Field simulation of urban surfaces runoff and estimation of runoff with experimental curve numbers

In this study, runoff responses of typical urban surfaces were investigated by scale models under artificial rainfall simulation, and the Soil Conservation Service (SCS) model was used to assess the impacts of land use changes and green infrastructures implementation on surface runoff of Beijing urban areas. The results showed that: Runoff coefficient of the impervious surface was about 2.1 times than that of the grassland. Time to runoff of the grassland was about 22.0 times that of the impervious surface. The concaved grassland, compared with the impervious surface, can significantly delay by 6.2 minutes the time to runoff, while the porous pavement significantly reduces 28.1% of the runoff coefficient. The runoff coefficient of Beijing urban areas increased from 0.68 in 2002 to 0.72 in 2012, due to the substantially increased impervious surfaces. The runoff coefficient decreased by 2.7%, 15.3% and 22.2% respectively under three green infrastructure scenarios.