The Study On The Rainfall Runoff Pollution Process And Prevention Measure In Nanchang Urban

With the rapid development of urbanization, the proportion which the urban water-proof region occupies is getting bigger and bigger, that causes the massive surface runoff through the sewer to discharge directly the urban water body when it is rainy specially the rainstorm, the urban pollutant that runoff carries from road surface deposit, heavy metal, nourishing substance, toxic organic matter and so on becomes the primary pollution that makes the body water quality drops in the city, therefore the urban runoff pollution is the typical urban nonpoint source pollution. takes the Nanchang city as the region to research, the research includes the runoff pollution process and the prevention measur in different areas. This article studies emphasisly the runoff the pollutant change rule, and uses the model to estimate the pollutant load in the runoff, according to rule that pollutant changes in runoff, it proposes the proper prevention and control of pollution measure in Nanchang runoff.The discover through the runoff sample's analysis is that the pollutant distribution has obvious time rule in different urban in the Nanchang district. The test result indicates that in the entire rainfall process the instantaneous density of pollutant in the runoff has a big change, the time rule of density of pollutant is different in different areas.The density of pollutant presents the index attenuation rule with the inereasing of flow time in industrial area, commercial area and residential area.But in traffic area, the phenomena never happens because the continuous pollution source from the complicated human and vehicles aetivities.The paper carries on the quantitative analysis to the urban rainfall runoff contamination index by computing the EMC value in the runoff pollutant event.The EMC value of pollutant is quitely high in the different region and has a very big difference,the order of EMC value of TSS, CODcr, NH3-N, TP in four function area order is: traffic area > commercial area > residential area.> industrial area ; The highest EMC value of heavy metal is in the industrial area,the next is the traffic area and the commercial area, the lowest is the residential area. It uses the urban rainfall runoff pollution load estimate model to estimate the Nanchang runoff contamination index load,the result of contamination index in different area is: the highest load of TSS, CODcr, NH₃-N, TP, Cu, Zn, Pb, Cd and so on is in traffic area; Under the different rainfall intensity, the pollutant load is different, it increases when the rainfall intensity increases.At last,the paper bases on ecology plan principle and proposes measures such as landscape pattern and rain water converting into resources to prevent and control the rainfall runoff pollution in Nanchang city urban.