Implantação de jardins de chuva como técnica compensatória ao sistema de drenagem urbana na cidade de Santa Maria - RS

Abstract

The process of unplanned urbanization in the city of Santa Maria / RS incited the high frequency of floods and inundations throughout the perimeter of the city. Areas previously covered by permeable soil, are replaced by impermeable buildings and pavements, reducing the infiltration of rainwater into the soil and causing the runoff to reach significantly greater volumes. The city's urban drainage system, therefore, becomes insufficient to contain the consequent flow peaks. The purpose of the bio-retention systems is to compensate the inevitable impervious areas in the current scenario, through lowered spaces consisting of vegetation and porous soil, capable of infiltrating and filtering the rain runoff. For this reason, this study presents an analysis of the proposal for rain gardens in the district of Nossa Senhora das Dores, in Santa Maria / RS. The gardens were designed for different return times, in order to define a better project viability. Although the capacity to restore pre-urbanization regimes is limited, the dimensioned bioretention systems can result in an average reduction of 16.26% in the final volume drained to the hydrographic basin. Without significant differences between the adopted return periods, it is concluded that there is a greater logic in opting for 10 years as the return period. Finally, rain gardens are a great alternative as compensatory techniques to assist the current urban drainage system in controlling urban floods.