Evolução da paisagem em relevo de chapada no Cerrado

• Autor(a) principal: Borges, Mariley Gonçalves
• Data de Publicação: 2023
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/13140
• topic: Bacias hidrográficas; Superfícies de aplanamento; Áreas úmidas; Evolução geomorfológica; Geotecnologias; Watersheds; Planation surfaces; Wetlands; Geomorphological evolution; Geotechnologies; CIENCIAS HUMANAS::GEOGRAFIA

The objective of this research was to evaluate the relationship between the spatial representation of wetlands (veredas) in the context of the watershed from the Cerrado, the stage of evolution of the reliefs of planation surfaces and their reflections on the dynamics of the slopes and on the functioning of the river channels. The study was carried out in the watersheds of Catolé (BHCC) and Borrachudo (BHRB) rivers, in the North of Minas Gerais. It is justified by 1) the importance of understanding the evolution of the reliefs of planation surfaces in the Cerrado and its reflections on the landscapes, on the functioning of the slopes and on the hydrological dynamics of the river channels, in the context of the hydrographic basins; and 2) the environmental relevance of the Cerrado wetlands, which ar responsible for increasing the residence time of water in the basins, for the quality of river water, and for the stock of organic C. For this purpose, the morphometric study of the watersheds, the application of dissection and moisture indices, the estimation of soil loss potential (USLE) and the mapping and classification of wetlands were performed using geoprocessing. River discharge measurements, of the physical and physicochemical parameters of water analyzes were also carried out in loco and in the laboratory over a hydrological year. It was found that the wetlands of the BHCC have greater spatial representation than for BHRB, that is, 27.9 km² more area. The distribution of wetlands in the study area is associated with the areas of still preserved planation surfaces. Compared to the BHRB, it was found that the BHCC has less dissected relief, lower drainage density and lower slopes. Its moisture content is higher and the longitudinal profile of its main channel is less adjusted to the profile considered in "balance", that is, a significant part of the basin is located upstream of the main knickpoint of the channel, therefore not yet adjusted to the current baselevel. These characteristics are compatible with the hydrological, the physical and physicochemical parameters of water, which indicated that the Catolé river has a more regular flow and water with less turbidity, that is, less sediment transport in the basin. The results showed that the geomorphological evolution is at a more advanced stage in the BHRB, which indicates a natural tendency towards a decrease in wetlands area, predominance of dissected reliefs and greater transport of sediments by the river network.