城市地表径流-灰尘-污染物输移研究进展

A review on the study of transports of runoff-sediment-pollutant systems on urban surfaces

城市地表"径流-灰尘-污染物"作为一个三相介质系统,相互作用机理十分复杂。分别从城市地表灰尘颗粒对不同种类污染物的吸附效应及时空分布规律、地表(坡面)降雨径流特性及过程模拟、地表径流-灰尘-污染物协同输移与削减等方面,总结与分析了现有的研究进展。从本质上来看,城市地表灰尘可视为由不同粒径泥沙颗粒组成的综合体,有必要基于泥沙运动力学理论加强对地表径流中灰尘颗粒运动规律的研究,并以灰尘颗粒对不同污染物的吸附、沉淀作用为纽带,探讨"径流-灰尘-污染物"的协同输移与削减机制。其中,如何有效扩展城市调查样本容量,比较研究不同下垫面径流动力特性,并从径流能量或功率角度出发,研究不同粒径灰尘颗粒的分组起动与输移规律,并建立在径流输送过程中的挟沙力方程,将是今后需要深入研究的问题。

As a complex three-phase particle flow and the main carrier of non-point pollution,the coordinated transport processes and environmental effects of the runoff-sediment-pollutant systems on urban surfaces are very complicated. In this paper,the existing research on the transports of runoff-sediment-pollutant systems is summarized and analyzed from the perspectives of,the spatial-temporal distribution of urban surface sediment with absorbed pollutants,the hydrodynamic characteristics and simulation methods of urban surface rainfall-runoff,as well as the coordinated transport and reduction effects of runoff-sediment-pollutant systems. It is considered that the sediment dynamics theory can be used to study the urban surface sediment movement law during the rainfall-runoff process,and that the sediment deposition plays an important role in the reduction of particle pollutants due to the absorption effect. Finally,the following research actions should be carried out in the future: enlarging urban sample size;studying on dynamic characteristics of overland flow on different underlying surface;studying on incipient motion law for non-uniform sediment on urban surfaces, as well as sediment transport capacity for overland flow based on flow power theory.