Design Rainfall controls on Pluvial Flood Risk at different spatial and temporal scales – a U.S. case study

As Catastrophe models tend to focus more on Fluvial Flood Risk, Pluvial Flood Risk can be sometimes underestimated or neglected. However, when high intensity and short duration events such as hurricanes Ida and Ian occur in urban and semi urban areas, failure to account for Pluvial Flood Risk is consequential. To this end, the importance of accurately estimating Pluvial Flood Risk has strengthened.

In this study, we investigate the sensitivity of Pluvial Flood Risk to design rainfall characteristics. In particular, we explored the trade-off between flood extent and flood depths for different design rainfall durations, as well as the resulting economic losses at different spatial scales covering local, catchment and county levels. The study focuses on urban and semi-urban areas, where besides rainfall duration and intensity, drainage characteristics are expected to play a significant role in Pluvial Flood Risk.