Carpark pollutant yields from first flush stormwater runoff

• Urban carparks produce runoff with different pollutant characteristics. Vehicle traffic influence contaminant concentrations in first-flush stormwater. The highest yields originated from a high-traffic industrial carpark. Traffic characteristics metal partitioning and species ratios. Design of stormwater treatment systems should consider carpark Stormwater be treated to remove pollutants before they enter urban waterways; however, differences surrounding land use activities can result varying first flush types requiring specific approaches. An understanding potential variations is necessary design adequate systems. over 20 events three (university, hospital industrial) Christchurch, New Zealand were thus analyzed for Total Suspended Solids (TSS) heavy metals (Zn, Cu Pb) year. Pollutant found vary across the carparks, which largely driven by such as count, size vehicles, topography. Mean (both dissolved particulate) TSS significantly higher than other two had statistically similar mean concentrations. Specific ratios (Zn:Cu, Zn:Pb) relatively high carpark, indicating greater contribution wear tear large commercial vehicles. total Zn wash-off when it was non-operational (passive) lower operational (active), confirming that increase vehicular activity. Rainfall antecedent dry days rain intensity duration only have low positive correlation all carparks. findings this study highlight importance considering implementation on-site