Enhancing the storm water treatment performance of constructed wetlands and bioretention basins [SpringerBriefs in Water Science and Technology]

Urbanisation leads to both quantitative and qualitative changes to stormwater runoff. While the quantity changes have received much attention in the past, now the quality changes are beginning to receive significant attention. The quality changes are primarily due to a range of anthropogenic activities common to urban areas, which result in the generation of various types of pollutants. These pollutants accumulate on urban catchment surfaces and are eventually washed-off by stormwater runoff creating irreversible impacts in receiving water environments. In this context, structural stormwater treatment measures are introduced, promoting pollutant removal through physical, chemical and biological processes. They also detain, retain and regulate stormwater runoff to improve water quantity and quality characteristics. Bioretention basins and constructed wetlands are among the most common stormwater treatment systems and their treatment performance is closely dependent on hydrologic and hydraulic characteristics. Consequently, the in-depth understanding of the role of hydrologic and hydraulic factors in bioretention basin and constructed wetland treatment performance is important for effective urban stormwater design strategies. This research monograph presents the outcomes of a detailed investigation into the influence exerted by hydraulic and hydrologic factors on the treatment performance of bioretention basins and constructed wetlands. In relation to bioretention basins, the research outcomes confirmed that the antecedent dry period is an important factor influencing pollutant removal efficiency. A relatively long antecedent dry period will result in comparatively low moisture content in the filter media, which can enhance the runoff retention capacity and consequently improve treatment performance. This implies that planting of vegetation with a high evapotranspiration capacity would enhance treatment efficiency. Additionally, it was found that pollutant leaching influences bioretention basin treatment performance, particularly reducing the ability for nutrient removal. This highlights the importance of the selection of appropriate filter media and its timely replacement