Flood inundation of extreme storm events and its impact on urban residents

Flooding is a disaster that cause loss of lives and properties in cities. US Federal Emergency Management (FEMA) has created and updated regularly flood inundation maps for all urban areas across US. A large body of studies have devoted to predicting flood inundation areas for assessing potential damage. Most of these predictions provide static inundation maps, possibly represent the maximum extent of flood inundation. However, the degree of flood damage is not only related to the largest area being inundated, but also variable inundation depths during the flooding period. To reflect the dynamic impact of flooding process on urban environment, we simulated a projected 500-year storm event in the downtown area of a city using HEC-RAS 2D. By producing the dynamic changes of the inundation areas during the flood, we were able to determine spatial distribution of inundation depths and its temporal variations over the entire event. From these detailed results, we developed a new index that reflect the dynamic impact of flood inundation on buildings within the inundation zone (see details in Gao et al., 2021). This study lays foundation for future vulnerability analysis due to flooding and the associated socioeconomic effects.

A Flood Inundation Process