Assessing the Impact of Climate Change on Transportation Infrastructure Using the Hydrologic-Footprint-Residence Metric

Abstract

Climate change is likely to increase the frequency and intensity of flooding. Transportation infrastructure is vulnerable to extreme precipitation because it was designed using frequency, duration, and intensity relationships that do not represent future climate. Therefore, there is a need for a better understanding of how future climate can disrupt roadways and bridges. This study proposes evaluating flood impacts on the transportation infrastructure with two novel metrics: the HFRR (roads) and HFRB (bridges). These metrics were based on the hydrological footprint residence (HFR), which represents the dynamics of the inundation area and its duration. The Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS) and the Hydrologic Engineering Center River Analysis System (HEC-RAS) one-dimensional/two-dimensional (1D/2D) models were used to calculate the HFR metrics. These metrics were estimated for the transportation infrastructure of San Antonio, Texas, for 24-h 100- and 500-year storms for representative concentration pathway (RCP) 4.5 and 8.5 scenarios. Results show that climate change will increase flood impacts in the city. The new metrics presented a larger relative increase with climate change when compared to traditional metrics, such as maximum flooded areas. This study highlights the importance of using duration components to evaluate flood impacts on transportation infrastructure.