Correlação espacial e sazonal de parâmetros indicadores de qualidade da água da bacia hidrográfica do Alto Sorocaba associadas ao uso do solo
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Data
2018-03-09
Autores
Simonetti, Vanessa Cezar
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Universidade Estadual Paulista (Unesp)
Resumo
O avanço da degradação ambiental tem comprometido a qualidade de vida da população e os recursos naturais. A maioria das atividades antrópicas reflete negativamente causando diversos impactos ambientais, tais como alterações no uso da terra, alterações na qualidade da água, perda de florestas e biodiversidade. Diante do cenário atual, o sensoriamento remoto (SR) vem ganhando cada vez mais destaque ao que tange o monitoramento ambiental, por permitir a análise de vastas áreas e diversos aspectos ambientais. Nesse contexto, o presente estudo teve como objetivo à avaliação sazonal da qualidade da água a partir da análise de parâmetros físico-químicos e biológicos da água bem como a análise espacial da área de estudo. A área de estudo está inserida na Bacia Hidrográfica do Alto Sorocaba, sendo o Rio Una juntamente com os Rios Sorocabuçu e Sorocamirim que se convergem, constituindo o reservatório de Itupararanga, principal manancial de abastecimento de água do município de Sorocaba. Devido sua importância, a área foi instituída por lei como sendo Área de Proteção Ambiental (APA), tendo seus usos regulamentados. A metodologia utilizada consistiu na análise de parâmetros físicos, químicos e biológicos da água através de sonda multiparâmetros e análises laboratoriais. A análise espacial consistiu na geração de diferentes informações cartográficas que, por meio de análise multicritério, determinaram as classes de fragilidade e classes de risco das áreas de preservação permanente da APA Itupararanga. Os resultados indicaram que o Índice de Qualidade da Água (IQA) esteve na categoria Bom e Excelente em todos os pontos amostrados. O Índice de Estado Trófico (IET) foi categorizado como Hipereutrófico em todos os pontos. O Índice de Vida Aquática (IVA) realizado no período chuvoso foi classificado como Péssimo para o rio Sorocabuçu e Ruim para os demais pontos amostrados. A análise da Fragilidade Ambiental da APA revelou que 53,15% está inserida na categoria Muito Baixa e Baixa Fragilidade, enquanto 46,85% apresenta-se nas classes Média, Alta e Muita Fragilidade. No tocante às áreas de APP, às classes Muito Baixa e Baixa representaram 63,93%, e as classes Média, Alta e Muito Alta, totalizaram 36,07%. A análise do uso e ocupação do solo revelou uma intensa atividade agrícola, correspondendo a uma extensão de 122,75 km2. Quanto à análise das Classes de Riscos das APPs, foi possível inferir que 77,37% possuem cobertura vegetal. Os riscos obtidos indicaram que 15,46% das APPs apresentaram um risco Muito Baixo, Baixo (4,33), Médio (2,39%), Alto (0,42%) e Muito Alto (0,03%). A análise multivariada concernente aos Componentes Principais (ACP) revelou que os pontos amostrais não se distinguem em relação à sazonalidade. A ACP do uso do solo demonstrou forte correlação positiva entre as áreas agrícolas e o IET(P), fósforo total e resíduos totais. Entretanto, o estudo identificou que os maiores impactos advindos do uso do solo na APA Itupararanga são provenientes das grandes extensões agrícolas, resultado corroborado por meio dos altos valores tróficos obtidos no estudo.
The advance of environmental degradation has compromised the quality of life of the population and natural resources. Most anthropogenic activities reflect negatively, causing diverse environmental impacts, such as changes in land use, changes in water quality, loss of forests and biodiversity. In view of the current scenario, remote sensing (SR) has been gaining more and more prominence in relation to environmental monitoring, since it allows the analysis of vast areas and several environmental aspects. In this context, the present study had as objective the seasonal evaluation of the water quality from the analysis of physical-chemical and biological parameters of the water as well as the spatial analysis of the study area. The study area is located in the Alto Sorocaba Hydrographic Basin, with the Rio Una along with the Sorocabuçu and Sorocamirim Rivers that converge, constituting the Itupararanga reservoir, the main source of water supply in the municipality of Sorocaba. Due to its importance, the area was established by law as an Environmental Protection Area (EPA), and its uses are regulated. The methodology used consisted of the analysis of physical, chemical and biological parameters of water through multiparameter probe and laboratory analysis. The spatial analysis consisted in the generation of different cartographic information that, through multicriteria analysis, determined the fragility classes and risk classes of the permanent preservation areas of the Itupararanga EPA. The results indicated that the Water Quality Index (WQI) was in the category Good and Excellent in all the points sampled. The Trophic State Index (TSI) was categorized as Hypereutrophic at all points. The index of aquatic life (IAL) in the rainy season presented high values, being poor for the river Sorocabuçu and Bad for the other points sampled. The analysis of the Environmental Fragility of the EPA revealed that 53.15% is inserted in the category Very Low and Low Fragility, while 46.85% presents in the classes Medium, High and Many Fragility. Regarding the Permanent Preservation Areas (PPA), the Very Low and Low classes accounted for 63.93% of the study, and the Medium, High and Very High classes totaled 36.07%. The analysis of land use and occupation revealed an intense agricultural activity, corresponding to an extension of 122.75 km2. Regarding the analysis of the Risk Classes of PPAs, it was possible to infer that 77.37% have vegetal cover. Risks obtained indicated that 15.46% of PPAs presented Very Low, Low (4.33), Medium (2.39%), High (0.42%) and Very High (0.03%). The multivariate analysis concerning the Principal Components (PCA) revealed that the sampling points do not differ in relation to the seasonality. The land use PCA showed a strong positive correlation between the agricultural areas and the TSI(P), total phosphorus and total residues. However, the study identified that the greatest impacts from the use of the soil in the Itupararanga EPA come from large agricultural areas, a result corroborated by the high trophic values obtained in the study.
The advance of environmental degradation has compromised the quality of life of the population and natural resources. Most anthropogenic activities reflect negatively, causing diverse environmental impacts, such as changes in land use, changes in water quality, loss of forests and biodiversity. In view of the current scenario, remote sensing (SR) has been gaining more and more prominence in relation to environmental monitoring, since it allows the analysis of vast areas and several environmental aspects. In this context, the present study had as objective the seasonal evaluation of the water quality from the analysis of physical-chemical and biological parameters of the water as well as the spatial analysis of the study area. The study area is located in the Alto Sorocaba Hydrographic Basin, with the Rio Una along with the Sorocabuçu and Sorocamirim Rivers that converge, constituting the Itupararanga reservoir, the main source of water supply in the municipality of Sorocaba. Due to its importance, the area was established by law as an Environmental Protection Area (EPA), and its uses are regulated. The methodology used consisted of the analysis of physical, chemical and biological parameters of water through multiparameter probe and laboratory analysis. The spatial analysis consisted in the generation of different cartographic information that, through multicriteria analysis, determined the fragility classes and risk classes of the permanent preservation areas of the Itupararanga EPA. The results indicated that the Water Quality Index (WQI) was in the category Good and Excellent in all the points sampled. The Trophic State Index (TSI) was categorized as Hypereutrophic at all points. The index of aquatic life (IAL) in the rainy season presented high values, being poor for the river Sorocabuçu and Bad for the other points sampled. The analysis of the Environmental Fragility of the EPA revealed that 53.15% is inserted in the category Very Low and Low Fragility, while 46.85% presents in the classes Medium, High and Many Fragility. Regarding the Permanent Preservation Areas (PPA), the Very Low and Low classes accounted for 63.93% of the study, and the Medium, High and Very High classes totaled 36.07%. The analysis of land use and occupation revealed an intense agricultural activity, corresponding to an extension of 122.75 km2. Regarding the analysis of the Risk Classes of PPAs, it was possible to infer that 77.37% have vegetal cover. Risks obtained indicated that 15.46% of PPAs presented Very Low, Low (4.33), Medium (2.39%), High (0.42%) and Very High (0.03%). The multivariate analysis concerning the Principal Components (PCA) revealed that the sampling points do not differ in relation to the seasonality. The land use PCA showed a strong positive correlation between the agricultural areas and the TSI(P), total phosphorus and total residues. However, the study identified that the greatest impacts from the use of the soil in the Itupararanga EPA come from large agricultural areas, a result corroborated by the high trophic values obtained in the study.
Descrição
Palavras-chave
Qualidade da água, Sensoriamento remoto, Área de preservação permanente, Fragilidade ambiental, Water quality, Remote sensing, Permanent preservation area, Environmental fragility