Effects of Climate Change on Fragility Curves of Earthen Levees Subjected to Extreme Precipitations

Infrastructure adaption to climate change requires our improved understanding about the resilience of infrastructure to projected climatic extremes. The goal of this study is to investigate the effects of climate change on earthen levees subjected to extreme precipitations. For this purpose, the performance of Elkhorn levee in Sacramento, CA was numerically simulated using baseline (historical) and nonstationary projected (future) intensity-duration-frequency (IDF) of precipitations for the study area. A fully coupled 2D stress-variably saturated flow finite element model was developed to simulate the levee behavior under extreme precipitations combined with normal and flood water level conditions. The response of the levee was assessed under baseline and nonstationary projected scenarios for rainfall durations of 1 to 7 days for the events with recurrence intervals of 25, 50, and 100-year. The results were then used to develop baseline and projected fragility curves to assess and compare the probability of levee’s failure under historical and future climates. The comparisons show that the probability of levee’s failure increases 3% - 12% under projected extreme precipitations when compared to the baseline scenario.