Eficiência de acumulação de reservatórios anuais: aplicação da equação de esvaziamento

Abstract

The reservoirs of superficial waters have been the most applied solution for governments and people to live together with the hydrologic adverse regime of the Northeastern interiors. To the small reservoirs the paper of intra-annual regularization of waters is reserved and, for that, annual reservoirs are denominated. This article approaches the subject related to the annual dams, of the Brazilian semi-arid area. An equation was developed to esteem the time of emptying of a reservoir in function of the retreats and of the evaporation. Soon afterwards the equation was applied to evaluate the efficiencies of the reservoirs through the relationship among the volume used for hydro agriculture and the accumulated volume in the end of the humid station. The reservoir assumes the form of a cone (V = αh3) with the values of α equal to 1000, 5000 and 10000 and heights varying from one to eight meters. The times of emptying were taken equals to four and six months. The results showed that the efficiency with respect to the capacity varies a lot with the depth and, practically, it doesn't depend on the opening of the cone.