Flood impact on critical linear infrastructures

According to UNISDR, floods are the most frequent and damaging natural threat worldwide. Whereas the assessment of direct losses is well advanced, the evaluation of indirect impacts is less frequently applied. Indirect impacts are not due to the physical contact with flood water but result from the reduced performance of infrastructures. Linear critical infrastructures (such as roads and pipes) have an interconnected nature that may lead to failure propagation so that impacts extend far beyond the inundated areas and/or period. This work presents the analysis of two linear infrastructure systems, the water distribution system and the road network system. The evaluation of flood impact on the two networks is carried out for four scenarios, obtained by a coupled 1D-quasi 2D hydraulic model. Two methods are used for assessing the impacts on the water distribution system and on the road network, a Pressure-Driven Demand network model and a transport network disruption model respectively. The analysis is focused on the identification of: (i) impact metrics; (ii) vulnerable elements exposed to the flood; (iii) similarities and differences of the methodological aspects for the two networks. The study presents an application to the city of Florence (Italy).