Multifunctional infiltration swales - Optimized topsoil layer with substrate amendments for enhanced urban stormwater treatment

Overview & Synopsis

Infiltration swales with an optimized vegetated soil layer and biodiverse native planting can have a positive contribution as multifunctional blue-green infrastructure in urban areas. The aim of this research project is to develop an improved infiltration system regarding drainage safety, pollutant retention and additionally create a valuable plant- and animal-habitat. The improved retention of pollutants such as heavy metals from traffic area runoff and biocides from facade/green roof runoff in the vegetated soil layer by substrate amendments is in the focus of this study. In laboratory and semi-technical scale experiments good removal efficiency could be determined for particulate and dissolved heavy metals as well as for total and fine suspended solids. Biocides were retained in the lab-scale and semi technical scale experiments in the following order: Terbutryn, Diuron >> Mecoprop. Especially for Mecoprop a strong dependence between retention and inflow rate could be observed.