Relação entre variáveis limnológicas de canais fluviais da UGRHI-22 e do uso e cobertura da terra
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Data
2020-07-17
Autores
Fernandes, Mariana Ribeiro
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Universidade Estadual Paulista (Unesp)
Resumo
Ao longo dos anos, a região do Pontal do Paranapanema passou por diversas modificações no uso e cobertura da terra. Essas modificações, aliadas a outros fenômenos e processos naturais e antrópicos, podem levar a mudanças no estado das águas superficiais. Assim, o objetivo dessa pesquisa consistiu em analisar a correlação entre variáveis físicas, químicas e hidrológicas da água de canais fluviais da UGRHI-22, do Pontal do Paranapanema, juntamente com as classes de uso e cobertura da terra e a variável precipitação, para investigar os fatores antrópicos e naturais determinantes nas características das águas estudadas. O recorte espacial foi composto por áreas de drenagem e canais fluviais inseridos na UGRHI-22. As alíquotas de água foram amostradas em dez seções amostrais, pertencentes às seguintes bacias hidrográficas: do Rio Bonito, do Rio da Estação, do Ribeirão Cuiabá, do Ribeirão Vai-e-Vem, do Rio Pirapozinho, do Córrego da Areia Branca, do Córrego da Cascata e do Córrego do Burrinho. O estudo ocorreu em três etapas: trabalhos de campo (mensuração de variáveis físicas e químicas das águas e variáveis hidrológicas),que ocorreram nos meses de fevereiro e novembro de 2018, procedimentos laboratoriais (mensuração de variáveis físicas e químicas das águas) e atividades em gabinete (revisão bibliográfica, aquisição de dados de precipitação, elaboração de mapas de uso e cobertura da terra, aplicação de técnicas de estatística multivariada). As classes encontradas nos mapas de uso e cobertura da terra das bacias hidrográficas analisadas foram a pastagem, o solo exposto, a cultura temporária, a cobertura florestal e a área urbana. Os dados pluviométricos demonstraram uma variação sazonal em função dos diferentes períodos do ano, com um verão úmido e inverno seco. A Análise de Componente Principal (ACP) apresentou maiores valores de oxigênio dissolvido para o mês de menor precipitação e maiores valores do íon-amônio para o mês de maior precipitação. Estes resultados revelaram conectividade entre os ambientes aquáticos e terrestres em razão da precipitação. Além disso, a conectividade entre os ambientes terrestres e aquáticos promove entrada de nitrogênio amoniacal nos sistemas aquáticos. A Análise de Cluster (AC) indicou similaridade entre as classes solo exposto, pastagem, florestal e cultura temporária. Esta similaridade pode ser explicada em razão da apropriação do território pela classe cultura temporária, representada pela cana-de-açúcar. Os resultados da AC indicaram também que a classe urbana, quando há um aumento da vazão, há incremento de frações orgânicas e inorgânicas nas águas, como exemplo as frações de fósforo total e nitrogênio amoniacal em eventos de precipitação.
Over the years, the Paranapanema Pontal region has undergone several changes in land use and coverage. These changes, combined with other natural and man-made phenomena and processes, can lead to changes in the state of surface waters. Thus, the objective of this research was to analyze the correlation between physical, chemical and hydrological variables of the water of river channels of UGRHI-22, in Paranapanema Pontal, together with the classes of land use and cover and the variable precipitation, to investigate the anthropic and natural determining factors in the characteristics of the studied waters. The spatial cut was made up of drainage areas and river channels inserted in the UGRHI-22. The water aliquots were sampled in ten sample sections, belonging to the following hydrographic basins: Rio Bonito, Rio da Estação, Ribeirão Cuiabá, Ribeirão Vai-e-Vem, Rio Pirapozinho, Córrego da Areia Branca, Córrego Cascata and Córrego do Burrinho. The study took place in three stages: field work (measurement of physical and chemical variables of water and hydrological variables), which occurred in the months of February and November 2018, laboratory procedures (measurement of physical and water chemistry) and office activities (literature review, acquisition of precipitation data, preparation of land use and land cover maps, application of multivariate statistical techniques). The classes found in the land use and land cover maps of the hydrographic basins analyzed were pasture, exposed soil, temporary culture, forest cover and urban area. The rainfall data showed a seasonal variation depending on the different periods of the year, with a humid summer and dry winter. The Principal Component Analysis (PCA) showed higher values of dissolved oxygen for the month with less precipitation and higher values of ammonium ion for the month with higher precipitation. These results revealed connectivity between aquatic and terrestrial environments due to precipitation. In addition, connectivity between terrestrial and aquatic environments promotes the entry of ammoniacal nitrogen into aquatic systems. The Cluster Analysis (CA) indicated similarity between the classes exposed soil, pasture, forest and temporary culture. This similarity can be explained by the appropriation of the territory by the temporary culture class, represented by sugarcane. The CA results also indicated that the urban class, when there is an increase in the flow, there is an increase of organic and inorganic fractions in the waters, as an example the fractions of total phosphorus and ammoniacal nitrogen in precipitation events.
Over the years, the Paranapanema Pontal region has undergone several changes in land use and coverage. These changes, combined with other natural and man-made phenomena and processes, can lead to changes in the state of surface waters. Thus, the objective of this research was to analyze the correlation between physical, chemical and hydrological variables of the water of river channels of UGRHI-22, in Paranapanema Pontal, together with the classes of land use and cover and the variable precipitation, to investigate the anthropic and natural determining factors in the characteristics of the studied waters. The spatial cut was made up of drainage areas and river channels inserted in the UGRHI-22. The water aliquots were sampled in ten sample sections, belonging to the following hydrographic basins: Rio Bonito, Rio da Estação, Ribeirão Cuiabá, Ribeirão Vai-e-Vem, Rio Pirapozinho, Córrego da Areia Branca, Córrego Cascata and Córrego do Burrinho. The study took place in three stages: field work (measurement of physical and chemical variables of water and hydrological variables), which occurred in the months of February and November 2018, laboratory procedures (measurement of physical and water chemistry) and office activities (literature review, acquisition of precipitation data, preparation of land use and land cover maps, application of multivariate statistical techniques). The classes found in the land use and land cover maps of the hydrographic basins analyzed were pasture, exposed soil, temporary culture, forest cover and urban area. The rainfall data showed a seasonal variation depending on the different periods of the year, with a humid summer and dry winter. The Principal Component Analysis (PCA) showed higher values of dissolved oxygen for the month with less precipitation and higher values of ammonium ion for the month with higher precipitation. These results revealed connectivity between aquatic and terrestrial environments due to precipitation. In addition, connectivity between terrestrial and aquatic environments promotes the entry of ammoniacal nitrogen into aquatic systems. The Cluster Analysis (CA) indicated similarity between the classes exposed soil, pasture, forest and temporary culture. This similarity can be explained by the appropriation of the territory by the temporary culture class, represented by sugarcane. The CA results also indicated that the urban class, when there is an increase in the flow, there is an increase of organic and inorganic fractions in the waters, as an example the fractions of total phosphorus and ammoniacal nitrogen in precipitation events.
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Palavras-chave
Uso e cobertura da terra, Variáveis limnológicas, UGRHI-22, Land use and cover, Limnological variables