Characterizing sustainability of green stormwater infrastructure technologies using life cycle assessment and life...

Urban stormwater management often overlooks a holistic consideration of the functional, environmental, and economic aspects of green stormwater infrastructure (GSI). Life cycle assessment (LCA) and life cycle costing (LCC) tools are crucial for evaluating GSI; however, the variability in GSI implementation hinders generalizable conclusions for research, development, and deployment. To address this, we systematically reviewed 128 papers from Scopus and Web of Science that applied LCA and/or LCC to GSI, in alignment with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We defined three research questions: (i) How have LCA and LCC been applied across different GSI technologies to assess sustainability performance? (ii) How do different design decisions influence the performance, environmental, and economic impacts of GSI technologies? (iii) How have LCA and LCC for GSI technologies been utilized to inform decision-making, and what opportunities exist to further their development? Our findings suggest that effective GSI design should prioritize and balance: (1) sufficient system size and water quality volume (WQV) to attenuate flow and reduce normalized sustainability impacts, (2) the inclusion of vegetation to enhance pollutant removal, and (3) extended lifespans to offset the initial environmental and economic impacts. Due to challenges we faced when comparing the sustainability performance of GSI of different scales, designs, and functionalities from various studies, our study emphasized the need to standardize the reporting of life cycle environmental and cost impacts of GSI on a common per-functional unit normalized basis (e.g., per unit of WQV treated). Trade-off analysis revealed that a GSI design with low economic impact does not automatically align with low environmental impact per unit of water quality volume treated. Ultimately, our study suggests that practitioners should apply outcomes from LCC and LCA, coupled with other decision-making criteria for GSI, to adequately balance stormwater management and minimize sustainability impacts. Based on the findings from our study, we examined the potential impact of stormwater policy on GSI adoption and identified gaps and emerging opportunities for enhancing the sustainability of GSI technologies.