Avaliação da aplicação de técnicas de baixo impacto no desenvolvimento de bacias urbanas em região semiárida do Nordeste do Brasil.

Abstract

Low Impact Development Techniques (LIDs) are stormwater management strategies that can reduce the negative effects of urban sprawl. However, the evaluation of LIDs has only been carried out in the context of the environmental benefits, although these benefits are fundamental, the financial aspects are paramount when choosing an ideal LID device system. In this sense, the objective of this work is to rank different arrangements for the application of Low Impact Development techniques for decision making in the management of urban rainwater drainage in a semi-arid region, considering the environmental and economic aspects. For this, the application of different scenarios of infiltration trenches and permeable pavements in the Riacho do Prado basin, located predominantly in the city of Campina Grande-PB, seat of the homonymous municipality with semi-arid climate and located in the Brazilian Agreste mesoregion was analyzed. . The Storm Water Management Model (SWMM) software was used to carry out the hydrological and qualitative modeling of the waters of the basin and the multi-criteria and multi-decision analysis methods, PROMETHEE II and Copeland, respectively, to prioritize the scenarios with LIDs, considering the environmental criteria and economical. From the critical conditions found in the Riacho do Prado basin, two sub-basins were chosen to model six different scenarios, with the application of permeable pavements and infiltration trenches in 50% and 100% of the sidewalks. The simulation of these scenarios showed great potential in reducing runoff volumes and in the qualitative treatment of drainage water, with the scenarios with the application of both techniques simultaneously being the ones with the best performance. According to the multi criteria and multi-decision analysis, it was possible to build a hierarchy between the scenarios, enabling the manager to have a comprehensive view of the environmental and financial benefits of implementing these techniques. Scenario 5, which proposes the simultaneous application of the two LIDs in 50% of the sidewalks, despite not presenting the best environmental performance, due to its financial benefits, was elected as the best management alternative, considering the criteria of economic and environmental sustainability. This scenario showed a reduction of 9.11% in peak flow, 14.73% in the total volume drained and removal of 13061.79 kg of BOD, 25025.97 kg of COD and 356.32 kg of FT.