Combined statistical and hydrodynamic modelling of compound flooding in coastal areas - Methodology and application

This paper presents a robust cost-effective framework for assessment of coastal-fluvial flooding due to compound action multivariate dependent drivers. The methodology is an 8-step process that links statistical and hydrodynamic models determine probabilities multiple-driver flood events associated hazards. method involves individual combined extreme value analysis, dependencies interactions between drivers, joint probability determination accounting dependencies, high-resolution modelling scenarios derived from ultimately mapping inundation. Using Cork City, on the south coast Ireland, as study case, research shows tides, surges river flows affect severity when they occur jointly. Tide-surge have damping effect total water level, while dependence surge residual flow amplifies risk flooding. exceedance occurrence high discharges levels represents more realistic representation spatially variable surface profiles then univariate marginal scenarios. Multivariate analysis allows also considering multiple combinations solutions along RP iso-curves. results show quantification impacts must be performed entire curve. because physical/hydrological same-RP can very different leading substantially characteristics multi-scale nested model (MSN_Flood) was used simulate wave propagation over urban floodplains ensemble statistically runs provide inundation maps draw inferences about mechanisms impacts.