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Urban runoff, impervious surfaces, suspended solids, stormwater management, non- point source pollution


Pollutant load estimation is often required to evaluate stormwater management issues associated with water quality and urban development. Land use (e.g. residential, commercial) is commonly employed as a base to spatially characterize the pollutant generation from urban areas. This paper demonstrates an alternative approach of using surface type (e.g. road, roof, grassed) to define suspended solids loads in runoff from urban catchments. Three case studies are provided to illustrate the potential of using this surface based approach. The case studies analyzed are 1) a comparison of the suspended particle loads generated from residential and commercial land uses, 2) an assessment of the effect of exposed areas of bare soil on suspended particle loads generated from a residential catchment and 3) an evaluation of the effect that widespread adoption of rainwater tanks may have on the suspended particle concentration of residential urban runoff. The case studies demonstrate that the surface based approach provides a fundamental understanding of the main contributors to stormwater pollutant load generated from urban catchments. This level of understanding can not be gained by the more generic and lumped approach of using land use to define the hydrological and pollutant generation impacts of urban catchments. The surface based approach is also GIS compatible as briefly discussed in this paper.