Análise dos impactos ambientais na bacia hidrográfica do Igarapé do Cachorro, Itacoatiara – AM

Abstract

The landscape shift resulting from the appropriation of the environment by human actions intensifies the degrees of environmental vulnerability and, in turn, reflects on the triggering of environmental impacts in a given landscape. For this, it is necessary to understand the form and functionality of the landscape as an open system, which integrate and interact in their complexity in relation to the phenomena in their exchange of energy and matter that directly and indirectly influence the analyzed watershed. Thusly, the main objective was to analyze the possible areas of environmental impacts from the vulnerability of the landscape to soil loss in the watershed of Igarapé do Cachorro in Itacoatiara - AM, for this it was carried out the characterization of the physical-natural elements of the analyzed basin such as geology, pedology, geomorphology, vegetation and climate, it was also identified the types of land use and their influence on the change in the vulnerability of the landscape to soil loss. In the methodological procedures, data from the Annual Mapping of Land Use and Cover in Brazil (MAPBIOMAS) were used for vector data from the databases of the Brazilian Institute of Geography and Statistics (IBGE), Environmental Information Bank (BDIA), National Agency of Waters (ANA) through the National Spatial Database Infrastructure Viewer (INDE), altitude data from the Shuttle Radar Topography Mission (SRTM/TOPODATA), which were organized and processed in a Geographic Information System (GIS) environment for the acquisition of vector and matrix data, through manipulation in the Qgis software of versions 3.16.15 and 3.28.6, for data classification and analysis, observations were also carried out in field work, through the photographic records of the areas visited, aiming at the recognition of the types of land uses. Thus, the results achieved in the research were: the characterization of the study area; the elaboration of thematic maps of the Visited Areas in the Basin, Geology, Geomorphology, Pedology, Vegetation, Slope, Hypsometry, Land Use and Vegetation Cover of the years 1985, 1995, 2005, 2015 and 2020, the Vulnerability of the Landscape to soil loss, in addition to the Climate (precipitation and erosivity) with graphs and tables, as well as the photographic records during the fieldwork carried out in the months of July and August of the year 2021, the survey and organization of the theoretical framework. The multicriteria method AHP (Analytic Hierarchy Process) was used and the degree of vulnerability of Crepani et al. (2001) was adapted, which is 1 to 3, and in the present study the scale 0 to 1 was used, it was verified that the pelvis presents a predominance of Moderate (91.75%), High (7.93%) and Very low (0.33%) vulnerability, and Low and Very High was not observed. In the Igarapé do Cachorro watershed, it was found that high and moderate degrees of vulnerability are associated with variables that present classes with a high degree of environmental instability, such as Geology, Land Use, Slope, and Erosivity. In view of the above, it is considered that this research enabled surveys, organization and manipulation of scientific data applied to a watershed of unprecedented study, providing the importance of observing the landscape in the bias of environmental vulnerability based on the types of physical-natural elements of the formation of the basin intertwined with the anthropic interaction, thus shaping the environment, which in this case, already has 91.75% of moderate vulnerability in 2020, evidencing the importance of the application of environmental public policies for the proper management of the watershed in environmental planning.