Variação de índices iônicos em reservatórios no sertão cearense

• Ano de defesa: 2019
• Autor(a) principal: Souza, Stephanie de Oliveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: Saneamento; Água - Salinidade; Água - Qualidade; Regiões áridas; Semi-arid tropic; Salinity; Water quality indexes
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/40045

Water scarcity is a pressing challenge, with arid and semi-arid regions most affected. In these regions it is common to capture and store water in surface reservoirs, which are the main source of water supply for multiple uses. The semi-arid climate enhances the process of water salinization, which is one of the main water quality problems faced in reservoirs in these regions. In this context, the ionic quality of the surface water of the Ceará reservoirs Pereira de Miranda and Sítios Novos was evaluated through the calculation of water stability indexes, water quality for irrigation use and ion content. In addition, aridity rates were determined. The statistical approach (adhesion tests, Akaike's information criterion, variance analysis (parametric and non-parametric), Pearson's correlation and Monte Carlo simulation) of the water quality data of these reservoirs provided by COGERH , for the period from 2004 to 2014. The influence of the annual climate cycle and the operational level of the reservoirs, the temporal variation of the ionic indexes and the degree of failure of the main parameters according to the legal framework were determined. The results showed chloridated sodic waters, evidencing the influence of the local lithology and the proximity to the ocean. The aridity indices showed the decreasing tendency of precipitation and the vulnerability of the area to desertification. There was corrosive potential as indicated by most water stability indices. Regarding the suitability for use in irrigation, the waters were of medium salinity, low risk of sodicity, moderately hard and safe for irrigation purposes, as for permeability and the dangerous effect of CO32- and HCO3-. The water quality indexes for the ionic content indicated water with low restriction and quality ranging from good to excellent. Strong correlations between the available volume fraction and several ionic parameters were obtained. Turbidity and total dissolved solids showed the most significant failure degree according to the normative instruments used. The rainy and dry seasons influenced the significant differentiation only with respect to the aridity indices, even though the deterioration of the water quality in the period of drought is perceptible in the computation of the ionic indexes. It is concluded that the evaluation of the ionic content of surface waters of the Semi-Arid Tropic through indexes is an excellent tool for the management of the quality of these resources, indicating possible limitations of end uses and guiding preventive and corrective measures.