Análise multitemporal do uso e ocupação da bacia hidrográfica do rio jirau alto no município de Dois Vizinhos - PR, utilizando técnicas de sensoriamento remoto e diferença de NDVI

Abstract

Over the years, the quality of water for consumption has been suffering from index problems caused by agrochemicals, garbage and siltationof rivers used as water catchments. Thus, in order to identify a vegetative area degraded or recovered over the years in the Jirau Alto river basin (Dois Vizinhos - PR), a multitemporal analysis was conducted using remote sensing techniques and geographic information systems software (SIG). The study was carried out analyzing how possible changes occurred over time in Landsat 5 and 8 satellite images in four different periods, namely 1990, 2000, 2010 and 2020. To identify the changes that occurred, digital processing techniques were used of images (PDI), applied to correct geometrically and radiometrically as images. Next, the Normalized Difference Vegetation Index (NDVI) were calculated and using a 1990 image as a reference, the vegetation indices were subtracted, making it possible to generate maps with changes in the use and occupation of the studied area. As a result, it was found that there were changes in all types of vegetation over time, however, as areas classified as very tall vegetation, forests and well managed areas, important for the maintenance of the basins, increased by 24%.