Author
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Nearing, Mark |
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Submitted to: International Soil Conservation Organization Conference Abstracts
Publication Type: Abstract Only Publication Acceptance Date: 4/1/2004 Publication Date: 7/5/2004 Citation: Nearing, M.A. 2004. Capabilities and limitations of erosion models and data. International Soil Conservation Organization Conference Abstracts. Paper 420. Interpretive Summary: A new, multi-tracer method is used to track erosion, translocation, and re-deposition of sediment in a small watershed, thus allowing for the first time a complete, spatially distributed, sediment balance to be made as a function of landscape position. A 0.68 ha watershed near Coshocton, Ohio, USA was divided into six morphological units, each tagged with one of six rare earth element oxides. Sediment translocation was evaluated by collecting runoff and by spatially sampling the soil surface. Average measured erosion rate was 6.1 t ha-1, but varied between 40.4 t ha-1 loss from the lower channels to 24.1 t ha-1 gain on the toeslope. With this technique it was possible for the first time to itemize the sediment budget for landscape elements into three components: 1) the soil from the element that left the watershed with runoff, 2) soil from the element that was re-deposited on lower positions, with the spatial distribution of that deposition, and 3) soil originating from the upper positions and deposited on the element, with quantification of relative source areas. The results are incongruous with the current morphology of the watershed, suggesting that diffusion type erosion must also play a major role in defining the evolution of this landscape. Technical Abstract: A new, multi-tracer method is used to track erosion, translocation, and re-deposition of sediment in a small watershed, thus allowing for the first time a complete, spatially distributed, sediment balance to be made as a function of landscape position. A 0.68 ha watershed near Coshocton, Ohio, USA was divided into six morphological units, each tagged with one of six rare earth element oxides. Sediment translocation was evaluated by collecting runoff and by spatially sampling the soil surface. Average measured erosion rate was 6.1 t ha-1, but varied between 40.4 t ha-1 loss from the lower channels to 24.1 t ha-1 gain on the toeslope. With this technique it was possible for the first time to itemize the sediment budget for landscape elements into three components: 1) the soil from the element that left the watershed with runoff, 2) soil from the element that was re-deposited on lower positions, with the spatial distribution of that deposition, and 3) soil originating from the upper positions and deposited on the element, with quantification of relative source areas. The results are incongruous with the current morphology of the watershed, suggesting that diffusion type erosion must also play a major role in defining the evolution of this landscape. |
