An assessment of the effectiveness of vegetated filter strips for Heihe River headwaters area using numerical simulation

In order to investigate the feasibility of using numerical simulation to assessing the effectiveness of vegetative filter strips (VFS), the vegetative filter strip hydrology and sediment transport model (VFSMOD) is applied to the Heihe River headwaters area. The effect of VFS' width and slop on the removal rate of sediments is estimated by VFSMOD, and the appropriate design is subsequently determined for a VFS system. The VFS effectiveness for the load reduction of nonpoint source pollution in a watershed is assessed with the linear relationship between the sum of total phosphorus (TP) and total nitrogen (TN), and sediments. The results show that a grass filter strip with width in the range of 3-5 m is advisable and the slop gradient should be less than 60. The reduction of sediments, TP and TN would be 21.7%, 12.4% and 14.3%, respectively, after the installation of VFSs on all sensitive riparian zones of the Heihe River headwaters area. The study demonstrates that VFS can play an important role in the water quality control for the Heihe River headwaters area.