PNNL

Abstract

The resilience of defense infrastructure systems against climate change implications is critical for national security. Climate induced recurrent flooding is already affecting over 20 U.S. Air Force installations. This recurrence prompts urgency of re-visiting precipitation standards and subsequent stormwater infrastructure design. Despite increasing knowledge and a growing number of scientific tools for updating obsolete precipitation standards based on the assumption of climate stationarities, the adoption of climate informed analysis is not widely practiced. This study utilizes an existing framework for updating Intensity (or Depth)-Duration-Frequency (DDF) curves using ensemble of future climate projections and estimating precipitation estimates change factors and implementing the analyses at six USAF installations across the United States. We then utilize the projections to investigate the implication of climate-informed changes in DDF on stormwater infrastructure performance and flood analysis in Tyndall AFB. The study found that the current design precipitation estimates are likely to be obsolete in all six USAF bases by the end of the century. The uncertainties in change factors presented by the ensembles of 32 GCMs, indicates that infrastructure decision making process should embrace uncertainty into the planning process and new scientific information over time. The study also found that climate change effects are heterogenous over space and time horizon (near or far term futures), showing importance of local analysis for infrastructure decision making. The study supports ongoing DoD and societal efforts of implementing climate change action plans for improving infrastructure resilience.