Assessing the Impact of Climate Change on Flood Events Using HEC-HMS and CMIP5

Climate change may result in increased variability in rainfall intensity in the future, leading to more frequent flooding and a substantial loss of lives and properties. To mitigate the impact from flooding events, flood control facilities need to be designed and operated more efficiently, which requires a better understanding of the relationship between climate change and flood events. This study proposed a framework combining the Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) and the Coupled Model Intercomparison Project Phase 5 (CMIP5) general circulation models to assess the impact of climate change on flood events. HEC-HMS is one of the most commonly used hydrologic models in the USA, and CMIP5 provides the latest climate data for potential future climate scenarios. The proposed approach is applied to the Nippersink Creek watershed, which shows that 10-, 25-, 50-, and 100-year precipitations for the low, medium, and high emission scenarios are all greater than the historic observations. The corresponding 10-, 25-, 50-, and 100-year floods are remarkably higher than in the historic observations for the three climate scenarios. The high emission scenario results in dramatically increased flood risks in the future. The case study demonstrates that the framework combining HEC-HMS and CMIP5 is easy to use and efficient for assessing climate change impacts on flood events. It is a valuable tool when complicated and distributed hydrologic modeling is not an option because of time or monetary constraints.