Coastal submerged structures adaptation to sea level rise over different beach profiles

Abstract

The paper focuses on the analysis of the sea level rise and storms effects on natural or nourished beach profiles protected by submerged breakwaters. The increase in terms of intensity and frequency of extreme sea storms, and water levels produced by climate change, could lead to a deviation from the original trend of the beach. Typical Adriatic beaches will be considered as realistic study cases and a submerged structure for coastal protection of a natural or artificial (nourishment) beach is analysed in order to identify its resilience and its design adaptation. Different scenarios are taken into account, according to the 2019 special report of IPCC on climate change. A numerical model is here provided to evaluate beach response to wave set-up and sea level rise in the case of any beach profile protected by submerged breakwaters. The present model can provide useful information for the adaptation design of an existing defence submerged breakwater against coastal flooding and beach erosion. The shoreline position change, Δy, is evaluated by a large number of simulations varying both wave parameters (wave height Hi, wave length L) and the geometry of breakwater (submergence |Rc| berm width B, structure height hc). Different scenarios of sea level rises, as a consequence of climate change, and of storm conditions are considered in performing numerical simulations.