Análise do efeito da resolução espacial do modelo digital de elevação na obtenção do limiar topográfico para predição de processos erosivos

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The morphometric analysis has been applied to determine the threshold that conditions the erosion processes. Several authors propose an inverse relationship between contribution area (A) and mean slope (S). These parameters can be obtained by several methods, among them the geographic information system (GIS), because it facilitates the processing and integration of spatial data. Besides, the acquisition of the parameters depends on the elaboration of a digital elevation model (DEM) with appropriate spatial resolution that guarantees the representation of the geomorphological processes. The present work has for objectives to verify the influence of the spatial resolution of the DEM with 2, 10 and 30 meters, in the determination of the relationship contribution area and mean slope. The area of study is the watershed of the Córrego Alpes and Retiro, located in the municipality of São Pedro, state of São Paulo, with an approximate area of 7 km². The DEM, flow direction and slope were carried out in GIS and allowed to calculate for each erosion feature, the contribution area and mean slope. The data obtained by DEM with spatial resolution of (2m) presented more accurate results and they allowed to define a threshold of trigger of the most representative erosions in agreement with the characteristics of the area in study.