This study introduces a comprehensive modeling framework to assess the impacts of climate change on coastal and riverine flooding in European coastal cities. By integrating atmospheric data from the ALADIN63 regional climate model under the EURO-CORDEX project, researchers simulate future flood scenarios under RCP4.5 and RCP8.5 climate pathways. The modeling chain employs a wave model, storm surge model, river discharge model based on rainfall-runoff processes, and HEC-RAS for hydrodynamic simulations to assess flood extents and depths. The findings underscore the importance of high-resolution, integrated modeling approaches to accurately project and manage future flood risks in coastal urban areas.



Please find my review in the attached file.

This paper provides an example of flood modelling in two coastal cities due to storm surge and river discharge. The paper is well written and is relevant to NHESS. Some uncertainties - e.g. on compound events - are well discussed, but not all. However, before publishing this work, I recommend to: 

- provide more elements about the validation of this work

- assuming a proper validation of the total water levels at a tide gauge and waves offshore, the key uncertainty will result from the use of an empirical formula for the wave setup, which requires a high resolution shallow water bathymetry. It would be important to discuss it as the ambition is to provide a high resolution flood model, as illustrated by the use of a Lidar topographic data. 

- the context about sea-level rise is not well explained; it would be important to discuss what we know from sea-level rise, e.g. commitments over decades to centuries, the fact that meters of sea level rise can not be avoided on the long term and that this could happen earlier than projected in case of an ice sheet collapse - see e.g. the IPCC report WG1 published in 2021. Based on this review, I recommend to reconsider the statements starting lines 605 regarding future flooding in Massa. 

- The data used on sea-level projections are not clearly presented (no unit in Table 3, no source associated to the table). This should be precisely clarified. 

- Overall the paper would have more impact with a one or a few clear key messages that could be taken forward - e.g. that precise flood hazard assessment is required to assess future sea level rise impacts in coastal cities, that this can not be achieved at broad scale yet (no global Lidar DEM) and requires local assessments; 

These comments are moderate, but provided elements on the validation can be provided, they coulb be handled as minor comments. 

I hope that this review is useful

Sorry for submitting this review late 



Gonéri Le Cozannet, BRGM, 10/06/2025