不同地表雨水径流冲刷特性分析

选择北京市某城区典型地表(校园、自行车道、商业街和高架桥)的雨水径流作为研究对象,系统分析了不同地表雨水径流的冲刷特性。分析结果表明:不同地表初期冲刷现象都比较明显,控制不同地表20%的初期雨水可以削减污染物总量的40%～60%,高架桥初期雨水径流中COD、SS和TP浓度最高,校园初期雨水径流中TN浓度最高。不同地表雨水径流的水质优劣顺序为:校园>商业街>自行车道>高架桥。校园和自行车道在整个降雨过程中D50和D90粒径大小相近,分别为30μm和50μm左右,且变化幅度都较小。高架桥和商业街在雨水径流初期D50和D90粒径有明显减小,但后期均出现较大幅度的波动,其粒径明显大于校园和自行车道。上述研究成果对于城市不同地表雨水径流污染控制和场地开发具有重要意义。

Analysis on characteristics of stormwater runoff flush on different land surfaces

Selected stormwater runoff from typical land surfaces(at campus,cycle way,business street and viaduct) in Beijing as the research objects,characteristics of stromwater runoff in different land surfaces were analyzed.The results showed that the first flush phenomenon of different land surfaces were very obvious.Controlling 20% of the initial stormwater,it is possible to remove 40%~60% of the pollutant total quantity.COD,SS and TP concentrations in the viaduct initial stromwater runoff were the highest,and the highest concentration of TN was from the campus initial stromwater runoff.For different land surfaces,the superior sequence of stromwater runoff water quality was followed: campus,business street,cycle way,viaduct.The particle size of D50 and D90 were almost equal during the entire rainfall process of the campus and cycle way,which were about 30 μm and 50 μm,separately,and the variation range was small.For the business street and viaduct,the particle size of D50 and D90 decreased obviously in initial rainfall,but they had markedly fluctuation in the later period,and the partical size was significantly greater than that from the campus and cycle way.The research results will play an important role in the control of urban stormwater runoff pollution of different land surfaces and sites development.