A conceptual model for determining soil erosion by water

Anthony J. Parsons, John Wainwright, D. Mark Powell, Jörg Kaduk and Richard E. Brazier

Earth Surface Processes and Landforms 29(10): 1293-1302.


Evidence shows that present estimates of rates of soil erosion by water obtained from plot studies are incompatible with estimations of long-term lowering of large drainage basins. This paper argues that traditional arguments to bring together these two disparate rates are flawed. The flux of sediment leaving a specified area has traditionally been converted to a yield simply by dividing by the area. There is not, however, a simple correlation between flux and area. An approach that is based upon the entrainment rates and travel distances of individual particles is developed to determine erosion rates. There is limited available empirical data which is consistent with the predictions of the approach developed. It is necessary to parameterize the equations to take account of factors such as gradient and sediment supply to proceed from the conceptual framework to quantitative measurements of erosion. However, the conceptual model developed solves the apparent paradox of the sediment delivery ratio, resolves recent discussion about the validity of erosion rates made using USLE erosion plots, and potentially can reconcile erosion rates with known lifespans of continents. The results shown imply therefore that previous estimates of soil erosion are misleading.

Key words

soil erosion; erosion rates; sediment delivery