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为了解城市合流制管道系统降雨径流的水文水质变化过程与特征,于2007年7～9月对上海中心城区合流制排水系统(CSS)4类强度降雨(小雨、中雨、大雨和暴雨)的降雨量、径流量和污染浓度进行了同步连续监测与分析.结果表明,径流过程线滞后于降雨过程线约15～25min,形态与降雨过程线相似,波动幅度低于降雨过程线.4类强度降雨的径流系数分别为:0.33、0.62、0.67和0.73.CSS基本存在30/30标准的降雨径流初始冲刷现象,污染物浓度过程线滞后于降雨过程线约30～40min.4类强度降雨径流的pH值和重金属Cu、Zn、Cr、Cd、Pb、Ni的事件平均浓度(EMC)均符合地表水环境质量标准Ⅴ类水要求,COD、BOD5、NH4+-N和TP的EMC的变化范围分别为225.0～544.1、31.5～98.9、8.9～44.2和1.98～3.52mg·L-1,平均分别超过Ⅴ类水标准9.3、5.6、11.7和6.1倍,接近国外城市CSS的平均污染水平.SS与COD、BOD5、NH4+-N和TP在p<0.01水平上均具有一定的正相关性(R为0.359～0.736),颗粒态有机类和营养类污染物的比例平均为70.21%.
In order to understand the process and characteristics of hydrological and water quality changes of rainfall and runoff in urban combined pipe system, four types of intensity rainfall (light rain, moderate rain, heavy rain and heavy rain) of CSS in Shanghai Central City Rainfall, runoff and pollution concentration were measured and analyzed.The results showed that the runoff process line lagged behind the rainfall process line for about 15 ~ 25min, the morphology was similar to the rainfall process line, and the fluctuation range was lower than the rainfall process line. The runoff coefficients of rainfall were 0.33, 0.62, 0.67 and 0.73, respectively. There was basically 30/30 standard runoff initial scouring in CSS. The process line of pollutant concentration lagged behind the rainfall course for about 30-40 minutes. The average incidental concentration (EMC) of pH and heavy metals Cu, Zn, Cr, Cd, Pb and Ni all met the requirements of Grade V of surface water environmental quality standard. The ranges of EMC of COD, BOD5, NH4 + -N and TP were 225.0 ~ 544.1, 31.5 ~ 98.9, 8.9 ~ 44.2 and 1.98 ~ 3.52mg · L-1, respectively, which exceeded the average of 9.3, 5.6, 11.7 and 6.1 times of Grade V water standard, respectively, BOD5, NH4 + -N and TP at p <0.01 (R = 0.359-0.736). The average proportion of particulate organic and nutritive pollutants was 70.21%.