Director - Stormwater Regulatory Management Contech, United States
Abstract Submission: Bioretention water quality performance is well understood; however, knowledge gaps exist regarding long-term performance and maintenance – specifically testing methods and protocols to measure mass capacity of stormwater solids and pollutants. The proliferation of LID and infiltrating control measures has focused the industry on volume reduction, but there is a lack of focus on the pollutant mass that is responsible for clogging media systems and triggering maintenance needs. This presentation utilizes long-term water quality studies to model the pollutant mass capacity of both conventional bioretention (BR) and high rate biofiltration (HRBF). Influent characteristics, continuous flow data, and TSS removal performance were extracted from Technology Assessment Protocol - Ecology (TAPE) studies and was used to model the mass capacity of HRBF. Data was also extracted from long-term BR field studies and used to create a similar mass capacity model. Results suggest design, media procurement, and testing protocols all play a significant role in predicting mass capacity of bioretention media. Results also suggest safety factors could be needed in some cases to meet the desired maintenance schedules of different BR and HRBF systems. Recommendations will be made on how to improve mass capacity testing protocols and data collection methods in both the field and lab. Understanding the longevity and mass capacity of bioretention media is critical to protect our receiving waterways.
