ASCE has honored Jose D. Salas, Ph.D., Dist.M.ASCE; Michael L. Anderson, Ph.D., P.E., M.ASCE; Simon M. Papalexiou; and Felix Frances with the 2022 ASCE State-of-the-Art of Civil Engineering Award for the paper “PMP and Climate Variability and Change: A Review,” Journal of Hydrologic Engineering, December 2020.   

Given the current relevance of climate change and variability, one of the immediate challenges is how to conduct hydrologic design and estimate risk. Hydraulic structures that cannot be allowed to fail because of catastrophic consequences to life and property are particularly vulnerable in this regard. Examples of such structures include spillways, flood defenses, and protection of nuclear power plants. Design of such structures is based on the idea of extreme events of precipitation and flow that have a very small likelihood of occurrence. The concepts of probable maximum precipitation (PMP) and probable maximum flood (PMF) are “theoretically the greatest depth of precipitation for a given (storm) duration that is physically (meteorologically) possible over a given-size storm area at a particular geographical location at a certain time of the year.” While these can be estimated, current practices have not allowed for climatic changes.

The authors use this backdrop to provide a deep review of PMP estimation, looking at relevant research on both physical methods of climate dynamics as well as statistical methods that are used for extreme events specifically for PMP estimation. The uncertainty resulting from atmospheric moisture, its transport into storms and wind, and their future changes are assessed to ascertain risk. Of particular note is that the procedures adopted in several countries and agencies for PMP estimation are evaluated. 

The ASCE State-of-the-Art of Civil Engineering Award is presented to the individual, individuals, or committee that has prepared, for the benefit of the profession, the most outstanding paper which reviews and interprets state-of-the-art scientific and technical information.