The study compared three types of stormwater treatment systems: bioretention basins, constructed wetlands, and roadside swales. Bioretention basins are best for reducing stormwater flow, while constructed wetlands are better for improving water quality. Roadside swales are not as effective at treating stormwater. To design an effective treatment system, it's recommended to use a bioretention basin before a constructed wetland, and a swale as a pretreatment device.