Analysis of performance criteria and sustainability index in urban stormwater systems under the impacts of climate change

Abstract

Urban stormwater systems are of important infrastructures in urban planning, and any mitigation in their design and implementation can be problematic. Changes in the hydrologic regime due to the climate change lead to exacerbation of extreme events such as flood. In this study, firstly, the impacts of climate change in the extreme precipitations of a part of Tehran in Iran were investigated during the period 2020–2049 using 10 Atmospheric-Ocean General Circulation Models (AOGCMs) under two Representative Concentration Pathway scenarios (i.e., RCP2.6 and RCP8.5). Then, Using the Storm Water Management Model (SWMM), the urban stormwater system of the study area was modelled during the base period (1981–2010) along with the moderate, pessimistic and optimistic conditions of the AOGCM models during the future period (2020–2049). Finally, the network performance was evaluated based on reliability, resiliency, and vulnerability criteria, along with the sustainability index. The simulation results revealed that the sustainability of the urban stormwater system is 77.89% during the base period while its value will be 77.73% and 77.61% under RCP2.6 and RCP8.5 scenarios, respectively, during the future period based on the moderate conditions of the AOGCM models. Furthermore, the network sustainability was 73.10% and 81.98%, respectively, according to the results of CanESM2 model for pessimistic and CESM1-WACCM model for optimistic conditions under RCP2.6 scenario. It was found that during the future period, under the influence of both studied scenarios, there will be no significant increase in the number of network flooding points compared to the baseline period. The approach presented in this study can be used to evaluate the performance of stormwater systems in other urban areas.