Estudo de viabilidade de reservatórios coletivos no amortecimento de vazões de pico em drenagem de águas pluviais para um condomínio em Curitiba – PR

Abstract

The lack of urban planning combined to disordered population growth and increase of superficial runoff has contributed in a significantly way for problems related to flooding in urban centers. The current drainage system, focused on the plumbing, is based on a quickly flow of rainwater over downstream, contributes to increase the peak flows and intensify this problem. Thus, it becomes necessary alternative measures for the anagement of pluvial water. This essay presents a study about collective full containment tank in a condo in the city of Curitiba - PR, an alternative to the problems of flooding faced by Brazilian cities. In addition to the sizing of the collective tank, there was a comparison between the implementation of the collective tank and the implementation of individual tanks per lot, in which individual ones were sized in other research. The city in which it was executed the work owns the 176th Municipal Decree that establishing criteria for implementation of flood containment mechanisms. The study area consists of 131 residential lots, streets, sidewalks, lawns and woods, resulting in a total of 0.041 km² (41,000 m²). The drainage system of the condo has been designed by the "classic" method, in other words, all the pluvial runoff is directed towards gutters and captured by sluice gates, only in a manner for being overcome the hydraulic capacity of the gutters, being subsequently forwarded to the galleries. The parameters adopted for the design of the collective tank of the study area are based on the Rational Method and on the decree mentioned previously. With the recommended volume by decree for a 444m² of tank area, the amortization was only 11.75%. Thus, it chose to maintain the area and consider a volume of 450m³, which resulted in a damping of 49.05%. When performing the comparison of individual tanks and the collective tanks, the costs were R$ 200,454.03 with the damping of peak flow at 33% for individual tanks and R$ 219,749.92 with the damping of peak flow at 49.05% for the collective one. From the obtained results by the implementation of the collective tank and by the analysis of the costs for the system implementation, it is possible to percept the importance of the use of this type of system in order to reduce output flows that are forwarded to the street. Comparing to individual tanks, the collective one has a higher damping and a more simplified drainage system. However, through the comparison since the peak flow reductions until the volumes studied, it is possible to realize that there are still no regulations for Curitiba`s city that covering satisfactorily large tanks.