Effect of storm sewer sediment on first flush

It is important to control runoff pollution flushed to the water-system,and avoid large amounts of pollutants from catchments and pollutants settled and accumulated in storm sewers from being washed out to receiving waters in wet weather.A discharge law of different source pollutants(from catchments and sewer)was analyzed by theory and experiment.It was shown that the pollutant discharge law from catchments accords with an exponential washoff model,but sediment pollutants in the sewer fit a rating curve washoff model.The more the sediments,the weaker the first flush effects would be.To ensure high running efficiency of runoff control facilities,source pollution control is important,and effective storm sewer system maintenance is a significant measure to avoid accumulation of contaminants.