Impact of storms along the coastline of Emilia-Romagna: The morphological signature on the Ravenna coastline (Italy)

The coastal zone of the Emilia-Romagna region in Italy is exposed to risk from coastal flooding and erosion during storms. The vulnerability of this coastline is a topic of interest for future planning as this area provides large revenue for coastal communities and the whole region. An assessment of the historical record of storm events for the period 2000-2004 was carried out using a wave prediction model, forced by archived atmospheric circulation data. High-resolution air-borne laser detection technology (LIDAR) and video-monitoring (ARGUS) were used to undertake a feasibility study for the assessment of coastal erosion and flooding patterns along one of the best-preserved dune systems of the area. The object of the work was the comparison between two LIDAR flights at an interval of one year (July, 2003-September, 2004) with the second flight carried out after a major storm occurred in September, 2004. Following this event the whole coastal system was severely eroded. The study presented in this paper suggests that for the coast of the Emilia-Romagna region the critical factor that controls dune destruction and inland flooding is the joint occurrence of storm waves and surges. Beach slope is the main morphological control on wave run-up and the impact evaluation for the exceptional event has proved that a wide beach can provide a factor of safety. A small beach replenishment (33,000 m3) was undertaken on the test site but this resulted to be ineffective because of the small volume. Larger-scale beach recharge schemes should be undertaken at the site on a regular basis to provide wider beaches at the dune toe.