城市地表污染物累积和降雨径流冲刷过程研究进展

城市地表污染物是城市降雨径流污染的主要来源，其累积和降雨冲刷过程分别是沉降-悬浮-再沉降以及悬浮-沉淀-再悬浮的动态过程。描述累积过程的模型主要有线性、指数、对数等形式，其中以指数及一些变形形式发展相对成熟并得到了广泛的应用。这些模型都将雨前干期天数（ADWP）作为主要的影响因子。而描述冲刷过程的模型主要基于一级反应动力学假设，这类模型已被人们广泛接受。为使冲刷模型更接近实际，人们进一步在其中引入了雨天排污因素，并取得较好的成效。虽然城市地表径流的研究取得了较大的进步，但是目前的模型基本属于经验型或基于大量监测数据的统计学模型，尚缺对污染物输移过程的机理性描述。因此，从城市地表污染物输移过程的机理出发，建立城市地表污染物累积和降雨冲刷过程的物理模型是今后城市降雨径流污染研究工作中一个亟待解决的问题.

ADVANCES IN RESEARCH ON THE BUILD-UP AND RAINFALL RUNOFF WASH-OFF OF URBAN SURFACE POLLUTANTS

Urban surface pollutants are the major source of urban rainfall runoff pollution.The build up and rainfall runoff wash off of urban surface pollutants and the related models are reviewed.Particles settled on the impervious surface can be suspended in the air by external force，for example，wind，and then resettled again in build up process.Also when it rains，they can enter the surface runoff by raindrop induced ejection and then precipitate again in wash off process.The rest of process may be deduced by analogy.There are many kinds of the models describing the build up process in the previous research，such as the linear model，the exponential model and the logarithmic model etc.The exponential and its related forms are more authentic comparatively among these models.Antecedent Dry Weather Period (ADWP) is considered as the major impact factor among these models.The wash off model based on the first order reaction kinetics assumption has been setup and been wildly used.In order to improve accuracy of wash off model，the wet weather pollutants have been taken into consideration.At present，much progress has made in the research on urban surface runoff pollution，however，most models rely on experience or extensive calibration by a number of monitoring data which do not clearly represent the physical mechanisms of particles detachment and transportation.As recent emphasis on reducing non point source pollution has increased interest in implementing pollution management practices in urban areas in China，reasonable and predictive models is urgent needed.Greater insight into the underlying physical mechanisms of urban rainfall runoff pollution can provide a better understanding of the movement of pollutants in the urban area and more scientifically justifiable management practices for urban runoff pollution control.