Resumo:
Low Impact Development (LID) are measures aimed at soil conservation and permeability by integrating natural aspects with already urbanized areas. The infiltration or retention processes of these practices contribute to the reduction of flooding. In this context, this study aims to assess, through modeling in the SWMM software, the effectiveness of applying these measures in reducing recurrent flooding in the central region of Caxambu-MG. To support the modeling, the design rainfall was determined through frequency analysis of rainfall, adjusted by probability functions, and subjected to to adherence tests using the ALEA software. Daily precipitation was discretized using the Isozona method and temporally distributed using the Huff 1st Quartile method with a 50% exceedance probability. Surface runoff was estimated using the dynamic wave method for hydraulic transport and the CN-SCS method for infiltration losses. Based on site-specific data obtained from soil maps and aerial surveys by drone, the zero scenario was modeled, representing the basin with its current configurations. With the determination of the critical rainfall, the zero scenario was calibrated for a return period (RP) of 1 year based on the Curve Number, Manning's coefficient, depression storage parameters, and citizen science observation data. Serving as the reference scenario, the zero scenario was compared to two proposed scenarios with the implementation of LID techniques at proportions of 5.20% (Scenario 01 – Permeable pavements, rain gardens, and green roofs on 50% of the buildings) and 9.27% (Scenario 02 – Permeable pavements, trench and infiltration well, green roofs on 100% of the buildings). Overall, LID techniques contributed to a reduction in runoff at an average rate of 32.55% considering 9.27% LID implementation in the basin. At the same proportion of LID, hydraulic performance was achieved in reducing runoff volume at an average rate of 43.52%. Generally, the evaluated LID techniques showed good performance in managing low-intensity rainfall events (RP up to 10 years).
