Aim of the study:
The aim of this study is to assess the vulnerability of municipalities located in the Gidra River Basin to fluvial floods. We have calculated a fluvial flood vulnerability index (FFVI) related to the year 2021 for twelve municipalities, which fall into the Gidra River Basin.

Material and methods:
Three indicators of economic vulnerability and seven indicators of social vulnerability were used to determine the respective economic flood vulnerability sub-index (EFVsI) and social flood vulnerability sub-index (SFVsI). We normalized the original values of indicators using the maximum method and treated all of the indicators as equally important. In the last step, we determined the FFVI for each municipality at a scale [0, 1] by an aggregation of the EFVsI and SFVsI, which both had equal weights.

Results and conclusions:
The highest values of the EFVsI were recorded in the municipalities of Častá (0.81), Cífer (0.66), and Budmerice (0.64), which are located in central (Cífer) and upper (Častá and Budmerice) parts of the basin. The highest values of SFVsI were recorded in the municipalities of Píla (0.79) and Štefanová (0.76), which are both located in the upper part of the basin. Based on the values of the final FFVI, we can conclude that the highest vulnerability to fluvial floods is in the municipalities of Častá (0.75), Budmerice (0.67), and Cífer (0.67). On the contrary, the lowest values can be seen in the municipalities of Ružindol (0.37), Pavlice (0.38), and Jablonec (0.40).