Influência dos fenômenos climáticos El Niño e La Niña no aproveitamento de águas pluviais

Abstract

Water is a scarce and fundamental natural resource for the maintenance of life, and its rational use should be a concern of all. The reduction in water consumption in building facilities can be made possible in several ways, depending on the construction characteristics and its purpose of use. In this context, the research analyzes the building facilities of the Porto Campus of the Federal University of Pelotas, indicating changes for a more efficient use of water in the educational institution. Based on the site study, the proposed changes range from reducing the volume of leaks and changes in sanitary appliances to the use of rainwater for less noble purposes, where the potability standard is not necessary. An important component of the rainwater utilization system is the reservoir, which its dimensioning occurs through the rainfall regime, usually using the historical average of records of the project locality. However, the use of average precipitation does not consider the variations associated with the El Niño, La Niña and neutral climatic periods, which historically alternate and represent rainfall averages that alter the system's supply efficiency, which is one of the focuses of this research. The results obtained indicate that the Porto Campus could present greater efficiency in water consumption through the use of discharge with 3 and 6 liters in sanitary basins, flow reducers in washbasins and timed discharge valve in urinals, in addition to the execution of the preventive maintenance plan. The application of these measures provides an estimated reduction in water consumption of approximately 3,163m³ per year, a volume corresponding to 27.83% of the volume recorded on the university campus during 2019. In view of the use of rainwater for non-potable purposes, the rainfall characterization of El Niño, La Niña and neutral events applied to reservoir sizing methods indicates that the use of reserve volume with 40m³ represents the best opportunity for the university campus, presenting a potential for reduction in the demand of treated water between 1,906m³ and 2,693m³ per year , and this variation occurs due to the distribution and intensity of rainfall of climatic events associated with the temperature of the central Pacific Ocean. Adopting all the measures suggested at the Porto Campus, a reduction in the demand for treated water is projected between 44.6% and 51.5% of consumption recorded in 2019, which corresponds to a volume greater than 5,000m³ per year and a reduction in the annual budget of the educational institution between R$ 42,748.42 and R$ 46,164.53, in addition to the environmental and social benefits provided by the rational use of water resources.