植被过滤带水土保持和水质净化效益研究

植被过滤带是水土保持和面源污染防控的重要措施之一。本研究于2016年8月在鹫峰人工降雨大厅通过土槽植草冲刷试验，观测不同宽度和坡度的植被过滤带(高羊茅)对地表径流、总悬浮物(TSS)以及污染物(TN、TP、K)的削减效果，定量分析植被过滤带宽度、坡度及入流流量大小等因素对植被过滤带径流拦蓄、TSS拦截和水质净化效益的影响。结果表明:植被过滤带的宽度对径流拦蓄效益影响较大，宽度为1、3和5 m植被过滤带的径流削减率分别为25.9%、79.6%、79.7%；污染物(TN、TP、K)削减率随着宽度逐渐增大，分别为51.7%~92.9%、44.4%~98.8%、31.7%~97.9%；TSS削减率分别为97.6%、99.4%和77.4%。随着坡度的增加(3°、7°和10°)，径流和TSS的削减率呈逐渐减小趋势。对于同一个植被过滤带而言，较小的入流流量所对应的径流和TSS削减率较大，而污染物负荷削减率较小。研究表明，植被过滤带能有效拦蓄径流、拦截悬浮固体等污染物质，具有较好水土保持和水质净化效益。 

Effects of soil and water conservation and water purification by vegetative filter strips

Vegetative filter strip ( VFS) is one of the commonly used practices for soil and water conservation and non-point source pollution control. In August 2016, a simulated scouring experiment on soil boxes was conducted in Beijing to quantitatively evaluate the interception and removing effects of VFS ( all planted with Festuca arundinacea) on runoff, total suspended solid (TSS), and pollutants (TN, TP, K) . The differences between volumes of runoff and concentrations of TSS, TN, TP and K of the inflow and outflow of VFSs with different width, slope and inflow rate were examined to analyze the influence of width, slope and inflow rate on soil and water conservation and water purification effects of VFS. The results showed that the runoff reduction rate was greatly influenced by the width of VFS. The VFSs with 1 , 3 , and 5 m width could reduce runoff by 25. 9%, 79. 6% and 79. 7%, respectively; the reduction rate of pollutants ( TN, TP, K ) increased with the increasing width, which were 51. 7%--92. 9%, 44. 4%--98. 8%, and 31. 7%--97. 9% correspondingly; and the reduction rate of TSS was 97. 6%, 99. 4% and 77. 4%, respectively. Besides, the reduction rates of runoff and TSS decreased with increasing slope of VFS (3°, 7°, 10°). For the same VFS, decreasing inflow rate corresponded to increasing reduction rate of runoff and TSS, while the removal efficiencies of TN, TP and K were decreasing. The results indicate that VFS is an effective practice for reducing runoff, removing TSS and pollutants.