Análise dos processos erosivos: aplicação de modelos preditivos na bacia hidrográfica do Rio do Peixe, São Paulo - Brasil
Data
2021-11-08
Autores
Pereira, Gleice Santana
Título da Revista
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A pesquisa propõe uma análise acerca da suscetibilidade à erosão laminar e linear na Unidade de Gerenciamento de Recursos Hídricos do Rio do peixe (UGRHI 21) e projeção de cenário por meio da simulação da restauração florestal das Áreas de Preservação Permanentes (APPs) afim de avaliar o papel da vegetação ciliar no abatimento de perdas de solo por erosão laminar e na diminuição da exportação de sedimentos para os cursos fluviais. Para os estudos relacionados à erosão laminar foi aplicada a estimativa de perdas de solo através da aplicação da Equação Universal de Perdas de Solo (EUPS) e no que diz respeito à análise das erosões lineares elaborou-se o Mapa de Fragilidade Ambiental, baseado nos pressupostos metodológicos estabelecidos por Ross (1990, 1994, 1995 e 1996). Os resultados obtidos com a aplicação da EUPS indicam que 67% da UGRHI 21 está inserida na classe de perda de solo equivalente a “>100 ton.ha/ano” (grau de erosão muito alto) e em relação a Fragilidade Ambiental, 65% se encontra na classe “Alto”. Para a projeção de cenário, os resultados indicaram que as áreas que apresentam perdas de solo “> 100 ton.ha/ano” tiveram uma redução de 3%, enquanto as áreas com perdas de “< 10 ton.ha/ano” (grau de erosão muito baixo) apresentaram um aumento de 7%. Os resultados obtidos para a exportação de sedimentos revelaram um aumento de 3% da classe “<10 ton.ha/ano” e decréscimos de 1% para a classe de “10 a 20 ton.ha/ano” e 2% para a classe “>100 ton.ha/ano”. Do mesmo modo, analisando a estimativa de exportação de sedimentos por Unidades de Planejamento Hidrográfico (UPH) e comparando o cenário atual com a projeção, aprontamos que houve diminuição em todas as UPHs, sendo que a UPH “Baixo Curso” apresentou redução de 13%, a “Médio Curso” apresentou redução de 8,5% e “Alto Curso”, redução de 25%.
The research proposes an analysis of the susceptibility to laminar and linear erosion in the Rio do Peixe Water Resources Management Unit (UGRHI 21) and a scenario projection by simulating the forest restoration of Permanent Preservation Areas (APPs) in order to evaluate the role of riparian vegetation in reducing soil losses due to laminar erosion and in reducing the export of sediment to river courses. For studies related to laminar erosion, the estimation of soil losses was applied through the application of the Universal Soil Loss Equation (USLE) and with regard to the analysis of linear erosions, the Environmental Fragility Map was prepared, based on the assumptions methodologies established by Ross (1990, 1994, 1995 and 1996). The results obtained with the application of the USLE indicate that 67% of the UGRHI 21 is included in the class of soil loss equivalent to “>100 ton.ha/year” (very high degree of erosion) and in relation to Environmental Fragility, 65% is found in the “High” class. For the scenario projection, the results indicated that the areas with soil losses "> 100 ton.ha/year" had a reduction of 3%, while the areas with losses of "< 10 ton.ha/year" (degree very low erosion) showed an increase of 7%. The results obtained for the export of sediments revealed an increase of 3% for the class “<10 ton.ha/year” and decreases of 1% for the class of “10 to 20 ton.ha/year” and 2% for the class “>100 ton.ha/year”. Likewise, the estimate of sediment export by Hydrographic Planning Units (HPU) was analyzed and comparing the current scenario with the projection, it was possible to conclude that there was a decrease in all HPU, being that the HPU “Low Course” presented a reduction of 13%, the “Middle Course” presented a reduction of 8.5% and “High Course”, a reduction of 25%.
The research proposes an analysis of the susceptibility to laminar and linear erosion in the Rio do Peixe Water Resources Management Unit (UGRHI 21) and a scenario projection by simulating the forest restoration of Permanent Preservation Areas (APPs) in order to evaluate the role of riparian vegetation in reducing soil losses due to laminar erosion and in reducing the export of sediment to river courses. For studies related to laminar erosion, the estimation of soil losses was applied through the application of the Universal Soil Loss Equation (USLE) and with regard to the analysis of linear erosions, the Environmental Fragility Map was prepared, based on the assumptions methodologies established by Ross (1990, 1994, 1995 and 1996). The results obtained with the application of the USLE indicate that 67% of the UGRHI 21 is included in the class of soil loss equivalent to “>100 ton.ha/year” (very high degree of erosion) and in relation to Environmental Fragility, 65% is found in the “High” class. For the scenario projection, the results indicated that the areas with soil losses "> 100 ton.ha/year" had a reduction of 3%, while the areas with losses of "< 10 ton.ha/year" (degree very low erosion) showed an increase of 7%. The results obtained for the export of sediments revealed an increase of 3% for the class “<10 ton.ha/year” and decreases of 1% for the class of “10 to 20 ton.ha/year” and 2% for the class “>100 ton.ha/year”. Likewise, the estimate of sediment export by Hydrographic Planning Units (HPU) was analyzed and comparing the current scenario with the projection, it was possible to conclude that there was a decrease in all HPU, being that the HPU “Low Course” presented a reduction of 13%, the “Middle Course” presented a reduction of 8.5% and “High Course”, a reduction of 25%.
Descrição
Palavras-chave
Erosão pluvial, Determinação de perda de solo, Modelagem, Projeção de cenários, Geomorfologia, Bacia hidrográfica, Erosão, Rain erosion, Determination of soil loss, Modeling, Projection of scenarios