Concept of probable rainfall applied to the design of rainwater reservoirs

Abstract

Problems related to the water crisis are increasingly evident, so there is a need to find solutions for the use of lower quality water for non-potable purposes, being the use of rainwater interesting. Therefore, the present paper was developed with the purpose to analyze the application of Probable Rainfall concept to obtain the volume of reservoirs for rainwater storage in residences of the municipality of Formiga, MG, Brazil, in a technical way. For such, the monthly and annual probable rainfall were adjusted following the Gamma distribution, being the volume of rainwater reservoirs simulated, based on different monthly and annual probable rainfall and calculation methods presented by ABNT 15527, in addition to considering non-potable water demands. It was observed that the month of July shows the lowest precipitation in the municipality, regardless of the probability considered for this, while the highest probable precipitations are obtained in December and January. On an annual scale, the highest probable precipitation is 1564.54 mm while the lowest, 935.19 mm. According to the results, the application of the concept of probable rainfall is more effective when using the Rippl and Australian Practical Methods, as they present greater absolute differences between reservoirs volumes obtained from the different precipitations. However, the two have antagonistic behaviors regarding the consideration of larger or smaller precipitated water depths.