Urban Climate Modeling to Quantify Runoff Reduction from Ground-Based Green Stormwater Infrastructure Implementation

As urban infrastructure continues to age, the worldwide urban population continues to rise and climate change effects are being increasingly felt in urban environments. Urban flooding and runoff have become prominent issues for many cities and regions, arising from a combination of altered precipitation patterns, urban growth, development in floodplains, and increases in impervious surfaces. Coupled together, these factors have placed significant stress on the urban landscape. Additionally, climate models consistently project that frequency, severity, and duration of hydroclimatic extremes will increase over this century under climate change. Green stormwater infrastructure (GSI) implementation has been identified as a possible tactic to combat these effects of urbanization and climate change and to help make cities more resilient and livable. Using the Community Earth System Models (CESM) urban land model, the Community Terrestrial System Model (CTSM), we simulate runoff reduction benefits of GSI implementation in Contiguous U.S. cities, projected over a 35-year time period (2015-2050) at a 10-kilometer resolution under future climate change scenarios. We bridge microscale vegetation modeling and macroscale climate modeling by representing ground-based GSI installations (e.g., rain gardens) using key parameters (e.g., hydraulic conductivity) in an Earth system model to simulate the resilience outcomes of widespread green infrastructure in urban areas on large scales. Our results demonstrate the capabilities of large-scale climate models to reflect small-scale GSI implementation within the urban environment.