State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
Sci Total Environ. 2022 Apr 1;815:152533. doi: 10.1016/j.scitotenv.2021.152533. Epub 2022 Jan 10.
An in-depth understanding of particle size distribution as well as total suspended solids (TSS) in surface runoff is essential for managing urban diffuse pollution. In this study, field experiments and model simulation were undertaken to explore and confirm the dynamic runoff behaviour of TSS and their influencing factors. Field observation results showed that samples with high TSS concentrations contained coarser particles (>100 μm) during three natural rainfall events. Particle size distribution as well as road-deposited sediments (RDS) amount before and after these rainfall events also confirmed that a higher percentage of washed-off coarser particles resulted in higher TSS concentrations in surface runoff water. The impacts of rainfall characteristics, urban-rural gradients, surface roughness, and climate difference on particle distribution as well as TSS concentration were analyzed using the wash-off formula of particle size. These factors mainly affected the contribution rate of RDS to TSS by altering particle size composition; rates ranged from 4% to 44% under different rainfall characteristics. The critical particle size (<100 μm) was developed according to the mass percentage of particles with different sizes in RDS and TSS. Our results can provide a simple and effective way of assessing RDS contribution to TSS in surface runoff.
深入了解地表径流水体中颗粒大小分布以及总悬浮固体（TSS）对于管理城市分散性污染至关重要。本研究采用现场实验和模型模拟的方法，探讨并确认了 TSS 的动态径流行为及其影响因素。现场观测结果表明，在三次自然降雨事件中，TSS 浓度较高的水样中含有较粗颗粒（>100μm）。降雨前后的颗粒大小分布以及道路沉积物（RDS）数量也证实，冲刷出更多的较粗颗粒会导致地表径流水体中的 TSS 浓度更高。利用颗粒冲刷公式分析了降雨特征、城乡梯度、地表粗糙度和气候差异对颗粒分布和 TSS 浓度的影响。这些因素主要通过改变颗粒大小组成来影响 RDS 对 TSS 的贡献率，在不同降雨特征下，其贡献率范围为 4%至 44%。根据 RDS 和 TSS 中不同粒径颗粒的质量百分比，确定了临界粒径（<100μm）。本研究结果可为评估地表径流水体中 RDS 对 TSS 的贡献提供一种简单有效的方法。
