Study On The Characteristics Of Road Runoff Pollution In Yixing City And The Volume Of Storage Pond

As the most polluted part of urban surface runoff,road runoff has a serious impact on the accepted water body,which has attracted wide attention of scholars at home and abroad.At present,there are few studies on setting runoff sedimentation ponds at the source with road runoff pollution control as the target.Therefore,in this study,sampling points were set up at the rainwater inlet of the main trunk road,the secondary trunk road and the branch road of Yixing city,and corresponding rainfall data and road runoff rainwater samples were collected during rainfall.Select five typical rainfall events and runoff water quantity as the whole process of analysis.In order to provide technical reference for the construction of road runoff sedimentation tank project,the volume calculation method of road runoff sedimentation tank in Yixing city was studied.The main conclusions of this paper are as follows.The type of rain,the average rainfall intensity and the average rainfall intensity before the runoff begain,were the main factors influencing the change rule of road runoff.The correlation coefficient of rainfall and runoff in 5 rainfall events were0.9575,0.95276,0.69309,0.64772 and 0.93755.The correlation coefficient of three rainfall which reached 0.93,the previous average rainfall intensity was strong and continuous.The initial concentration of SS,COD,TN and TP were very high.The values varied between?64¹76?mg/l??56.6²11.7?mg/l??4.05¹2.62?mg/l??0.48¹.17?mg/l.The pollutants concentration tended to be a stable low in the later stages of rainfall.If there was a peak of rainfall intensity,the pollutants concentration would rise first,and then a large decreased.COD?TN?TP was an increasing value of SS and SS could be taken as the target pollutant for runoff water quality control.The curves were all above the diagonal of 45 degrees,indicated that the initial scour effect was observed.The specific steps to choose the amount of rain to regulate D were as follows:1)Choose the data h_i which was close to 4 mm to 8 mm,then according to the correlation equation between the amount of rainfall and the quality load of pollutants,the removal rate of SS mass load was obtained under the condition of h_i.2)Evenly selected the amount of storage?h₁…h_n?that was close to the data range of 4mm⁸mm,and repeated the previous step.3)Using the squeeze method,the rainwater storage volume D was accurately positioned between h₁ and h_n.