## 5 Discussion
### Comparison Between the Two Floods  
By analyzing records of the flood impacts across multiple flood events, the scale offers the ability to identify trends in the temporal evolution of flood disasters, assessing their severity over extended periods. It can also highlight the most severe disasters, aiding in understanding their characteristics and frequency. Within this long-term context, impact maps can be compared with other cartographic products, such as population density maps, to uncover potential patterns or thresholds where severity escalates. Furthermore, when several events are mapped in the same region, these maps can be compared with existing flood hazard and risk maps for validation or to guide necessary adjustments and corrections. Impact comparisons provide valuable insights into the dynamics of flooding, including its causes and effects, and the efficacy of mitigation strategies. By examining the differences and similarities in flood impacts, researchers and policymakers can better understand the interplay between hydrological, geographical, and anthropogenic factors that influence flood severity. This understanding is critical for developing targeted interventions to reduce vulnerability and enhance resilience in flood-prone regions. The present tool provides an approach to obtain an overview of the impacts in space for each event, and therefore, it allows easy comparisons of their spatial distribution between events. One key benefit of such comparisons is the identification of patterns and trends in flood behavior and its impacts. For example, comparative analysis can reveal how variations in the rainfall intensity, land use, urbanization, or floodplain management affect the extent of flooding and the magnitude of the associated damage. This information can help in predicting potential risks in areas that share similar characteristics but have not yet experienced severe flooding. Furthermore, comparing flood impacts aids in evaluating the effectiveness of mitigation and adaptation measures over time. For instance, the assessment of structural interventions, such as levees and floodwalls, or non-structural measures, such as improved drainage systems and community education programs, can be enriched by analyzing their performance across different flood events. This evidence-based approach has the potential to enable decision-makers (e.g., local authorities, risk professionals, etc.) to allocate resources more efficiently and adopt specific practices or measures that have the maximum efficiency. In addition, understanding the differential impacts of floods on various communities or regions highlights disparities in vulnerability and adaptive capacity. This knowledge can inform more inclusive and just policies, ensuring that marginalized or high-risk populations receive appropriate attention and support. It also helps in fostering a culture of learning from past events to build back better and mitigate future risks. It is observed that the severity scale of the impacts of both floods range from Class II to VIII. Notably, in 2020, a greater number of areas were affected by higher severity classes compared to 2009. In 2009, higher severity classes were recorded near the delta of the Lilas River, mainly focused on the impacts on the built environment, with a maximum range of Classes VI to VIII, as well as on the natural environment, with a maximum range of Classes V to VII. In 2020, the highest severity classes were recorded upstream of the Lilas river delta, with focused areas near Vassiliko, Filla, Afrati, and along the Afrati-Pissonas road network. These impacts included those on the built environment, with a maximum severity range of Classes VII to VIII, and on the natural environment, with a maximum severity range of Classes VI to VII. Focusing on the built environment, the observed discrepancy can largely be attributed to significant alterations in the river channel's morphology following the 2009 flood. The riverbed underwent considerable widening, which enhanced the discharge capacity.