Erosione dei suoli: applicazioni tramite il software GRASS GIS

The evaluation of the sediment yield and the location of the areas under conditions of risk erosion are important applications of the G.I.S. Some soil erosion models are more used than others, but sometimes they model the soil erosion processes using empirical and too much simple ways. The new soil erosion models generation try to use a physical approach. These new models need to be tested and calibrated to carefully evaluate the parameters involved in the simulation of the soil erosion and sediment transportation processes. A small catchment near Collazzone (Piedicolle Creek, Umbria, central Italy) was used as a case study in order to test some different models, and evaluate the difference between them. RUSLE model uses an erosion limited approach; this model simulates only soil erosion, neglecting sediment deposition processes. USPED model uses a different approach defined transport limited. USPED may evaluate also depositional processes. The comparison shows how USPED model, sometime considered applicable only for a qualitative approach, can produce results not too different than those obtained by the RUSLE model, but improved by the definitions of the sedimentation areas. SIMWE (soil erosion and sediments transportations model) is a theoretical evolution of the USPED model. SIMWE doesn’t use, as USPED, empirical parameters, but it’s a physical based model. SIMWE needs of a long phase of testing and although it has high potentiality and perspective, it should be applied carefully and on small and steep basins.