A comparison between investment in hydraulic infrastructures and the consequent risk reduction: a case study in Italy

Flooding constitutes the most frequent and one of the most destructive natural disasters, and every year it affects millions of people worldwide causing loss of life, disruption of many essential services. Even in Italy, floods represent one of the most widespread extreme events, increasingly common and hazardous.

Due to the big discrepancy, highlighted in an Italian recent report, between funds spent before and after the occurrence of a flood event, respectively for risk prevention and for recovery, it is of major interest understanding where money is spent both from a geographical perspective and from a risk level area point of view.

Through a deep analysis on the economic and technical criteria used to design infrastructures for flood risk protection, based on the Italian ReNDiS database (Repertorio Nazionale degli interventi per la Difesa del Suolo – National Database of soil protection measures) a comparison between type of hydraulic infrastructures and their cost, and official risk maps produced in accordance with the EU flood Directive (2007/60/EC) have been done.

Moreover, this work also aims to understand if the current criteria with which flood risk maps are produced catch the effects in terms of benefit of the flood risk mitigation measures.

The authors want to prove the importance of a risk-based design for mitigation measures instead of a simple application of the current legislation that does not catch all the components of the risk.