A distribuição espacial de processos erosivos e as variáveis geoambientais na bacia hidrográfica do Rio São Francisco Verdadeiro – PR

Abstract

Among the environmental problems that affect the soil, a water erosion of the linear type is one of the most common processes. The State of Paraná has already been considered a reference in soil management and conservation practices. However, this condition has been gradually changed and currently several regions of the State, with soil degradation processes, such as erosion in its different forms. The western region of the State of Paraná does not escape this reality, with numerous erosive processes being observed in this grain-producing area. The availability of geotechnology data and as different geoenvironmental variables, it is questioned whether remote sensing data on an average spatial scale allows the identification of areas more susceptible to erosion and environmental qualification has a greater influence on erosion processes, being as adopted: Declivity, NDVI, Soil classes and Use and occupation. In this context, the objective of this work is to verify if the remote sensing data on a medium spatial scale ignores the identification of areas susceptible to linear erosion and which geoenvironmental variable of greatest influence in the São Francisco Verdadeiro (BSFV) basin, which covers a large part the so-called Paraná Basin 3 (BP3). The procedures include the vectorization of linear erosive processes (furrows, ravines and gullies) from Google Earth and the use of a Digital Elevation Model from the SRTM to obtain the variables of the area (Slope, ITU, IMF), using if also the use and coverage of the soil (Sentinel-2), NDVI (Sentinel-2 Band 8 and 4) and soil classes provided by Embrapa. Supported by the Fuzzy Logic technique and the Kolmogorv-Smirnov test (Ks) to spatialize as areas susceptible to linear water erosion. With the Ks test, it was possible to identify the critical D and the maximum D for each analyzed variable, where the maximum D in decreasing order was 0.2111 for the land use and occupation class, 0.1808 for the NDVI, related to values with exposed areas or without vegetation cover, 0.1797 for the slope in the class of 6 to 12% and 0.0526 for the classes of soils of the BSFV. With the Dmax values above the critical D, it is assumed that the erosive processes are being influenced in order by the variables: form of land use, form of vegetation cover (NDVI), slope and soil classes.