The VFSMOD Model Applicability Study Of Interception Effects Of Vegetative Filter Strips On Runoff And Sediment

Vegetative filter strip (VFS) can significantly reduce farmland runoff and the pollutants carried. It is a best management measure of agricultural non-point source pollution control, and mathematical model is an effective tool for its design. This study, by means of water erosion simulation test, tends to discuss the interception effect herbaceous vegetation filter belts, with different widths (1,2,3,5.5,7.5,10.5m) and different slops (5%,6.7%), has on runoff and sediment; to verify the applicability of VFSMOD; then, based on this model, to analyze the sensitivity of the factors as slope, width, incoming flow water, incoming flow sediment concentration, initial soil water content and surface roughness of the vegetative filter strips with interception effect. The results are stated as follows:(1) The simulated deviations of VFSMOD to VFS in runoff and sediment concentration were within±20%respectively, and the Nash-Sutcliffe Efficiency coefficient were0.86and0.91respectively, which verify the high applicability of VFSMOD and indicate that this model can have a good simulation of the interception effect VFS has on runoff and sediment. So that this modle do not need to be corrected, What’s more, NSErun off<NSEsilt concentrationsuggests that the simulated effect of VFSMOD on runoff is weaker than that on sediment concentration.(2) The interception effect of VFS on runoff and sediment has a negative correlation with slop, incoming flow water and initial soil water content; incoming flow sediment concentration has no correlation with the interception effect of VFS on runoff; however, negative linear correlation is found between it and the interception effect of VFS on sediment. The interception effect of VFS with same slope, incoming flow water, initial soil water content and incoming flow sediment concentration on runoff and sediment is significantly affected by width.(3) The interception effect of VFS on runoff and sediment has a positive correlation with width and surface roughness. And the interception effect of VFS with same width on runoff and sediment is, to some extent, affected by slope, while that of VFS with same surface roughness is significantly affected by width. (4) In terms of the interception effect of VFS on runoff, the sensitivity of width is stronger than that of slop, incoming flow sediment concentration, initial soil water content, surface roughness, but weaker than that of incoming flow water; In terms of the interception effect of VFS on sediment, the sensitivity of width is stronger than that of slop, incoming flow wate, initial soil water content, surface roughness, but weaker than that of incoming flow sediment concentration.