Effect of Rainfall and Underlying Surface Characteristics of Runoff Pollution

Pearson correlation coefficient method was used to analyze the effect of rainfall characteristics and land surface parameters on runoff pollution. Results showed that rainfall characteristics and surface characteristics affected pollutant EMCs.The pollutant EMCs increased as the increase of dry days,average rainfall intensity and traffic volume,and decreased as the increase of rainfall depth,rainfall duration,maximum rainfall intensity and catchment area. Dry days,rainfall,rainfall duration and traffic flow were the main factors of rainfall runoff pollution. There existed a critical rainfall intensity or range.When the rainfall intensity was less than the critical rainfall intensity,the pollutants were washed and dissolved,and the pollutant concentration increased with the increase of rainfall intensity. When the rainfall intensity was greater than the critical rainfall intensity,the pollutant was diluted and the pollutant concentration decreased with the increase of rainfall intensity.The critical rainfall intensity of the grass swales in the park was 0.15~0.49 mm/min. The study would provide basis for the optimization of design,evaluation of regional rainfall runoff pollution and control scheme.