The potential vulnerability indices as tools for natural risk reduction. The Volturno coastal plain case study

Coastal areas are exposed to many hazardous events often exacerbeted by the sea-level rise with its related effects. The knowledge of vulnerability make possible to plan the actions aimed at reducing the risk and promoting the development of a resilient community. In this frame, the evaluation of potential vulnerability of coastal area only due to the human presence is the topic of the geo-spatial model proposed in this work. At this aim, a dataset of urban areas and population of last 200 years was used to assess the trend of these two factors and four vulnerability indices: urban density, population density, occupied buildings density and buildings surplus. The urban density and population density indices communicate the human pressure due to the presence of men while occupied buildings density and buildings surplus indices identify the zones where accommodation measures, as land use changes, could be applied to improve the coastal system adaptive capacity. This model was implemented at both municipality and censual administrative unit scales and it is well transferable to other areas exposed to hazard, allowing a comparison among regions. The method was applied to the case study of Volturno coastal plain (VCP), located in the north-western zone of Campania Plain (Southern Italy): indeed, the exposure to many natural hazards (coastal erosion, marine inundation, subsidence, salt water intrusion) coupled with the intense urbanization make the VCP a good test area to validate the methodology here proposed. The model evidenced a low constant value of population growth and the achievement of a sill for the urban development after the nineties, moreover the greatest part of censual districts close to the VCP shoreline have a high percentage of total unoccupied buildings. These conditions make concrete the possibility to change the land use from urban to natural land for wide coastal sectors.