Investigation of stormwater particles generated from common urban surfaces

Pollution due to urban stormwater runoff is a significant environmental issue. Large regional devices including sediment ponds and constructed wetlands are common features in the urban landscape to treat runoff. In keeping with this approach, data requirements to evaluate stormwater impacts have mainly been met by the monitoring of sizeable urban catchments, typically greater than 10ha in area. Urban runoff characteristics have thus been conventionally linked with broadly defined catchment attributes. Land use, as defined by zonings such as Residential, Commercial and Industrial, is an attribute often used to evaluate stormwater runoff from urban catchments. The emergence of Water Sensitive Urban Design (WSUD) in Australia is changing the management focus from the reliance on a small number of large-scale devices to many smaller-scale source controls distributed throughout the catchment. This paradigm shift in stormwater management places greater emphasis on small-scale processes within urban areas. Subsequently there is a need for more knowledge about stormwater generated from specific urban surfaces (roads, roofs, grassed areas etc). The objective of this study was to demonstrate how urban stormwater quality can be managed on the basis of urban surfaces. The study involved the collection of data for typical urban surfaces and the development of predictive models to estimate stormwater quality. A series of case studies is provided to illustrate the use of surface-related data and modelling tools in stormwater management, particularly in the context of WSUD. Non-Coarse Particles (NCP), defined as suspended solids less than 500μm in size, was selected as the stormwater pollutant under consideration. NCP is divided into the following particle size classes; Very Fine Particles (VFP,