Uso de série temporal de imagens de satélite na análise de mudanças morfológicas e sedimentares causadas por ações antrópicas no Rio Cuiabá (MT), Pantanal
Data
2023-01-09
Autores
Fernandes, Beatriz Silva [UNIFESP]
Orientadores
Pupim, Fabiano do Nascimento [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A alteração no uso e ocupação do solo, bem como a implantação de barragens para uso hidrelétrico, têm afetado a produção de sedimentos nas vertentes e disponibilidade destes nos rios do Centro-Oeste do Brasil nas últimas décadas. Ainda são poucos os estudos que quantifiquem tais impactos, dificultando o entendimento da resposta dos rios frente às mudanças ambientais passadas e em curso. Procurando preencher parte dessa lacuna, esta pesquisa teve como objetivo investigar a resposta geomorfológica e sedimentar do Rio Cuiabá (MT) frente a essas intervenções antrópicas desde o ano de 1985. Foram analisados três parâmetros no canal: as barras fluviais, largura e taxa de migração. Para isso, utilizou-se série temporal de imagens de satélite da missão Landsat. Os resultados demonstram que um aumento significativo das barras fluviais entre 1985 e 2000 foi causado pela intensa conversão de vegetação nativa em terras agrícolas, o que favoreceu a erosão dos solos e disponibilidade de sedimentos para o canal. Após o ano de 2000, observou-se uma diminuição das barras fluviais, sugerindo uma diminuição no aporte de sedimentos devido à instalação da hidroelétrica de Manso e outras barragens menores. Com relação à taxa de migração do canal e largura não foram encontradas alterações muito significativas ao longo do período analisado. Assim, entende-se que as mudanças antrópicas na Bacia Hidrográfica do Rio Cuiabá afetam diretamente a estrutura e funcionamento do canal, sendo as barras fluviais mais sensíveis a tais alterações.
The change in land use and occupation, as well as the implementation of dams for hydroelectric use, has affected the production of sediments in the slopes and their availability in the rivers of Central-West Brazil in recent decades. There are still few studies that quantify such impacts, making it difficult to understand the response of rivers to past and ongoing environmental changes. Seeking to fill part of this gap, this research aimed to investigate the geomorphological and sedimentary response of the Cuiabá River (MT) to these human disturbances since 1985. Three parameters were analyzed in the channel: river bars, width and migration rate. A time series of satellite images from the Landsat mission was used for this. The results demonstrate that a significant increase in river bars between 1985 and 2000 was caused by the intense conversion of native vegetation to agricultural land, which favored soil erosion and sediment load for the channel. After the year 2000, there was a decrease in river bars, suggesting a decrease in the contribution of sediments due to the installation of the Manso hydroelectric plant and other smaller dams. Regarding the channel migration rate and width, no significant changes were found over the analyzed period. Thus, it is understood that human changes in the Cuiabá River Basin directly affect the structure and functioning of the channel, with the river bars being more sensitive to such changes.
The change in land use and occupation, as well as the implementation of dams for hydroelectric use, has affected the production of sediments in the slopes and their availability in the rivers of Central-West Brazil in recent decades. There are still few studies that quantify such impacts, making it difficult to understand the response of rivers to past and ongoing environmental changes. Seeking to fill part of this gap, this research aimed to investigate the geomorphological and sedimentary response of the Cuiabá River (MT) to these human disturbances since 1985. Three parameters were analyzed in the channel: river bars, width and migration rate. A time series of satellite images from the Landsat mission was used for this. The results demonstrate that a significant increase in river bars between 1985 and 2000 was caused by the intense conversion of native vegetation to agricultural land, which favored soil erosion and sediment load for the channel. After the year 2000, there was a decrease in river bars, suggesting a decrease in the contribution of sediments due to the installation of the Manso hydroelectric plant and other smaller dams. Regarding the channel migration rate and width, no significant changes were found over the analyzed period. Thus, it is understood that human changes in the Cuiabá River Basin directly affect the structure and functioning of the channel, with the river bars being more sensitive to such changes.