Role of urban surface roughness in road-deposited sediment build-up and wash-off

• Published in: Journal of hydrology (Amsterdam) Vol. 560; pp. 75 - 85
• Main Authors: Zhao, Hongtao, Jiang, Qian, Xie, Wenxia, Li, Xuyong, Yin, Chengqing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2018
• Subjects: Asphalt and concrete surface; Build-up and wash-off; First flush effect; Road surface roughness; Street cleaning effectiveness; Asphalt and concrete surface; First flush effect; Road surface roughness; Build-up and wash-off; Street cleaning effectiveness
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2018.03.016

[Display omitted] •Paired experiment design was used to distinguish the role of surface roughness.•Asphalt can retain a larger amount of RDS with coarser particles than concrete.•The settleable particles (44–149 μm) were notably influenced by surface roughness.•First flush phenomena tended to occur more on concrete surfaces.•Asphalt has larger RDS wash-off loads and lower wash-off percentages than concrete. Urban road surface roughness is one of the most important factors in estimation of surface runoff loads caused by road-deposited sediment (RDS) wash-off and design of its control measures. However, because of a lack of experimental data to distinguish the role of surface roughness, the effects of surface roughness on RDS accumulation and release are not clear. In this study, paired asphalt and concrete road surfaces and rainfall simulation designs were used to distinguish the role of surface roughness in RDS build-up and wash-off. Our results showed that typical asphalt surfaces often have higher depression depths than typical concrete surfaces, indicating that asphalt surfaces are relatively rougher than concrete surface. Asphalt surfaces can retain a larger RDS amount, relative higher percentage of coarser particles, larger RDS wash-off loads, and lower wash-off percentage, than concrete surfaces. Surface roughness has different effects in RDS motilities with different particle sizes during rainfall runoff, and the settleable particles (44–149 μm) were notably influenced by it. Furthermore, the first flush phenomenon tended to be greater on relatively smooth surfaces than relatively rough surfaces. Overall, surface roughness plays an important role in influencing the complete process of RDS build-up and wash-off on different road characteristics.