Impacto do aumento da taxa de permeabilidade na eficiência da drenagem urbana. Estudo de caso: Centro de Campina Grande - PB

Abstract

The tumultuous increase of the urban centers and, consequently, the alteration of the native relief and the growth of the impermeable areas, cause an interference in the system of natural infiltration, generating high superficial flows that, sometimes, it is not supported by the artificial drainage network, causing damages and disorders to the population. The present paper uses computational modeling with the purpose of evaluating the impacts of exceeding waterproofing in the urban environment, comparing scenarios and aiming at improving the existing drainage network. For this purpose, an area located in the center of the city of Campina Grande ­PB was used, which shares similar problems to other districts of the city, such as flood and flood points in high precipitation events. The study was carried out from the Urban Base Map of Campina Grande­PB and through Field survey, as well as applications such as Google Maps and Street View. For the modeling the software SWMM (Storm Water Management Model) was used. During the study, three scenarios were developed: the first presents the real condition of the region that has on average 92.78% of area covered by pavements that hinder permeability; the second perspective was simulated a situation with 20% of area destined to infiltrate the water in each lot; the third scenario presents the addition of 5% permeable area due to the use of interlocking blocks, totaling 25%. The results obtained for Scenario 1 show that the system shows failures even after 60 minutes of the end of the rainy event, in at least 20 areas if a return time of 10 years is considered. When applying the current law (Scenario 2), there is a 25% reduction in the number of plots considered critical. Scenario 3 showed positive results in relation to Scenario 1, but discrete in relation to Scenario 2. Plots with large surface areas remain, even after 60 minutes of rainfall, with critical runoff, but in these locations it would be possible to implement of blocks interlocked throughout the area, without any damage with the chosen layout. It is hoped that the results found will contribute to the development of sustainable solutions that will reconcile costs with a correct use of the soil and respect to the existing laws.