Estratificação térmica e química em reservatório do semiárido brasileiro

• Autor(a) principal: Silva, Rennyer Holanda
• Data de Publicação: 2016
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Ceará (UFC)
• Texto Completo: http://www.repositorio.ufc.br/handle/riufc/31205
• topic: Regiões áridas; Reservatórios; Estratificação térmica; Clima de regiões áridas

Water scarcity is a problem observed throughout the world, though in semi-arid regions it becomes even stronger for a number of peculiarities. In the Brazilian semi-arid, this shortage is intensified by the rainfall irregularity, by prolonged drought eventsand by the mismanagement in the storage and distribution of the water resources. In the context of the evolution of water resources management in the semi-arid regions of Ceará, the actions and intentions on quantitative aspects of water availability still predominate over water quality requirements. Studies on water quality on reservoirs of semi-arid regions contribute to guide the management and development of models that are suitable for the peculiar climatic conditions of this region. Thus, the objective of this study was to evaluate the influence of some climatic, hydrological and morphometric factors on thermal and chemical stratification and other mixing processes of the weir Pereira de Miranda, located at the city of Pentecoste, Ceará state. For such, variables of water temperature, dissolved oxygen, pH and electrical conductivity were used in order to evaluate the behavior and the formation of thermal and chemical gradients on the vertical profile of the reservoir. The water transparency was measured with a Secchi Disk to characterize and limit the extent of the photic zone. These measurements were done between 2010 and 2011 in three previously selected sampling points. The analyses of the water variables were done together with climatic (rainfall rates, air temperature, relative humidity and wind speed) and hydrological data (theoretical time of hydraulic retention and variations on water levels). During the research, the Miranda Pereira weir presented thermal and chemical gradients slightly detachedin the rainy season and in complete mixed conditions during the dry season. Thevariationrange on a dailybasis presented low values of temperature,pH and dissolved oxygen concentrations; beingindicative of the weir’s vulnerability for thermal and chemical micro-stratification duringthe rainy season ofthe two years of research. The results presented reinforce the evidence that climaticand hydrological variations in semi-arid regionshaveinfluence overthe spatial-temporal variation of physical and chemical variables, as a result of the structuring of alternating periods of stratification and mixtures of water masses