Informal Seminar: Projecting Flooding Across the United States: Climate Change as a Risk Multiplier

There is a growing recognition that flooding has been changing in recent decades across different parts of the contiguous United States, with climate change acting as a risk multiplier. However, the standard practice in the design of our physical infrastructure assumes stationarity, which implies that what we experienced in the past will manifest itself again in the future and is at odds with the idea of change. Given that many engineering projects are designed to be in operation for several decades, how do we provide basic information to develop best practices for addressing non-stationarity, flood frequency estimation and risk management in a world in which the past may no longer be representative of the future? 
 

This presentation will provide a path forward on how we can incorporate climate change to design our infrastructure for the future, not for the past. At the core of the proposed approach there is the need to gain insights into the factors responsible for the year-to-year changes we observe in the historical discharge records. The improved understanding of the processes responsible for flood events has challenged the traditional notion that floods result from a single-population causative mechanism. This paradigm stresses the fact that all floods are not created equal and is based on the premise that different flood agents are responsible for different events, moving us closer to a process-driven flood frequency analysis. This approach not only more accurately describes the flood records but also represents an alternative way to investigate how flooding is projected to change in a warmer climate: we can use climate model outputs to examine how the drivers of these major flood agents are projected to change and then use this information to infer how flood frequencies are bound to change. The goal is to learn from the past and to then use this information to provide better insights into future changes in flooding, providing a scientific basis for the engineering design of flood mitigation alternatives and the management of the water resources.