A field experiment under simulated rainfall was carried out to assess the characteristics of pollution and runoff yield at five different rainfall intensities on barren grassland slope in Qingshan catchment

Lin'an City

Zhejiang Province.Results showed that runoff volume was positively correlated with rainfall intensity and the correlation coefficient was 0.873 2.Sediment concentration in runoff was not significantly correlated with rainfall intensity.Pollutants ranked in the descendant order of COD

TN

TP

and water-soluble P in terms of concentration and the concentration became smaller and smaller with increased rainfall intensity

which means that rainfall can dilute pollutant concentration.The secondary pollutant modulus of different pollutants was positively correlated with rainfall intensity and the correlation coefficient was above 0.9

which showed that pollutant was bigger with the increased rainfall intensity.