Observational evidence and climate simulations indicate that extreme precipitation has intensified and will continue to intensify in most of the U.S. due to climate change. As a result, stormwater infrastructure at Department of Defense (DoD) sites and surrounding communities are at higher risk of failure, causing more frequent flooding. The main goal of this project is to increase the climate resilience of DoD installations and close communities by adding new functionalities in the DoD System Master Planner-Net Zero Planner (SMPL) tool to support the design of new and assessment of existing stormwater infrastructure under nonstationary climate conditions.

SMPL includes a stormwater planning module where the design storm is computed through the potentially flawed assumption of climate stationarity. In this Phase I project, the project team will add new functionalities in SMPL that (1) expand the ability to choose design parameters under stationary climate conditions, and (2) allow performing the design of new and the assessment of existing infrastructure while accounting for the effect of nonstationary climate conditions. For this aim, the project team will incorporate nonstationary intensity-duration-frequency design values from a previously DoD-funded study and a novel model based on peak-over-threshold series and weather types. Installation planners will be able to visualize the design storms computed through stationary and nonstationary methods, including novel approaches specifically designed to account for non-stationarity extreme regimes. The new SMPL functionalities will be tested at one DoD installation with recent re/development sites and several types of existing infrastructure. New visualization and quantification tools for SMPL will be designed, along with a preliminary strategy to integrate the new functionalities. Finally, a Demonstration and Validation Plan will be drafted to extend the application of the updated SMPL at other DoD sites in a potential Phase II project.

This work will improve the current capabilities of the existing DoD SMPL stormwater planning tool, which has already been used for over 100 studies at more than 64 installations. The new functionalities added to SMPL will be crucial to reducing the risk of infrastructure failure and/or better quantifying this key metric to support the implementation of flooding mitigation and adaptation measures. This, in turn, will increase the climate resilience of DoD installations and close communities and reduce the cost of construction and maintenance of stormwater systems, as well as the damages caused by their potential failure. The functionalities, in short, will help to ensure mission sustainment over the intended lifespan of the infrastructure and assets.