Assessing the Watershed-Scale Impact of Real-Time Control in Sustainable Stormwater Management

This study evaluates the effectiveness of real-time control (RTC) in enhancing the performance of stormwater control measures (SCMs) at the watershed scale. A process-based hydrological model of the Hickey Run watershed in Washington, D.C., with an area of 5.39 km2, impervious fraction 56%, and a simulation period of 2014 to 2016, developed using OpenHydroQual, was calibrated and validated with observed hydrographs. The model simulates surface and subsurface hydrologic processes, sewer system dynamics, and SCMs. Two SCM types—a detention pond and a bioretention system—were evaluated by retrofitting impervious areas at coverage levels of 10%, 50%, and 90%. For each coverage level, simulations were performed under two control approaches: passive control and RTC. RTC algorithms used rainfall forecasts smoothed by Gaussian or exponential kernel functions, with parameters optimized to minimize peak flows at selected exceedance probabilities. Results show negligible effects at 10% coverage but substantial benefits at higher coverage levels. Improvements were similar for both kernel schemes. These findings demonstrate the potential of RTC to improve hydrologic performance, reduce flood risks, and enhance baseflows, which are sustained low-flow augmentations that mitigate hydrologic intermittency during dry periods in urban watersheds, particularly when implemented at large scales.