Sea level rise, the global and relative increase in the surface of the oceans, caused primarily by the thermal expansion of water due to global warming and the melting of glaciers and polar ice caps, poses risks to coastal areas, such as flooding and erosion. Correct mapping of the risk areas is essential for a correct understanding of the impacts of the phenomenon and for planning interventions aimed at preserving and improving natural and man-made defense works to counteract such impacts. A very simple method, known as the bathtub model, allows for rapid mapping of floodable areas by directly comparing the terrain elevations derived from Digital Elevation Model (DEM) with the predicted value of the sea level rise in the examined area: the pixels below this rise are submerged when the flow of water coming from the sea is not impeded. This article has a dual purpose: on the one hand, to evaluate the feasibility of implementing the bathtub method in a GIS environment, on the other, to establish how the DEM resolution can influence the flood risk mapping. The study area is the coast of Casal Velino, an Italian municipality located in Cilento (southern Campania). Four different scenarios envisaged by the COPERNICUS project for sea level rise by the year 2100 are considered, that is, relating to different hypotheses such as different concentrations of greenhouse gases in the air. Two DEMs with different resolutions are used, one at 10 m, the other at 5 m. The results confirm the easy implementation of the bathtub method in GIS and the high variability of the flood risk maps in relation to the resolution of the DEM used.
Using GIS Tools For Mapping Sea Level Rise Impacts On Casal Velino Coast (Italy)
Falchi U.;Maglione P.;Mercogliano P.;Parente C.
2026-01-01
Abstract
Sea level rise, the global and relative increase in the surface of the oceans, caused primarily by the thermal expansion of water due to global warming and the melting of glaciers and polar ice caps, poses risks to coastal areas, such as flooding and erosion. Correct mapping of the risk areas is essential for a correct understanding of the impacts of the phenomenon and for planning interventions aimed at preserving and improving natural and man-made defense works to counteract such impacts. A very simple method, known as the bathtub model, allows for rapid mapping of floodable areas by directly comparing the terrain elevations derived from Digital Elevation Model (DEM) with the predicted value of the sea level rise in the examined area: the pixels below this rise are submerged when the flow of water coming from the sea is not impeded. This article has a dual purpose: on the one hand, to evaluate the feasibility of implementing the bathtub method in a GIS environment, on the other, to establish how the DEM resolution can influence the flood risk mapping. The study area is the coast of Casal Velino, an Italian municipality located in Cilento (southern Campania). Four different scenarios envisaged by the COPERNICUS project for sea level rise by the year 2100 are considered, that is, relating to different hypotheses such as different concentrations of greenhouse gases in the air. Two DEMs with different resolutions are used, one at 10 m, the other at 5 m. The results confirm the easy implementation of the bathtub method in GIS and the high variability of the flood risk maps in relation to the resolution of the DEM used.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
