Sustainability is meeting the needs of the present without jeopardizing quality of life for future generations. Adaptation is adjustment of resource utilization and planning by current generations to ensure sustainability. Mitigation, for this study, narrowly refers to damage repair and restoration costs incurred after natural hazard occurrence. Climate is dynamic and ever changing. Recent observed changes in weather patterns identify that drought and intense precipitation, leading to flooding, are more likely to occur in the near future. An example dynamic probabilistic risk assessment (PRA) for flood inundation is created and applied to understand benefits to, and limitations on, PRA for sustainable water resource management. This example addresses the issue of sustainable decision making related to outdated, but historically regulatory compliant, infrastructure. The observed increase in likelihood for large floods means that many assets were designed for inapplicable conditions and are more likely to be damaged in the future. Results from this example PRA demonstrate that it provides for optimizing the degree of sustainability included in resource management and decision making. Sustainability optimization is obtained by balancing likelihood for future mitigation costs against potential cost savings garnered from present-day adaptation.

Abstract: Sustainable decision making addresses resource and cost sharing among current and future generations. Adaptation costs are incurred by current and damage mitigation costs are borne by future generations. Circularity extends sustainability by including resource regeneration and benefits from resource re-use. Climate change and associated global warming are producing more frequent extreme events with different probabilities of occurrence than historically observed. Traditional approaches to asset and infrastructure design tend to be backward-looking for weather- and climate-related bases and to introduce too little variability to compensate for uncertainty, resulting in infrastructure that was designed for irrelevant future conditions. An example dynamic probabilistic risk assessment (PRA) for flood inundation is developed and implemented to examine the usefulness and limitations of PRA for sustainable water resource management. It specifically addresses the issue of sustainable decision making related to outdated but historically regulatorycompliant assets under non-stationary climatic conditions. Weather attribution provides improved extreme event frequency expectations to, generates the dynamic component of, and allows for incorporation of additional uncertainty to the PRA. Results from the PRA provide decision making optimization between current adaptation and future mitigation costs. A limitation of PRA is that it analyzes failure and risk and not benefits accruing from resource regeneration.