ARS | Publication request: A REVISED EROSION PROCESS MODEL CONCEPT

Submitted to: Soil Science Society of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 5, 2000
Publication Date: N/A

Technical Abstract: The advantage of using a process-based erosion prediction model, such as Water Erosion Prediction Project (WEPP), is its capability to predict sediment detachment and deposition on the hillslope, in addition to predicting total sediment delivery from the hillslope. In the WEPP model, erosion and deposition are modeled separately and the sediment transport capacity (Tc) was used to determine whether erosion or deposition occurs. Therefore, the accuracy of predicting erosion and deposition depends on how the Tc was estimated. Recent laboratory experiments conducted in a multiple-box system produced data sets challenged the Tc concept. Observations showed erosion and deposition occurred simultaneously and different surface, flow and rainfall conditions triggered the dominance of one process over the other. A revised sediment mass balance equation, which contains both erosion and deposition terms, is used to model sediment transport. An analytic solution for the revised erosion equation was derived and the solution examined for conditions similar to the laboratory experiments. The analytic solution reproduced experimental data trends and was able to simulate sediment mass balance scenarios ranging from deposition- to detachment- and transport-dominated regimes. This proposed modification may lead to a better understanding of erosion processes, and consequently, an improved erosion prediction model.