Retardation of Heavy Metals in Stormwater Runoff by Highway Grass Strips

摘要

To determine the effectiveness of these grass strips as a retention mechanism, afull-scale grass strip model was constructed that allowed control of slope and stormwater contaminant feed rate. The model was 1.2 m wide (perpendiular to flow path) and contained a 3 m grass section. A simulated highway stormwater was developed that contained sediment, lead, cadmium, copper, and zinc. The research approach was divided into three main areas: (1) determination of the hydraulic retention time for various slope and flow combinations, (2) estimation of retention times for selected metals, (3) analysis of the fate of the metal contaminants with regard to spatial location as well as plant uptake. Hydraulic detention time over a range of slope/flow combinations was estimated using a bromide tracer technique.