A systematic review of climate change impacts on sewer overflow.

Climate change has posed a serious threat to wastewater infrastructure, intensifying sewer overflow (SO) failures and associated public health risks. Innovative approaches for capturing and predicting climate change effects on SOs are continuously developed, providing valuable insights into the key processes and drivers of SOs and supporting the design of adaptation strategies. However, a comprehensive summary with rigorous evidence evaluation for the impacts of all potential climate scenarios on SOs is still lacking. This paper reviews 72 recent studies and proposes future perspectives on climate change effects on SOs. Based on the systematic analysis, we identify five critical research domains to analyse key climate hazards and evaluate different modelling frameworks and adaptation strategies. Rainfall-induced combined sewer overflows (CSOs) are the primary concern, as they exacerbate pollutant loads in receiving waters and elevate infection risks. To simulate such scenarios, SWMM is the most widely applied tool, but it requires enhanced integration with the geographic information system (GIS). Sustainable urban drainage systems (SuDS) have been recognized as effective adaptation frameworks to alleviate the climate change impacts, and their potential can be advanced through an automatic multi-objective decision support system to balance trade-offs among runoff reduction, pollution control and costs. This review provides policymakers and researchers with a comprehensive understanding of climate-induced SO issues, facilitating targeted decision-making to enhance urban drainage infrastructure resilience under climate change.