Stormwater runoff from urban surfaces transports pollutants, such as suspended solids, to downstream water bodies, leading to significant degradation of water quality. Green stormwater infrastructure (GSI) can mitigate these pollutants; however, the concentrations of pollutants in the effluent of GSI can still be high relative to influent concentrations. The goal of this study is to address this challenge by integrating end-of-pipe treatment baffles into GSI underdrains as a final treatment step to remove particulate pollutants. To meet this goal, two end-of-pipe baffles with flow modulation were designed, tested in a laboratory, and installed at the underdrain of two bioswales located in Milwaukee, WI. For captured storm events, solids in the baffles were vacuumed, dried, weighed, and sieved. Results indicate that the baffles are able to provide additional solids removal from the underdrain of GSI. The outcomes of this study aim to provide valuable insights into additional treatment steps for GSI that can help to improve pollutant mitigation and protect downstream water quality.
