Influence of pollutant build-up on variability in wash-off from urban road surfaces

• Published in: The Science of the total environment Vol. 527-528; pp. 344 - 350
• Main Authors: Wijesiri, Buddhi, Egodawatta, Prasanna, McGree, James, Goonetilleke, Ashantha
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.09.2015
• Subjects: Accumulation; Environmental Monitoring; Hazardous Substances - analysis; Mathematical models; Models, Chemical; Particle size; Pollutant build-up; Pollutant wash-off; Pollutants; Process variability; Rain; Roads; Storms; Stormwater; Stormwater pollutant processes; Stormwater quality; Strategy; Transportation; Water Movements; Particle size; Process variability; Pollutant wash-off; Stormwater pollutant processes; Pollutant build-up; Stormwater quality
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2015.04.093

Variability in the pollutant wash-off process is a concept which needs to be understood in-depth in order to better assess the outcomes of stormwater quality models, and thereby strengthen stormwater pollution mitigation strategies. Current knowledge about the wash-off process does not extend to a clear understanding of the influence of the initially available pollutant build-up on the variability of the pollutant wash-off load and composition. Consequently, pollutant wash-off process variability is poorly characterised in stormwater quality models, which can result in inaccurate stormwater quality predictions. Mathematical simulation of particulate wash-off from three urban road surfaces confirmed that the wash-off load of particle size fractions <150μm and >150μm after a storm event vary with the build-up of the respective particle size fractions available at the beginning of the storm event. Furthermore, pollutant load and composition associated with the initially available build-up of <150μm particles predominantly influence the variability in washed-off pollutant load and composition. The influence of the build-up of pollutants associated with >150μm particles on wash-off process variability is significant only for relatively shorter duration storm events. •Key characteristics of pollutant wash-off process variability are identified.•Variability of pollutant build-up process influences pollutant wash-off process.•Pollutant wash-off is a function of the build-up of particles <150μm and >150μm.•Particles <150μm generate significant variability in pollutant wash-off process.