Soil Erosion pp 181-197 | Cite as

A Process-Based Evaluation of a Process-Based Soil-Erosion Model

  • A. J. Parsons
  • J. Wainwright
Part of the Environmental Science book series (ESE)


In recent years, efforts to achieve better prediction of soil erosion by overland flow have emphasized the development of process-based models. It is claimed that process-based erosion models provide several advantages over empirically based erosion-prediction technology, amongst which is the capability to estimate spatial and temporal distributions of soil loss (Nearing et al. 1989). Evaluation of such process-based models has, however, been generally made in terms of their outputs rather than in terms of their correct representation of the erosion processes (see, for example, the evaluations reported in Boardman and Favis-Mortlock 1998). Such evaluation is limited for two reasons. First, a match between the output of the model and observed values for erosion does not demonstrate that the model is successfully representing the operation of processes. As Grayson and Moore (1992) have convincingly demonstrated in the context of overland flow hydrographs, the same output can be generated from a variety of sources and types of overland flow. These authors showed that a match of the runoff hydrograph is insufficient to demonstrate that the model is adequately representing the hillslope processes that generate the runoff. Secondly, where model output and observed runoff and erosion rates do not agree, an evaluation only in terms of model output provides no basis for identifying an explanation for the disparity that would lead to improvements to the model.


Erosion Rate Soil Erosion Sediment Yield Overland Flow Flow Depth 
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© Springer-Verlag Berlin Heidelberg 2000

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  • A. J. Parsons
  • J. Wainwright

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