Cyclones and sea storms, the number of rigid defence works on Italian coasts is growing

The effects of climate change are being felt and the number of 'hard' coastal defence works against storm surges and Mediterranean cyclones is growing. As of 2020, more than 1.5 thousand kilometres of coastline, equal to 18%, with an increase on 2000 figures of 27%, over 200 kilometres. Outlining the scenario affecting the entire national territory is the work produced and distributed free of charge by Ispra, in the form of a geoDB. Inside, the data identify and characterise the stretches of Italian coastline affected by the presence of installed "rigid defence works", those stretches affected by the influence of structures such as reefs, groynes, concrete sea walls or cliffs grazing the coast.

An examination of the work shows that 'Calabria, more than other regions, has seen the coastline affected by these structures grow by 66%'.

Underlying these actions, as the experts point out, are climate changes that "have led to an increase in the frequency and intensity of extreme weather phenomena, such as Mediterranean cyclones and storm surges". "The rise in sea level and alterations in wind regimes and currents," emphasise the Institute for Environmental Protection, "amplify wave energy, accelerating coastal erosion processes and increasing the vulnerability of already fragile coastlines.

And this also includes episodes such as the cyclone Harry, which recently hit the coasts of Sicily, Calabria and Sardinia. "These are signs of a structural trend that," the researchers argue, "adds to the effects of certain human activities and requires increasingly integrated and evidence-based coastal adaptation and management strategies". Hence the need to start from a mapping of 'rigid defence works'.

In recent decades, according to the researchers' reconstruction, almost 11,000 rigid defence works have been installed along the coast, interacting in different ways with the surrounding natural areas. "For example, in Liguria, the installation of groynes, i.e. reefs perpendicular to the coast capable of trapping sedimentary dynamics, are very common," the Ispra institute points out. Along the Adriatic regions, the bulk of beaches are affected by the presence of various types of reefs detached from the shoreline, capable of limiting waves and thus the effect of storm surges. Rigid works often acquire particular shapes for specific functions, such as the system of large 'T-shaped' groins along the Tyrrhenian coast of Calabria'.