The Effects of Climate Change on Low Impact Development (LID) Performance-A Case of Study in Sao Carlos, Brazil

摘要

Urbanization increases runoff volume and velocity, resulting in higher risks of flooding and the higher amount of pollutants carried by stormwater. To mitigate these impacts, low impact development practices (LID), such as bioretention, have been used to treat stormwater runoff enhancing the sustainability of urban drainage systems. However, climate change is expected to alter the rainfall regime and, consequentially, the efficiency of LID controls, and its impacts need to be better evaluated. In addition, there are few studies analyzing LID performance under a subtropical climate, which has different rainfall regimes and runoff generation process when compared to temperate climates. This study, in particular, estimated the efficiency of a bioretention in Sao Carlos, Brazil, in a subtropical region, for 4 different future periods (2020-2039, 2040-2059, 2060-2079, and 2080-2099) with estimated precipitation for 2 RCP scenarios (4.5 and 8.5), forced by HADGEM2-ES global model. These scenarios were based on the ETA regional climate model and downscaled to Sao Carlos by the Brazilian National Institute for Space Research and compared to the period of 1980-1999. The income and outlet of runoff and pollutants were modeled to estimate the bioretention efficiency during this century, with climate changes impacts on rainfall regime. The analyzed periods presented water retention efficacy closed to 80%, suggesting that climate change has little effect on it. However, the pollutants removal depends on their wash off characteristics, those with higher wash off rates have higher removal potential.