Author(s): Ha Minh Do; Gerald Corzo Perez; Chris Zevenbergen

Linked Author(s): Gerald Augusto Corzo Perez

Keywords: Delayed rainfall timing; Spatiotemporal flood; Urban flood

Abstract: Conventional flood risk models frequently oversimplify the intricate interaction between geographical and temporal rainfall fluctuations, opting instead for aggregated time series data. This technique fails to consider essential subtleties, such as the varying effects of urban microclimates and convective rainfall on flooding. This research addresses this gap by examining the impact of varied rainfall events, both in terms of location and time, on urban flood dynamics in the Do Lo area of Hanoi, Vietnam. A storm Water Management Model (SWMM) performs a comprehensive examination of how the combined sewer system reacts to various flood situations caused by changes in rainfall patterns. This study utilised an innovative approach that divided the research region into three zones based on drainage saturation velocities. It also applied a hydraulic model to simulate 1,000 iterations of rainfall events, with each iteration representing a 1-minute interval, over 36 hours under harsh weather conditions. Our findings reveal the possibility of effectively reducing the impact of floods by deliberately controlling the timing of rainfall in certain areas. More precisely, a 29-minute delay in the start of rainfall between different areas led to a 6% decline in the extent of flooded areas and a 21.1% drop in the speed at which the flood expanded. This highlights the need to include the variation in rainfall patterns across space and time in assessments of flood risk. Doing so will offer valuable insights for creating focused strategies for managing floods. Our research focuses on the significance of comprehending the earliest areas affected by flooding and the periods of saturation before flooding occurs in urban drainage systems. This approach provides a more detailed and sophisticated method for managing urban floods.

DOI: https://doi.org/10.64697/HIC2024_P310

Year: 2024