Trend ananlysis of runoff generation characteristics of Luanhe River Basin

The runoff generation characteristics have changed with the change of underlying surface since 1980s.So the runoff generation mechanism was found to have changed accordingly from infiltration excess to saturation excess runoff generation through the analysis of runoff coefficient and the relation between precipitation and runoff.To estimate the effects of the change of runoff patterns on runoff generation volume,Xin'an jiang model and infiltration-excess model were applied to simulate several typical floods chosen from the sub-catchments after 1980.The differences of the modeled runoff volume between the results from Xin'an jiang model and those from infiltration-excess model were the effects of runoff generation characteristics changes on runoff reduction.Here,it showed that the runoff of Luanhe River Basin decreased about 26.9% mainly due to the change of runoff generation characteristics.