The considered parameters are: the granulometric characters of the sea bottom between the shoreline and the offshore, the maps showing the dimension of landslides on the cliffs, the seasonal variations of the backshore over the last 20 years, the shoreline regression or advancement over the last 50 years expressed in m/year, the increased bottom slope between the shoreline and the wave breaker zone over the last 50 years expressed as a percentage. The examination and comparison of these parameters permit the possibility of preventive action, following the evolutive prediction, to face the erosive phenomena at its beginning.