The late Pleistocene-Holocene changing morphology of the Volturno delta and coast (northern Campania, Italy): Geological architecture and human influence

The present geomorphology of the Volturno River delta system and related strandplain is largely a product of complex, long-lived relationships between geological evolution and human impacts. In order to assess the main drivers of the changed landscape in the last centuries, a multidisciplinary study was carried out by combining geological and historical data. The study was based on geological and geophysical data, including about 1800 stratigraphic well logs to reconstruct the stratigraphic architecture of the delta plain and ca. 180 km of very high resolution single channel reflection profiles to image the stratigraphic pattern of the continental shelf and the offshore delta. Cartographic sources from the last 150 years were acquired, georeferenced and managed into a GIS environment, to support geomorphological interpretation. Land use maps were reconstructed for the 1957, 1990 and 2012. The Late Pleistocene and Holocene reconstruction of the Volturno coastal plain evolution evidenced the control of climatic changes (and consequently sediment supply and global eustatic variations) on the depositional history. The present landscape appears largely inherited by the past MIS5 and LGM landscapes. A progressive increment of anthropic forcing took place in the last 2000 years but the strongest modifications of the landscape occurred since the end of the XVII century, when, during the Spanish vice-kingdom, it was subjected to major land reclamation. More than 500 km of canals were built in the coastal area and resulted in the development of agriculture and farming on reclaimed land, promoting urbanization and increasing landscape fragmentation. A peak of major alterations of the deltaic environment, and retreat of the coastline was attained between the 1960s and the 1990s. Severe urbanization along the coastline, coupled with intensification of agricultural and tourism activities, resulted in a significant loss of natural ecosystems including humid coastal areas, lacustrine/marshy back-dune areas and mostly the beach-dune system. The negative sedimentary balance resulting from the reclamation works on the river courses, along with the interventions along the Volturno river basin, resulted in an accelerated and severe coastal erosion. The latter, coupled with subsidence rates and sea level rise, increase the vulnerability of the coast to flooding and storm surge and aquifer salinization.