Stormwater management is essential to reducing the occurrence of flooding events in urban areas and to adapting to climate change. The construction of stormwater Best Management Practices (BMPs) entails a series of life cycle environmental impacts but also implies avoided burdens, such as replacing urban infrastructure after flooding. The aim of this paper is to integrate flood damage prevention into the life cycle assessment (LCA) of BMPs for quantifying their net environmental impact (NEI) and environmental payback (EP) from a consequential LCA standpoint. As a case study, the application of a filter, swale and infiltration trench (FST) in a Brazilian neighborhood was assessed considering a high-intensity rainfall event. The potential avoided impacts were related to cars and sidewalks that were not destroyed due to flooding. In terms of CO2eq. emissions, the environmental investment related to the FST was recovered when the destruction of one car or 84 m 2 of sidewalk was prevented. The NEI of the FSTs resulted in significant impact reductions (up to 700%) with respect to not accounting for the avoided products. This approach can be implemented to any type of BMP, and more accurate estimations can be made with data for different events and different types of material damage.

Abstract:Green and grey stormwater management infrastructures, such as the filter, swale and infiltration trench (FST), can be used to prevent flooding events. The aim of this paper was to determine the environmental and economic impacts of a pilot FST that was built in São Carlos (Brazil) using Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). As a result, the components with the greatest contributions to the total impacts of the FST were the infiltration trench and the grass cover. The system has a carbon footprint of 0.13 kg CO 2 eq./m 3 of infiltrated stormwater and an eco-efficiency ratio of 0.35 kg CO 2 eq./USD. Moreover, the FST prevented up to 95% of the runoff in the area.Compared to a grey infrastructure, this system is a good solution with respect to PVC stormwater pipes, which require a long pipe length (1070 m) and have a shorter lifespan. In contrast, concrete pipes are a better solution, and their impacts are similar to those of the FST. Finally, a sensitivity analysis was conducted to assess the changes in the impacts with the varying lifespan of the system components. Thus, the proper management of the FST can reduce the economic and environmental impacts of the system by increasing its durability.

Highlights• Urban resilience is a multi-objective task requiring a multi-disciplinary approach • A primary feasibility study is key to identify suitable SuDS strategies in an area • Integrated spatial optimisation of SuDS can enhance urban resilience planning • SuDS investment should prioritise the inclusion of quality of life index • Flood resilience and water quality resilience demonstrate some correlations

Neste trabalho objetivou-se monitorar e modelar um plano de infiltração, construído em escala real, para manejo de águas pluviais com área de 3.001 m². Foram monitorados a precipitação, a vazão de entrada e o nível de água no interior do plano. Os equipamentos foram calibrados por meio de ensaios de campo com o esvaziamento controlado, por meio do descarregamento de 9,3 m 3 de água em ensaios em triplicada. Foram monitorados 32 eventos de chuvas, sendo que destes 7 apresentaram registros de lâmina. O método de PULS foi empregado para modelagem. O modelo foi calibrado empregando condutividade hidráulica variável e constante. Na etapa de calibração os valores de R 2 médios foram de 0,75 e 0,72 respectivamente. Na validação obtiveram-se valores de R 2 de 0,71 para duas condutividades. Os tempos de esvaziamento, em torno de 25 min, foram explicados pelas altas taxas e áreas de infiltração. Os valores médios observados de tempo de retardo variaram em média 5,9 min; de tempo de pico em média 28,3 min e do tempo de escoamento na superfície do plano em média 12,2 min. Os resultados indicaram que o método de PULS pode ser aplicado com restrições, tendo em vista as vazões iniciais calculadas pelo PULS foram maiores que as observadas. Tal fato foi atribuído aos baixos valores de lâminas de água registrados e as irregularidades topográficas no plano gramado, os quais incorreram em imprecisão na relação nível de água e volume inicial.

No abstract