Pollution Of Rainfall Runoff In The Center Of Fuzhou City

With the rapid development of urbanization, the properties of land-use change alot in the city, and the proportion of the areas of impervious surfaces is increasing,furthermore, as the disturbance of human activities on nature intensifies, theconditions of urban rainwater have significant changes, which leads to thedifferences of the the surface runoff pollution emission laws and pollution loadgenerated by different land-use types. Presently, urban rainfall runoff pollution hasbecome an important reason for the deterioration of the water environment in the city,which is concerned on and paid attention to by the international community.The region of research in the paper is the center of Fuzhou city，the collection,laboratory analysis and data processing of road runoff, roof runoff and natrualrainfall were done for several rainfalls in2009, to study the temporal and spatialdistribution and pollution load of the rainfall runoff in the region. By comparing therunoff water quality indicators and the relevant water quality standards, the waterquality of the three kinds of water is evaluated respectively, and the correlationbetween various indicators and SS index of the rainfall runoff is analyzed. Finally,with the combination of domestic and international experiences, control measures onthe pollution of road runoff and roof runoff are proposed separately according to thenatural, economic, social situations and so on in the urban of Fuzhou.Through the analysis of temporal distribution, the conclusion is that thepollutants in both road runoff and roof runoff present the phenomenon of first flush,that is to say, the initial concentration of pollutants in runoff is high, subsequently theconcentration begins to decline, and gradually becomes a stable level with theextension of duration of rainfall.It is found by the analysis of spatial distribution that the concentration ofindicators in different function areas is different. The order of mean concentration of SS and CODCris: traffic area> industrial area> commercial area> residential area>educational area. The distribution of mean concentration of NH3-N in the fivefunction areas is: industrial area> traffic area> residential area> commercial area>educational area. The presentation of mean concentration of TP is: residential area> traffic area> industrial area> educational area> commercial area.It is analyzed about the correlation between various indicators and SS index,and there is significant correlation between the index of CODCr, NH3-N, TP, TN andSS index. Moreover, according to the comparison of the average correlationcoefficient of each index with SS in the road runoff, the order of correlation is:CODCr> TP> TN> NH3-N, and the order in the roof runoff is: TP> CODCr>NH3-N> TN.The results of pollution load estimation about different land-use types show that,the order of the contribution rate to SS and CODCris: main roads> residential area>industrial area> commercial area> public building area, while the comparison ofcontribution rate to NH3-N, TN and TP is: residential area> main roads> industrialarea> commercial area> public building area.