Title: Flow-retarding effects of vegetation and geotextiles on soil detachment during concentrated flow
Authors: Knapen, Anke ×
Smets, Toon
Poesen, Jean #
Issue Date: Aug-2009
Publisher: Wiley
Series Title: Hydrological Processes vol:23 issue:17 pages:2427-2437
Abstract: Roughness elements at the soil surface (e.g. crop residues, rock fragments, vegetation, geotextiles) strongly reduce the erosivity
of overland flow (both interrill and concentrated overland flow) and hence soil detachment rates. Common methods for shear
stress partitioning that allow the calculation of effective flow shear stress in the presence of roughness elements originate from
river hydraulics but seem invalid for overland flow. An alternative method to estimate the effective flow shear stress in the
presence of a soil surface cover has been presented and tested for soil detachment by concentrated runoff on soil surfaces
covered by crop residues by Knapen et al., (2008). In this method, the estimation of effective flow shear stress is based on
the recalculation of the hydraulic radius for covered soil surfaces using flow hydraulics on uncovered surfaces. However, the
applicability of this method for roughness elements different from crop residues and under field conditions needs to be tested
to confirm its validity. Therefore, runoff data from three experimental studies (conducted on geotextile and grassed-covered
soil surfaces) are analysed in this study. The results show that effective flow shear stress, calculated using this method, is not
only a good soil detachment predictor for soil surfaces covered with crop residues but also for the tested soil surfaces with a
vegetation or geotextile cover. However, the geotextile experiments point to one of the shortcomings of the method. At high
flow shear stress levels, vortex erosion due to flow turbulence is reported for the thickest geotextiles. These flow turbulences
are not accounted for since the method is based on average flow characteristics.
ISSN: 0885-6087
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Division of Geography & Tourism
× corresponding author
# (joint) last author

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