Flood impacts in the commercial sector: insights from field surveys in Belgium

When major floods occur, they have an extensive impact across different sectors, such as residential areas, public infrastructure, and commercial properties. The commercial sector poses a particular challenge for damage assessment, as the assets are more heterogeneous than in the residential sector, and less information about flood impacts is available. This study presents novel damage data for the commercial sector, collected from 130 in-person surveys conducted after the 2021 floods in Belgium. This data includes information on hazard, exposure, vulnerability, emergency and precautionary measures, and both direct and indirect damage. After imputation of missing data, statistical analysis was applied including Spearman correlation rank and variance inflation factor.

With a median water depth of around 1.4 m, the analysis indicates that the maximum direct damage is one order magnitude higher than in the residential sector in the same area for the same event. Furthermore, the results show that the median revenue loss corresponds to approximately 25% of the reported direct damage. However, in some cases, revenue losses were even greater than 100% of direct damage, highlighting the importance of accounting for indirect impacts in damage assessments. After the event, the most popular precautionary measure was the adaptation of the use of floors for the exposed assets. In summary, this research combines field-based data collection with subsequent statistical analysis, to identify relationships between observed damage and underlying drivers. It also provides guidance for designing measures to enhance preparedness and resilience to future flood events.