Click on “Download PDF” for the PDF version or on the title for the HTML version.
If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.
FLOW PATHWAYS AND SEDIMENT TRAPPING IN A FIELD-SCALE VEGETATIVE FILTER
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.orgCitation: Transactions of the ASAE. 48(3): 955-968. (doi: 10.13031/2013.18508) @2005
Authors: M. J. Helmers, D. E. Eisenhauer, M. G. Dosskey, T. G. Franti, J. M. Brothers, M. C. McCullough
Keywords: Flow convergence, Grass filters, Overland flow, Sediment trapping, Vegetative filters
Vegetative filters (VF) are a best management practice installed in many areas to control sediment movement to water bodies. It is commonly assumed that runoff proceeds perpendicularly across a VF as sheet flow. However, there is little research information on natural pathways of water movement and performance of field-scale VF. The objectives of this study were: (1) to quantify the performance of a VF where the flow path is not controlled by artificial borders and flow path lengths are field-scale, and (2) to develop methods to detect and quantify overland flow convergence and divergence in a VF. Our hypothesis is that flow converges and diverges in field-scale VF and that flow pathways that define flow convergence and divergence areas can be predicted using high-resolution topography (i.e., maps). Overland flow and sediment mass flow were monitored in two 13 15 m subareas of a 13 225 m grass buffer located in Polk County in east-central Nebraska. Monitoring included a high-resolution survey to 3 cm resolution, dye tracer studies to identify flow pathways, and measurement of maximum flow depths at 51 points in each subarea. Despite relatively planar topography (a result of grading for surface irrigation), there were converging and diverging areas of overland flow in the buffer subareas. Convergence ratios ranged from -1.55 to 0.34. Predicted flow pathways using the high-resolution topography (i.e., map) closely followed actual flow paths. Overland flow was not uniformly distributed, and flow depths were not uniform across the subareas. Despite converging and diverging flow, the field-scale VF trapped approximately 80% of the incoming sediment.(Download PDF) (Export to EndNotes)