Avaliação do uso de cisternas na bacia do Pajeú para atenuação de picos de cheia utilizando o swmm

Abstract

Compensatory techniques on urban drainage has become quite recurrent due to the continuous process of urbanization of the last decades. The objective of this work was to evaluate the influence of cisterns as a solution to reduce storm water runoff. The study area was the Pajeú basin, located in Fortaleza, in which flood events are common during the rainy season. To perform this simulation, the Storm Water Management Model - SWMM software was used. The effects on the runoff peak reduction caused by the construction of cisterns in the basin were quantified. For this, a four-hour rainfall event was simulated, and different return periods were also analyzed (5, 10, 20 and 50 years). Therefore, two scenarios were evaluated: the first one, without the use of Low Impact Development (LID) devices, and the second one, with several applications of cisterns in the basin. The results of the simulations showed that the usage of compensatory measures (cisterns) has considerable effects on the attenuation of the runoff peak, which vary according to the percentage of LID occupation of the basin. The usage of cisterns in 50% of the basin can reduce up to 64% the maximum outflow at the outfall. It is important to emphasize the importance of works of this character, since this kind of hydrological simulations may be of great importance for urban drainage planning.