城市场次降雨径流污染负荷快速估算方法

Rapid estimation method of pollution load from each rainfall-runoff in urban area

城市降雨径流污染是城市水质恶化的重要原因之一,定量计算城市降雨径流污染负荷,是实施城市水环境污染总量控制管理的基础和关键,可为城市水环境治理和污染控制提供科学依据.本文以污染物累积冲刷理论为基础,提出了“特征面积”的概念和计算公式,建立了场次降雨径流污染负荷数学模型,并结合案例,对数学模型在有效性、预测精度、适用性和局限性等方面进行评价.结果表明,特征面积较好地反映了污染物在各类土地上的污染负荷特性,场次降雨径流污染负荷与特征面积和降雨量的乘积呈正比.利用3场及以上降雨径流污染负荷结果,可较好地率定模型,从而可快速且较准确地估算单场次降雨径流污染负荷.该方法简单实用,获取数据工作量小,适用地区广.对于小降雨事件,建议采用降雨量相近的观测结果对模型进行率定,以提高模型的预测精度.

Urban rainfall-runoff pollution is one of the important reasons for the deterioration of urban water quality.Quantitative calculation of urban rainfall-runoff pollution load is the basis and key for implementing total urban water environmental pollution control management,which can provide scientific basis for urban water environment management and pollution control.Based on the theory of pollution build-up and wash-off,this paper put forward the concept and calculation formula of“the characteristic area”,and established a mathematical model of pollution load from each rainfall runoff.Combined with the case studies,the validity,accuracy,applicability,and limitation of the mathematical model were evaluated.The results showed that the characteristic area better reflected the pollution load characteristics on various types of land,the rainfall-runoff pollution load was proportional to the product of the characteristic area and rainfall.The model established in this paper could be calibrated by 3 or more sample data of rainfalls,so that the rainfall-runoff pollution load could be estimated quickly and more accurately.This method was simple and practical and could be used in a wide range of areas,furthermore,it could greatly reduce the workload of data acquisition.For small rainfall events,it was recommended to calibrate the model with observation results of similar rainfall to improve the prediction accuracy of the model.