Non-stationary precipitation design standards for stormwater infrastructure modernization at USAF installations

• Derived future change factors for precipitation at 6 USAF installations. • By the end of the century current precipitation standards will be obsolete. • Forecasted changes shows significant increase in peak flooding at Tyndall AFB. • Approach can be adopted to any project to incorporate climate risk into design. The resilience of defense infrastructure systems to climate change is critical for national security. Climate induced recurrent flooding is already impacting over 20 U.S. Air Force installations, underscoring the urgency of revisiting precipitation standards and 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 to update Intensity (or Depth)-Duration-Frequency (DDF) curves using an ensemble of future climate projections. Change factors in precipitation estimates are derived and applied to six USAF installations across the U.S. The analysis is further extended to evaluate the implications of climate-informed DDFs on stormwater infrastructure performance and flood analysis at Tyndall AFB. Results indicate that the current design precipitation estimates are likely to become obsolete in all six USAF bases by the end of the century. The wide range of change factors across 32 GCM ensembles highlights the need to integrate uncertainty and evolving scientific data into infrastructure planning. The study also found that the climate change impacts vary spatially and temporally, emphasizing the value of localized analysis for infrastructure decision making. The work advances ongoing DoD and societal efforts of implementing climate change action plans for enhancing infrastructure resilience.