Nonpoint source (NPS) particulate pollutants are a major source of urban surface pollution. It is essential to better understand and model the dynamic process of NPS pollutants to inform the design of effective strategies for urban stormwater management and pollution control. This work presents a novel coupled hydrodynamic and particle-based model to simulate the full-process dynamics of NPS particulate pollutants from detachment, transport to deposition in urban areas. A particle-based approach is proposed to represent the physical processes of pollutant detachment and deposition. The transport of pollutant particles is simulated using a random-walk particle-tracking model, which can directly trace out the trajectories of individual particles and hence identify the pathways of pollutants. The new coupled hydrodynamic and particle-based stormwater quality model is successfully validated against several analytical and experimental test cases to demonstrate its capability in accurately simulating the full-process dynamics of NPS particulate pollutants in urban areas.

非点源（NPS）颗粒污染物是城市表面污染的主要来源。更好地理解和建模NPS污染物的动态过程，对于设计有效的城市雨水管理和污染控制策略至关重要。这项工作提出了一种新颖的基于水动力和颗粒的耦合模型，以模拟NPS颗粒污染物从分离，运输到市区沉积的全过程动力学。提出了一种基于粒子的方法来表示污染物分离和沉积的物理过程。使用随机游走粒子跟踪模型模拟污染物颗粒的运输，该模型可以直接追踪单个颗粒的轨迹，从而确定污染物的途径。