Evaluation of the cost-effectiveness of Green Infrastructure in climate change scenarios using TOPSIS

Abstract

Urban hydrological changes caused by uncertain climate affect the implementation of water management strategies. Recently, more attention has been paid to the hydrological performance of green infrastructure (GI) in future climate scenarios. In this study, the Storm Water Management Model (SWMM) was applied to undertake integrated assessments of the runoff and water quality control effect of GI. Eight GI scenarios were proposed in Guangzhou’s Tianhe Smart City, and simulated rainfall events under different climate scenarios were assessed. Considering the factors of runoff volume control, peak flow reduction, pollutant removal, and life cycle cost, the advantages of different GI combinations were compared using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). The results confirmed that GI affect runoff control under changing climatic conditions, but its application to future large rainfall events is limited. According to the results of the TOPSIS assessment, decision-makers can consider different cost weights to determine the optimal scenario of GI implementation. The conclusions can be applied to GI construction planning projects to enhance the adaptability of urban water resource management systems.