Avaliação do efeito de diferentes alternativas de drenagem sustentável no controle do escoamento superficial

Abstract

The storm water drainage system in Brazil follows, mostly, a hygienist concept, created in the early 20th century, in which the main objective is to collect and channelize the water seeking to avoid flooding and its consequences such as economic, environmental e social damages. Nevertheless, this kind of drainage system does not solve permanently the problems related to flooding, it just transfers it downstream, often increasing peak flows and making them happen within smaller time periods. The increase of impervious surfaces in urban areas has been intensifying this drainage techniques’ inefficiency, thus the search for new alternatives is increasing significantly. The use of techniques with low environmental impact appears as a way of flow control, decreasing them and distributing them better over time, in addition to seeking a qualitative improvement of the collected water. This work aims to evaluate the efficiency of several sustainable drainage systems proposed to an urban area located in the city of João Pessoa and analyze which one presents the best cost-benefit. Eight systems were proposed, in which infiltration trenches, permeable pavements and detention tanks were considered. Each system had its devices dimensioned (Rain Envelope Method for the infiltration devices and Puls Method for the detention tanks) and its flow control efficiency evaluated using the free software SWMM. Results have shown that the most efficient systems were the ones involving detention tanks, either being the only control measure or integrated with permeable pavements. A simplified budget made for the systems showed that the ones where the detention tanks were the only flow control measure were the least costly, therefore presenting the best cost-benefit.