The sedimentary dynamics of Apulian sandy beaches through a multidisciplinary approach

Beaches constitute extremely variable environments where different natural processes act simultaneously with many human activities due to the increase of density population along many coasts of the world. Consequently, numerous problems have materialized along many of the world’s coasts through a destabilization of ecosystems, sedimentary budgets and processes that originally kept a complex system such as that of a beach in balance. A better knowledge of the way beaches work is fundamental to provide possible remedies aimed to correct the imbalances caused by human activities. This is particularly true for a country like Italy which has a significant developed coastal system and for some regions such as Apulia (southern Italy) which has a coastal sandy stretch of about 650 km where the growth of the urbanization in the last decade, coupled with the concentration of the economic and tourist facilities, have led these coastal areas to be affected by erosional processes. With this aim we investigated few Apulian beaches through a multidisciplinary approach, in order to build a standard procedure for monitoring their morpho-sedimentary processes by analyzing the textural and compositional characteristics of the sands and quantifying the volumes involved in the coastal dynamics during a period of time of three years. In particular, sedimentological and ecological investigations allowed us to describe the textural and compositional characteristics of the beach sands by interpreting their sand provenance and the physical/biological interactions within the beach. We used these data to establish the erosive or stable-prograding tendency of these beaches, the peculiar compositional sediment features, consisting mainly of bioclastic debris, being the Apulia Region almost characterize by the absence of watercourses that could supply the coastal sectors. Topographic surveys were carried out with a Terrestrial Laser Scanner and an Optical Total Station, aimed to quantify the variations of sediment volume of the beaches, whereas the Delft3d software was applied to analyse the effects of the dominant wave motion on the sedimentary dynamics. Geophysical techniques which included sub bottom profiler procedures, ground penetrating radar investigation and resistivity models enabled us to see the geometry and the thickness of the coastal wedges and their stratigraphic relationships with the underlying bedrock in the light of their most recent Holocene evolution.