Assessment of flood susceptibility in coastal peri-urban areas: an alternative MCDA approach for ungauged catchments.

The sustainable development of coastal peri-urban areas is associated with the awareness of the local vulnerability to natural disasters, such as flood hazards. In ungauged basins, statistical and modelling approaches combined with geographic information systems have been widely used for the evaluation of different scenarios. In the current study, a multicriteria decision analysis (MCDA) simulated the response of the floodplains to the variations of the most dominant criteria, which affected the flood susceptibility of the area. An index of flood susceptibility is proposed to compare the simulated outcomes of the different scenarios. We provide a thorough discussion about improving the accuracy of the MCDA method through calibration and validation procedures, in association with the HEC-RAS 2D model. Observed and simulated inundation depths were compared for the validation process. The derived maps effectively revealed the flood susceptibility of the area upon the criteria variation, particularly the elevation and the rainfall. [ABSTRACT FROM AUTHOR]