Evolução da paisagem em relevo de chapada no Cerrado
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2023-08-11
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Universidade Federal de Goiás
Resumo
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.
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BORGES, M. G. Evolução da paisagem em relevo de chapada no Cerrado. 2023. 165 f. Tese (Doutorado em Geografia) - Instituto de Estudos Socioambientais, Universidade Federal de Goiás, Goiânia, 2023.