Análise da conjuntura dos recursos hídricos para abastecimento: Jaú – SP
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Data
2018-09-04
Autores
Rizzo, Luiz Rafael
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Universidade Estadual Paulista (Unesp)
Resumo
Com o crescimento da população urbana mundial, há um aumento na demanda pelo abastecimento público de água, que é fornecidapelas águas doces de rios, lagos e águas subterrâneas. Segundo a ANA (Agência Nacional de Águas, 2017), o abastecimento urbano de água foi o segundo maior usuário de recursos hídricos de água doce do Brasil em 2016. Com uma oferta finita e uma demanda crescente, muitas cidades em todo o país tem enfrentado escassez de água. Além do consumo, as atividades antrópicas em torno de áreas urbanas podem causar impactos negativos na qualidade dos recursos hídricos locais utilizados para o abastecimento, diminuindo ainda mais a disponibilidade de água doce. O objetivo desta pesquisa foi estudar a vulnerabilidade das águas subterrâneas à contaminação antrópica e identificar fontes potenciais de contaminação às águas subterrâneas e superficiais. Esta análise foi realizada no município de Jaú, São Paulo, visando identificar possíveis soluções para evitar prováveis crises de escassez de água, como as enfrentadas nos últimos anos. A área de estudo incluiu a área urbana do município e três microbacias localizadas a montante da cidade que contêm os mananciais que são utilizados para abastecimento de água. Primeiro, foi gerado um mapa de vulnerabilidade dos recursos hídricos subterrâneos que foi desenvolvido para a área usando o método DRASTIC (ALLER et al., 1987). Os resultados mostraram que 50% da área tinham uma vulnerabilidade média, enquanto 25% da área apresentavam uma vulnerabilidade muito alta à contaminação antrópica no lençol freático. Em seguida, um mapa de uso da terra foi desenvolvido usando imagem de satélite para identificar possíveis fontes de contaminação antrópica que poderiam afetar a qualidade dos recursos hídricos usados para o abastecimento. Ao sobrepor os resultados do modelo DRASTIC com o mapa do uso da terra, pode-se correlacionar estrategicamente a disposição dos empreendimentos com o uso adequado da terra. Para verificar os resultados, foram analisados relatórios de qualidade da água dos recursos hídricos subterrâneos (Portaria 2.914/2011) da área urbana e dos mananciais superficiais (CONAMA 357/2005) quanto à contaminação antrópica. Enquanto as amostras de águas subterrâneas não mostram sinais de contaminação antrópica, houve contaminação frequente por coliformes termotolerantes em amostras de águas superficiais. Quando comparado ao mapa de uso da terra e dados de precipitação, foi possível identificar sua origem a partir das atividades antrópicas identificadas e propor soluções de manejo. Finalmente, concluiu-se que há uma grande necessidade de implementação de projetos e programas de gestão, produção e conservação de águas como medida de solução para melhorar a quantidade e a qualidade da água na área de estudo.
With a growing urban population globally, there is increasing demand for urban water supply and the consumption of freshwater resources from rivers, lakes, and groundwater. According to ANA (National Agency of Water, 2017), urban water supply was the second largest user of freshwater resources in Brazil in 2016. With a finite supply and an increasing demand, this is leading to water shortages in cities across the country. In addition to consuming water, human activities around urban environments can cause a degradation in the water quality of the local freshwater resources used for urban water supply, further decreasing the availability of freshwater resources. The objective of this research was to study the vulnerability of groundwater to anthropogenic contamination and identify potential sources. This analysis was carried out using in the municipality of Jaú, São Paulo in order to identify possible solutions to the water shortage crisis that it has faced in recent years. The study area included the urban area surrounding the municipality and three micro-basins located upstream of the city which contain rivers that are used for urban water supply. First, a vulnerability map of the groundwater resources was developed for the area using the DRASTIC method (ALLER et al., 1987). The results showed that 50% of the area had a medium vulnerability while 25% of the area had very high vulnerability of anthropogenic contamination in the groundwater table. Then a land use map was developed using satellite images to identify potential sources of anthropogenic contamination which could impact the quality of groundwater and surface water used for urban public supply. By overlapping the results of the DRASTIC model with the land use map, one can strategically correlate the disposition of enterprises to the appropriate use of land. To verify the findings, water quality samples from groundwater resources in the urban area and surface water resources from the upstream river were analyzed for anthropogenic contamination. While the groundwater samples shows no signs of anthropogenic contamination, there was frequent contamination of thermotolerant coliforms in surface water samples. When compared to the land use map and precipitation data, it was possible to identify its origin from human activities and to propose management solutions. Finally, it was concluded that there is a great need for the implementation of water management projects and programs as a solution to improve the quantity and quality of the water in the study.
With a growing urban population globally, there is increasing demand for urban water supply and the consumption of freshwater resources from rivers, lakes, and groundwater. According to ANA (National Agency of Water, 2017), urban water supply was the second largest user of freshwater resources in Brazil in 2016. With a finite supply and an increasing demand, this is leading to water shortages in cities across the country. In addition to consuming water, human activities around urban environments can cause a degradation in the water quality of the local freshwater resources used for urban water supply, further decreasing the availability of freshwater resources. The objective of this research was to study the vulnerability of groundwater to anthropogenic contamination and identify potential sources. This analysis was carried out using in the municipality of Jaú, São Paulo in order to identify possible solutions to the water shortage crisis that it has faced in recent years. The study area included the urban area surrounding the municipality and three micro-basins located upstream of the city which contain rivers that are used for urban water supply. First, a vulnerability map of the groundwater resources was developed for the area using the DRASTIC method (ALLER et al., 1987). The results showed that 50% of the area had a medium vulnerability while 25% of the area had very high vulnerability of anthropogenic contamination in the groundwater table. Then a land use map was developed using satellite images to identify potential sources of anthropogenic contamination which could impact the quality of groundwater and surface water used for urban public supply. By overlapping the results of the DRASTIC model with the land use map, one can strategically correlate the disposition of enterprises to the appropriate use of land. To verify the findings, water quality samples from groundwater resources in the urban area and surface water resources from the upstream river were analyzed for anthropogenic contamination. While the groundwater samples shows no signs of anthropogenic contamination, there was frequent contamination of thermotolerant coliforms in surface water samples. When compared to the land use map and precipitation data, it was possible to identify its origin from human activities and to propose management solutions. Finally, it was concluded that there is a great need for the implementation of water management projects and programs as a solution to improve the quantity and quality of the water in the study.
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Palavras-chave
Vulnerabilidade natural, Aquífero, DRASTIC, Enquadramento dos corpos de água, Abastecimento público de água, Natural vulnerability, Aquifer, Water bodies framework, Public water supply