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Vegetated filter effects on sedimentological connectivity of agricultural catchments in erosion modelling: A review
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Contact: gumiere@supagro.inra.fr. International audience. The sedimentological connectivity of agricultural catchments may be affected by anthropogenic structures (land management practices) established to reduce sediment exportation from agricultural plots to water streams. Distributed erosion models may in theory provide information about where and how these structures should be installed in catchments to reduce sediment exportation. The interaction between sediment exportation and land management practices is very complex from both theoretical and experimental points of view. Vegetated filters are a widely used land management practice. They interact with water flow, change turbulence conditions, and ultimately affect sediment transport and deposition processes. Experimental results have shown that the efficiency of sediment trapping in vegetated filters is influenced by flow characteristics, sediment size, and vegetation type, as well as by the slope and width of the filter in the streamwise direction. At the catchment scale, the spatial organisation of management practices is crucial for the global sedimentological connectivity. Present-day erosion models propose different approaches to simulate the influence of management practices on soil loss and sediment export for agricultural catchments. Some of them use the Sediment Delivery Ratio (SDR) or P-factor to describe sediment transport from source to sink areas. Others, such as in the TRAVA and VSFMOD, rely on process-based descriptions involving changes in roughness and infiltrability along flow paths to study the effect of management practices. From the literature review conducted herein, we identified the lack of an approach of intermediate complexity, that would be more physically relevant than SDR and P-factor approaches, but simpler and easier to spatialise than TRAVA and VSFMOD-type models
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