Sediment movement and filtration within laboratory and riparian vegetation buffer strips

Laboratory and field rainfall simulations were conducted to determine the influence of soil and vegetation characteristics on sediment yield from vegetated buffer strips. The laboratory experiment was used to compare the influence of three lengths of vegetation buffer strips and two vegetation heights on sediment filtration. The field experiments were used to evaluate the influence of two riparian communities, three vegetation heights, two plot sizes, and two particle size distributions on sediment filtration from overland flow. It was hypothesized that increased vegetation height alone was not sufficient to increase sediment filtration, but that several vegetation and soil surface characteristics were required to decrease sediment yield.; Rainfall (50 mm{dollar}cdot{dollar}hr{dollar}sp{lcub}-1{rcub}){dollar} was simulated in the laboratory over six trays (0.6 m x 1.0 m). Concurrently, sediment laden overland flow was introduced to the up-slope end of the trays (50 mm{dollar}cdot{dollar}hr{dollar}sp{lcub}-1{rcub}).{dollar} Two trays contained 12.5 cm, two trays contained 25.0 cm, and two trays contained 50.0 cm of Kentucky bluegrass (Poa pratensis L.) buffer strips within each simulation run. Paired buffer length trays either were clipped to the soil surface or had 10 cm tall grass. Vegetation height did not significantly affect sediment yield, but the length of bluegrass buffers did affect sediment yield. The 50 cm buffer length filtered more sediment than either the 12.5 or 25 cm buffers.; Field rainfall simulations (60 mm{dollar}cdot{dollar}hr{dollar}sp{lcub}-1{rcub}){dollar} were performed over two macro-plots (3 m x 10 m) and two micro-plots (0.6 m x 2 m) simultaneously. Overland flow (25 mm{dollar}cdot{dollar}hr{dollar}sp{lcub}-1{rcub}){dollar} containing sediment (two particle size distributions) was introduced simultaneously to the up-slope end of the plots.; Sediment yield was not affected by vegetation height or vegetation community. The micro-plots yielded more sediment than the macro-plots. Coarse sediment ({dollar}>{dollar}200 {dollar}mu{dollar}m) traveled further down-slope in the clipped to the soil surface treatment than in either the 10 cm or natural height vegetative treatments.; Study results indicated that vegetation height is not an important variable effecting sediment yield, but that height may be relevant on a small scale basis for coarse particle movement.