Validation of Morgan, Morgan and Finney erosion model in experimental plots

The fact that there are so many erosion models makes it necessary to critically selectone of them as all have some limitations. Models are formulations of processes andlogics as represented by the modeler. The formulations may be representations of eithersimple processes or complicated ones as the modeler deems necessary to solve aspecific problem. These variables must be derived by a procedure of calibration for aspecific case. The Soil erosion model of Morgan, Morgan and Finny (1982) from alarge list of soil erosion models, have been applied to test the validity of the model inSanganeh research station, Mashhad, Iran. After a field survey, plots with sheet erosion,were selected and their data was collected. Rainfall, slope and soil data were derivedfrom station archive, vegetation cover and root depths were determined from fieldobservations and some other parameters were tested on site. Soil loss was calculated byusing overland flow for each plot after each rainfall and the measured records werecompared with model estimations. The results show that in most plots, predictionsdeviated from the observations and in 28.21% of plots the results seem acceptable. Thefinal result of present research shows that the model performs reasonably well for plotswith lower density of vegetation cover (less than 20%), steep area with more than 40percent, and soil depths of less than 10 centimeter.