Eduardo Martínez-Gomariz (Spain) 1; Luca Locatelli (Spain) 2; Beniamino Russo (Spain) 2; Montse Martínez (Spain) 2
1 - Cetaqua, Water Technology Centre; 2 - AQUATEC, Water Advanced Solutions
Heavy rainfalls are expected to be more frequent due to climate change; therefore, an increase of urban flood risks has to be faced. In Badalona (Spain), future extreme rainfall intensities according to CORDEX projections (RCP 2.6 and 8.5) of the period 2050-2100 are higher than the actual ones, producing an increase of the future potential flood risk. A comprehensive socio-economic risk assessment has been conducted focusing on people safety (pedestrian and vehicular circulation) and damage on properties and vehicles.
Design storms (current and future scenarios), for different return periods (i.e. 2, 10, 100, and 500 years), have been used as input for a detailed 1D/2D (drainage network/surface runoff) coupled hydrodynamic model in order to obtain surface water depths and velocities in Badalona and provide useful for risk analysis.
The flood risk for people safety was quantified in terms of both pedestrian and vehicle risks. Firstly, the maps of spatially distributed hazard in Badalona are obtained by combing hazard criteria, based on experimental campaigns that estimated the stability threshold for both pedestrians and vehicles, with simulated maximum surface water depth and velocities. Secondly the vulnerability (i.e. exposure, susceptibility and lack of resilience) was assessed, by considering characteristics of the population (e.g. age, density and percentage of foreign residents) and the location of vulnerable infrastructures for the pedestrians’ assessment, and vehicles flow intensities on the roads for the vehicles’ assessment. Finally, risks maps have been computed by crossing hazard and vulnerability maps. Furthermore, future risks conditions have been assessed using different climate change scenarios based on CORDEX simulations of RCP 2.6 and RCP 8.5.
Furthermore, damages for both vehicles and properties have been estimated. In order to assess the damages, two new GIS-based methodologies have been developed within BINGO project. For both cases, depth damage curves are required; in case of vehicles the ones proposed by the US Army Corp of Engineers (2009) have been selected as the most comprehensive in the literature, while new tailored curves for buildings in Badalona have been achieved based on a fieldwork.
Once the damage assessment is conducted for both buildings and vehicles, and for the different return periods (current and future scenarios), a unique (i.e. including vehicles and buildings damages) Expected Annual Damage (EAD) is calculated, in order to compare present and future scenarios in terms of potential direct damages due to urban floods in Badalona.