1237 | 526 | Susceptibility to pluvial flash floods and the local perception of risk in the urban area of Gospić (Croatia) | Silvija Šiljeg, Rina Milošević, Ivan Marić, Ante Šiljeg, Fran Domazetović, Lovre Panđa, Rajko Marinović

Pluvial flash flooding (PFF) is triggered by short-duration intensive rainfall events. It occurs when the volume of water exceeds the capacity of the urban drainage system and the soil’s ability to infiltrate the water. PFF is a growing problem in urban areas, especially where impervious surfaces predominate. The frequency and intensity of heavy rainfall events are expected to increase in the coming years due to climate change and rapid urbanization. PFF causes massive human and economic losses and is related to residents’ risk awareness, preparedness for the hazard, and implementation of precautionary measures. To prevent potential losses, it is necessary to identify flood-prone areas and implement long-term mitigation measures jointly with the public. This study aimed to generate a pluvial flash flood susceptibility model (PFFSM) for Gospić and investigate the public perception of pluvial flash flood risk (PFFR). PFFSM was created using the multicriterial GIS analyses (GIS-MCDA) and analytical hierarchy process (AHP) based on grouped criteria: topographical, hydrological, and environmental. The accuracy of PFFSM was assessed using ROC curves based on flood cadastre data. Public perception of PFFR was examined among 0.5% of the city population within adults (18+ years old). The questionnaire encompassed five factors: (F1) risk awareness, (F2) anthropogenic and (F3) natural causes of PFF, (F4) potential consequences, and (F5) preparedness. According to the Cronbach Alpha test all factors were highly reliable (> 0.71). PFFSM indicates a generally high susceptibility to PFF. Contrary, the respondents do not consider PFF as a significant threat. Risk awareness is generally low (2.7) with a standard deviation of 0.9. Anthropogenic factors are perceived as the leading cause of PFF, but residents’ preparedness for the hazard is moderate (3.1). Results from this study can facilitate communication between experts, decision-makers, and citizens regarding

Silvija Šiljeg, Rina Milošević, Ivan Marić, Ante Šiljeg, Fran Domazetović, Lovre Panđa, Rajko Marinović
Center for geospatial technologies, University of Zadar
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