宁波市城区不同下垫面降雨径流水质特征分析

ANALYSIS ON WATER-RUNOFF POLLUTIONS OF DIFFERNET UNDERLYING SURFACES IN NINGBO

分析了宁波市城区5种不同下垫面(屋面、绿地、居民区道路、工业区道路、商业区道路)的7~10场降雨的径流水质,研究其污染程度和变化规律。监测项目包括p H、SS、COD、TN、TP、NH3-N、重金属。结果表明:各污染物浓度在径流初期均较高,存在较明显的初期冲刷效应,随降雨历时逐渐下降并趋于稳定。不同下垫面径流污染程度顺序为:商业区道路>工业区道路≈居民区道路>屋面>绿地。除绿地外,各下垫面的径流水质均较差,超过了GB 3838—2002《地表水环境质量标准》V类标准。相比于国内其他城市,宁波城区径流污染总体属于中等水平。

The purpose of this study was to investigate the characteristics of urban runoff and its evolution. Five different underlying surfaces,including roof,lawn,road in residential lot,traffic road in industrial district and traffic road in shopping center in the city of Ningbo were selected for sampling and studied during 7 ~ 10 storm events. Quality parameters such as p H,NH3-N,SS,COD,TN,TP and heavy metal were analyzed. The results showed that the pollutant concentrations were high at beginning,and decreased to a relative stable level with the continuous rain. The pollution level followed the order of road of shopping center > road of industrial area≈road of residential area > roof > lawn. Except the lawn,the water qualities of other four underlying surfaces were all lower than the grade V standard of surface water quality. The pollution degree of water runoff in Ningbo was medium level compared with other cities.