Research On The Pollution Characteristic Of Surface Runoff In The Main City Of Lingang In Shanghai

With the development of urbanization, the areas of impervious surfaces like roadsparking lots and rooftops increase constantly, which leads to the happening about lots ofrunoff from impervious surfaces during raining, especially storm water, and the runoffwith lots of contaminants, for example, sediment, heavy metal, N、P nutrition, toxicityorganic compounds drain to the urban rivers, lakes and estuaries and become the mainpollution source which decline the water quality. Urban runoff pollution is the typicalurban non-point pollution. The region of research in the paper is the main city ofShanghai Lingang New city, which included road runoff and roof runoff in differentfunction area. It analyzes the pollution process and researches the management practice.Among the content, the important points include the space-time rule of contaminants inrunoff, first flush effects, and the estimation of load of contaminants in runoff usingmodels. In addition, the sediments of various function areas were collected to analyze.On the basis of BMPs, the runoff management measures were proposed to control thenon-point pollution in Shanghai Lingang New city.It is founded by analysis samples from roof runoff and road runoff in lab that thereis evident time rule about contaminants regulation in runoff in Shanghai Lingang Newcity. The result indicates that the instant concentration in runoff changes constantlyduring the process of rainfall. In the strong rain event, the concentration ofcontaminations presents the evident index attenuation rule with the increasing of flowtime. But in the weak rain event, the time rule of concentration of contaminants isdifferent in different function area. The concentration of contaminants presents a slightattenuation rule with the increasing of flow time in the road runoff. However, theconcentration of contaminants presents a slight upward rule with the increasing of flowtime in the roof runoff.Based on runoff water quality monitoring, the characteristics of the spatialdistribution of road runoff and roof runoff pollutions were analyzed. The result indicatesthat the median concentrations of TN and CODMnwere more serious in traffic andcommercial area than that in cultural&educational area. In the traffic road runoff, the median concentration of TN is more than the surface water class V standard2.7timesand the median concentration of CODMnin the surface water class V standard. In thecommercial road runoff, TN is more than the surface water class V standard3.1timesand CODMnbelow the surface water class V standard. In the roof runoff, the medianconcentration of TN, CODMn, NH3-N, and TP were respectively2.14,23.7,1.22and0.41mg/L in green roof of commercial area. The median concentration of TN, CODMn,NH3-N, and TP were respectively2.23,4.43,0.64and0.13mg/L in tile roof runoff ofcultural&educational area. Different roof material impacting on runoff water quality,the tile roof runoff water quality was significantly better than the green roof waterquality. In green roof runoff, the median concentration of CODMnand TP is5.3and3.2times than the median concentrations in tile roof runoff, respectively.It is analyzed about first flush effects of contaminants in road runoff and roofrunoff by using dimensionless cumulative curve and parameter b. The result indicatesthat in the traffic road runoff, the dimensionless cumulative curve of the pollutants ofTN, TP and CODMnlocated above the angle bisectors. Different rain events present thefirst flush effects in the traffic road runoff. However, in the commercial and cultural&educational road runoff, the dimensionless cumulative curve of the TN, TP and CODMnseparated at the sides of the angle bisector. Different rain events present different firstflush effects. In the commercial and cultural&educational roof runoff is the same too.In most cases, the first flush effects in strong rain events are stronger than that in weakrain events. The most percentage of parameter b in the road runoff events located in1to3areas. It is mean that most of the rainfall events have moderate and weak first flusheffects. But the most percentage of parameter b in the roof runoff events located in4to6areas. It means that most of the rainfall events havn’t the first flush effects.By calculating event mean concentrations of runoff pollutants and combining themodel about the load of contaminants to estimate the urban runoff load in ShanghaiLingang New city. Different functional areas have the different annual pollutant load ofper unit area. The annual road runoff pollutant load in Cultural&educational area is thelowest, and the load of TN, TP and CODMnare11.16,1.03and33.33kg/hm2/a,respectively. The annual roof runoff pollutant load in commercial area is the highest,and the load of TN, TP and CODMnare31.49,5.61and174.87kg/hm2/a, respectively.The annual pollutant load in green roof runoff is higher than that in the tile roof runoff.Finally, it puts forward the management practice of runoff pollution in Shanghai Lingang New city which base on the BMPs and figure of the Lingang New cityexperimental results. The practices include the structure practices and non-structurepractices to control the non-point source pollutant in Shanghai Lingang New city.