Research on Rapid Assessment Technique of Slope Surface Runoff

Soil thickness in the upstream region of Yangtze River is thin with a poor water storage capacity.Because of concentrated rainfall,flood and drought disasters occurred alternately.Runoff regulation of reducing soil moisture to control soil erosion should be taken as an important approach for watershed management.A rapid runoff assessment can provide data support for the runoff regulation.Through field survey and soil samples test,we got thicknesses and physical parameters of different soils in the upstream of Yangtze River,and counted the 24-hour maximum rainfall that encountered once within 5 years.According to the runoff formation theory,the surface runoff coefficient of the counted result is 0.53 and the subsurface runoff occupies a mean ratio 30% of the total runoff in different region of the Yangtze River upper reaches.All of these could provide theoretical support for the runoff regulation.