Validation of the Applicability of a Walking-Time-Based Evacuation Model under a Dam-Break Scenario at Namgang Dam

With the growing risks of extreme precipitation and potential dam failures driven by climate change, empirical validation of theoretical evacuation models has become a critical priority for robust disaster management. The practical applicability of flood evacuation route analysis under a Namgang Dam breach scenario was examined in this study by comparing conventional theoretical calculations with empirical pedestrian data. Although contemporary frameworks predominantly rely on deterministic models based on standardized walking speeds, there is a significant lack of empirical evidence that reflects age-specific physiological characteristics and heterogeneous field conditions. To address this issue, preliminary surveys were conducted along primary evacuation routes ($R1$-$R7$), followed by synchronized field walking measurements involving nine participants in three age groups, with all participants departing simultaneously from each designated starting point. The results showed that observed walking times across all age groups were consistently shorter than theoretical predictions, with the discrepancy tending to increase with age. This suggests that current theoretical walking speed criteria yield conservative estimates of evacuation time under normal walking conditions. However, spatial analysis revealed that low-lying sectors near the dam ($R1$-$R3$) present severe constraints for horizontal evacuation due to accelerated flood arrival and high-magnitude inundation, necessitating the integration of vertical or preemptive evacuation strategies. By reinforcing the reliability of theoretical models through empirical verification, this paper provides a foundational framework for developing sophisticated, site-specific flood mitigation and emergency response guidelines.