Aplicação de técnicas de desenvolvimento de baixo impacto no controle da poluição de águas em sistemas de drenagem urbana.

Abstract

The inadequate land use and occupation, combined with deficiencies in basic sanitation, generate major impacts on Brazilian watersheds. The clandestine release of domestic sewage and solid waste into the drainage system is a reality found throughout the country, resulting in the pollution of urban water bodies. This work analyzes the application of low impact development measures (Low Impact Development - LID) in the drainage area of Canal das Piabas, Campina Grande - PB. A qualitative hydrological modeling of water pollution indicators is adopted, using the Storm Water Management Model (SWMM) program. To this end, 6 points in the drainage channel were monitored, with an analysis of physical-chemical indicators of water quality, in addition to determining the flow in 5 points of the channel and 4 points of sewage contributions. The diagnosis of the study area shows that the high rates of urbanization and soil waterproofing, the release of domestic sewage, and the presence of solid waste contribute to the point and diffuse pollution of the canal waters. In the application of SWMM to model water quality in the dry period, which simulates the continuous discharge of sanitary sewage, it was found that the flow propagation process increases the concentrations of the indicators along the channel. In the rainy season, it was observed that the intensity of precipitation and the number of previous days without rain influence the pollutant load accumulated in the sub-basins and leached by runoff. In this rainy scenario, there is also a dilution of the indicator concentrations in events with large precipitated volumes. The last scenario simulated the application of LIDs measures, with the insertion of permeable pavements, bio-retention cells, and interception of sewage contributions. It is observed that the adoption of sustainable measures results in the reduction of polluting loads from runoff and in the improvement of the quality of the channel waters. The use of the SWMM software proved to be adequate for the purposes of this work, with satisfactory results in the simulations and compatible with the values obtained in the laboratory analyzes.