Coastal retreat and marine flooding scenario for 2100: a case study along the coast of Maddalena Peninsula (southeastern Sicily)

Proceedings of the International Conference “GEOSUB 2016″, Ustica, Italy 13 – 16 September, 2016 (Furlani S., Antonioli A., Scicchitano G. & Busetti M. Guest Editors)

Abstract

The coastal area of southeastern Sicily (Italy) is undergoing weak land subsidence, heavy coastal retreat, land flooding and exposed to severe storms associated with high-waves, also in consequence of the global sea level rise, which is expected to raise even more that 1 m by 2100 AD depending on different estimates. This value will be even larger in subsiding coasts, entailing widespread environmental changes, coastal retreat, marine flooding and loss of land, which will be subtracted to human activities. To understand the impact of rising sea level on the coast of Maddalena Peninsula, near the town of Siracusa, we realized a very high resolution Digital Terrain Model (DTM) through aerial photogrammetric surveys, obtained by Unmanned Aerial Vehicles (UAV) on which we projected the expected coastline for 2100 AD. Here we show a detailed marine flooding scenario for 2100, as generated from: i) high resolution DTM, ii) rate of land subsidence from GPS data and iii) predicted sea level projections from the IPCC AR5 reports (RCP2.6 and RCP8.5). Our analysis estimates a maximum relative sea level rise at 0.20 m and 0.65 m for 2050 AD and 2100 AD, respectively for AR 8.5 scenario. The increased sea levels will cause relevant morphological changes to the investigated coast with a maximum beach retreat of 27 m and a loss of land of 7400 m2, affecting building integrity and people safety.