The Performance Impacts of Real-Time Control on Bioretention

Bioretention is a green infrastructure practice used to restore natural hydrologic regimes and improve stormwater quality. Extreme weather combined with demands for treatment of a growing number of priority pollutants has put a strain on these systems, making meeting performance goals difficult. The addition of smart stormwater technology has the potential to help address these issues as more control is provided to modify internal conditions and optimize sometimes conflicting outcomes. The use of real-time control is tested in this research to determine how bioretention performance is impacted by this technology. Column studies incorporating forecasts and historic rainfall were used to test two real-time control designs and compare them to traditional free draining and internal water storage bioretention systems. Water quality, hydrologic, and microbial data were all collected to analyze the influence of real-time control on nutrient reduction, volume reduction, and microbial populations. Results of this study show that real-time control can strike a balance between traditional bioretention designs in regard to water quality and hydrologic performance. Real-time control systems also promoted higher growth of nitrifying and denitrifying bacteria by creating a more dynamic wet and dry zone within the soil media. Further research into the role of weather uncertainty is necessary to determine if the predictive elements of the systems are truly necessary. This work can also be expanded to other pollutants of interest and should lead to field studies where laboratory results can be verified. Finally, additional research regarding functional genes in microbial communities will also be necessary to fully understand the activity of nitrifying and denitrifying bacteria in these systems.