Mathematical interpretation of pollutant wash-off from urban road surfaces using simulated rainfall

Egodawatta, Prasanna K., Thomas, Evan C., & Goonetilleke, S. Ashantha (2007) Mathematical interpretation of pollutant wash-off from urban road surfaces using simulated rainfall. Water Research, 41(13), pp. 3025-3031.

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In the context of stormwater quality modelling, an in-depth understanding of underlying physical processes and the availability of reliable and accurate mathematical equations which can replicate pollutant processes are essential. Stormwater pollutants undergo three primary processes, namely, build-up, wash-off and transport, before accumulating into receiving waters. These processes are expressed mathematically by equations in stormwater quality models. Among the three processes, wash-off is the least investigated. This paper presents the outcomes of an in-depth investigation of pollutant wash-off processes on typical urban road surfaces.

The study results showed that a storm event has the capacity to wash-off only a fraction of pollutants available and this fraction varies primarily with rainfall intensity, kinetic energy of rainfall and characteristics of the pollutants. These outcomes suggest that the exponential equation commonly used for mathematically defining pollutant wash-off would need to be modified in order to incorporate the wash-off capacity of rainfall. Consequently, the introduction of an additional term referred to as the ‘capacity factor’ CF is recommended. CF primarily varies with rainfall intensity. However, for simplicity three rainfall intensity ranges were identified where the variation of CF can be defined. For rainfall intensities less than 40mm/hr, CF varies linearly from 0 to 0.5. For rainfall intensities from 40 to around 90mm/hr, CF is a constant around 0.5. Beyond 90mm/hr CF varies between 0.5 and 1.

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ID Code: 8736
Item Type: Journal Article
Refereed: Yes
Keywords: pollutant wash, off, urban water quality, rainfall simulation
DOI: 10.1016/j.watres.2007.03.037
ISSN: 0043-1354
Subjects: Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > CIVIL ENGINEERING (090500) > Water Quality Engineering (090508)
Australian and New Zealand Standard Research Classification > AGRICULTURAL AND VETERINARY SCIENCES (070000) > OTHER AGRICULTURAL AND VETERINARY SCIENCES (079900) > Agricultural Hydrology (Drainage Flooding Irrigation Quality etc) (079901)
Australian and New Zealand Standard Research Classification > ENGINEERING (090000) > ENVIRONMENTAL ENGINEERING (090700) > Environmental Engineering Modelling (090702)
Divisions: Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering
Copyright Owner: Copyright 2007 Elsevier
Copyright Statement: Reproduced in accordance with the copyright policy of the publisher.
Deposited On: 23 Jul 2007 00:00
Last Modified: 29 Feb 2012 13:36

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