The performance of grass filter strips in controlling high‐concentration suspended sediment from overland flow under rainfall/non‐rainfall conditions

There is little information on the performance of vegetative filter strips (VFS) in filtering high-concentration sediment from subcritical overland flow. Flume experiments on simulated grass strips were conducted using combinations of three slope gradients (3°, 9° and 15°), five 1-m-wide slope positions (from upslope to downslope), two flow rates (60 and 20 L min-1 m-1) and sediment concentrations of 100–300 kg m-3 under simulated rainfall and non-rainfall conditions. The results showed that sediment deposition efficiency increased with VFS width as a power function. Rainfall significantly reduced sediment deposited within VFS. Higher sediment concentration corresponded to a larger sediment deposition load but reduced deposition efficiency. Flow rate had a negative effect on deposition efficiency but no effect on deposition load. Sediments were more easily deposited at the upper slope position than downslope, and the upper slope position had a higher percentage of coarse sediments. The deposited sediment had significantly greater median diameters (D50) than the inflow sediment. A greater proportion of coarse sediments larger than 25 µm in diameter were deposited, and particles smaller than 1 µm and of 10–25 µm had a better deposition performance than particles of 1–10 µm. Rainfall reduced the deposited sediment D50 at a slope gradient of 3° and had no significant influence on it at 9° or 15°. A higher sediment concentration led to a smaller D50 of the deposited sediment. Rainfall had no significant effect on overland flow velocity. Both the deposited sediment load and D50 decreased with increasing flow velocity, and flow velocity was the most sensitive factor impacting sediment deposition. The results from this study should be useful to control sediment flowing into rivers in areas with serious soil erosion. Copyright © 2013 John Wiley & Sons, Ltd.

[1]  P. M. van Dijk,et al.  Retention of water and sediment by grass strips , 1996 .

[2]  N. Syversen,et al.  Retention of soil particle fractions and phosphorus in cold-climate buffer zones , 2005 .

[3]  Guanghui Zhang,et al.  Correction factor to dye-measured flow velocity under varying water and sediment discharges , 2010 .

[4]  Hossein Ghadiri,et al.  Prediction of surface flow hydrology and sediment retention upslope of a vetiver buffer strip , 2007 .

[5]  Bofu Yu,et al.  Sediment deposition from flow at low gradients into a buffer strip—a critical test of re-entrainment theory , 2003 .

[6]  Hossein Ghadiri,et al.  The influence of grass and porous barrier strips on runoff hydrology and sediment transport. , 2001 .

[7]  Gerard Govers,et al.  The influence of rainfall on sediment transport by overland flow over areas of net deposition , 2002 .

[8]  G. R. Foster,et al.  Depositional Patterns of Sediment Trapped by Grass Hedges , 1995 .

[9]  G. Julien,et al.  Evaluation of buffer zone effectiveness in mitigating the risks associated with agricultural runoff in Prince Edward Island. , 2011, The Science of the total environment.

[10]  Ramesh P. Rudra,et al.  Experimental investigation of runoff reduction and sediment removal by vegetated filter strips , 2004 .

[11]  Ana Deletic,et al.  Modelling of water and sediment transport over grassed areas , 2001 .

[12]  J. W. Gilliam,et al.  Sediment and Chemical Load Reduction by Grass and Riparian Filters , 1996 .

[13]  Dennis C. Flanagan,et al.  Sediment particle sorting on hillslope profiles in the WEPP model. , 2000 .

[14]  Bahram Gharabaghi,et al.  Effectiveness of Vegetative Filter Strips in Removal of Sediments from Overland Flow , 2006 .

[15]  C.–X. Jin,et al.  EXPERIMENTAL STUDIES OF FACTORS IN DETERMINING SEDIMENT TRAPPING IN VEGETATIVE FILTER STRIPS , 2001 .

[16]  L. D. Meyer,et al.  Sediment-trapping effectiveness of stiff-grass hedges , 1995 .

[17]  Decheng Zhou,et al.  The Grain for Green Project induced land cover change in the Loess Plateau: A case study with Ansai County, Shanxi Province, China , 2012 .

[18]  G. Frasier,et al.  Efficiency of Grass Buffer Strips and Vegetation Height on Sediment Filtration in Laboratory Rainfall Simulations , 1997 .

[19]  R. Morgan,et al.  Contour grass strips: a laboratory simulation of their role in soil erosion control , 1995 .

[20]  Craig Allan,et al.  Suspended Sediment Removal by Vegetative Filter Strip Treating Highway Runoff , 2005, Journal of environmental science and health. Part A, Toxic/hazardous substances & environmental engineering.

[21]  John C. Hayes,et al.  Filtration of Sediment by Simulated Vegetation I. Steady-State Flow with Homogeneous Sediment , 1979 .

[22]  Minghua Zhang,et al.  Major factors influencing the efficacy of vegetated buffers on sediment trapping: a review and analysis. , 2008, Journal of environmental quality.

[23]  Hossein Ghadiri,et al.  Sediment retention by a stiff grass hedge under subcritical flow conditions , 2007 .

[24]  Saied Mostaghimi,et al.  Vegetative Filter Strips for Agricultural Nonpoint Source Pollution Control , 1989 .

[25]  C. T. Haan,et al.  Sediment deposition patterns in simulated grass filters , 1977 .

[26]  Peter B. Hairsine,et al.  Rainfall Detachment and Deposition: Sediment Transport in the Absence of Flow-Driven Processes , 1991 .

[27]  Richard M. Cruse,et al.  Vegetative filter strip effects on sediment concentration in cropland runoff , 1996 .

[28]  Lan Ma,et al.  Effectiveness of grass strips in trapping suspended sediments from runoff , 2010 .

[29]  Z. Shangguan,et al.  Runoff hydraulic characteristics and sediment generation in sloped grassplots under simulated rainfall conditions , 2006 .

[30]  Allen L. Thompson,et al.  Grass Barrier and Vegetative Filter Strip Effectiveness in Reducing Runoff, Sediment, Nitrogen, and Phosphorus Loss , 2004 .

[31]  J. E. Parsons,et al.  Modeling hydrology and sediment transport in vegetative filter strips , 1999 .