Estimated water soil erosion by the Water Erosion Prediction Project model in the Gigante Stream Basin, Minas Gerais, Brazil

ABSTRACT

The objective of the present work was to monitor and identify erosive precipitations and monitor soil losses through experimental plots installed in the Córrego do Gigante sub-basin, to calibrate the Water Erosion Prediction Project (WEPP) model, in its slope version, based on the results obtained in the plots, and apply it to the sub-basin area to estimate soil losses due to water erosion. The rainfall regime during the study period showed high degrees of erosivity and concentration, since 57% of the events were erosive, of which, the four most erosive events corresponded to 47.2% of the annual erosivity. The areas covered by the interactions between soil class, slope, and land use, in the experimental plots, totaled 174.32 ha (50% of the sub-basin area), whose values obtained resulted in a weighted average loss of 0.623 t ha^-1 year^-1, which were a reference in the adjustment of the WEPP model in the hillside version, with an estimate of 0.651 t ha^-1 year^-1. The application of the model on a surface with 93.0% coverage of the sub-basin resulted in an estimate of 0.802 t ha^-1 year^-1 for the soil loss rate. The exposed soil areas, although accounting for only 7.9% of the sub-basin area, produced 85.1% of the estimated soil losses, which, on the other hand, reflects the positive influence of vegetation cover in the decrease of water erosion. Simulating the implementation of cover in the form of field/pasture and/or reforestation in the areas of bare soil significantly reduced the rates of soil losses in the sub-basin to 0.215 t ha^-1 year^-1.

Keywords:
soil loss modeling; experimental plots; erosive rainfall