Runoff and sediment yield process and characteristics research on litter slopes in simulated rainfall

Litter is a key factor for determining erosion rates, to provide quantitative information for hydrological soil processes in litter covered slopes, different rainfall intensities(30, 60, 90 mm/h)were conducted under different litter coverage(0, 50, 100, 150, 200, 250 g/m2)with the method of artificial rainfall in laboratory. The results show that runoff and sediment yield rates increase with increasing rainfall intensity and decrease with increasing litter coverage, the correlation relationships are exponential function; relatively stable runoff in runoff-duration curve is mainly affected by rainfall intensity; relatively stable sediment in sediment-duration curve are affected by rainfall intensity, litter and other factors; litter has significant influence on runoff dynamic characteristics, compared with the bare land, runoff velocity of slopes covered with 50, 100, 150 and 200 g/m2 litter decreased by 17.7%, 26.8%, 37.9% and 26.8%, respectively, decrement of Reynolds number are 11.2%, 18.7%, 26.3% and 18.7%, and decrement of Froude number are 21.3%, 30.3%, 42.9% and 30.3%, respectively. Darcy-Weisbach resistance coefficient increase by 0.5-5.6 times; there is a logarithmic relationship between Darcy-Weisbach resistance coefficient and sediment yield rate, a linear relationship between runoff shear stress, runoff power and sediment yield rate. The correlation coefficients between sediment yield rate and hydrodynamic parameters decrease in the following order: Re>w>V>P>Fr>f>t. © 2017, China Water Power Press. All right reserved.