Estimativa de perda de solo na bacia hidrográfica do Rio Azul, centro-oeste do Paraná

Abstract

Water erosion is one of the natural processes that occur in a hydrographic basin, however, it can be aggravated by human action. Mapping the main points of soil loss, using GIS tools, in a hydrographic basis is one of the ways to analyze the conservation practices that are being applied. The aim of this study was to elaborate thematic maps that quantify the different factors applied in the Universal Soil Loss Equation and find the areas most susceptible to soil loss in the Azul River basin in the centerwest of the State of Paraná. This basin is located in three municipalities: Palotina, Maripá and Assis Chateaubriand, with a total drainage area of 432km². Mappings of each component of the model were generated: erosivity, erodibility, slope and slope length, conservation practices and soil management. Rain data from the last 22 years provided by the National Water Agency were used. The Pedology of the region was obtained from Água e Terra Institute. The digital elevation model was acquired from the Topodata project, from the National Space Research Institute. Land cover and land use data were obtained from the MapBiomas project database. For each term of the model, a bibliographic survey of the coefficients were made and the average value was used in the modeling. Erosivity values found were below the literature for the same region in another period. The mappings of each component of the applied model were presented. The magnitude of soil loss in the basin was defined by the rainfall erosivity, this erosivity presented values below the literature for the same region, the calculations of morphometric factors of the basin corroborated with the values obtained for slope and slope factor. The results showed that soils with greater erodibility, such as the typical eutrophic red clay soil, and greater slope tend to have greater soil erosion. In general, 86% of the area presents soil loss of up to 3 t.ha1. year1, indicating low soil loss, however, the regions with greater soil loss are close to the basin's outlet, where there is the soil with the highest erodibility value, requiring attention to local conservation practices. In general, the area presents an annual loss of 150g.ha1, a relatively low value.