Estimating the Potential Benefits of Green Stormwater Infrastructure on Developed Sites Using Hydrologic Model Simulation

This manuscript outlines a novel approach to predicting green stormwater infrastructure (GSI) performance by utilizing continuous simulations with the Environmental Protection Agency's Stormwater Management Model (SWMM). Simulations using continuous rain data were used to estimate the long-term (annual) benefits of implementing bioretention cells (BRCs) at selected sites instead of focusing on their performance during large events (e.g., 10 yr storm) for which these practices were not designed. In addition, the simulations (66 total) provided estimates of potential runoff volume reduction (22%-76% of runoff volume) for comparing BRC implementation on a wide range of soil types (saturated hydraulic conductivity 0.07-18.18 cm/h). This study indicates that soils (Types A, B, and C) with saturated hydraulic conductivity of 0.3 cm/h can result in a minimum of 50% reduction in annual runoff. For soils with hydraulic conductivities of less than 0.3 cm/h, the soil property, effective suction at the wetting front (S-f), was an important indicator of infiltration rate since those soils in the "higher" range of effective suction at the wetting front, resulted in substantially higher infiltration. The models for this work were built and tested based on the geographic information system (GIS) analysis of readily available parcel data (e.g., geographic location, soil, and area) and remote sensing data (e.g., site imperviousness) for Lucas County, Ohio. It was estimated that over 60% of the developed land in Lucas County, OH is suitable for installing bioretention cells, which could significantly (>70%) reduce stormwater runoff from parking lots. This transferable approach can be used to identify preferred sites for installing green stormwater infrastructure, where the hydrologic performance benefits are maximized. (C) 2016 American Institute of Chemical Engineers Environ Prog, 36: 557-564, 2017