Assessing Watershed-Scale Stormwater Green Infrastructure Response to Climate Change in Clarksburg, Maryland

Stormwater green infrastructure (GI) practices are implemented in urban watersheds to control stormwater runoff, reduce pollution, and adapt to climate change. This study evaluated the robustness of a watershed with stormwater GI and a watershed with traditional stormwater controls in Clarksburg, Maryland, to future climate change. The USDA Soil and Water Assessment Tool (SWAT) was calibrated to USGS daily streamflow data from 2011 to 2016 to evaluate watershed-scale daily and seasonal runoff responses to multiple future climate and management scenarios. The stormwater GI watershed had less runoff than the traditional management watershed in climate change scenarios for most days with rainfall (>98% of days). However, the climate change scenarios resulted in increased seasonal fall and winter runoff compared to current conditions in both watersheds. Simulated expansion of GI implementation reduced runoff in both watersheds under future climate scenarios. This study assesses climate robustness of existing stormwater GI at a watershed scale and confirms previous evaluations of hypothetical stormwater GI effectiveness for adapting watersheds to climate change.