Impactos antropogênicos na dinâmica sedimentar e morfologia do canal do rio São Lourenço, Pantanal de Mato Grosso
Data
2023-01-09
Autores
Souza, Ana Luiza Faria de [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
O rápido e desordenado crescimento das atividades agrícolas na região Centro-Oeste do Brasil a partir da década de 1970 geraram mudanças significativas no uso da terra, devido o desmatamento para implantação de pastos e monoculturas, o que torna o solo mais suscetível aos processos erosivos. Ainda, houve a necessidade da implantação de usinas hidrelétricas para garantir o abastecimento dos novos centros urbanos e o complexo agroindustrial, acarretando alterações diretas na dinâmica dos rios. A região dos planaltos da bacia do rio São Lourenço, no sudeste do estado do Mato Grosso, foi uma das mais impactadas por esse avanço do sistema produtivo, com indícios de alterações ambientais significativas como o assoreamento dos canais, distúrbios na frequência de inundações e perda de biodiversidade. Em virtude disso, para compreender as condições vigentes da dinâmica fluvial e melhorar as previsões de como as atividades antropogênicas afetam os sistemas fluviais, essa pesquisa tem como objetivo avaliar as alterações na morfologia do canal e no aporte de sedimentos decorrentes da mudança no uso da terra e implantação de hidrelétricas na bacia hidrográfica do rio São Lourenço (MT). Para isso, foi utilizada uma série temporal de imagens da coleção Landsat, com amostras anuais de 1985 a 2020, para quantificar as variações na taxa de migração do canal, largura e número de barras fluviais de um trecho de 100 km ao longo do médio curso rio São Lourenço. Os resultados obtidos indicam que não houveram mudanças significativas na largura e taxa de migração do canal, somente alterações evidentes no número e na área em planta das barras fluviais, sendo que essas mudanças possuem relação direta com as alterações no uso do solo e instalações de pequenas centrais hidrelétricas na bacia. Esses resultados poderão auxiliar no desenvolvimento de políticas públicas ambientais e de gestão do uso solo com o intuito de desenvolver um manejo sustentável da bacia hidrográfica do rio São Lourenço, o segundo maior rio que drena o Pantanal.
The quick and disorderly growth of agricultural activities in the Brazil’s Centro-Oeste from the 1970s onwards led to an intense change in land use, due to the implantation of pastures and monocultures, which cause the deforestation of native vegetation and make the soil even more susceptible to erosive processes. There was a need to implement hydroelectric plants to guarantee the supply of new urban centers and agro-industrial complexes, causing straight changes in the river’s dynamics. The São Lourenço River watershed, Mato Grosso’s state, was one of the most impacted by these productive advances, with signs of significant changes such as siltation of the channel, more frequent flooding and loss of biodiversity. Due to the fact, to understand the current conditions of fluvial dynamics and improve predictions of how anthropogenic activities affect river systems, this project aims to assess changes in channel´s morphology and sediment input into the watershed resulting from change in use of land and installation of hydroelectric plants in São Lourenço River watershed (Mato Grosso). A temporal series of images from the Landsat collection, from 1985 to 2020 will be used to quantify the variations in channel migration, width and number of river bars in a 100 km stretch along the middle course of the São Lourenço River. Afterwards, it is expected that the results obtained make it possible to determine if there were significant changes in the morphology and sedimentology of the São Lourenço channel and whether such changes are related to anthropogenic changes in the drainage watershed. The results obtained indicate that there were no significant changes in the width and migration rate of the channel, only evident changes in the number and area of the river bars. These changes are directly related to anthropogenic changes in the drainage basin, mainly changes in the use of the soil, and installations of small hydroelectric plants in the basin.These results may help in the development of public policies for environmental conservation and land use management in order to develop sustainable management of the São Lourenço river basin, the second largest river that drains the Pantanal.
The quick and disorderly growth of agricultural activities in the Brazil’s Centro-Oeste from the 1970s onwards led to an intense change in land use, due to the implantation of pastures and monocultures, which cause the deforestation of native vegetation and make the soil even more susceptible to erosive processes. There was a need to implement hydroelectric plants to guarantee the supply of new urban centers and agro-industrial complexes, causing straight changes in the river’s dynamics. The São Lourenço River watershed, Mato Grosso’s state, was one of the most impacted by these productive advances, with signs of significant changes such as siltation of the channel, more frequent flooding and loss of biodiversity. Due to the fact, to understand the current conditions of fluvial dynamics and improve predictions of how anthropogenic activities affect river systems, this project aims to assess changes in channel´s morphology and sediment input into the watershed resulting from change in use of land and installation of hydroelectric plants in São Lourenço River watershed (Mato Grosso). A temporal series of images from the Landsat collection, from 1985 to 2020 will be used to quantify the variations in channel migration, width and number of river bars in a 100 km stretch along the middle course of the São Lourenço River. Afterwards, it is expected that the results obtained make it possible to determine if there were significant changes in the morphology and sedimentology of the São Lourenço channel and whether such changes are related to anthropogenic changes in the drainage watershed. The results obtained indicate that there were no significant changes in the width and migration rate of the channel, only evident changes in the number and area of the river bars. These changes are directly related to anthropogenic changes in the drainage basin, mainly changes in the use of the soil, and installations of small hydroelectric plants in the basin.These results may help in the development of public policies for environmental conservation and land use management in order to develop sustainable management of the São Lourenço river basin, the second largest river that drains the Pantanal.