Studies carried out (between 1992 and 1995) on stormwater quality in Auckland Region, New Zealand, reveal that suspended solids, heavy metals (such as lead, copper and zinc), and petroleum-based hydrocarbons are present in significant concentrations in stormwater. The main source of these contaminants is the transport system, including run-off from roads and emissions from vehicles.
A catchbasin-insert device designed to trap stormwater sediments in run-off from roads was tested and evaluated for improving stormwater quality in selected catchbasins in the Auckland Region. The project demonstrated that the devices were effective in removing sediments from stormwater, and may promote the removal of contaminants that are sorbed onto sediment surfaces because they cause increased detention of sediments that would otherwise have been discharged to receiving waters.
Keywords: catchbasin, contaminants, devices, Auckland, New Zealand, pollution, run-off, roads, stormwater, transport