Runoff and Sediment Reduction by Riparian Buffer Filters on Steep Slopes

Vegetative filter strips (VFSs) have been studied extensively and are widely recommended for improving surface water quality as a kind of Best Management Practice. The objective of this study was to assess the influence of buffer width, inflow rate and vegetation type on overall reduction of surface runoff and sediment mass. In the headwater catchment of Hunhe River, twenty four VFS plots were tested, with three replicated plots of three vegetation types and two filter widths. The plots received simulated runoff carrying 2700 mg/L sediment in consecutive four phases with decreasing inflow rates. All plots reduced at least 70% of incoming runoff. The 4.5 m plots and 9 m plots trapped 73.9% and 88.1% of the incoming sediment mass on average, respectively. Decreased inflow rates promised better and more stable performance of the VFS in trapping sediment. Vegetation cover imposed effect on sediment trapping efficiency (STE) for 9 m plots compared with control but there was no difference among different vegetation types.