RAINFALL EROSIVITY IN THE UPPER PARAGUAI RIVER BASIN, BRAZIL

Resumo

Mapping rainfall erosivity is a practical and indispensable tool for land use planning at regional scale, like large river basins. The objective of this study was to evaluate the spatial distribution of the annual erosive potential of rainfall for the Upper Paraguai Basin (BAP) in Brazil. For this, 125 pluviometric stations located in BAP and its surroundings were analyzed. The rainfall erosivity was estimated for each station using the Modified Fournier Index. For the spatial distribution of the erosive potential, the values for erosivity in each station were interpolated using the kriging method. Annual erosivity at BAP ranged from 5,105 to 9,169, with an average of 6,800 MJ mm ha-1 h-1. Erosivity was classified as moderate to strong in 69% of BAP and in 31% of the basin the erosive potential of rainfall was classified as strong. An increase in erosivity going from southwest to northeast was also observed. Areas with high values of rainfall erosivity in BAP, associated with upland areas and with soils that are more susceptible to erosion show the greatest vulnerability to natural rainfall erosion. These lands should be carefully managed to minimize soil erosion and its impacts on the Pantanal