GIS-aided historical data for assessing rainfall-related effect along a transportation network of a coastal Mediterranean area (Calabria, southern Italy)

We present the results of an historical investigation focusing on rainfall-related impact on the transportation network of a coastal Mediterranean area (Calabria, southern Italy) recorded throughout 220 years. The entire series of documentary data gathered allowed us to identify the most frequently and/or severely hit sectors, and GIS elaboration was performed to produce a vulnerability map of the study area, highlighting sectors most prone to be affected and the most probable kind of hazard to be expected as impact source.

On the other side, the 220-year damage series and its comparison with daily rainfall data, available since 1938, allowed us to identify rainfall thresholds able to trigger either severe territorial crisis or temporary and light impact on transport facilities, and to identify the long-term temporal/seasonal trend of past damaging events. The study area, around 70 km² wide, is the sum of the surface of two Calabrian municipalities (Scilla and Bagnara Calabra) located in the southernmost regional province of Reggio Calabria. Beside to historical data about landslides, floods, and storm surges contained in the database ASICal (Italian acronym of historically flooded areas), a data catalogue maintained by CNR-IRPI researchers, we collected further data performing specific surveys in local State archives and in the website of the companies which own and maintain roads and railways of the area, as well as in press archives of regional and national newspapers.

The total number of damage-related reports collected was about 280 over 220 years. Damage caused by landslides (85 %) was more numerous than those caused by floods (15 %). Probably due to the largest number of data sources characterizing most recent years, the highest event’s occurrence (27%) pertains to the decade 2010-2019, with a seasonal distribution higher in autumn-winter period (36%). The study delves into the pros and cons of the use of historical data and their usefulness for the identification of critical points and management of territorial crisis in the light of climate change in a Mediterranean study area.

This work was funded by the Next Generation EU—Italian NRRP, Mission 4, Component 2, Investment 1.5, call for the creation and strengthening of ‘Innovation Ecosystems’, building ‘Territorial R&D Leaders’ (Directorial Decree n. 2021/3277)—project Tech4You—Technologies for climate change adaptation and quality of life improvement, n. ECS0000009. This work reflects only the authors' views and opinions, neither the Ministry for University and Research nor the European Commission can be considered responsible for them.