Sediment filtration in a montane riparian zone under simulated rainfall
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Authors: R. A. Pearce, G. W. Frasier, M. J. Trlica, W. C. Leininger, J. D. Stednick, and J. L. Smith
Date: 1998
Journal: Journal of Range Management
Volume: 51
Number: 3
Pages: 309-314
Summary of Methods: The effectiveness of two riparian communities (grass and sedge) to filter sediment from overland water flow was examined in a 2 year study conducted during summer along Sheep Creek in the Roosevelt National Forest of Colorado. Three levels of clipping (unclipped, clipped to 10 cm, and clipped to soil surface) at two size scales (microplot and macroplot) were evaluated within in each riparian community. A rainfall simulator (60 mm/hr) was used to simulate a rainfall event. Sediments (sandy loam and ground silica loam) were introduced at the upper end of the plots at a rate of 25 mm/hr. Runoff was measured 5 min after runoff equilibrium was reached and every 6 min thereafter. Soil surface, vegetation surface, canopy cover, species composition, biomass and soil surface roughness were recorded.
Article Summary / Main Points: Silica loam produced higher overland flow sediment yields than the sandy loam soil. Sediment yield was higher in micro-plots compared to macro-plots. Micro-plots were more sensitive to plant communities and treatment differences compared to larger plots. Overall, as vegetation height increased there was no increase or decrease in sediment yields. Regardless of vegetation height or community, in the macro-plots, 98% of the introduced sediment was filtered out and remained on site, while 94% remained in the micro-plots; showing that riparian buffer strips are effective sediment filters.
Vegetation Types: Riparian and Wetlands
MLRA Ecoregions: 48A Southern Rocky Mountains
Agrovoc Control Words: Riparian zones Runoff Sediment retention
Article Review Type: Refereed
Article Type: Experimental Research
Keywords: stubble height, erosion, vegetation filter strip, runoff, nonpoint source pollution
Annotation: This replicated research is applicable to a wide range of montane riparian areas. These results suggest that accurate prediction of sediment filtration requires consideration of a combination of vegetation and soil surface characteristics. This study was only conducted for 2 years and it is therefore unclear how much year to year variation might exist in sediment filtration in any riparian area under simulated rainfall. Additionally, Pearce et al. (1997, J. Environ. Quality 26:139-144) studied the effectiveness of grass buffer strips on sediment filtration in lab simulations and Pierce et al. (1998, J. Range Manage. 51:301-308) looked at sediment movement through montane vegetation under simulated rainfall and overland flow, also available on the RSIS website. Together all three Pierce et al. articles present important research on the understanding of sediment filtration in riparian areas.
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