不同盖度草地过滤带拦沙效应研究

he performances of vegetative filter strips (VFS) trapping sediment under gentle slope gradients and low sediment concentration has been reported in the literature, this study focused on effectiveness of VFS according to soil erosion characteristics of the loess plateau of China. At steep slope of 15 , and inflow rates of about 0.25L/som and 0.50 L/som and sediment concentrations of about 25kg/m3 and 35kg/m3, the effectiveness of VFS trapping sediment increased with vegetative cover. Rainfall significantly decreased sediment trapping efficiency of VFS, but the effectiveness diminished under great vegetative cover of 70% and 90% and high runoff rate. Generally coarse sediments were subject to be trapped within VFS, and rainfall had a negative effect on coarse sediments removal. The flow velocity increased as the vegetative cover increased. There was no significant difference between the adjacent two covers, but a clear difference among the other covers. Rainfall had no significant influence on mean flow velocity, but made the velocity distribution more uniform.