Impacts of water depth on pedestrian speed, gait, and stability: results from an experimental study

Abstract

Under rapid socio-economic development and increasingly frequent extreme weather events, flood disasters have led to growing losses and casualties, highlighting the importance of understanding pedestrian dynamics in flooded environments. This study conducted controlled movement experiments involving 188 participants across four water depths (0, 0.35, 0.60, and 0.90 m) to investigate the effects of water depth on walking behavior. Results show that water depth significantly influences pedestrian speed and gait characteristics. When depth increased from 0m to 0.35 m, pedestrian speed decreased by 38.6% for males and 44.8 % for females, lateral swaying amplitude increased by 69 % and 133.3 %, and step length shortened by 37.0 % and 32.0 %, respectively. Further increases in depth resulted in progressively smaller changes. Water also exacerbated gender differences in walking speed, while disparities in stride frequency, step length, and swaying amplitude were most pronounced under dry conditions. At depths up to 0.90 m, the coefficients of variation for step length and stride frequency increased, indicating diminished gait stability. These findings clarify how water depth affects pedestrian movement and stability, reveal gender-specific behavioral responses, and provide essential empirical data to improve flood evacuation modeling and enhance pedestrian safety during flood events.